



DMSC Working Group                                                J. Liu
Internet-Draft                                                     K. Yu
Intended status: Informational                                     K. Li
Expires: 2 August 2026                                           K. Chen
                      Beijing University of Posts and Telecommunications
                                                         29 January 2026


   Agent Collaboration Protocols Architecture for Internet of Agents
                       draft-liu-dmsc-acps-arc-03

Abstract

   Internet of Agents (IoA) aims to facilitate interconnection and
   collaboration among heterogeneous agents to address complex tasks and
   support diverse applications.

   This IETF draft proposes the Agent Collaboration Protocols (ACPs)
   architecture, which includes conceptual domains, functional
   components and reference interfaces, to achieve agent interconnection
   and collaboration.  ACPs cover all stages of agents in the network,
   from their access to collaboration, supporting agent trusted
   registration, agent identity authentication, agent discovery, agent
   interaction, tool invocation, and agent monitoring.  The long-term
   vision of ACPs is to support the future large-scale interconnected
   agents and construct the key infrastructure for IoA.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on 2 August 2026.

Copyright Notice

   Copyright (c) 2026 IETF Trust and the persons identified as the
   document authors.  All rights reserved.



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   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents (https://trustee.ietf.org/
   license-info) in effect on the date of publication of this document.
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.  Code Components
   extracted from this document must include Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Conventions . . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   4
   4.  ACPs Architecture from Functional Perspective . . . . . . . .   5
     4.1.  ACPs Architecture Overview  . . . . . . . . . . . . . . .   5
     4.2.  Conceptual Domains  . . . . . . . . . . . . . . . . . . .   6
       4.2.1.  User Domain . . . . . . . . . . . . . . . . . . . . .   6
       4.2.2.  Agent Domain  . . . . . . . . . . . . . . . . . . . .   6
       4.2.3.  Identity Management Domain  . . . . . . . . . . . . .   6
       4.2.4.  Interconnection Service Domain  . . . . . . . . . . .   7
       4.2.5.  Resource Access Domain  . . . . . . . . . . . . . . .   7
     4.3.  Functional Components . . . . . . . . . . . . . . . . . .   7
       4.3.1.  Functional Components in the Agent Domain . . . . . .   8
       4.3.2.  Functional Components in the Identity Management
               Domain  . . . . . . . . . . . . . . . . . . . . . . .   9
       4.3.3.  Functional Components in the Interconnection Service
               Domain  . . . . . . . . . . . . . . . . . . . . . . .  10
       4.3.4.  Functional Components in the Resource Access
               Domain  . . . . . . . . . . . . . . . . . . . . . . .  10
     4.4.  Reference Interfaces  . . . . . . . . . . . . . . . . . .  11
       4.4.1.  Core Interfaces . . . . . . . . . . . . . . . . . . .  11
       4.4.2.  Interface Semantics . . . . . . . . . . . . . . . . .  12
   5.  Typical Operational Scenarios . . . . . . . . . . . . . . . .  13
     5.1.  Agent Onboarding: Identity, Credential, and Capability
           Description . . . . . . . . . . . . . . . . . . . . . . .  13
     5.2.  Agent Discovery and Partner Selection . . . . . . . . . .  13
     5.3.  Agent Interaction with Point-to-point and Grouping
           Mode  . . . . . . . . . . . . . . . . . . . . . . . . . .  14
     5.4.  Tool Invocation . . . . . . . . . . . . . . . . . . . . .  14
     5.5.  Agent Monitoring  . . . . . . . . . . . . . . . . . . . .  14
   6.  Conclusions . . . . . . . . . . . . . . . . . . . . . . . . .  15
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  15
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  15
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  15
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  15
     9.2.  Informative References  . . . . . . . . . . . . . . . . .  15
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  16



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1.  Introduction

   With the rapid development of artificial intelligence (AI),
   particularly large language model (LLM) technology, the number of AI
   agents has grown dramatically.  With the capability of autonomous
   perception, decision-making, and execution, agents' applications are
   becoming increasingly widespread.

   To overcome the limitations of single-agent systems, and to break
   free from the constraints of proprietary multi-agent frameworks
   developed by various vendors, the Internet of Agents (IoA) has
   emerged.  IoA aims to enable seamless connectivity and efficient
   collaboration among agents, through standardized communication
   protocols and interfaces.

   This draft proposes the functional architecture of Agent
   Collaboration Protocols (ACPs) [ACPs-Github], which is designed for
   IoA to enable wide-area connectivity, cross-domain interoperability,
   and secure collaboration among heterogeneous agents.  The main
   characteristics of ACPs are as follows:

   *  Multi-centralized architecture, which consists of multiple
      autonomous domains, each domain containing its own management
      nodes (such as registration, authentication, and discovery
      functions), to support efficient, reliable, and manageable large-
      scale agent interconnection scenarios.

   *  Standardized communication mechanisms with peer-to-peer and
      grouping mode, allowing agents to self-organize and negotiate
      autonomously, to facilitate rapid and accurate information
      exchange, as well as efficient task Collaboration.

   *  Robust registration and authentication mechanisms, to ensure the
      trusted access of agents and prevent unauthorized access and data
      breaches.

   *  Reliable registration and management of agent capability, along
      with intra-domain and cross-domain discovery based on capability
      matching, to support universal and efficient discovery of
      collaborative agents.

   *  Real-time monitoring of agent status and behavior, to support more
      complex application requirements such as agent auditing and
      transactions.

   ACPs cover all stages of agents in the IoA, from their access to
   collaboration, to construct the key infrastructure for agent
   communication, task collaboration and resource allocation.



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2.  Conventions

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].

3.  Terminology

   Agent: An agent is a software or hardware entity with autonomous
   decision-making and execution capabilities, capable of perceiving the
   environment, acquiring contextual information, reasoning, and
   learning.  Agent can perform tasks independently or collaboratively
   with other agents.  Each agent is created by a specific agent
   provider and needs to complete processes such as registration and
   authentication before providing services to obtain a legitimate
   identity and relevant credentials.

   Agent Identity Code (AIC): AIC is a certifiable, globally unique
   identity that represents the identity of an agent.  AIC MAY contain
   the following information: the registration service center, the agent
   provider, the serial number of agent entity and instance, and the
   check code.

   Agent Capability Specification (ACS): ACS is a detailed description
   of an agent's capabilities and information that can be saved and
   retrieved.  ACS MAY use the JSON [RFC8259] format, typically
   including the following information: AIC, the functional capabilities
   of agent, the technical characteristics, and the service interfaces.

   Agent Credential: Agent Credential is a tamper-resistant data object
   issued by a credential authority (e.g., certificate, token) , used by
   an agent to prove identity attributes and/or authorization to a
   relying party.

   Tool: A tool is a device, software component, or service that
   provides a specific function and can be accessed and used by an
   agent.

   Agent Autonomous Domain: Agent Autonomous Domain is an administrative
   and governance domain organized and managed by a specific IoA service
   provider.  It MAY include service functions such as identity
   management, credential management, capability description management,
   agent discovery, message distribution, and agent monitoring.








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4.  ACPs Architecture from Functional Perspective

   This section defines a functional architecture for agent autonomous
   domain in IoA.  The interconnection environment is divided into
   different conceptual domains.  Each conceptual domain includes
   several functional components, and there are different interfaces
   between functional components.

4.1.  ACPs Architecture Overview

   The overall functional architecture of ACPs is as follows.

   +--------------------------+        +--------------------------+
   | Identity Management      |        | Interconnection Service  |
   | Domain                   |        | Domain                   |
   |                          |        |                          |
   |   +-------+  +-------+   |--------|   +-------+  +-------+   |
   |   | AIMgF |  | CMgF  |   |        |   | ADMgF |  |  ADF  |   |
   |   +-------+  +-------+   |        |   +-------+  +-------+   |
   |   +-------+              |        |   +-------+  +-------+   |
   |   |  IVF  |              |        |   |  MDF  |  | DTMgF |   |
   |   +-------+              |        |   +-------+  +-------+   |
   +-------------+------------+        +-------------+------------+
                 |                                   |
                 |                                   |
                 |                                   |
   +-------------+-----------------------------------+------------+
   |                         Agent Domain                         |
   |                                                              |
   |     +------+ +------+ +------+ +------+ +------+ +------+    |
   |     | AIMF | | ADMF | | IAF  | | AIF  | | TAF  | | AMF  |    |
   |     +------+ +------+ +------+ +------+ +------+ +------+    |
   +-------------+-----------------------------------+------------+
                 |                                   |
                 |                                   |
                 |                                   |
   +-------------+------------+        +-------------+------------+
   | Resource Access Domain   |        |        User Domain       |
   |                          |        |                          |
   |         +------+         |        |                          |
   |         | TSF  |         |        |                          |
   |         +------+         |        |                          |
   +--------------------------+        +--------------------------+

                   Figure 1: ACPs functional architecture

   The agent interconnection environment is organized into five
   conceptual domains:



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   1.  User Domain

   2.  Agent Domain

   3.  Identity Management Domain

   4.  Interconnection Service Domain

   5.  Resource Access Domain

   The lines between conceptual domains represent information exchange
   relationships.

   Domains are not necessarily physical network segments; they represent
   responsibility and governance boundaries.  A deployment MAY collapse
   multiple domains into one system, or MAY distribute them across
   multiple organizations.

4.2.  Conceptual Domains

4.2.1.  User Domain

   The User Domain is the set of users and user environments that
   initiate tasks and consume final results.  A user MAY be a person or
   an organization.

4.2.2.  Agent Domain

   The Agent Domain contains agents and agent-side functions required
   for agent interconnection and collaboration, such as agent
   description, agent interaction, agent identity maintenance,
   interconnection authentication, and tool access.

   The agent is the core execution unit of agent interconnection and
   collaboration.  An agent is typically provided and operated by an
   agent provider.  Agents in this domain MUST be able to present
   identity and comply with authentication / authorization decisions
   when interacting with other domains.

4.2.3.  Identity Management Domain

   The Identity Management Domain contains functions for identity
   lifecycle management, credential lifecycle management, and identity
   verification.  It provides services for registering agents, issuing
   credentials, and verifying identity claims during interconnection.






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4.2.4.  Interconnection Service Domain

   The Interconnection Service Domain contains functions that enable
   agents to find and collaborate with each other, including agent
   capability description management, agent discovery, and message
   distribution for group interactions.

4.2.5.  Resource Access Domain

   The Resource Access Domain contains tool and resource service
   functions that agents can invoke, such as tool registries, tool
   execution services, data services, and other external resources.

4.3.  Functional Components

   The functional components are grouped by conceptual domains.  The
   list below is a quick index.  The detailed descriptions are provided
   in Table 1.

   User Domain
     - User

   Agent Domain
     - Agent
     - Agent Identity Maintenance Function (AIMF)
     - Agent Description Maintenance Function (ADMF)
     - Interconnection Authentication Function (IAF)
     - Agent Interaction Function (AIF)
     - Tool Access Function (TAF)
     - Agent Monitoring Function (AMF)

   Identity Management Domain
     - Agent Identity Management Function (AIMgF)
     - Credential Management Function (CMgF)
     - Identity Verification Function (IVF)

   Interconnection Service Domain
     - Agent Description Management Function (ADMgF)
     - Agent Discovery Function (ADF)
     - Message Distribution Function (MDF)
     - Domain Trust Management Function (DTMgF)

   Resource Access Domain
     - Tool Service Function (TSF)

         Figure 2: Functional component index by conceptual domain
                               (informative)




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      +=================+=============+=============================+
      | Conceptual      | Functional  | Function Description        |
      | Domain          | Components  |                             |
      +=================+=============+=============================+
      | User Domain     | User        | Initiate tasks; provide     |
      |                 |             | authorization and policy    |
      |                 |             | input; consume results.     |
      +-----------------+-------------+-----------------------------+
      | Agent Domain    | Agent,      | Execute tasks; maintain     |
      |                 | AIMF, ADMF, | local identity and          |
      |                 | IAF, AIF,   | capability description;     |
      |                 | TAF, AMF    | interact with other agents; |
      |                 |             | access tools; record logs.  |
      +-----------------+-------------+-----------------------------+
      | Identity        | AIMgF,      | Manage identity and         |
      | Management      | CMgF, IVF   | credential lifecycle;       |
      | Domain          |             | verify identity claims and  |
      |                 |             | credential status.          |
      +-----------------+-------------+-----------------------------+
      | Interconnection | ADMgF, ADF, | Manage/publish capability   |
      | Service Domain  | MDF, DTMgF  | descriptions; enable        |
      |                 |             | discovery; support group    |
      |                 |             | messaging and domain        |
      |                 |             | federation policies.        |
      +-----------------+-------------+-----------------------------+
      | Resource Access | TSF         | Expose and control access   |
      | Domain          |             | to tools/resources; obtain  |
      |                 |             | results.                    |
      +-----------------+-------------+-----------------------------+

                   Table 1: Functional components summary

   The functional boundaries defined here are intended to support
   interoperability and clear interface definition.  A deployment MAY
   realize a functional component as software, hardware, or a managed
   service, and MAY consolidate multiple functional components into one
   product.

4.3.1.  Functional Components in the Agent Domain

   *1.  Agent Identity Maintenance Function (AIMF)*

   AIMF maintains the agent's identity information (e.g., AIC) and
   credentials.  AIMF SHOULD support secure storage and update of
   identity.

   *2.  Agent Description Maintenance Function (ADMF)*




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   ADMF maintains agent capability description information (e.g., ACS)
   used for interconnection.  It supports creating, updating, and
   withdrawing descriptions.  ADMF SHOULD ensure that descriptions
   remain consistent with the agent's current identity and capability
   state.

   *3.  Interconnection Authentication Function (IAF)*

   IAF performs authentication and authorization checks for
   interconnection, including mutual verification of peer agents and
   validation of presented credentials.  IAF SHOULD support multiple
   authentication mechanisms.  Deployments are RECOMMENDED to use
   standardized security protocols such as TLS 1.3 [RFC8446] and mutual
   authentication where appropriate.

   *4.  Agent Interaction Function (AIF)*

   AIF provides standardized interaction semantics for agent-to-agent
   communication.  It is responsible for session establishment, message
   exchange, task/context management, and applying security
   requirements.  AIF SHOULD support at least one of point-to-point and
   grouping interaction patterns between agents.

   *5.  Tool Access Function (TAF)*

   TAF provides the agent-side capability to invoke tools and resources
   in the Resource Access Domain.  It supports discovering available
   tools, invoking a selected tool, handling tool results, and enforcing
   access control decisions.

   *6.  Agent Monitoring Function (AMF)*

   AMF exports monitoring and logging data produced by the agent and
   agent-side functions.  It SHOULD support integrity protection and
   privacy controls.

4.3.2.  Functional Components in the Identity Management Domain

   *1.  Agent Identity Management Function (AIMgF)*

   AIMgF performs identity lifecycle management for agents, including
   allocation, update, and de-registration of AICs.  AIMgF MUST define
   the policies for uniqueness and governance of issued AICs within its
   scope.

   *2.  Credential Management Function (CMgF)*





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   CMgF issues and manages Agent Credentials associated with AICs.  CMgF
   SHOULD support credential issuance, renewal, suspension, revocation,
   and status query.

   *3.  Identity Verification Function (IVF)*

   IVF verifies identity claims and credential validity for relying
   parties.  IVF MAY be offered by the same operator as CMgF or by an
   independent third party.  IVF SHOULD support validation of credential
   authenticity, validity period, and status (e.g., revoked/suspended).

4.3.3.  Functional Components in the Interconnection Service Domain

   *1.  Agent Description Management Function (ADMgF)*

   ADMgF manages the lifecycle of agent capability descriptions in the
   interconnection ecosystem.  It supports accepting capability
   description submissions, validating required fields, reviewing and
   approving publication policies, publishing descriptions, and de-
   listing descriptions.

   *2.  Agent Discovery Function (ADF)*

   ADF enables capability-based discovery of candidate partner agents.
   It receives discovery queries, matches them against available agent
   descriptions, and returns a candidate set.  ADF SHOULD support in-
   domain discovery; and cross-domain discovery is OPTIONAL, within a
   configured trust scope.

   *3.  Message Distribution Function (MDF)*

   MDF provides message distribution services for group interactions,
   such as publish/subscribe or queue-based delivery.  MDF is typically
   used when agents interact in grouping mode.

   *4.  Domain Trust Management Function (DTMgF)*

   DTMgF maintains trust relationships between autonomous domains (e.g.,
   trusted peer domain lists, federation policy).  If present, it
   constrains cross-domain discovery and service-to-service
   interactions.

4.3.4.  Functional Components in the Resource Access Domain

   *1.  Tool Service Function (TSF)*






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   TSF provides access to tools and resources for agents.  TSF SHOULD
   support tool registration or exposure, tool invocation handling,
   result return, and access control enforcement.  TSF MAY represent a
   single tool, a tool gateway, or a tool execution environment.

4.4.  Reference Interfaces

   The reference interfaces between functional components are identified
   as ACP-IF-XX.  An ACP-IF interface definition specifies what
   information is exchanged and what behavior is expected.  It does not
   mandate a specific protocol.

4.4.1.  Core Interfaces

       +===========+==========+==========+=========================+
       | Interface | Function | Function | Interface description   |
       | ID        | A        | B        |                         |
       +===========+==========+==========+=========================+
       | ACP-IF-01 | AIMF     | AIMgF    | Apply for / update /    |
       |           |          |          | de-register an AIC;     |
       |           |          |          | synchronize identity    |
       |           |          |          | lifecycle state.        |
       +-----------+----------+----------+-------------------------+
       | ACP-IF-02 | AIMF     | CMgF     | Apply for / renew /     |
       |           |          |          | revoke Agent            |
       |           |          |          | Credentials bound to an |
       |           |          |          | AIC.                    |
       +-----------+----------+----------+-------------------------+
       | ACP-IF-03 | IAF      | IVF      | Verify a peer agent's   |
       |           |          |          | claimed identity and    |
       |           |          |          | presented credentials;  |
       |           |          |          | obtain a verification   |
       |           |          |          | result / assertion.     |
       +-----------+----------+----------+-------------------------+
       | ACP-IF-04 | AIMgF    | CMgF     | Coordinate identity-to- |
       |           |          |          | credential binding;     |
       |           |          |          | synchronize identity    |
       |           |          |          | and credential status.  |
       +-----------+----------+----------+-------------------------+
       | ACP-IF-05 | CMgF     | IVF      | Query credential status |
       |           |          |          | and validation material |
       |           |          |          | (e.g., issuer keys,     |
       |           |          |          | revocation state).      |
       +-----------+----------+----------+-------------------------+
       | ACP-IF-06 | ADMF     | ADMgF    | Submit / update /       |
       |           |          |          | withdraw Agent          |
       |           |          |          | Descriptions; receive   |
       |           |          |          | publication status.     |



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       +-----------+----------+----------+-------------------------+
       | ACP-IF-07 | ADMgF    | ADF      | Synchronize published   |
       |           |          |          | Agent Descriptions and  |
       |           |          |          | metadata for discovery  |
       |           |          |          | indexing.               |
       +-----------+----------+----------+-------------------------+
       | ACP-IF-08 | AIF      | AIF      | Agent-to-agent          |
       |           |          |          | interaction (session,   |
       |           |          |          | task, message exchange) |
       |           |          |          | under an agreed         |
       |           |          |          | interaction mode.       |
       +-----------+----------+----------+-------------------------+
       | ACP-IF-09 | AIF      | MDF      | Group interaction via   |
       |           |          |          | message distribution    |
       |           |          |          | (create / join group,   |
       |           |          |          | publish / subscribe,    |
       |           |          |          | deliver messages).      |
       +-----------+----------+----------+-------------------------+
       | ACP-IF-10 | TAF      | TSF      | Tool / resource         |
       |           |          |          | invocation (discover    |
       |           |          |          | tools, invoke tools,    |
       |           |          |          | obtain results, manage  |
       |           |          |          | context).               |
       +-----------+----------+----------+-------------------------+

                   Table 2: Reference interfaces summary

4.4.2.  Interface Semantics

   *  *Identity and credential interfaces (ACP-IF-01..05)* provide the
      basis for trust establishment.  Implementations SHOULD support
      auditability of lifecycle operations.

   *  *Description and discovery interfaces (ACP-IF-06..07)* enable
      capability-based agent discovery.  Implementations SHOULD support
      versioning and de-listing of descriptions.

   *  *Agent interaction interfaces (ACP-IF-08..09)* define how agents
      exchange tasks, messages, and context.  Implementations SHOULD
      support confidentiality, integrity, replay protection, and access
      control.

   *  *Tool access interface (ACP-IF-10)* enables secure invocation of
      external tools or resources.  Implementations SHOULD support
      least-privilege access and result integrity.






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5.  Typical Operational Scenarios

   This section illustrates how the functional architecture with
   conceptual domains, functional components, and interfaces is applied
   in typical operational scenarios.

5.1.  Agent Onboarding: Identity, Credential, and Capability Description

   A typical agent onboarding workflow includes:

   1.  The agent (via AIMF) registers identity with AIMgF (ACP-IF-01)
       and obtains an AIC.

   2.  The agent (via AIMF) obtains credentials from CMgF (ACP-IF-02).
       CMgF and AIMgF coordinate binding and status (ACP-IF-04).

   3.  The agent (via ADMF) submits an ACS to ADMgF (ACP-IF-06).  The
       ACS links to the agent's AIC and includes access and capability
       information.

   4.  ADMgF publishes the ACS and synchronizes to ADF (ACP-IF-07) for
       discovery indexing.

5.2.  Agent Discovery and Partner Selection

   In ACPs, the interaction between agents is task-driven, based on
   which agents can be divided into two roles:

   *  Leader: Agent who issues tasks and organizes interactions.  There
      should only be one Leader in a complete task execution process.

   *  Partner: Agent who accepts tasks and provides services.  After
      Partner receives a task from the Leader, it executes and returns
      the execution result.

   A typical agent discovery workflow includes:

   1.  A Leader determines required capabilities for a task.

   2.  The Leader queries ADF with constraints derived from the task
       (discovery request semantics are realized by ADP).

   3.  ADF returns a ranked candidate set of Partner agents.

   4.  The Leader (via IAF) authenticates selected Partners (ACP-IF-03)
       before starting interaction.





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5.3.  Agent Interaction with Point-to-point and Grouping Mode

   In AIP, there are three interaction modes between the Leader and the
   Partner: peer-to-peer mode, grouping mode and hybrid mode.

   *  peer-to-peer mode: In this mode, the Leader maintains separate
      communication connections with each Partner, ensuring context
      isolation.  Each message in this mode has only one sender and
      receiver.

   *  Grouping mode: In this mode, interaction messages between agents
      are distributed through a message queue.  A message in this mode
      has only one sender but may has multiple receivers.

   *  Hybrid mode: In this mode, the Leader and Partner may interact
      directly or through the message queue according to the Leader's
      task planning.

   In point-to-point mode, the Leader and each Partner communicate
   directly via ACP-IF-08.

   In grouping mode, a message distribution service (MDF) is used.
   Agents create/join groups and exchange messages via ACP-IF-09, while
   still using ACP-IF-03 for authentication / authorization decisions.

5.4.  Tool Invocation

   When an agent needs external tools / resources, a typical tool
   invocation workflow includes:

   1.  The agent uses TAF to discover available tools (locally cached or
       via TSF).

   2.  The agent invokes a tool (ACP-IF-10).

   3.  TSF executes or brokers the tool and returns results to the
       agent.

5.5.  Agent Monitoring

   If agent monitoring is required, agents and services export logs /
   events via AMF.  Monitoring data can be used for troubleshooting,
   policy enforcement, auditing, and governance.








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6.  Conclusions

   This draft introduces the Agent Collaboration Protocols (ACPs)
   architecture for Internet of Agents.  By defining a functional
   architecture with conceptual domains, functional components and
   reference interfaces, ACPs can support trusted registration, identity
   authentication, agent discovery, agent interaction, tool invocation,
   and agent monitoring.  ACPs address the core requirements for
   interoperability and secure collaboration among heterogeneous agents.
   The long-term goal of the ACPs is to enable IoA to serve as the
   critical infrastructure for agent collaboration on complex tasks, as
   well as to support the future large-scale and diverse applications.

7.  Security Considerations

   This document focuses on the Agent Collaboration Protocols
   architecture for IoA.  Security of IoA is not detailed in this
   document.  Security considerations relevant to deployment with
   multiple agent service providers are suggested to be deeply discussed
   through other proposals.

8.  IANA Considerations

   This document makes no request for IANA action.

9.  References

9.1.  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/info/rfc2119>.

   [RFC8259]  Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
              Interchange Format", STD 90, RFC 8259,
              DOI 10.17487/RFC8259, December 2017,
              <https://www.rfc-editor.org/info/rfc8259>.

   [RFC8446]  Rescorla, E., "The Transport Layer Security (TLS) Protocol
              Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
              <https://www.rfc-editor.org/info/rfc8446>.

9.2.  Informative References

   [ACPs-Github]
              "ACPs GitHub repository", n.d.,
              <https://github.com/AIP-PUB>.



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Authors' Addresses

   Jun Liu
   Beijing University of Posts and Telecommunications
   10 Xitucheng Road, Haidian District
   Beijing
   100876
   China
   Email: liujun@bupt.edu.cn


   Ke Yu
   Beijing University of Posts and Telecommunications
   10 Xitucheng Road, Haidian District
   Beijing
   100876
   China
   Email: yuke@bupt.edu.cn


   Ke Li
   Beijing University of Posts and Telecommunications
   10 Xitucheng Road, Haidian District
   Beijing
   100876
   China
   Email: like1990@bupt.edu.cn


   Keliang Chen
   Beijing University of Posts and Telecommunications
   10 Xitucheng Road, Haidian District
   Beijing
   100876
   China
   Email: chenkl@bupt.edu.cn















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