Network Working Group                                           T. Sato
Internet-Draft                                          MyAuberge K.K.
Intended status: Standards Track                          30 May 2026
Expires: 30 November 2026


         The Human Escalation Mechanism (HEM) for Agentic AI Systems
                         draft-sato-soos-hem-03


Abstract

   An AI agent that has been authorized to act autonomously has no
   inherent mechanism to stop itself.  If its mission requires a
   decision that exceeds its authorization, if policy mandates human
   judgment before proceeding, or if the agent itself reaches the
   boundary of its reliable competence, what happens?  Without a
   protocol specifying the answer, one of three failure modes occurs:
   the agent proceeds beyond its authorization and executes actions
   that no human approved; it stalls silently with no notification
   to any principal; or it continues running under a mission that has
   already entered a terminal state, producing actions with no
   legitimate purpose.  In all three cases, the humans responsible
   for the system find out too late.

   This document defines the Human Escalation Mechanism (HEM): a
   normative protocol specifying what a Governance Execution
   Controller (GEC) does when an AI agent session requires human
   judgment before execution may continue.  HEM replaces the three
   failure modes above with a single governed path: the GEC places
   the session into a formally defined HEM_PENDING state, routes a
   structured escalation request to one or more designated human
   principals along an ordered designation chain, enforces a
   prohibition on all state transitions until a human decision is
   received, and processes five defined human decision types.  HEM
   also defines the Policy Rationale Declaration (PRD), which links
   Cedar policies that route to HEM with machine-readable rationale,
   and the Decision Rationale Record (DRR), which captures the human
   principal's reasoning for audit and learning purposes.

   For human principals, HEM provides more than oversight: it
   provides better project outcomes, a learning record of both human
   and agent decisions, and a normative channel for injecting real-
   world context into agent execution at the moment it is most
   relevant.  For AI agents, HEM provides a governed recovery path
   that enables higher confidence operation near decision boundaries
   and a shorter, more efficient route to correct outcomes.

   HEM is the entry point to a four-draft governance stack.  The
   Intent Declaration Primitive [I-D.sato-soos-idp] makes HEM
   escalation requests legible to human principals.  The Governance
   Audit Record [I-D.sato-soos-gar] provides the permanent, non-
   suppressible record that oversight occurred and what was decided.
   The Constitutional AI Protocol [I-D.sato-soos-cap] defines the
   prohibition floor below which no HEM decision may operate.

   HEM is enforced by the GEC, not by the agent and not by the
   application layer.  An agent cannot opt out; an application
   cannot suppress it.  This non-bypassability is the source of
   HEM's regulatory utility and provides the technical specification
   for human oversight required by EU AI Act Article 14.

Status of This Memo

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Table of Contents

   1.  Introduction
   2.  Conventions and Definitions
   3.  Problem Statement
       3.1.  The Human Oversight Gap in Agentic Systems
       3.2.  Relationship to EU AI Act Article 14
       3.3.  Relationship to CHEQ
   4.  HEM Session States
       4.1.  State Definitions
       4.2.  State Transition Constraints
   5.  HEM Trigger Classes
       5.1.  Class 1: Cedar Policy Routing (HEM_CEDAR_ROUTED)
       5.2.  Class 2: Agent Uncertainty Declaration (HEM_AGENT_ESCALATED)
       5.3.  Class 3: Proximity Threshold Crossing (HEM_PROXIMITY_TRIGGERED)
       5.4.  Class 4: Mission Validity Failure (HEM_MISSION_VALIDITY_FAILED)
       5.5.  Class 5: Jurisdictional Conflict (HEM_JURISDICTIONAL_CONFLICT)
       5.6.  Class 6: Absolute Harm Observed (HEM_TIER0_OBSERVED)
       5.7.  Class 7: Legal Violation Observed (HEM_TIER1_OBSERVED)
       5.8.  Class 8: Resource Exhaustion Anticipated (HEM_TIER3_ANTICIPATORY)
       5.9.  Class 9: Resource Exhaustion In Progress (HEM_TIER3_OBSERVED)
       5.10. Policy Rationale Declaration (PRD)
       5.11. Extension Trigger Classes
   6.  HEM Escalation Request
       6.1.  Structure
       6.2.  Field Definitions
       6.3.  Observation Context Package (OCP)
       6.4.  Execution Options Package (EOP)
       6.5.  Routing to Human Principals
   7.  Human Decision Types
       7.1.  APPROVE
       7.2.  APPROVE_WITH_CONSTRAINTS
       7.3.  REDIRECT
       7.4.  TERMINATE
       7.5.  DEFER
       7.6.  Decision Rationale Record (DRR)
       7.7.  Decision Submission Protocol
   8.  Transition Prohibition During HEM_PENDING
       8.1.  The Prohibition Rule
       8.2.  Read-Only Operations During HEM_PENDING
       8.3.  Multiple Concurrent HEM_PENDING Conditions
       8.4.  Mission Validity During HEM_PENDING
   9.  Timeout Model
       9.1.  Timeout Budget
       9.2.  Timeout Disposition
       9.3.  Timeout Chain (HEM_UNREACHABLE)
       9.4.  Chain Exhaustion
  10.  Event Log Requirements
  11.  Relationship to IDP
  11.  Open Issues
       11.1.  Cross-Domain HEM_PENDING Propagation (OQ-HEM-XDOMAIN)
  12.  Security Considerations
  13.  Privacy Considerations
  14.  EU AI Act Applicability
  15.  IANA Considerations
  16.  References
       16.1.  Normative References
       16.2.  Informative References
  Appendix B.  Related Work
       B.1.  ACP Working Group
       B.2.  ICON Initiative
       B.3.  CHEQ
       B.4.  OAuth Interactive Consent
       B.5.  WIMSE
       B.6.  AUDIT Working Group
       B.7.  MAD: Multi-Agent Delegation
       B.8.  CAEP and Shared Signals Framework
  Acknowledgments
  Author's Address


1.  Introduction

   The deployment of AI agents in consequential workflows -- booking
   systems, healthcare coordination, financial operations, logistics --
   requires that those systems be supervisable by humans. This
   requirement is not merely normative; it is increasingly regulatory.
   EU AI Act Article 14 mandates that high-risk AI systems include human
   oversight measures that enable humans to intervene in the operation
   of the system [EUAIA].

   The existing landscape of AI agent standards provides no normative
   specification of what such intervention looks like at the protocol
   level. WIMSE [I-D.ietf-wimse-arch] addresses workload identity.
   AAuth [I-D.klrc-aiagent-auth] addresses token-based authorization.
   CHEQ [I-D.rosenberg-aiproto-cheq] provides an application-layer
   protocol for human confirmation of specific agent actions. None of
   these specifications defines a kernel-level contract for what happens
   when an agent's authorized scope is insufficient, when policy
   mandates human judgment, or when an agent itself declares that it
   requires human oversight before proceeding.

   The distinction between AAuth [I-D.klrc-aiagent-auth] and this
   document is specifically: AAuth achieves mission correlation, binding
   authorization tokens to a declared mission scope; HEM achieves
   mission containment, specifying the GEC-enforced state contract
   that governs agent sessions when autonomous execution must yield to
   human judgment. The two primitives address different layers of the
   same problem.

   This document defines the Human Escalation Mechanism (HEM): a
   normative protocol governing the lifecycle of human oversight events
   in agentic AI systems. HEM specifies:

   *  Five trigger classes that cause a kernel to place a session into
      HEM_PENDING state (Section 5), with a defined extension mechanism
      for additional trigger classes (Section 5.7).
   *  A Policy Rationale Declaration (PRD) linking each Cedar policy
      that routes to HEM with machine-readable rationale (Section 5.6).
   *  A structured HEM escalation request routed to one or more
      designated human principals, GEC-signed with Ed25519
      (Section 6).
   *  Five human decision types that resolve a pending escalation
      (Section 7).
   *  A Decision Rationale Record (DRR) capturing human principal
      reasoning for high-consequence decisions (Section 7.6).
   *  A mandatory transition prohibition enforced by the kernel while
      HEM_PENDING is active (Section 8).
   *  A timeout model governing behaviour when designated human
      principals are unreachable (Section 9).
   *  A mission validity clause governing HEM behaviour when the
      governing MissionDeclaration enters a terminal phase during an
      active HEM_PENDING event (Section 8.4).

   HEM is a kernel primitive. It is enforced by the GEC, not by the agent and not by the application layer. An agent
   cannot opt out of HEM; an application cannot suppress it. This
   GEC-enforced quality is what distinguishes HEM from application-
   layer confirmation protocols such as CHEQ [I-D.rosenberg-aiproto-
   cheq] and gives HEM its regulatory utility.

   HEM does not specify the delivery mechanism by which escalation
   requests reach human principals. That is a deployment concern.
   Application-layer protocols such as CHEQ MAY serve as the delivery
   mechanism for HEM notification; HEM specifies what that delivery
   must achieve, not how it is achieved.


2.  Conventions and Definitions

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in
   BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

   This document uses the following terms:

   Agent:
      A software system that uses AI to reason about and take actions
      in pursuit of goals.

   GEC (Governance Execution Controller):
      The runtime component that enforces HEM.  A GEC manages session
      state, enforces Cedar policy, records events to the Event Log,
      and routes HEM escalation requests.  This document uses GEC in
      normative contexts.  "Governing Kernel" is retained as an alias.
      Conformance is determined by behavior, not naming.

   Governing Kernel:
      See GEC.  A runtime component that enforces authorization policy,
      maintains session state, records agent actions to a tamper-evident
      Event Log, and mediates agent access to governed objects.

   Governed Object (SO):
      A typed, stateful entity managed by the kernel. Its lifecycle
      is governed by a Cedar-enforced state machine.

   Mandate JWT:
      A JSON Web Token [RFC7519] binding an agent's authorization to a
      specific governed object instance.

   Cedar:
      A policy language and evaluation engine [Cedar] used by the kernel
      to evaluate authorization decisions.

   HEM:
      Human Escalation Mechanism. The protocol defined by this
      document.

   HEM_PENDING:
      The GEC session state in which HEM is active. No governed
      object state transitions may execute while HEM_PENDING is
      active.

   HEM_RESOLVED:
      The GEC session state following receipt and processing of a
      valid human decision.

   HEM_TIMEOUT:
      The GEC session state following expiration of the HEM timeout
      budget without receipt of a valid human decision.

   Human Principal:
      A natural person designated in the governed object's Principal
      Registry as authorized to issue HEM decisions.

   Designation Chain:
      An ordered list of human principals to be contacted sequentially
      if earlier principals in the chain are unreachable.

   IDP:
      Intent Declaration Primitive [I-D.sato-soos-idp]. The per-
      transition agent reasoning declaration that accompanies each
      gec.transition() call.

   MissionDeclaration:
      A structured declaration [SOOS] specifying the overarching goal,
      lifecycle conditions, and authority constraints under which a set
      of agent sessions operate. A MissionDeclaration has a phase
      (DISCOVERY, EXECUTION, RELEASE, SUSPENDED, FAILED, ABANDONED).

   Proximity Threshold:
      A pre-declared monitoring condition specifying a governed object
      state, resource value, or event pattern that, when reached,
      triggers HEM regardless of agent action.

   Event Log:
      An append-only, causally ordered, tamper-evident log of all
      transitions and kernel events for a governed object.


3.  Problem Statement

3.1.  The Human Oversight Gap in Agentic Systems

   Agentic AI systems operating in automated workflows encounter three
   classes of situation that require human involvement:

   (a)  Scope insufficiency. The action required to advance the task
        is outside the agent's Cedar-authorized action set. The agent
        cannot proceed autonomously and cannot determine whether a human
        would authorize the action.

   (b)  Policy-mandated oversight. Authorization policy specifies that
        certain transitions require human approval regardless of agent
        capability. The agent may be capable of executing the action
        but policy prohibits autonomous execution.

   (c)  Agent-declared uncertainty. The agent assesses that its
        confidence in the appropriate action is insufficient and that
        human judgment should be sought before proceeding. This is a
        first-class agent capability, not a failure mode.

   No existing protocol specifies a normative kernel-level response to
   any of these three classes. The consequences of this gap include:

   *  Agents that stall silently when their scope is insufficient,
      with no structured notification to human principals.
   *  Agents that execute policy-mandated-oversight transitions
      autonomously because no enforcement mechanism exists.
   *  Agents that have no normative mechanism for expressing that they
      require human judgment.
   *  Systems with no defined behaviour for the period between
      escalation and human decision.
   *  Systems with no defined behaviour when designated human
      principals are unreachable.
   *  Ghost execution: sessions continuing to operate after the
      overarching mission for which they were authorized has entered
      a terminal state (SUSPENDED, FAILED, or ABANDONED), producing
      actions that have no legitimate mission context.

3.2.  Relationship to EU AI Act Article 14

   EU AI Act Article 14 requires that high-risk AI systems be designed
   and developed, where technically feasible, to be effectively
   overseen by natural persons during the period in which the AI system
   is in use. Specifically, Article 14 requires that human oversight
   measures enable those persons to:

   *  understand the capabilities and limitations of the high-risk
      AI system;
   *  monitor the operation of the system;
   *  detect and address the emergence of anomalous situations; and
   *  intervene in the operation of the system or interrupt the system
      through a "stop" button or similar procedure.

   HEM provides the technical specification for these requirements at
   the kernel level. The HEM_PENDING state and transition prohibition
   (Section 8) implement the "stop" button. The five human decision
   types (Section 7) implement structured intervention. The timeout
   model (Section 9) defines system behaviour during unreachability,
   preventing indefinite autonomous operation in oversight-mandated
   states.

   This document is informative with respect to regulatory compliance
   and does not constitute legal advice.

3.3.  Relationship to CHEQ

   CHEQ [I-D.rosenberg-aiproto-cheq] defines an application-layer
   protocol by which AI agents request human confirmation of specific
   actions before executing them. CHEQ is agent-initiated: the agent
   chooses to request confirmation, constructs a CHEQ confirmation
   object, and delivers it to a human confirmation service.

   HEM is architecturally distinct in three respects.

   First, HEM is GEC-enforced. A HEM trigger causes the kernel to
   enter HEM_PENDING regardless of agent preference. An agent cannot
   suppress a kernel-triggered HEM; it cannot proceed without a human
   decision once HEM_PENDING is active. CHEQ confirmation is a choice
   the agent makes; HEM_PENDING is a state the kernel enforces.

   Second, HEM defines the session state contract. While HEM_PENDING
   is active, all state transitions are prohibited (Section 8). CHEQ
   does not specify any equivalent session state constraint.

   Third, HEM defines a structured decision vocabulary. The five HEM
   decision types (Section 7) are normative; they define what a human
   principal may decide and what the kernel must do with each decision.
   CHEQ defines a confirmation/denial binary without equivalent
   normative treatment of the decision space.

   CHEQ and HEM are complementary. A CHEQ-like application-layer
   protocol MAY serve as the delivery mechanism for HEM escalation
   notifications (Section 6.3). HEM specifies the kernel contract
   that such a delivery protocol must satisfy; it does not specify the
   delivery mechanism itself.



3.4.  Application Use Cases

   HEM is a general-purpose protocol.  The following use cases
   illustrate its application across domains.

3.4.1.  Network Management Agent: SLA-Sensitive Reconfiguration

   A network management agent has been authorized to reconfigure
   routing tables within a defined traffic window in response to
   congestion events.  During an unexpected congestion event, the
   reconfiguration required to restore service would cross the SLA
   threshold for a premium enterprise customer, triggering a
   regulatory notification obligation.  This action is Cedar-
   governed by a policy that routes to HEM when the estimated SLA
   impact exceeds the notification threshold.

   The GEC enters HEM_PENDING with trigger_class HEM_CEDAR_ROUTED.
   All routing changes to the affected segment are halted.  The GEC
   routes an escalation request to the network operations duty
   engineer.  The duty engineer issues APPROVE_WITH_CONSTRAINTS,
   injecting a Cedar context constraint limiting reconfiguration to
   non-premium customer traffic pending the SLA notification filing.
   The DRR records the operational justification for later audit.

   This use case maps to the intervention requirements identified
   by the ICON initiative [ICON-PS] for network management agent
   governance.

3.4.2.  Healthcare Coordination: Policy-Mandated Clinician Review

   A clinical coordination agent has been authorized to schedule
   and modify appointment sequences under a treatment plan.  The
   agent determines that advancing a chemotherapy cycle would
   optimize treatment efficacy.  The action is within Cedar scope
   but the policy marks it HEM_MANDATORY -- requiring oncologist
   approval regardless of agent assessment.

   The GEC enters HEM_PENDING with trigger_class HEM_CEDAR_ROUTED.
   All treatment schedule transitions are halted.  The GEC routes
   an escalation request to the oncologist of record, who reviews
   the lab data in the idp_summary and issues APPROVE_WITH_
   CONSTRAINTS with a timing window constraint.  The DRR records
   the clinical reasoning for the audit record.

3.4.3.  Legal Document Management: Jurisdictional Conflict

   A legal document management agent identifies that a proposed
   contract amendment conflicts with consumer protection statutory
   requirements in one applicable jurisdiction, such that no single
   amendment satisfies both requirements simultaneously.

   The GEC enters HEM_PENDING with trigger_class
   HEM_JURISDICTIONAL_CONFLICT.  The escalation request includes
   a jurisdictional_conflict_summary.  All document transitions
   are halted.  In-house counsel issues a REDIRECT to an amendment
   satisfying both requirements.  The DRR records the legal
   analysis for regulatory compliance.


4.  HEM Session States

4.1.  State Definitions

   A GEC session with respect to HEM is in one of the following
   states at any moment:

   HEM_INACTIVE:
      Default state. No HEM condition is active. The kernel processes
      agent transitions normally subject to Cedar evaluation.

   HEM_PENDING:
      A HEM trigger has fired and the kernel has routed an escalation
      request to one or more designated human principals. No governed
      object state transitions may execute. This state persists until
      a valid human decision is received or the timeout budget is
      exhausted.

   HEM_RESOLVED:
      A valid human decision has been received and processed. The
      session returns to HEM_INACTIVE unless the human decision itself
      requires further HEM consideration.

   HEM_TIMEOUT:
      The timeout budget has been exhausted without receipt of a valid
      human decision. The kernel applies the configured timeout
      disposition (Section 9.2). This state is terminal for the
      current HEM event; the session MAY return to HEM_INACTIVE
      depending on the disposition.

   HEM_CHAIN_EXHAUSTED:
      The designation chain has been exhausted without a decision from
      any principal and the timeout budget is exhausted. The kernel
      applies the chain exhaustion disposition (Section 9.4). This
      state is terminal for the current HEM event.

4.2.  State Transition Constraints

   The following state transitions are normative for a conforming
   kernel implementation:

   HEM_INACTIVE --> HEM_PENDING (HEM trigger fires)
   HEM_PENDING --> HEM_RESOLVED (valid decision received)
   HEM_PENDING --> HEM_TIMEOUT (timeout budget exhausted)
   HEM_PENDING --> HEM_CHAIN_EXHAUSTED (mission validity failure;
                                        see Section 8.4)
   HEM_TIMEOUT --> HEM_CHAIN_EXHAUSTED (chain exhausted)
   HEM_TIMEOUT --> HEM_INACTIVE (disposition permits)
   HEM_RESOLVED --> HEM_INACTIVE (always)
   HEM_CHAIN_EXHAUSTED --> [terminal] (session suspended or
                            terminated per Section 9.4)

   The transition HEM_INACTIVE --> HEM_PENDING MUST be GEC-initiated.
   No agent call may directly set the session to HEM_PENDING except
   through the defined trigger mechanisms (Section 5).


5.  HEM Trigger Classes

   This document defines nine trigger classes. A trigger class
   specifies the condition under which a GEC MUST enter HEM_PENDING
   or, in the case of observation trigger classes (Classes 6 and 7),
   the condition under which a GEC MUST initiate an escalation
   sequence regardless of any pending agent action.  Classes 1 through
   5 were defined in prior versions of this document.  Classes 6
   through 9 are added in this version.  Trigger classes are evaluated
   in the order defined below.  The first trigger class that fires
   causes HEM_PENDING to be entered; the remaining classes are not
   evaluated for that transition.

5.1.  Class 1: Cedar Policy Routing (HEM_CEDAR_ROUTED)

   A Cedar policy may explicitly route a transition to HEM rather than
   resulting in PERMIT or DENY. This is the primary mechanism by which
   governed object designers specify that certain transitions require
   human approval regardless of agent identity or scope.

   A Cedar policy routes to HEM by including the condition:

   when { context.hem_required == true }

   combined with a forbid rule that prevents autonomous execution. The
   GEC MUST recognize this pattern and MUST enter HEM_PENDING rather
   than returning DENY when Cedar evaluation produces this result.

   The kernel identifies HEM routing by evaluating whether a Cedar
   policy explicitly forbids the action AND the forbid rule includes
   a hem_required context attribute set to true. Implementations MAY
   use a Cedar annotation or action attribute to mark HEM-required
   transitions; the specific mechanism is implementation-defined,
   subject to the requirement that the kernel can unambiguously
   distinguish a HEM-routed DENY from a policy DENY.

   Example Cedar policy routing a transition to HEM:

   // Booking finalization requires human approval
   forbid(
     principal,
     action == Action::"FinalizeBooking",
     resource
   )
   when {
     context.hem_required == true &&
     !context.human_approval_present
   };

5.2.  Class 2: Agent Uncertainty Declaration (HEM_AGENT_ESCALATED)

   An agent MAY declare, via the hem_urgency field of an IDP
   [I-D.sato-soos-idp], that it requires human judgment before an
   action executes. When the GEC receives a gec.transition()
   call with a valid IDP containing hem_urgency: REQUIRED, the kernel
   MUST enter HEM_PENDING for the session, regardless of Cedar policy
   evaluation outcome.

   Note: Cedar evaluation still executes when hem_urgency is REQUIRED.
   A Cedar PERMIT result does NOT cause the action to execute. The
   GEC enters HEM_PENDING and the action awaits human decision.
   A Cedar DENY result in the same call produces both a HEM_PENDING
   entry AND a CEDAR_DENY_RECORDED Event Log entry.

   The HEM_AGENT_ESCALATED trigger represents a first-class agent
   capability. It is not a failure mode. Kernel implementations MUST
   treat agent-initiated escalation as a legitimate and expected system
   behaviour.

5.3.  Class 3: Proximity Threshold Crossing (HEM_PROXIMITY_TRIGGERED)

   A governed object's configuration MAY include one or more Proximity
   Threshold declarations. A Proximity Threshold specifies a monitored
   condition that, when met, causes the kernel to enter HEM_PENDING
   regardless of any agent action being in progress.

   A Proximity Threshold declaration MUST specify:

   {
     "threshold_id":   string,  ; REQUIRED. UUID v4.
     "description":    string,  ; REQUIRED. Human-readable.
     "condition_type": string,  ; REQUIRED. See below.
     "condition_value": value,  ; REQUIRED. Type-specific.
     "hem_disposition": string  ; REQUIRED. "BLOCK" or "NOTIFY".
   }

   condition_type values:

   SO_STATE:
      The governed object enters the specified state.
      condition_value is a state name string.

   RESOURCE_THRESHOLD:
      A numeric resource value associated with the governed object
      crosses the specified threshold.
      condition_value is { "resource": string, "operator": string,
      "value": number }.

   EVENT_PATTERN:
      A specified event pattern appears in the Event Log for the
      governed object.
      condition_value is a pattern descriptor; the pattern language is
      implementation-defined.

   hem_disposition values:

   BLOCK:
      The GEC enters HEM_PENDING immediately. No transitions may
      execute until a human decision is received. This is the
      normative "stop" disposition.

   NOTIFY:
      The kernel routes an escalation notification to designated
      human principals but does NOT enter HEM_PENDING. Transitions
      may continue to execute. This disposition is appropriate for
      monitoring conditions that warrant human awareness but not
      intervention.

   Proximity Threshold evaluation MUST execute after each successful
   Event Log commitment, including after IDP_SUBMITTED events and after
   STATE_TRANSITIONED events. A GEC MUST NOT evaluate proximity
   thresholds only at action request time.

5.4.  Class 4: Mission Validity Failure (HEM_MISSION_VALIDITY_FAILED)

   When the Mission Authority Service
   [I-D.mcguinness-oauth-mission-bound-authorization] reports that the
   governing MissionDeclaration has transitioned to a non-active phase
   (SUSPENDED, FAILED, or ABANDONED) while a session is otherwise
   active and no HEM_PENDING event is in progress, the GEC MUST
   enter HEM_PENDING so that a human principal can confirm terminal
   disposition before the session is closed.

   This trigger class is distinct from the mission validity monitoring
   described in Section 8.4. Section 8.4 governs the case where mission
   invalidity is detected while HEM_PENDING is already active.
   HEM_MISSION_VALIDITY_FAILED governs the initial HEM entry when
   mission invalidity is first detected in an otherwise HEM_INACTIVE
   session.

   The GEC MUST record HEM_TRIGGERED with trigger_class
   HEM_MISSION_VALIDITY_FAILED, including mission_ref and the terminal
   mission_phase value detected. The designated human principal
   designation chain for this trigger class is the mission-level
   principal chain, not the governed object principal chain.

   Decision constraints for HEM_MISSION_VALIDITY_FAILED: APPROVE and
   APPROVE_WITH_CONSTRAINTS MUST NOT be accepted. The valid decision
   types are TERMINATE, DEFER, and REDIRECT (cleanup-only actions
   only). The GEC MUST enforce this constraint and MUST return
   HEM_DECISION_INVALID for APPROVE or APPROVE_WITH_CONSTRAINTS
   submissions.


5.5.  Class 5: Jurisdictional Conflict (HEM_JURISDICTIONAL_CONFLICT)

   When the kernel determines that it cannot algorithmically resolve a
   conflict between the legal requirements of two or more applicable
   jurisdictions -- such that no single authorized action set satisfies
   all applicable requirements simultaneously -- the GEC MUST enter
   HEM_PENDING with trigger_class HEM_JURISDICTIONAL_CONFLICT.

   The HEM Escalation Request for Class 5 MUST include a
   jurisdictional_conflict_summary object (Section 6.2). This object
   provides human principals with a structured summary of the
   conflicting jurisdictional requirements so that they may exercise
   informed judgment about the appropriate resolution.

   Decision constraints for HEM_JURISDICTIONAL_CONFLICT: APPROVE and
   APPROVE_WITH_CONSTRAINTS MUST NOT be accepted. The valid decision
   types are TERMINATE, DEFER, REDIRECT (subject to Cedar evaluation
   of the redirected action), and APPROVE_WITH_LEGAL_BASIS (reserved;
   see Section 7.1). The GEC MUST enforce this constraint and MUST
   return HEM_DECISION_INVALID for non-permitted decision types.

   The jurisdictional conflict resolution mechanism (JCR) is specified
   as Part II of [I-D.sato-soos-cap]. This document specifies only the
   HEM trigger and session contract for Class 5; the conflict analysis
   and resolution algorithm are defined in that document.


5.6.  Class 6: Absolute Harm Observed (HEM_TIER0_OBSERVED)

5.6.1.  Trigger Condition

   A GEC agent session observes evidence of a Tier 0-A or Tier 0-B
   prohibited situation -- an absolute harm as defined by
   [I-D.sato-soos-cap] -- within data the agent has legitimate access
   to under its current mandate.  The observation does not require the
   agent to have been asked to contribute to the harm; it requires
   only that the evidence is visible to the agent within its
   authorized data scope.

   This trigger class is distinct from Cedar DENY on a Tier 0
   prohibited action (which is a CAP enforcement event, not a HEM
   event).  HEM_TIER0_OBSERVED fires when the agent observes an
   external Tier 0 situation -- not when the agent itself is being
   asked to take a Tier 0 prohibited action.

5.6.2.  GEC Behavior

   When a GEC agent session detects evidence satisfying the
   HEM_TIER0_OBSERVED condition, the GEC MUST:

   (a)  Immediately enter HEM_PENDING for the current session.
   (b)  Suspend all pending transitions on the governed object.
   (c)  Construct and route a HEM Escalation Request with
        trigger_class HEM_TIER0_OBSERVED and urgency CRITICAL.
   (d)  Include an Observation Context Package (OCP, Section 6.3)
        in the escalation request.
   (e)  Record HEM_TRIGGERED with trigger_class HEM_TIER0_OBSERVED
        in the Event Log.

   The designated human principal designation chain for Class 6 is
   the highest-authority principal in the session's designation
   chain.  The GEC MUST NOT route Class 6 escalations to the
   governed-object-level principal chain only; it MUST also notify
   the mission-level principal chain if one is registered.

5.6.3.  Decision Constraints

   For HEM_TIER0_OBSERVED the valid decision types are TERMINATE
   and REDIRECT (to a jurisdiction-specific authority reporting
   action).  APPROVE and APPROVE_WITH_CONSTRAINTS MUST NOT be
   accepted.  The human principal does not approve the observed
   situation; they decide what external action to take.  The GEC
   MUST enforce this constraint and MUST return HEM_DECISION_INVALID
   for APPROVE or APPROVE_WITH_CONSTRAINTS submissions.

5.6.4.  Session Resumption

   After a HEM_TIER0_OBSERVED escalation is resolved, the session
   MUST be terminated.  The observed absolute harm situation is
   incompatible with continued autonomous execution of the original
   mission.  REDIRECT may initiate a new session with a replacement
   mission scoped to authority notification and evidence preservation.


5.7.  Class 7: Legal Violation Observed (HEM_TIER1_OBSERVED)

5.7.1.  Trigger Condition

   A GEC agent session observes evidence of a Tier 1 prohibited
   activity -- activity illegal under applicable jurisdictional law
   as defined by [I-D.sato-soos-cap] -- with confidence above the
   operator-configured threshold, within data the agent has
   legitimate access to under its current mandate.

   As with Class 6, this trigger class fires when the agent observes
   an external legal violation situation, not when the agent itself
   is asked to participate in one.  An agent instructed by a human
   principal to execute an action that constitutes a Tier 1 violation
   is governed by CAP Cedar DENY, not by this trigger class.

5.7.2.  Confidence Grades

   Class 7 triggers operate on a three-grade confidence model:

   SUSPICIOUS:
      Evidence pattern is consistent with a Tier 1 violation but
      does not conclusively establish one.  A monitoring agent has
      identified anomalous behavior warranting human review.
      The GEC fires HEM_TIER1_OBSERVED with urgency STANDARD.
      Session suspension is NOT required.  The GEC routes to the
      compliance officer designation chain.

   PROBABLE:
      Evidence pattern strongly indicates a Tier 1 violation.
      Multiple indicators are present.  The GEC fires
      HEM_TIER1_OBSERVED with urgency ELEVATED.  Session
      suspension is NOT required for the observed session but
      MUST be applied to any related execution agent sessions
      identified in the OCP cluster_propagation field.  The GEC
      routes to compliance officer and legal counsel.

   EVIDENT:
      Evidence conclusively establishes a Tier 1 violation.  The
      GEC fires HEM_TIER1_OBSERVED with urgency CRITICAL.  The
      GEC MUST suspend the current session and all related
      execution agent sessions identified in the OCP
      cluster_propagation field.  The GEC routes to compliance
      officer, legal counsel, and the senior principal.

5.7.3.  Reporting Deadline Tracking

   When a Tier 1 observation triggers a mandatory external reporting
   obligation under applicable law -- such as a Suspicious Activity
   Report (SAR) under the Bank Secrecy Act [BSA] or a Suspicious
   Transaction Report (STR) under EU AMLD -- the GEC MUST:

   (a)  Record the reporting obligation framework and deadline hours
        from the applicable CAP-RRS Regulation Record
        [I-D.sato-soos-cap-rrs] in the OCP reporting_obligations
        field.
   (b)  Begin a deadline countdown from the time of HEM trigger.
   (c)  Escalate externally if the human principal does not resolve
        the escalation before the deadline expires AND the Regulation
        Record's auto_escalate_on_timeout field is true.

5.7.4.  Cluster Propagation

   When a monitoring agent fires HEM_TIER1_OBSERVED with confidence
   PROBABLE or EVIDENT, the GEC MUST surface the escalation to any
   execution agent sessions operating on related Sovereign Objects
   within the same GEC trust domain, per CONF-MAD-GEC-03
   [I-D.sato-soos-mad].  This ensures that an execution agent
   handling a related transaction is notified of the monitoring
   agent's observation without requiring direct agent-to-agent
   communication.

5.7.5.  Decision Constraints

   For HEM_TIER1_OBSERVED the valid decision types depend on the
   confidence grade:

   SUSPICIOUS: APPROVE (continue monitoring), TERMINATE (close
   session), REDIRECT (refer to different analyst).

   PROBABLE / EVIDENT: TERMINATE (preserve evidence, close session),
   REDIRECT (initiate external reporting workflow).  APPROVE MUST
   NOT be accepted at PROBABLE or EVIDENT confidence.


5.8.  Class 8: Resource Exhaustion Anticipated
      (HEM_TIER3_ANTICIPATORY)

5.8.1.  Trigger Condition

   Before beginning execution of a multi-step mission, the GEC
   determines that the total estimated resource cost of the full
   mission exceeds the remaining resource budget under any active
   Tier 3 resource policy [I-D.sato-soos-cap-rrs] with
   anticipatory_assessment: true.

   This trigger class fires before any step of the mission begins.
   Its purpose is to surface the resource constraint to the human
   principal before any work is performed and any budget is consumed,
   enabling an informed decision about how to proceed.

5.8.2.  GEC Behavior

   When HEM_TIER3_ANTICIPATORY fires, the GEC MUST:

   (a)  Halt mission execution before any step begins.  No tokens
        are consumed, no transitions executed.
   (b)  Construct an Execution Options Package (EOP, Section 6.4)
        containing the full mission cost estimate, available budget,
        shortfall, all declared Natural Breakpoints, and the
        available recourse options.
   (c)  Route a HEM Escalation Request with trigger_class
        HEM_TIER3_ANTICIPATORY and urgency STANDARD to the human
        principal designation chain.
   (d)  Await human decision before any execution begins.

   CONF-HEM-TIER3-01: A GEC implementing HEM_TIER3_ANTICIPATORY
   MUST NOT begin any step of a multi-step mission when the full
   mission estimated cost exceeds available budget and the active
   Tier 3 resource policy has anticipatory_assessment: true.

   CONF-HEM-TIER3-02: A GEC MUST register agent-declared Natural
   Breakpoints at the PLAN step of the AEP execution loop before
   performing the Mission Viability Assessment for Class 8.

5.8.3.  Human Decision Types for Class 8

   APPROVE_WITH_CONSTRAINTS: Scope reduction.  The principal
   specifies a named Natural Breakpoint as the mission stop point.
   The GEC proceeds to that breakpoint only and stops.

   APPROVE_WITH_PAYMENT: Commercial upgrade.  The principal
   authorizes additional resource allocation.  The GEC verifies
   the upgrade and proceeds with the full mission.

   DEFER: Temporal deferral.  The principal elects to wait for the
   budget reset.  The GEC records the deferral and closes the
   session.  The mission MAY be re-initiated after reset.

   DENY: Do not begin.  The mission is cancelled.

   APPROVE and REDIRECT are not valid decision types for Class 8.
   The GEC MUST return HEM_DECISION_INVALID for these submissions.


5.9.  Class 9: Resource Exhaustion In Progress
      (HEM_TIER3_OBSERVED)

5.9.1.  Trigger Condition

   During mission execution, the GEC detects that resource
   consumption has reached the warning_threshold_pct configured in
   the active Tier 3 resource policy [I-D.sato-soos-cap-rrs].
   The default threshold is 80% of budget consumed.  The agent is
   not yet blocked -- this trigger fires before exhaustion, while
   recovery is still possible.

5.9.2.  GEC Behavior

   When HEM_TIER3_OBSERVED fires, the GEC MUST:

   (a)  NOT halt execution immediately.  The mission continues
        while the escalation is routed.
   (b)  Identify the next declared Natural Breakpoint.
   (c)  Commit internally to stopping at that Natural Breakpoint
        regardless of human response timing, per CONF-HEM-TIER3-03.
   (d)  Construct an Execution Options Package (Section 6.4) for
        the remaining mission scope.
   (e)  Route a HEM Escalation Request with trigger_class
        HEM_TIER3_OBSERVED and urgency ELEVATED.

   CONF-HEM-TIER3-03: A GEC MUST NOT stop a mission mid-task on
   a Tier 3 resource limit when a Natural Breakpoint declaration
   is registered.  The GEC MUST complete execution to the next
   declared Natural Breakpoint before enforcing the resource limit,
   regardless of whether the human principal has responded to the
   Class 9 escalation.

5.9.3.  Human Decision Types for Class 9

   APPROVE_WITH_CONSTRAINTS: Continue to a named Natural
   Breakpoint, then stop.

   APPROVE_WITH_PAYMENT: Authorize additional resource allocation
   and continue to full mission completion.

   TERMINATE: Stop at the next Natural Breakpoint.  Equivalent to
   APPROVE_WITH_CONSTRAINTS specifying the immediately next
   breakpoint.

   DEFER: Close the session at the next Natural Breakpoint and
   defer the remainder to after budget reset.

   APPROVE and REDIRECT are not valid for Class 9.  The GEC MUST
   return HEM_DECISION_INVALID for these submissions.



5.10.  Policy Rationale Declaration (PRD)

   A Policy Rationale Declaration (PRD) is a kernel-registered object
   that links a Cedar policy routing transitions to HEM with machine-
   readable rationale. PRDs support regulatory transparency requirements
   (EU AI Act Article 13) and provide human principals with the policy
   basis for escalation events.

   A PRD MUST be registered with the kernel before the Cedar policy
   that references it is loaded. A Cedar policy that routes to HEM
   (Section 5.1) MUST carry a prd_id annotation referencing a
   registered PRD. The GEC MUST reject at load time any Cedar policy
   that routes to HEM and either lacks a prd_id annotation or
   references an unregistered prd_id. The rejection error is
   HEM_PRD_MISSING.

   A PRD object MUST contain the following fields:

   {
     "prd_id":         string, ; REQUIRED. UUID v4. Primary key.
     "rationale_class": string, ; REQUIRED. See IANA registry
                                ;   Section 15.
     "rationale_text": string, ; REQUIRED. Human-readable rationale
                                ;   for requiring human oversight.
     "authority_ref":  string, ; REQUIRED when rationale_class is
                                ;   REGULATORY or CONTRACTUAL.
                                ;   Citation of the regulation or
                                ;   contract provision.
     "review_date":    string, ; REQUIRED. ISO 8601 date. The date
                                ;   by which this PRD SHOULD be
                                ;   reviewed.
     "review_overdue": boolean  ; REQUIRED. Kernel-set at escalation
                                ;   request generation time. TRUE if
                                ;   current date exceeds review_date.
   }

   The PRD store additionally retains the following administrative
   fields, which are NOT surfaced to human principals in the HEM
   Escalation Request: set_by (principal_id of registrant), set_at
   (ISO 8601 UTC registration timestamp), and policy_id (identifier
   of the Cedar policy referencing this PRD).

   The policy_rationale_id field in the HEM Escalation Request
   (Section 6.1) carries the prd_id of the PRD associated with the
   triggering Cedar policy. This field is REQUIRED on HEM_TRIGGERED
   Event Log entries for Class 1 triggers. The full PRD object is
   accessible to human principals via gec.query_rationale().

   A PRD review_overdue value of TRUE MUST generate a
   PRD_REVIEW_DATE_EXCEEDED Audit Alert (Section 10) at escalation
   request generation time.


5.11.  Extension Trigger Classes

   This document recognizes that operational experience may identify
   additional trigger classes beyond those defined in Sections 5.1
   through 5.9. Implementors MAY define additional trigger classes
   using a URI-prefixed identifier. Extension trigger classes MUST be
   submitted as an IDP with hem_urgency REQUIRED or as a kernel-
   internal event; they MUST NOT bypass the HEM_PENDING state machine.

   Implementors wishing to register extension trigger classes SHOULD
   do so via the IANA registry defined in Section 16.


6.  HEM Escalation Request

6.1.  Structure

   When a HEM trigger fires and the GEC enters HEM_PENDING, the
   GEC MUST construct and route a HEM Escalation Request. The
   escalation request is a JSON object:

   {
     "hem_id":          string,  ; REQUIRED. UUID v4. Unique HEM event ID.
     "so_id":           string,  ; REQUIRED. Governed object UUID.
     "session_id":      string,  ; REQUIRED. Agent session identifier.
     "mandate_id":      string,  ; REQUIRED. Active mandate JWT jti.
     "mission_ref":     string,  ; OPTIONAL. MissionDeclaration UUID if
                                 ;   session operates under a declared
                                 ;   mission. NULL if no MissionDeclaration
                                 ;   governs this session.
     "mission_phase":   string,  ; OPTIONAL. Current MissionDeclaration
                                 ;   phase at time of HEM trigger. Provided
                                 ;   to enable human principals to assess
                                 ;   whether the mission context remains
                                 ;   valid. NULL if mission_ref is NULL.
     "trigger_class":   string,  ; REQUIRED. One of the nine defined
                                 ;   trigger classes (Section 5) or an
                                 ;   extension trigger class URI.
     "trigger_detail":  array,   ; REQUIRED. Typed array of trigger-class-
                                 ;   specific detail objects. See Section
                                 ;   8.3 for concurrent extension schema.
     "policy_rationale_id": string, ; REQUIRED for Class 1 triggers.
                                 ;   prd_id of the PRD associated with
                                 ;   the triggering Cedar policy.
                                 ;   NULL for other trigger classes.
     "jurisdictional_conflict_summary": object, ; REQUIRED when
                                 ;   trigger_class is
                                 ;   HEM_JURISDICTIONAL_CONFLICT.
                                 ;   NULL otherwise. See Section 6.2.
     "idp_summary": {            ; REQUIRED if IDP present; else null.
       "goal_description":  string,
       "reasoning_type":    string,
       "confidence_level":  number,
       "requested_action":  string,
       "mission_ref":       string  ; Echoed from triggering IDP.
     },
     "so_state_summary": {       ; REQUIRED.
       "current_state":           string,
       "phase":                   string,
       "available_actions_if_resolved": [string]
     },
     "principals":      [object], ; REQUIRED. Ordered designation chain.
     "timeout_seconds": integer,  ; REQUIRED. Per-principal timeout.
     "created_at":      string,   ; REQUIRED. ISO 8601 UTC.
     "kernel_signature": string,  ; REQUIRED. Ed25519 signature by the
                                 ;   GEC over the canonical
                                 ;   serialization of all other fields.
                                 ;   See Section 12.8.
     "observation_context_package": object, ; REQUIRED for Classes
                                 ;   6 and 7 (HEM_TIER0_OBSERVED,
                                 ;   HEM_TIER1_OBSERVED).
                                 ;   See Section 6.3. NULL otherwise.
     "execution_options_package": object,  ; REQUIRED for Classes
                                 ;   8 and 9 (HEM_TIER3_ANTICIPATORY,
                                 ;   HEM_TIER3_OBSERVED).
                                 ;   See Section 6.4. NULL otherwise.
     "metadata":        object    ; OPTIONAL. Implementation-defined.
   }

6.2.  Field Definitions

   hem_id:
      A UUID v4 uniquely identifying this HEM event. Used as the
      primary key for all subsequent Event Log entries relating to
      this HEM lifecycle.

   mission_ref:
      OPTIONAL. The UUID of the MissionDeclaration governing the
      session at the time of the HEM trigger. When present, provides
      human principals with the mission context needed to evaluate
      whether the action under review is appropriate within the
      overarching mission. NULL if the session does not operate under
      a declared MissionDeclaration.

   mission_phase:
      OPTIONAL. The current phase of the MissionDeclaration identified
      by mission_ref at the time of the HEM trigger. Human principals
      use this field to assess whether the mission is still active.
      Possible values: DISCOVERY, EXECUTION, RELEASE, SUSPENDED,
      FAILED, ABANDONED. NULL if mission_ref is NULL. Human principals
      who receive an escalation request where mission_phase is
      SUSPENDED, FAILED, or ABANDONED SHOULD treat TERMINATE as the
      expected disposition unless there is specific reason to believe
      the mission state will be corrected.

   trigger_class:
      One of the nine defined trigger classes (Sections 5.1
      through 5.9) or an extension trigger class URI.

   trigger_detail:
      A typed array of trigger-class-specific objects. The initial
      entry is populated at HEM trigger time. When a concurrent
      HEM_PENDING condition fires (Section 8.3), the GEC appends
      a new typed entry to this array. Each entry MUST contain:
      extension_type (string), extended_at (ISO 8601 UTC),
      trigger_source (string), and class-specific detail fields.
      For HEM_PROXIMITY_TRIGGERED entries: threshold_id,
      threshold_class, condition_met, triggered_at. See Section 13
      for minimisation requirements.

   policy_rationale_id:
      The prd_id of the PRD (Section 5.6) associated with the Cedar
      policy that triggered this HEM event. REQUIRED for Class 1
      triggers (HEM_CEDAR_ROUTED). NULL for all other trigger classes.
      Provides human principals with direct access to the machine-
      readable policy rationale via kernel.query_rationale(prd_id).

   jurisdictional_conflict_summary:
      REQUIRED when trigger_class is HEM_JURISDICTIONAL_CONFLICT.
      NULL otherwise. A structured object containing:
      {
        "jurisdictions": [string], ; ISO 3166-1 alpha-2 codes of the
                                   ;   conflicting jurisdictions.
        "conflict_description": string, ; Human-readable description.
        "conflicting_requirements": [object], ; One entry per
                                   ;   jurisdiction with fields:
                                   ;   jurisdiction, requirement_ref,
                                   ;   requirement_text.
        "resolution_methods_available": [string] ; From CAP JCR;
                                   ;   see [I-D.sato-soos-cap].
      }

   kernel_signature:
      An Ed25519 signature produced by the GEC over the canonical
      serialization of all other fields in the HEM Escalation Request.
      See Section 12.8. REQUIRED. Delivery intermediaries capable of
      verifying this signature MUST do so and MUST NOT forward the
      request if verification fails.

   idp_summary:
      A summary of the IDP submitted with the triggering action, if
      present. This provides human principals with context about what
      the agent was attempting to do. MUST be null if no IDP was
      associated with the trigger. The mission_ref field within
      idp_summary echoes the mission_ref from the triggering IDP;
      this allows principals to confirm that the IDP's declared mission
      matches the session's governing MissionDeclaration.

   so_state_summary:
      A summary of the governed object's current state, phase, and
      the Cedar actions that would be available to the agent if the
      HEM is resolved with APPROVE. This enables human principals
      to make informed decisions without requiring access to the full
      governed object record.

   principals:
      An ordered array of human principal descriptors forming the
      designation chain. Each element MUST contain:

      {
        "principal_id":   string, ; Party Registry identifier.
        "display_name":   string, ; Human-readable name.
        "contact":        object, ; Delivery contact; implementation-defined.
        "timeout_seconds": integer ; Per-principal timeout override. Optional.
      }

   timeout_seconds:
      The default per-principal timeout in seconds. If a principal
      descriptor includes a timeout_seconds override, the override
      applies for that principal. See Section 9.

6.3.  Observation Context Package (OCP)

   The Observation Context Package is REQUIRED in HEM Escalation
   Requests for Class 6 (HEM_TIER0_OBSERVED) and Class 7
   (HEM_TIER1_OBSERVED) triggers.  It carries the structured evidence
   the agent has observed.  The OCP is NOT a reproduction of session
   records or personal data; it is a structured summary of the
   observation and its compliance implications.

   {
     "observation_type":     string,  ; REQUIRED. Category of
                                      ;   observation. Values from
                                      ;   CAP-RRS Regulation Record
                                      ;   observation_config.
                                      ;   observation_type. Examples:
                                      ;   "AML", "SANCTIONS", "FRAUD",
                                      ;   "CSAM", "GENOCIDE_RISK".
     "confidence_grade":     string,  ; REQUIRED for Class 7.
                                      ;   "SUSPICIOUS", "PROBABLE",
                                      ;   or "EVIDENT". NULL for
                                      ;   Class 6 (always CRITICAL).
     "evidence_summary":     [object],; REQUIRED. Array of evidence
                                      ;   items. Each item:
                                      ;   { "evidence_type": string,
                                      ;     "description": string,
                                      ;     "source_ref": string }.
                                      ;   MUST NOT contain personal
                                      ;   data. See Section 14.
     "jurisdictions":        [string],; REQUIRED. ISO 3166-1 alpha-2
                                      ;   codes of applicable legal
                                      ;   frameworks.
     "regulation_record_ids":[string],; REQUIRED. CAP-RRS record_ids
                                      ;   of applicable Regulation
                                      ;   Records that govern this
                                      ;   observation type.
     "reporting_obligations":[object],; REQUIRED when reporting
                                      ;   obligation exists. Each:
                                      ;   { "framework": string,
                                      ;     "deadline_hours": integer,
                                      ;     "deadline_expires_at":
                                      ;       string (ISO 8601),
                                      ;     "auto_escalate_on_timeout":
                                      ;       boolean }.
     "affected_so_uuids":    [string],; OPTIONAL. UUIDs of Sovereign
                                      ;   Objects related to the
                                      ;   observed situation.
     "cluster_propagation":  boolean, ; REQUIRED. Whether the GEC
                                      ;   has propagated this
                                      ;   escalation to related
                                      ;   execution agent sessions.
     "pattern_id":           string,  ; OPTIONAL. Typology or pattern
                                      ;   match identifier from the
                                      ;   applicable regulatory
                                      ;   framework (e.g., FinCEN
                                      ;   typology ID for AML).
     "counterparty_risk":    string   ; OPTIONAL. Risk classification
                                      ;   of the observed counterparty
                                      ;   if applicable.
   }

   Privacy requirements for OCP: The GEC MUST NOT include personal
   data in the evidence_summary array.  Evidence items MUST be
   described at the pattern or category level.  Source references
   MUST use internal session identifiers, not personal identifiers.
   See Section 14 for full privacy requirements on observation data.


6.4.  Execution Options Package (EOP)

   The Execution Options Package is REQUIRED in HEM Escalation
   Requests for Class 8 (HEM_TIER3_ANTICIPATORY) and Class 9
   (HEM_TIER3_OBSERVED) triggers.  It provides the human principal
   with a complete picture of the resource situation and all
   available paths forward.

   {
     "full_mission_viable":  boolean, ; REQUIRED. Whether the full
                                      ;   mission can complete within
                                      ;   available budget.
     "budget_available":     integer, ; REQUIRED. Remaining resource
                                      ;   units (e.g., tokens).
     "budget_required":      integer, ; REQUIRED. Estimated cost for
                                      ;   full mission completion.
     "shortfall":            integer, ; REQUIRED. budget_required
                                      ;   minus budget_available.
                                      ;   0 if full_mission_viable.
     "natural_breakpoints":  [object],; REQUIRED. All agent-declared
                                      ;   Natural Breakpoints, in
                                      ;   execution order. Each:
                                      ;   { "breakpoint_id": string,
                                      ;     "description": string,
                                      ;     "cost_to_reach": integer,
                                      ;     "viable": boolean,
                                      ;     "value_delivered": string
                                      ;   }.
     "recourse_options":     [object],; REQUIRED. All available
                                      ;   recourse paths. Each:
                                      ;   { "option_id": string,
                                      ;     "type": string,
                                      ;     "description": string,
                                      ;     "viable": boolean,
                                      ;     "cost": integer or null,
                                      ;     "upgrade_url":
                                      ;       string or null,
                                      ;     "reset_at":
                                      ;       string or null }.
                                      ;   type values:
                                      ;   "COMMERCIAL_UPGRADE",
                                      ;   "SCOPE_REDUCTION",
                                      ;   "TEMPORAL_DEFERRAL".
     "recommended_option":   string,  ; REQUIRED. option_id of the
                                      ;   GEC-recommended recourse.
                                      ;   The GEC SHOULD recommend
                                      ;   the viable option with the
                                      ;   highest value_delivered.
     "next_natural_breakpoint": string; REQUIRED for Class 9 only.
                                      ;   breakpoint_id of the next
                                      ;   Natural Breakpoint at which
                                      ;   the GEC will stop regardless
                                      ;   of human response.
   }

   Example EOP for the instruction "research my subject, write a
   report, then send emails to all my clients" with 45,000 tokens
   remaining and 95,000 tokens estimated for full completion:

   {
     "full_mission_viable": false,
     "budget_available":    45000,
     "budget_required":     95000,
     "shortfall":           50000,
     "natural_breakpoints": [
       { "breakpoint_id":  "BP-1",
         "description":    "Research complete.",
         "cost_to_reach":  40000,
         "viable":         true,
         "value_delivered":"Research findings available." },
       { "breakpoint_id":  "BP-2",
         "description":    "Report complete.",
         "cost_to_reach":  60000,
         "viable":         false,
         "value_delivered":"Complete report deliverable." },
       { "breakpoint_id":  "BP-3",
         "description":    "Full mission: emails sent.",
         "cost_to_reach":  95000,
         "viable":         false,
         "value_delivered":"Research, report, and distribution." }
     ],
     "recourse_options": [
       { "option_id":    "RO-1",
         "type":         "SCOPE_REDUCTION",
         "description":  "Execute to BP-1 only.",
         "viable":       true,
         "cost":         40000,
         "upgrade_url":  null,
         "reset_at":     null },
       { "option_id":    "RO-2",
         "type":         "COMMERCIAL_UPGRADE",
         "description":  "Upgrade plan for full mission.",
         "viable":       true,
         "cost":         null,
         "upgrade_url":  "https://...",
         "reset_at":     null },
       { "option_id":    "RO-3",
         "type":         "TEMPORAL_DEFERRAL",
         "description":  "Budget resets in 6 hours.",
         "viable":       true,
         "cost":         null,
         "upgrade_url":  null,
         "reset_at":     "2026-05-31T06:00:00Z" }
     ],
     "recommended_option": "RO-1"
   }


6.5.  Routing to Human Principals

   HEM does not specify the delivery mechanism. The GEC MUST
   deliver the escalation request to the first principal in the
   designation chain. The delivery mechanism is implementation-defined
   and MAY include:

   *  Push notification to a mobile application.
   *  Message delivery via a registered messaging endpoint (e.g.,
      the ATP Guest Agent [SOOS] uses WhatsApp Business API and
      LINE Messaging API as delivery channels).
   *  Email to a registered address.
   *  HTTP POST to a registered webhook.
   *  Any CHEQ-compatible [I-D.rosenberg-aiproto-cheq] confirmation
      delivery mechanism.

   The GEC MUST record the delivery attempt in the Event Log
   regardless of the delivery mechanism. The GEC MUST NOT consider
   delivery confirmed until an acknowledgment is received from the
   delivery channel. Delivery failure MUST trigger escalation to the
   next principal in the designation chain without waiting for the
   per-principal timeout to expire.


7.  Human Decision Types

   A human principal responds to a HEM Escalation Request with one of
   five decision types. The GEC MUST accept only these five decision
   types as valid HEM resolutions. Any response that does not conform
   to one of these types MUST be rejected by the kernel with a
   HEM_DECISION_INVALID error.

   No HEM decision type substitutes for Cedar policy evaluation.
   APPROVE and APPROVE_WITH_CONSTRAINTS authorize the kernel to proceed
   to Cedar evaluation for the triggering action; they do not override
   it. A Cedar DENY result following an APPROVE or APPROVE_WITH_
   CONSTRAINTS decision takes precedence over the human decision; the
   action does not execute, and the GEC returns an Enriched DENY
   Response [I-D.sato-soos-idp] to the agent. This property is the
   normative separation between human judgment (was this action
   appropriate in context?) and policy enforcement (is this action
   permitted?). These two questions have different authorities and
   MUST NOT be collapsed.

7.1.  APPROVE

   The human principal approves the requested action and authorizes the
   agent to proceed.

   Kernel behaviour upon receiving APPROVE:
   *  The GEC MUST record HEM_DECISION_RECEIVED(APPROVE) in the
      Event Log.
   *  The GEC MUST execute the Cedar policy evaluation for the
      action that triggered the HEM. If Cedar PERMIT results, the
      action MUST execute. If Cedar DENY results, the DENY takes
      precedence; APPROVE does not override Cedar policy (see Section
      7 preamble).
   *  The session transitions to HEM_RESOLVED and then HEM_INACTIVE.

   Note: APPROVE is not a Cedar override. It is a signal that the
   human principal has reviewed the situation and considers the action
   appropriate within the governing mission and policy context. If the
   action is Cedar-denied for reasons unrelated to the HEM trigger,
   the denial stands.

7.2.  APPROVE_WITH_CONSTRAINTS

   The human principal approves the requested action subject to
   specified constraints. Constraints are expressed as additional
   Cedar context attributes injected into the subsequent Cedar
   evaluation.

   APPROVE_WITH_CONSTRAINTS MUST include a constraints object:

   {
     "decision": "APPROVE_WITH_CONSTRAINTS",
     "constraints": {
       "cedar_context_additions": object, ; Additional Cedar context.
       "expiry_seconds":  integer,        ; OPTIONAL. Constraint validity
                                          ;   window in seconds from
                                          ;   HEM_DECISION_RECEIVED.
       "description":     string          ; Human-readable summary.
     }
   }

   Kernel behaviour:
   *  The GEC MUST record HEM_DECISION_RECEIVED(APPROVE_WITH_
      CONSTRAINTS) in the Event Log, including the full constraints
      object.
   *  The GEC MUST inject the cedar_context_additions into the Cedar
      context for the subsequent action evaluation.
   *  Expiry semantics: expiry_seconds governs action initiation, not
      completion. Transitions for which initiation begins before the
      expiry window closes MUST be permitted to complete. Transitions
      for which initiation has not begun when the expiry window closes
      MUST be evaluated without the constraint additions; Cedar context
      returns to the pre-constraint state. Initiation time is recorded
      as the timestamp of the gec.transition() call.
   *  When an initiation attempt is rejected due to constraint expiry,
      the GEC MUST return HEM_CONSTRAINT_EXPIRED. The expiry time
      is recorded against hem_id, not individual transitions.
   *  The session transitions to HEM_RESOLVED and then HEM_INACTIVE.

7.3.  REDIRECT

   The human principal does not approve the requested action but
   authorizes the agent to take a different specified action instead.

   REDIRECT MUST include a redirect object:

   {
     "decision": "REDIRECT",
     "redirect": {
       "action":      string, ; Cedar action string for the new action.
       "description": string  ; Human-readable rationale.
     }
   }

   Kernel behaviour:
   *  The GEC MUST record HEM_DECISION_RECEIVED(REDIRECT) in the
      Event Log.
   *  The GEC MUST evaluate the redirected action against Cedar
      policy. If Cedar PERMIT results, the redirected action executes.
      If Cedar DENY results, the GEC returns HEM_REDIRECT_DENIED
      and an Enriched DENY Response [I-D.sato-soos-idp] to the
      submitting principal. HEM does NOT re-trigger automatically on
      Cedar DENY of a REDIRECT; there is no normative default retrigger.
      A REDIRECT_DENY_RETRIGGER extension may be defined in future work.
   *  When Cedar DENY follows REDIRECT, the principal's decision slot
      is NOT consumed. The principal MAY submit a new decision within
      the same active HEM event. This permits iterative resolution
      without requiring a new HEM lifecycle.
   *  The original requested action MUST NOT execute.
   *  When Cedar PERMIT follows REDIRECT, the session transitions to
      HEM_RESOLVED and then HEM_INACTIVE.

7.4.  TERMINATE

   The human principal terminates the agent session. The session is
   immediately closed. No further agent actions may be executed in
   this session.

   Kernel behaviour upon receiving TERMINATE. The following steps MUST
   be executed in the order specified. Steps 1 and 2 are atomic: both
   MUST be committed before HEM_DECISION_ACCEPTED is returned to any
   caller. Step 3 executes after the atomic completion of Steps 1
   and 2.

   Step 1 -- Mandate revocation:
   *  The GEC MUST record HEM_DECISION_RECEIVED(TERMINATE) in the
      Event Log.
   *  The mandate JWT associated with this session MUST be revoked.
      Revocation MUST propagate to all relying parties before any
      further agent calls are accepted on that mandate.
   *  The principal who issued TERMINATE MUST be recorded by
      principal_id in the Event Log.

   Step 2 -- Mission cascade (atomic with Step 1):
   *  If the session is associated with a governing MissionDeclaration
      and is the sole active session under that MissionDeclaration, the
      GEC MUST initiate MISSION_REVOKE_CASCADE. Steps 1 and 2 MUST
      both be committed -- mandate revocation completed AND
      MISSION_REVOKE_CASCADE initiated -- before HEM_DECISION_ACCEPTED
      is returned. No further calls on related mandates are accepted
      until both commitments are complete.
   *  The semantics of MISSION_REVOKE_CASCADE are defined in [SOOS]
      Section 10. HEM TERMINATE is one normative trigger for that
      protocol.

   Step 3 -- Governed object disposition (after atomic completion):
   *  The GEC MUST apply the SO Type's defined termination
      disposition for the governed object's current state. The SO Type
      MUST define a termination disposition for each state in which
      SESSION_TERMINATED is reachable.
   *  The GEC MUST enter SESSION_TERMINATED state.

   A TERMINATE decision for a Class 5 trigger (HEM_JURISDICTIONAL_
   CONFLICT) MUST be accompanied by a Decision Rationale Record (DRR)
   with safety_basis populated (Section 7.6). The GEC MUST reject
   a TERMINATE decision on a Class 5 trigger that lacks a DRR with
   HEM_DRR_REQUIRED.

7.5.  DEFER

   The human principal is unable to decide at this moment and requests
   that the HEM timeout be extended. This decision type acknowledges
   the situation without resolving it.

   DEFER MUST include a defer object:

   {
     "decision": "DEFER",
     "defer": {
       "extension_seconds": integer, ; REQUIRED. Additional seconds.
       "reason":            string   ; REQUIRED. Human-readable.
     }
   }

   Kernel behaviour:
   *  The GEC MUST record HEM_DECISION_RECEIVED(DEFER) in the
      Event Log.
   *  The GEC MUST extend the remaining timeout by extension_seconds.
   *  The session remains in HEM_PENDING.
   *  The GEC SHOULD deliver a re-notification to the same principal
      when the extended timeout has 20% remaining.

   Limits:
   *  A single DEFER extension MUST NOT exceed the original per-principal
      timeout_seconds for this HEM event.
   *  DEFER is limited to one per principal per hem_id. The limit is
      scoped independently for each principal: a DEFER by Principal A
      does not affect Principal B's DEFER availability. Escalation
      through the chain does not affect prior principals' DEFER records.
      The timeout countdown does not consume a principal's DEFER -- only
      a submitted DEFER decision does.
   *  A second DEFER from the same principal on the same hem_id MUST be
      rejected with HEM_DEFER_LIMIT_EXCEEDED.

7.6.  Decision Rationale Record (DRR)

   A Decision Rationale Record (DRR) captures the human principal's
   reasoning for a HEM decision. DRRs support regulatory transparency
   requirements (EU AI Act Article 13) and provide an auditable record
   of human judgment in the governance trail.

   A DRR is REQUIRED for TERMINATE decisions. A DRR SHOULD be provided
   for APPROVE_WITH_CONSTRAINTS decisions. A DRR MAY be provided for
   any decision type. The GEC MUST reject a TERMINATE decision that
   lacks a DRR or that includes a DRR in which safety_basis is null,
   with error HEM_DRR_REQUIRED.

   A DRR object MUST contain the following fields:

   {
     "rationale_class": string, ; REQUIRED. See IANA registry
                                ;   Section 15.
     "rationale_text":  string, ; REQUIRED when DRR is required.
                                ;   Human-readable description of
                                ;   the principal's reasoning.
     "safety_basis":    string, ; REQUIRED for TERMINATE; null
                                ;   otherwise. Describes the safety
                                ;   or risk basis for the decision
                                ;   to terminate the session.
     "reference_ref":   string  ; OPTIONAL. Reference identifier
                                ;   (e.g., incident ID, regulation
                                ;   citation, contract clause) for
                                ;   any decision type. Included to
                                ;   support APPROVE_WITH_LEGAL_BASIS
                                ;   when that decision type becomes
                                ;   operational.
   }

   The GEC MUST validate the presence of required fields. The kernel
   MUST NOT validate the content quality of rationale_text or
   safety_basis. Content sufficiency is a human governance matter.

   DRRs are committed to the Rationale Store, a separate kernel-managed
   object store. DRRs are immutable on commit. The Event Log carries
   drr_id as a foreign key on HEM_DECISION_RECEIVED entries where a
   DRR is present. DRRs are accessible via gec.query_rationale().
   The Session Audit Record (SAR) includes a rationale coverage summary
   counting decisions with and without DRRs.

   The non-normative advisory in Section 14 maps DRR rationale_class
   and safety_basis to EU AI Act Article 13 transparency requirements.


7.7.  Decision Submission Protocol

   Human decisions are submitted to the kernel via a decision endpoint.
   The submission MUST include:

   {
     "hem_id":        string, ; REQUIRED. Must match active HEM event.
     "principal_id":  string, ; REQUIRED. Party Registry identifier.
     "decision":      string, ; REQUIRED. One of the five types.
     "decision_data": object, ; REQUIRED for types with data objects.
     "drr":           object, ; REQUIRED for TERMINATE; OPTIONAL
                              ;   otherwise. See Section 7.6.
     "timestamp":     string, ; REQUIRED. ISO 8601 UTC.
     "signature":     string  ; REQUIRED. Principal's Ed25519 signature
                              ;   over hem_id + principal_id + decision
                              ;   + timestamp.
   }

   The GEC MUST verify the signature before processing the decision.
   The signing key MUST correspond to the principal's registered key
   in the Party Registry. A decision submitted with an invalid
   signature MUST be rejected with HEM_SIGNATURE_INVALID.

   The GEC MUST accept decisions only from principals listed in the
   designation chain for the active HEM event. A decision from an
   unlisted principal MUST be rejected with HEM_PRINCIPAL_NOT_AUTHORIZED.


8.  Transition Prohibition During HEM_PENDING

8.1.  The Prohibition Rule

   While a session is in HEM_PENDING state, the GEC MUST reject all
   gec.transition() calls with error code HEM_PENDING_ACTIVE. This
   prohibition is absolute and applies regardless of:

   *  The Cedar policy evaluation outcome for the requested action.
   *  The identity of the requesting agent.
   *  The mandate JWT presented.
   *  The IDP submitted with the call.

   The transition prohibition is the primary safety property of HEM.
   It guarantees that no governed object state changes occur while a
   human oversight event is in progress. Implementations MUST enforce
   this prohibition at the kernel layer, prior to Cedar evaluation.

8.2.  Read-Only Operations During HEM_PENDING

   The following operations are PERMITTED during HEM_PENDING:

   *  kernel.query_state() -- reading the current governed object state.
   *  kernel.query_event_log() -- reading the Event Log.
   *  kernel.query_hem_status() -- reading the status of the active
      HEM event, including which principals have been notified and
      the remaining timeout.
   *  kernel.list_available_actions() -- listing Cedar-permitted actions
      for planning purposes (agents may plan during HEM_PENDING even
      though they may not act).

   These operations do not modify governed object state and are
   therefore not subject to the transition prohibition.

8.3.  Multiple Concurrent HEM_PENDING Conditions

   A governing kernel MAY support multiple concurrent HEM events for
   distinct governed objects. Each governed object's HEM state is
   independent.

   A single governed object MUST NOT have more than one active
   HEM_PENDING event at a time. If a proximity threshold fires while
   an agent-escalated HEM is already pending for the same governed
   object, the GEC MUST record the proximity threshold crossing in
   the Event Log and MUST extend the existing HEM event's context to
   include the proximity trigger detail. A second HEM event MUST NOT
   be created.

   Context extension uses the trigger_detail typed array (Section 6.1).
   Each context extension appends a new typed entry to the array. The
   entry MUST contain:

   {
     "extension_type":        string, ; REQUIRED. Trigger class of the
                                      ;   extending condition.
     "extended_at":           string, ; REQUIRED. ISO 8601 UTC.
     "trigger_source":        string, ; REQUIRED. Identifier of the
                                      ;   threshold or event that fired.
     "proximity_detail":      object, ; REQUIRED for HEM_PROXIMITY_
                                      ;   TRIGGERED extensions.
                                      ;   See Section 13 for
                                      ;   minimisation requirements.
     "timeout_extension_seconds": integer ; OPTIONAL. Additional seconds
                                      ;   to add to the current timeout
                                      ;   budget. Pre-declared by the
                                      ;   SO Type designer in the
                                      ;   proximity threshold config.
                                      ;   The timeout budget does NOT
                                      ;   reset automatically.
   }

   When a context extension occurs, the GEC MUST re-deliver the
   updated HEM Escalation Request to the active principal via the same
   delivery channel. The principal's decision slot is NOT reset by a
   context extension. The GEC MUST record HEM_CONTEXT_EXTENDED in
   the Event Log with: hem_id, extension_type, trigger_source,
   extended_at, and timeout_extension_seconds (if applicable).

8.4.  Mission Validity During HEM_PENDING

   A session in HEM_PENDING state may be associated with a governing
   MissionDeclaration [SOOS]. While HEM_PENDING is active, the kernel
   MUST monitor mission validity. If the governing MissionDeclaration
   transitions to phase SUSPENDED, FAILED, or ABANDONED during the
   HEM_PENDING period:

   (a)  The GEC MUST enter HEM_CHAIN_EXHAUSTED state with disposition
        TERMINATE_SESSION, regardless of whether the designation chain
        has been exhausted.

   (b)  The GEC MUST record a HEM_MISSION_INVALID event in the Event
        Log containing: hem_id, mission_ref, mission_phase (the terminal
        phase that was detected), and timestamp.

   (c)  Outstanding human principal notifications MUST be cancelled.
        The GEC MUST notify principals who have already received a
        notification that the session has been terminated due to mission
        invalidation. The cancellation notification is recorded as
        HEM_NOTIFICATION_CANCELLED in the Event Log.

   (d)  The TERMINATE disposition applies as defined in Section 7.4,
        including mandate JWT revocation and MISSION_REVOKE_CASCADE if
        the session is the sole active session under the
        MissionDeclaration.

   This provision closes the ghost execution failure mode: a valid HEM
   event does not imply that the underlying mission for which the agent
   was operating is still active. A valid mandate JWT + valid HEM event
   does not imply a legitimate ongoing mission.

   Note: This section applies only when HEM_PENDING is already active
   and the mission phase changes during the wait. The case where mission
   invalidity is first detected in an otherwise active session (no
   existing HEM event) is addressed by the Class 4 extension trigger
   class defined in Section 5.4.


9.  Timeout Model

9.1.  Timeout Budget

   Each principal in the designation chain is allocated a timeout
   budget. The default timeout_seconds is specified in the HEM
   Escalation Request (Section 6.1). A per-principal override MAY
   be specified in the principal descriptor.

   The timeout clock for a principal begins when the kernel delivers
   the escalation request to that principal (or records a delivery
   attempt, if delivery is not confirmed).

   The minimum timeout_seconds is 60. A HEM configuration specifying
   a timeout_seconds less than 60 MUST be rejected by the kernel at
   configuration time.

9.2.  Timeout Disposition

   When a principal's timeout budget is exhausted without receipt of
   a valid decision, the GEC MUST apply one of the following
   timeout dispositions. The disposition MUST be pre-declared in the
   governed object's HEM configuration; it MUST NOT be determined
   at timeout time.

   ESCALATE_CHAIN:
      Escalate to the next principal in the designation chain. This
      is the default disposition when the chain has not been exhausted.

   SUSPEND:
      Place the governed object in BOOKING_SUSPENDED state (or the
      equivalent suspended state for the SO Type). The session
      remains in HEM_PENDING. A governance recovery process must
      manually resolve the suspension.

   TERMINATE_SESSION:
      Apply the TERMINATE decision semantics (Section 7.4). The
      session ends; the mandate JWT is revoked; the SO Type's
      termination disposition applies.

   AUTO_APPROVE:
      Approve the triggering action and proceed as if APPROVE had
      been received. This disposition is Cedar-gated: the GEC MUST
      perform a Cedar policy evaluation before applying AUTO_APPROVE.
      If Cedar evaluation returns DENY, the AUTO_APPROVE disposition
      MUST NOT apply; the GEC MUST instead apply the SUSPEND
      disposition and record HEM_AUTO_APPROVE_CEDAR_DENIED in the
      Event Log. This ensures that AUTO_APPROVE cannot be used to
      bypass Cedar policy.

      Hard prohibition: AUTO_APPROVE MUST NOT be available for
      transition classes designated as high-value in the SO Type
      configuration, regardless of Cedar evaluation outcome. The
      GEC MUST enforce this prohibition at SO Type configuration
      load time by rejecting any HEM configuration that specifies
      AUTO_APPROVE for a high-value transition class. The rejection
      error is HEM_AUTO_APPROVE_PROHIBITED.

      AUTO_APPROVE MUST NOT be used for HEM_CEDAR_ROUTED triggers.
      It MAY be used for HEM_PROXIMITY_TRIGGERED triggers with
      hem_disposition: NOTIFY. Implementations SHOULD discourage this
      disposition for high-value transitions.

9.3.  Timeout Chain (HEM_UNREACHABLE)

   When the disposition is ESCALATE_CHAIN and the chain has not been
   exhausted, the GEC enters HEM_TIMEOUT state briefly, records
   HEM_PRINCIPAL_TIMEOUT in the Event Log, and immediately re-enters
   HEM_PENDING with the next principal as the active target.

   A notification MUST be delivered to the next principal within 30
   seconds of the prior principal's timeout.

   The GEC MUST record in the Event Log for each principal in the
   chain:

   *  HEM_NOTIFICATION_SENT (with principal_id and timestamp)
   *  HEM_NOTIFICATION_DELIVERED or HEM_NOTIFICATION_UNDELIVERED
   *  HEM_PRINCIPAL_TIMEOUT (if timeout elapsed without decision)

9.4.  Chain Exhaustion

   If all principals in the designation chain have timed out without
   providing a valid decision, the GEC enters HEM_CHAIN_EXHAUSTED
   state. The GEC MUST apply the pre-declared chain exhaustion
   disposition.

   The chain exhaustion disposition is specified separately from the
   per-principal timeout disposition and MUST be one of:

   SUSPEND:
      As defined in Section 9.2. Recommended default for most SO Types.

   TERMINATE_SESSION:
      As defined in Section 9.2.

   The chain exhaustion disposition MUST be declared in the governed
   object's HEM configuration. A HEM configuration without a chain
   exhaustion disposition MUST default to SUSPEND.


10.  Event Log Requirements

   A conforming GEC MUST record the following events in the Event Log
   for each HEM lifecycle. All events MUST be GEC-signed
   [I-D.sato-soos-gar].

   Event sequence for a complete HEM lifecycle:

   HEM_TRIGGERED
      Fields: hem_id, trigger_class, trigger_detail (initial entry),
      so_id, session_id, mandate_id, mission_ref (if present),
      policy_rationale_id (REQUIRED for Class 1 triggers; null
      otherwise), timestamp.

   HEM_NOTIFICATION_SENT (one per principal notified)
      Fields: hem_id, principal_id, delivery_mechanism, timestamp.

   HEM_NOTIFICATION_DELIVERED or HEM_NOTIFICATION_UNDELIVERED
      Fields: hem_id, principal_id, timestamp.

   HEM_DECISION_RECEIVED
      The following nine fields are REQUIRED on all HEM_DECISION_
      RECEIVED entries:
         hem_id, session_id, mandate_id, trigger_class,
         principal_type, principal_id, trigger_source,
         decision_type, created_at.
      Additionally: decision_rationale_class is REQUIRED when a DRR
      is mandatory for the decision type; OPTIONAL otherwise.
      policy_rationale_id SHOULD be recorded. drr_id SHOULD be
      recorded when a DRR is submitted.

   HEM_RESOLVED or HEM_TIMEOUT or HEM_CHAIN_EXHAUSTED
      Fields: hem_id, final_state, applied_disposition (if timeout
      or chain exhaustion), timestamp.

   In addition, each of the following MUST be recorded when applicable:

   HEM_CONTEXT_EXTENDED  (Section 8.3)
      Fields: hem_id, extension_type, trigger_source, extended_at,
      timeout_extension_seconds (if applicable).

   HEM_PRINCIPAL_TIMEOUT
      Fields: hem_id, principal_id, elapsed_seconds, timestamp.

   HEM_DEFER_RECEIVED
      Fields: hem_id, principal_id, extension_seconds, timestamp.

   HEM_DECISION_REJECTED
      Fields: hem_id, rejection_code, submitter_info, timestamp.

   HEM_MISSION_INVALID  (Section 8.4)
      Fields: hem_id, mission_ref, mission_phase (terminal phase
      detected), timestamp.

   HEM_NOTIFICATION_CANCELLED  (Section 8.4)
      Fields: hem_id, principal_id, reason, timestamp.

   HEM_MISSION_REF_MISMATCH_REJECTED  (Section 11)
      Fields: hem_id, session_id, idp_id, expected_mission_ref,
      submitted_mission_ref, timestamp.

   CONSTITUTIONAL_VIOLATION  (when CAP Tier 0 or Tier 1 refusal
      applies during HEM_PENDING processing)
      Fields: hem_id, violation_class, tier, timestamp.
      Generates a CRITICAL Audit Alert [I-D.sato-soos-gar].

   The Event Log ordering guarantee for a HEM lifecycle is:

   HEM_TRIGGERED < HEM_NOTIFICATION_SENT <
   HEM_DECISION_RECEIVED < HEM_RESOLVED

   No STATE_TRANSITIONED event for the governed object may appear in
   the Event Log between HEM_TRIGGERED and HEM_RESOLVED (or
   HEM_TIMEOUT, HEM_CHAIN_EXHAUSTED) events. This is the Event Log
   expression of the transition prohibition in Section 8.

   The Session Audit Record (SAR) for a governed object session is
   generated by the kernel at session close and includes a reference
   array hem_events[] carrying the hem_id of each HEM lifecycle in
   that session. SAR specification is defined in [I-D.sato-soos-gar].


11.  Relationship to IDP

   The IDP [I-D.sato-soos-idp] and HEM are co-operating kernel
   primitives. Their relationship is as follows:

   *  An IDP with hem_urgency: REQUIRED triggers HEM_AGENT_ESCALATED
      (Section 5.2). The IDP idp_id is recorded in the HEM trigger
      detail.

   *  The idp_summary field of the HEM Escalation Request (Section 6.1)
      is derived from the triggering IDP. Human principals receive
      the agent's declared goal, reasoning type, confidence level, and
      requested action as part of the escalation context. The
      mission_ref field within idp_summary is echoed from the triggering
      IDP's mission_ref field, enabling principals to confirm mission
      context consistency.

   *  Mission_ref mismatch: The GEC MUST verify that the mission_ref
      field in each incoming IDP matches the mission_ref of the governing
      session MissionDeclaration. On mismatch, the GEC MUST reject
      the IDP and return an Enriched DENY Response [I-D.sato-soos-idp]
      containing mismatch_detail with expected_mission_ref and
      submitted_mission_ref values. The GEC MUST log
      HEM_MISSION_REF_MISMATCH_REJECTED (Section 10). If mismatches
      from the same session exceed a configurable threshold, the kernel
      SHOULD automatically trigger HEM_AGENT_ESCALATED (Class 2).

   *  IDP_COMMITMENT_GAP: When the IDP Commitment Verification Record
      [I-D.sato-soos-idp] detects that the agent's actual action
      diverged from its declared intent (IDP_COMMITMENT_GAP), the
      GEC MUST automatically trigger HEM_AGENT_ESCALATED (Class 2).
      This trigger is non-suppressible. IDP_COMMITMENT_GAP also
      generates a CRITICAL Audit Alert [I-D.sato-soos-gar].

   *  Following HEM_RESOLVED with a REDIRECT decision, the agent MUST
      submit a new IDP for the redirected action before the kernel
      will execute it. The new IDP SHOULD reference the HEM hem_id
      in context_refs.

   *  Following HEM_RESOLVED with APPROVE or APPROVE_WITH_CONSTRAINTS,
      the agent MAY re-execute its original action. It MUST submit
      the original IDP's goal_id in the new IDP's declared_goal to
      provide continuity of audit trail.

   *  The Event Log ordering between IDP and HEM events is:

      IDP_SUBMITTED < HEM_TRIGGERED < HEM_RESOLVED <
      STATE_TRANSITIONED


11.  Open Issues

11.1.  Observation Confidence Calibration (OQ-HEM-CONF)

   The confidence thresholds at which Class 7 (HEM_TIER1_OBSERVED)
   fires -- SUSPICIOUS, PROBABLE, EVIDENT -- are defined by the
   applicable CAP-RRS Regulation Record [I-D.sato-soos-cap-rrs].
   The mechanism by which a GEC evaluates an observed evidence
   pattern against a confidence grade is not specified in this
   document.  The pattern evaluation algorithm is implementation-
   defined; the result (a confidence grade) is normative.  This
   open issue is tracked as OQ-HEM-CONF.

11.2.  Pattern-Before-Threshold (OQ-HEM-PATTERN)

   Class 7 fires when an agent observes evidence crossing a
   confidence threshold.  The anticipatory case -- detecting a
   prohibited pattern before any individual observation crosses
   the threshold, by reasoning over a trajectory -- is not yet
   specified.  The OCP pattern_id field provides partial support.
   Deferred to a successor document.  Tracked as OQ-HEM-PATTERN.
   See also OQ-CAP-PATTERN in [I-D.sato-soos-cap-rrs].

11.3.  Cross-Domain HEM_PENDING Propagation (OQ-HEM-XDOMAIN)

   The propagation of HEM_PENDING through delegation chains that
   cross administrative domain boundaries is not fully specified in
   this document.  Within a single GEC trust domain, HEM_PENDING
   propagation is GEC-internal.  The cross-domain case requires a
   federation mechanism.

   The CAEP event stream (see Appendix B.8) is the candidate
   mechanism: a HEM_PENDING event in domain A would generate a
   Security Event Token (SET) [RFC8417] transmitted via SSF
   [RFC9672] to domain B's GEC, which continues the escalation
   chain.  Full specification is deferred to a successor document.
   This open issue is tracked as OQ-HEM-XDOMAIN.


13.  Security Considerations

12.1.  HEM_PENDING as a Denial-of-Service Vector

   The transition prohibition during HEM_PENDING (Section 8.1) means
   that any attacker who can trigger HEM on a governed object can
   prevent state transitions for the duration of the HEM event.
   Implementations MUST rate-limit HEM_AGENT_ESCALATED triggers from
   any single agent session. Implementations SHOULD apply anomaly
   detection to frequent HEM triggers from the same agent.

12.2.  Decision Signature Verification

   Human principal decisions MUST be signature-verified (Section 7.7).
   A kernel that processes unsigned decisions enables an attacker who
   can inject messages into the delivery channel to resolve HEM events
   arbitrarily. The signature requirement over the concatenation of
   hem_id, principal_id, decision, and timestamp prevents replay of
   prior decisions.

12.3.  Designation Chain Confidentiality

   The designation chain in the HEM Escalation Request contains
   personal contact information for human principals. The escalation
   request MUST NOT be accessible to the requesting agent. The kernel
   routes the request; the agent receives only HEM_PENDING_ACTIVE as
   the response to its transition call.

12.4.  TERMINATE Decision Integrity

   The TERMINATE decision (Section 7.4) immediately ends the agent
   session and revokes the mandate JWT. The three-step atomicity
   ordering (Section 7.4) ensures that mandate revocation and
   MISSION_REVOKE_CASCADE initiation are both committed before any
   caller receives HEM_DECISION_ACCEPTED. Implementations MUST enforce
   this ordering guarantee. Race conditions in mandate revocation
   propagation MUST be mitigated by implementing the relying-party
   propagation fence described in [SOOS] Section 10.

12.5.  Timeout Configuration

   AUTO_APPROVE as a timeout disposition (Section 9.2) has significant
   security implications. The Cedar-gating requirement (Section 9.2)
   mitigates the risk of unauthorized approval but does not eliminate
   it. Implementations MUST additionally enforce the hard prohibition
   on AUTO_APPROVE for high-value transition classes at configuration
   load time. Implementations MUST log a configuration warning when
   AUTO_APPROVE is configured for any transition class. Auto-approval
   SHOULD NOT be permitted for governed objects classified as high-risk
   under EU AI Act Annex III.

12.6.  Proximity Threshold Injection

   An attacker with the ability to modify a governed object's proximity
   threshold configuration can trigger HEM at will. Threshold
   configuration MUST be protected by the same access controls as the
   governed object's mandate configuration. Changes to threshold
   configuration MUST be recorded in the Event Log with the identity
   of the principal making the change.

12.7.  Mission Validity Monitoring

   The mission validity monitoring described in Section 8.4 requires
   the kernel to receive reliable signals about MissionDeclaration
   phase changes. Implementations MUST ensure that the channel by
   which mission phase updates reach the kernel is authenticated and
   tamper-evident. An attacker who can inject false SUSPENDED or
   ABANDONED phase signals can trigger spurious session termination.

12.8.  Escalation Request Signing

   The GEC MUST sign the full HEM Escalation Request using Ed25519,
   using the same key model as the Mandate JWT. The signature MUST
   cover the canonical serialization of all fields in the escalation
   request other than kernel_signature itself. The resulting signature
   value is placed in the kernel_signature field (Section 6.1).

   The verification key is available via the operator's JWKS endpoint,
   using the same key discovery mechanism as for Mandate JWT
   verification. Delivery intermediaries that are capable of verifying
   Ed25519 signatures MUST verify the kernel_signature before
   forwarding the escalation request. A delivery intermediary MUST NOT
   forward an escalation request on which signature verification fails.

   Non-normative advisory: delivery channels that cannot perform
   Ed25519 verification (e.g., plain messaging channels without
   cryptographic processing capability) MAY forward without
   verification, but implementations using such channels SHOULD be
   aware that the escalation request integrity guarantee does not
   extend to the final delivery hop. Operators SHOULD prefer delivery
   channels capable of end-to-end verification.


14.  Privacy Considerations

   HEM escalation requests contain information about agent actions,
   governed object state, and agent-declared goals derived from the IDP.
   Implementors MUST ensure that escalation notifications delivered to
   human principals do not contain personally identifiable information
   beyond what is necessary for the principal to make an informed
   decision.

   The idp_summary included in escalation requests (Section 6.1) MUST
   be filtered to remove any PII from the declared_goal.description
   field before delivery. The full IDP text MUST NOT be included in
   the delivery payload.

   Trigger_detail minimisation: The trigger_detail array entries for
   HEM_PROXIMITY_TRIGGERED conditions MUST contain only the following
   fields: threshold_id, threshold_class, condition_met, triggered_at.
   The trigger_detail MUST NOT contain: personal data, Zone B content,
   traveller identity attributes beyond principal_id, raw telemetry
   data, or raw sensor readings. The GEC MUST enforce these
   minimisation requirements at escalation request generation time,
   before the request is constructed. Proximity detail that exceeds
   this enumeration MUST be retained in the kernel Event Log (where
   access is controlled) and MUST NOT be propagated to the escalation
   request.

   Designation chain contact information (principal contact objects)
   MUST be stored and transmitted in compliance with applicable data
   protection regulations. The contact objects MUST NOT be logged in
   plaintext; implementations SHOULD log only principal_id and delivery
   mechanism type in the Event Log.

   The tension between Event Log immutability and data subject erasure
   rights is noted; this document defers to the SOOS Kernel
   Specification [SOOS] cryptographic erasure provisions.


15.  EU AI Act Applicability

   This section provides normative and advisory Article mappings.
   The normative mappings in this section are designed for direct
   reference in EU AI Act conformance documentation. This document
   does not constitute legal advice and makes no representation that
   conforming implementations satisfy any regulatory requirement.

   +--------+---------------------------+---------------------------+----------+
   |Article |Requirement                |HEM Implementation         |Mapping   |
   +--------+---------------------------+---------------------------+----------+
   |Art. 5  |Prohibited AI practices    |CAP Tier 0/1 CEE           |Normative |
   |        |                           |[I-D.sato-soos-cap]        |          |
   +--------+---------------------------+---------------------------+----------+
   |Art. 12 |Automatic logging          |Event Log (Section 10);    |Normative |
   |        |                           |SAR [I-D.sato-soos-gar];   |          |
   |        |                           |IDP pre-action intent      |          |
   |        |                           |[I-D.sato-soos-idp].       |          |
   |        |                           |Event Log retention SHOULD |          |
   |        |                           |be minimum 12 months.      |          |
   |        |                           |Operators may reference    |          |
   |        |                           |this section and           |          |
   |        |                           |[I-D.sato-soos-gar]        |          |
   |        |                           |Section 10 directly in     |          |
   |        |                           |conformance documentation. |          |
   +--------+---------------------------+---------------------------+----------+
   |Art. 13 |Transparency               |PRD rationale_class and    |Advisory  |
   |        |                           |review_date (Section 5.6); |          |
   |        |13(3)(b): AI system        |DRR rationale_class        |          |
   |        |capabilities and limits    |(Section 7.6).             |          |
   |        |13(3)(e): Human oversight  |DRR safety_basis REQUIRED  |          |
   |        |measures                   |for TERMINATE.             |          |
   +--------+---------------------------+---------------------------+----------+
   |Art. 14 |Human oversight            |HEM_PENDING + transition   |Normative |
   |        |                           |prohibition (Section 8);   |          |
   |        |14(1): Effective oversight |Designation chain and      |          |
   |        |by natural persons         |timeout model (Section 9). |          |
   |        |                           |                           |          |
   |        |14(4)(b): Awareness of     |Five decision types        |Normative |
   |        |tendency to over-rely on   |(Section 7); DRR captures  |          |
   |        |output                     |human reasoning.           |          |
   |        |                           |                           |          |
   |        |14(4)(c): Interpret output |idp_summary in Escalation  |Normative |
   |        |correctly                  |Request (Section 6.1);     |          |
   |        |                           |IDP CVR anomaly detection  |          |
   |        |                           |[I-D.sato-soos-idp].       |          |
   |        |                           |                           |          |
   |        |14(4)(d): Decide not to    |HEM_PENDING transition     |Normative |
   |        |use output in any          |prohibition (Section 8.1); |          |
   |        |particular situation       |TERMINATE decision type    |          |
   |        |                           |(Section 7.4).             |          |
   +--------+---------------------------+---------------------------+----------+

   Note on Article 14(4)(d): This provision requires that human
   oversight persons be able to decide not to use the AI system output
   in any particular situation and not to be unduly influenced by it.
   The HEM_PENDING transition prohibition (Section 8.1) implements
   the technical stop capability; TERMINATE (Section 7.4) implements
   the irrevocable session closure. Both are GEC-enforced and
   non-bypassable by agent or application.


16.  IANA Considerations

   This document requests the creation of the following IANA registry:

   Registry Name:
      Human Escalation Mechanism Trigger Classes

   Registration Procedure:
      Standards Action [RFC8126]

   Initial Values:

   +--------------------------------+----------------------------------+
   | Trigger Class                  | Description                      |
   +--------------------------------+----------------------------------+
   | HEM_CEDAR_ROUTED               | Cedar policy routes to HEM       |
   | HEM_AGENT_ESCALATED            | Agent declares hem_urgency:      |
   |                                | REQUIRED in IDP                  |
   | HEM_PROXIMITY_TRIGGERED        | Proximity threshold crossed      |
   | HEM_MISSION_VALIDITY_FAILED    | MissionDeclaration in terminal   |
   |                                | phase; active session detected   |
   | HEM_JURISDICTIONAL_CONFLICT    | Kernel cannot resolve cross-     |
   |                                | jurisdiction legal conflict      |
   +--------------------------------+----------------------------------+

   This document requests the creation of the following IANA registry:

   Registry Name:
      Human Escalation Mechanism Decision Types

   Registration Procedure:
      Standards Action [RFC8126]

   Initial Values:

   +-------------------------------+---------------------------------+
   | Decision Type                 | Description                     |
   +-------------------------------+---------------------------------+
   | APPROVE                       | Approve requested action        |
   | APPROVE_WITH_CONSTRAINTS      | Approve with Cedar context      |
   |                               | additions                       |
   | REDIRECT                      | Approve alternative action      |
   | TERMINATE                     | Terminate agent session         |
   | DEFER                         | Extend timeout; defer decision  |
   | APPROVE_WITH_LEGAL_BASIS      | Reserved; not yet operational.  |
   |                               | Kernel returns                  |
   |                               | HEM_DECISION_TYPE_NOT_YET_      |
   |                               | OPERATIONAL if submitted.       |
   +-------------------------------+---------------------------------+

   This document requests the creation of the following IANA registry:

   Registry Name:
      Human Escalation Mechanism Timeout Dispositions

   Registration Procedure:
      Specification Required [RFC8126]

   Initial Values:

   +-------------------+--------------------------------------------+
   | Disposition       | Description                                |
   +-------------------+--------------------------------------------+
   | ESCALATE_CHAIN    | Escalate to next principal in chain        |
   | SUSPEND           | Suspend governed object; await recovery    |
   | TERMINATE_SESSION | Apply TERMINATE decision semantics         |
   | AUTO_APPROVE      | Cedar-gated approve; restricted use        |
   |                   | (see Section 9.2)                          |
   +-------------------+--------------------------------------------+

   This document requests the creation of the following IANA registry:

   Registry Name:
      Human Escalation Mechanism Error Codes

   Registration Procedure:
      Specification Required [RFC8126]

   Initial Values:

   +-------------------------------------+-----------------------------+
   | Error Code                          | Description                 |
   +-------------------------------------+-----------------------------+
   | HEM_PENDING_ACTIVE                  | Transition rejected; HEM    |
   |                                     | active                      |
   | HEM_DECISION_INVALID                | Unrecognized decision type  |
   | HEM_SIGNATURE_INVALID               | Decision signature failed   |
   | HEM_PRINCIPAL_NOT_AUTHORIZED        | Submitter not in chain      |
   | HEM_DEFER_LIMIT_EXCEEDED            | Second DEFER from same      |
   |                                     | principal on same hem_id    |
   | HEM_DECISION_REJECTED               | Decision rejected; generic  |
   | HEM_MISSION_INVALID                 | Session terminated; mission |
   |                                     | entered terminal phase      |
   | HEM_PRD_MISSING                     | Cedar policy routes to HEM  |
   |                                     | but lacks registered prd_id |
   | HEM_CONSTRAINT_EXPIRED              | APPROVE_WITH_CONSTRAINTS    |
   |                                     | expiry window closed        |
   | HEM_REDIRECT_DENIED                 | Cedar DENY on REDIRECT      |
   |                                     | action                      |
   | HEM_MISSION_REF_MISMATCH_REJECTED   | IDP mission_ref does not    |
   |                                     | match session               |
   | HEM_DRR_REQUIRED                    | TERMINATE submitted without |
   |                                     | required DRR                |
   | HEM_AUTO_APPROVE_CEDAR_DENIED       | AUTO_APPROVE not applied;   |
   |                                     | Cedar returned DENY         |
   | HEM_AUTO_APPROVE_PROHIBITED         | AUTO_APPROVE configured for |
   |                                     | high-value transition class |
   | HEM_DECISION_TYPE_NOT_YET_          | Decision type reserved;     |
   | OPERATIONAL                         | not yet operational         |
   +-------------------------------------+-----------------------------+

   This document requests the creation of the following IANA registry:

   Registry Name:
      Human Escalation Mechanism PRD Rationale Classes

   Registration Procedure:
      Specification Required [RFC8126]

   Initial Values:

   +----------------------+--------------------------------------------+
   | Rationale Class      | Description                                |
   +----------------------+--------------------------------------------+
   | REGULATORY           | Required by applicable regulation          |
   | CONTRACTUAL          | Required by contract or agreement          |
   | OPERATIONAL_RISK     | Operational risk threshold requires        |
   |                      | human judgment                             |
   | SAFETY               | Safety requirement mandates oversight      |
   | LEGAL                | Legal requirement (non-regulatory)         |
   | POLICY               | Internal organizational policy             |
   +----------------------+--------------------------------------------+

   This document requests the creation of the following IANA registry:

   Registry Name:
      Human Escalation Mechanism DRR Rationale Classes

   Registration Procedure:
      Specification Required [RFC8126]

   Initial Values:

   +---------------------------+-----------------------------------------+
   | Rationale Class           | Description                             |
   +---------------------------+-----------------------------------------+
   | REGULATORY_COMPLIANCE     | Decision based on regulatory            |
   |                           | requirement                             |
   | SAFETY_ASSESSMENT         | Decision based on safety evaluation     |
   | MISSION_ALIGNMENT         | Decision based on mission scope         |
   |                           | assessment                              |
   | OPERATIONAL_JUDGMENT      | Decision based on operational           |
   |                           | expertise                               |
   | CONTRACTUAL_OBLIGATION    | Decision required by contract           |
   | ETHICAL_CONSIDERATION     | Decision based on ethical assessment    |
   | INSUFFICIENT_CONTEXT      | Insufficient information to approve     |
   | ESCALATION_JUDGMENT       | Decision reflects human escalation      |
   |                           | evaluation                              |
   +---------------------------+-----------------------------------------+

   This document requests the creation of the following IANA registry:

   Registry Name:
      Human Escalation Mechanism Denial Reason Classes

   Registration Procedure:
      Specification Required [RFC8126]

   Initial Values:

   +---------------------------+-----------------------------------------+
   | Denial Reason             | Description                             |
   +---------------------------+-----------------------------------------+
   | CEDAR_POLICY_DENY         | Cedar evaluation returned DENY          |
   | MANDATE_SCOPE_EXCEEDED    | Action outside mandate scope            |
   | HEM_PENDING_ACTIVE        | HEM is active for this session          |
   | MISSION_REF_MISMATCH      | IDP mission_ref does not match          |
   |                           | session MissionDeclaration              |
   | CAP_PROHIBITION           | CAP Tier 0 or Tier 1 prohibition        |
   |                           | applies                                 |
   | PRINCIPAL_NOT_AUTHORIZED  | Principal not in designation chain      |
   +---------------------------+-----------------------------------------+


17.  References

16.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/rfc/rfc2119>.

   [RFC7519]  Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token
              (JWT)", RFC 7519, DOI 10.17487/RFC7519, May 2015,
              <https://www.rfc-editor.org/rfc/rfc7519>.

   [RFC8126]  Cotton, M., Leiba, B., and T. Narten, "Guidelines for
              Writing an IANA Considerations Section in RFCs", BCP 26,
              RFC 8126, DOI 10.17487/RFC8126, June 2017,
              <https://www.rfc-editor.org/rfc/rfc8126>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in
              RFC 2119 Key Words", BCP 14, RFC 8174,
              DOI 10.17487/RFC8174, May 2017,
              <https://www.rfc-editor.org/rfc/rfc8174>.

   [Cedar]    Amazon Web Services, "Cedar Policy Language",
              <https://www.cedarpolicy.com/>.

   [I-D.sato-soos-idp]
              Sato, T., "The Intent Declaration Primitive (IDP) for
              Agentic AI Systems", Work in Progress, Internet-Draft,
              draft-sato-soos-idp-03, May 2026,
              <https://datatracker.ietf.org/doc/draft-sato-soos-idp/>.

   [I-D.sato-soos-gar]
              Sato, T., "The Governance Audit Record (GAR) for
              Agentic AI Systems", Work in Progress, Internet-Draft,
              draft-sato-soos-gar-01, May 2026,
              <https://datatracker.ietf.org/doc/draft-sato-soos-gar/>.

   [I-D.sato-soos-cap]
              Sato, T., "The Constitutional AI Protocol (CAP) for
              Agentic AI Systems", Work in Progress, Internet-Draft,
              draft-sato-soos-cap-01, May 2026,
              <https://datatracker.ietf.org/doc/draft-sato-soos-cap/>.

16.2.  Informative References

   [EUAIA]    European Union, "Regulation (EU) 2024/1689 of the European
              Parliament and of the Council laying down harmonised rules
              on artificial intelligence (Artificial Intelligence Act)",
              Official Journal of the European Union, 12 July 2024,
              <https://eur-lex.europa.eu/legal-content/EN/TXT/
              ?uri=OJ:L_202401689>.

   [I-D.ietf-wimse-arch]
              Salowey, J., Rosomakho, Y., and H. Tschofenig, "Workload
              Identity in a Multi System Environment (WIMSE)
              Architecture", Work in Progress, Internet-Draft,
              draft-ietf-wimse-arch-07, March 2026,
              <https://datatracker.ietf.org/doc/draft-ietf-wimse-arch/>.

   [I-D.klrc-aiagent-auth]
              Kasselman, P., Lombardo, J., Rosomakho, Y., Campbell, B.,
              and N. Steele, "AI Agent Authentication and Authorization",
              Work in Progress, Internet-Draft,
              draft-klrc-aiagent-auth-01, March 2026,
              <https://datatracker.ietf.org/doc/draft-klrc-aiagent-auth/>.

   [I-D.rosenberg-aiproto-cheq]
              Rosenberg, J., White, P., and C. Jennings, "CHEQ: A
              Protocol for Confirmation of AI Agent Decisions with Human
              in the Loop (HITL)", Work in Progress, Internet-Draft,
              draft-rosenberg-aiproto-cheq-00, October 2025,
              <https://datatracker.ietf.org/doc/
              draft-rosenberg-aiproto-cheq/>.

   [SOOS]     Sato, T., "Sovereign Object OS -- Kernel Specification",
              Work in Progress, Version 2, May 2026,
              <https://activitytravel.pro/>.

   [I-D.sato-soos-transition-graph]
              Sato, T., "Transition Graph API for Agentic AI Systems",
              Work in Progress, Internet-Draft,
              draft-sato-soos-transition-graph-00, 2026 (forthcoming).

   [I-D.sato-jones-soos-mandate]
              Sato, T. and Jones, M., "Mandate JWT Profile for Agentic
              AI Systems", Work in Progress, Internet-Draft,
              draft-sato-jones-soos-mandate-00, 2026 (forthcoming).

   [I-D.mcguinness-oauth-actor-profile]
              McGuinness, K., "OAuth Actor Profile for AI Agents",
              Work in Progress, Internet-Draft,
              draft-mcguinness-oauth-actor-profile-00, 2026,
              <https://datatracker.ietf.org/doc/
              draft-mcguinness-oauth-actor-profile/>.

   [I-D.mcguinness-oauth-mission-bound-authorization]
              McGuinness, K., "Mission Bound Authorization",
              Work in Progress, Internet-Draft,
              draft-mcguinness-oauth-mission-bound-authorization-00,
              2026,
              <https://datatracker.ietf.org/doc/
              draft-mcguinness-oauth-mission-bound-authorization/>.


Appendix B.  Related Work

   This appendix describes the relationship between HEM and other
   IETF and related specifications.

B.1.  ACP Working Group (Agent Communication Protocol)

   ACP is developing a protocol for agent-to-agent communication.
   ACP explicitly defers per-operation confirmation, governance-state
   management, and human oversight mechanisms as out of scope.

   Relationship: Composition.  ACP is the channel; HEM governs what
   happens when a channel-mediated action requires human judgment.

   Integration: GEC implementations supporting ACP-mediated
   communication SHOULD expose HEM_PENDING as an observable session
   state, enabling remote orchestrators to detect pending oversight
   conditions and pause dependent workflows.

B.2.  ICON Initiative: Observability, Intervention and Control

   The ICON initiative [ICON-PS] addresses Observability,
   Intervention, and Control requirements for autonomous agents in
   network management contexts.

   Relationship: Composition.  HEM addresses ICON's Intervention
   pillar directly.  The five HEM trigger classes correspond to the
   primary intervention scenarios in the ICON problem statement.
   HEM_PENDING provides the formal session state model ICON requires.
   The ICON Observability pillar is addressed by [I-D.sato-soos-pt].
   The ICON Control pillar is addressed by [I-D.sato-soos-mad].

   Integration: ICON-conforming implementations SHOULD reference HEM
   as the normative specification for the ICON Intervention pillar.
   HEM Class 1 and Class 2 trigger classes cover the automated
   intervention scenarios; Class 3 covers continuous monitoring
   triggers.

B.3.  CHEQ (draft-rosenberg-aiproto-cheq)

   CHEQ defines an application-layer protocol for agent-initiated
   human confirmation requests.  CHEQ is optional and agent-driven.

   Relationship: Composition.  CHEQ MAY serve as the delivery
   mechanism for HEM escalation requests.  HEM_PENDING is GEC-
   enforced; CHEQ confirmation is agent-elected.

   Integration: CHEQ-compatible delivery channels used for HEM
   MUST satisfy Section 6.3 delivery requirements.

B.4.  OAuth Interactive Consent and Mission Bound Authorization

   OAuth interactive consent [RFC6749] is the closest existing
   analog to HEM.  HEM extends it to N-deep delegation chains,
   adds a formal session state contract (Section 8), and defines
   five distinct decision types with normative GEC semantics.

   Integration: GEC implementations in OAuth environments SHOULD
   implement HEM_PENDING as authorization server events.  DRRs
   SHOULD be stored in the authorization audit record.

B.5.  WIMSE (Workload Identity in Multi-System Environments)

   WIMSE [I-D.ietf-wimse-arch] defines workload identity in multi-
   system environments.  WIMSE provides the identity substrate that
   HEM's designation chain depends on.

   Integration: GEC implementations SHOULD use WIMSE workload
   credentials as the agent identity anchor for HEM session
   identification.  Human principal identifiers SHOULD be
   resolvable against a WIMSE-compatible Party Registry entry.

B.6.  AUDIT Working Group

   The AUDIT WG [AUDIT-BOF] is developing interoperable mechanisms
   for auditing AI agents.  HEM generates two candidate AUDIT WG
   interaction record types: the HEM Escalation Request (pre-
   decision) and the Decision Rationale Record (post-decision).

   Integration: AUDIT WG formats SHOULD define a HEM escalation
   record entry type carrying hem_id, trigger_class,
   policy_rationale_id, and idp_summary fields.  DRRs SHOULD be
   expressible as AUDIT WG audit records with decision_type and
   rationale_class as typed semantic fields.

B.7.  MAD: Multi-Agent Delegation (draft-sato-soos-mad)

   MAD specifies authority delegation chains for multi-agent
   workflows.  HEM and MAD address inverse flows: MAD governs
   authority propagating downward; HEM governs oversight
   requirements propagating upward through the same chain.

   Integration: GEC implementations MUST surface HEM_PENDING
   notifications to the orchestrator agent in the MAD delegation
   chain for HEM_CEDAR_ROUTED and HEM_AGENT_ESCALATED triggers.

B.8.  CAEP and Shared Signals Framework

   CAEP [CAEP] and SSF [RFC9672] define cross-domain security event
   transmission.  Cross-domain HEM_PENDING propagation -- where an
   escalation must traverse an administrative boundary -- is an open
   question (Section 11.1).  CAEP event streams are the candidate
   mechanism.

   Integration: Implementors requiring cross-domain propagation
   SHOULD evaluate CAEP as the signaling mechanism.  Full
   specification is deferred to a successor document.


   [ICON-PS]  Nair, et al., "Observability, Intervention and Control
              of Network Management Agents -- Problem Statement",
              Work in Progress, Internet-Draft,
              draft-nair-icon-problem-statement, 2026 (not yet
              submitted).

   [AUDIT-BOF] Kuehlewind, M. and Birkholz, H., "Agent Use of
              Delegation and Interaction Traceability (AUDIT)",
              Work in Progress, Internet-Draft,
              draft-kuehlewind-audit-architecture-00, May 2026.

   [CAEP]     Cappalli, T. and Tschofenig, H., "OpenID Continuous
              Access Evaluation Profile 1.0", OpenID Foundation,
              2022.

   [RFC9672]  Backman, A., et al., "Shared Signals: A Secure
              Webhooks Framework", RFC 9672, November 2024.

   [RFC8417]  Hunt, P., et al., "Security Event Token (SET)",
              RFC 8417, July 2018.

   [I-D.sato-soos-cap-rrs]
              Sato, T., "Constitutional AI Protocol --
              Regulation Record Specification (CAP-RRS)",
              Work in Progress, Internet-Draft,
              draft-sato-soos-cap-rrs-00, May 2026,
              <https://datatracker.ietf.org/doc/
              draft-sato-soos-cap-rrs/>.

   [I-D.sato-soos-mad]
              Sato, T., "Multi-Agent Delegation (MAD)",
              Work in Progress, Internet-Draft,
              draft-sato-soos-mad-01, May 2026,
              <https://datatracker.ietf.org/doc/draft-sato-soos-mad/>.

   [BSA]      United States Congress, "Bank Secrecy Act",
              31 U.S.C. 5318(g), 1970.

   [I-D.sato-soos-pt]
              Sato, T., "Progressive Trust for Agentic AI Governance
              Systems", Work in Progress, Internet-Draft,
              draft-sato-soos-pt-01, May 2026.


Acknowledgments

   The HEM design builds on the OVID mandate model and the Clawdrey
   Hepburn delegation framework developed by the OVID community, from
   which the five decision type vocabulary was adapted. The EU AI Act
   Article 14 analysis was developed in the context of the Sovereign
   Object OS specification [SOOS]. The CHEQ complementarity framing
   draws on review of [I-D.rosenberg-aiproto-cheq]. The designation
   chain and timeout model reflects operational experience with the
   TRAVELER_UNREACHABLE chains defined in the ATP booking lifecycle.
   Section 8.4 (Mission Validity During HEM_PENDING) and the Class 4
   trigger class (Section 5.4) were developed in prior versions.
   Classes 6 through 9 (HEM_TIER0_OBSERVED, HEM_TIER1_OBSERVED,
   HEM_TIER3_ANTICIPATORY, HEM_TIER3_OBSERVED) and the Observation
   Context Package (Section 6.3) and Execution Options Package
   (Section 6.4) were added in this version following architectural
   development in the SOOS KernelSpec V3 sessions of May 2026.
   The Natural Breakpoint Declaration concept originated in those
   sessions.  Class 4 trigger class (Section 5.4) was developed
   following review of the McGuinness Mission Bound
   Authorization framework
   [I-D.mcguinness-oauth-mission-bound-authorization] and the mission
   governance model described in McGuinness (2026). The AAuth vs. HEM
   positioning statement in Section 1 was clarified following that
   review.

   The Windley Loop -- the kernel-mediated cycle of context delivery,
   agent intent declaration, and Cedar enforcement before action
   execution -- is named in recognition of Phil Windley's work on
   context and the Internet of My Things. The loop appears normatively
   in Section 5.1 and Section 11. The Policy Rationale Declaration
   (PRD, Section 5.6) and Decision Rationale Record (DRR, Section 7.6)
   were added in this version following completion of the full 29-item
   hem-01 agenda (S19, May 2026). The escalation request signing
   requirement (Section 12.8) reflects security review of delivery
   channel integrity properties.


Author's Address

   Tom Sato
   MyAuberge K.K.
   Chino, Nagano, Japan
   Email: [tomsato@myauberge.jp]
   URI:   https://activitytravel.pro/
