Internet-Draft Credential Delegation for AI Agents July 2026
Sweeney Expires 29 January 2027 [Page]
Workgroup:
WIMSE
Internet-Draft:
draft-sweeney-wimse-credential-delegation-00
Published:
Intended Status:
Standards Track
Expires:
Author:
K. Sweeney

Credential Delegation Protocol for AI Agents in Multi-System Environments

Abstract

Autonomous AI agents increasingly require access to protected resources across multiple service providers on behalf of human users. Existing OAuth 2.0 extensions address individual aspects of this problem (token exchange, proof-of-possession, and structured authorization) but no current specification defines how these mechanisms compose into a coherent credential delegation framework for AI agents.

This document specifies the Credential Delegation Protocol: a profile of OAuth 2.0 Token Exchange (RFC 8693), Demonstrating Proof-of-Possession (RFC 9449), Rich Authorization Requests (RFC 9396), and Client-Initiated Backchannel Authentication (OpenID Connect CIBA) that enables human users to delegate scoped, attenuated credentials to AI agents operating across heterogeneous service providers.

The protocol defines: agent identity lifecycle management using ephemeral key pairs; capability-shaped delegation tokens bound to specific operations and resources; credential wrapping semantics that prevent exposure of underlying OAuth tokens to agents; consent-gated delegation flows for asynchronous agents; real-time cascading revocation; and tamper-evident audit chains.

This document does not define new token formats, new OAuth grant types, or modifications to existing authorization server behavior. It specifies how existing mechanisms are combined to achieve secure, auditable credential delegation for AI agents.

About This Document

This note is to be removed before publishing as an RFC.

Status information for this document may be found at https://datatracker.ietf.org/doc/draft-sweeney-wimse-credential-delegation/.

Discussion of this document takes place on the Workload Identity in Multi System Environments (WIMSE) Working Group mailing list (mailto:wimse@ietf.org), which is archived at https://mailarchive.ietf.org/arch/browse/wimse/. Subscribe at https://www.ietf.org/mailman/listinfo/wimse/.

Source for this draft and an issue tracker can be found at https://github.com/cred-ninja/protocol.

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 29 January 2027.

Table of Contents

1. Introduction

1.1. Problem Statement

OAuth 2.0 [RFC6749] solved human-to-service authorization. When a user authorizes an application to act on their behalf, the application receives an access token representing that delegation. This model assumes a human present at a browser for the consent ceremony.

AI agents operate autonomously. They are ephemeral (spawned on demand), numerous (many agents per user per service), and adversarially promptable: a compromised prompt can direct an agent to misuse any credential it holds. Existing standards fail the agent delegation use case in seven specific ways:

  1. No agent identity primitive. OAuth clients require pre-registration. Agents are ephemeral and cannot register at instantiation time. SPIFFE requires admin provisioning. No standard defines bootstrapping an agent identity from nothing.

  2. No delegation chain attenuation. When Agent A sub-delegates to Agent B, existing standards do not enforce that authority can only narrow. RFC 8693 records delegation chains via nested act claims but treats them as "informational only": no enforcement, no structural guarantee. The delegation chain splicing vulnerability (disclosed to the OAuth WG mailing list, February 26, 2026 [OAUTH-SPLICING]) demonstrates that Sections 2.1-2.2 of [RFC8693] permit a compromised intermediary to present mismatched subject_token and actor_token from different delegation contexts, producing a properly-signed token asserting a delegation chain that never occurred.

  3. No credential wrapping. Agents need to use credentials at resource servers that do not understand delegation. No standard defines how a delegation token authorizes credential exercise without exposing the raw credential to the agent.

  4. No granular authorization. OAuth scopes are coarse string identifiers. Agents need resource- and operation-level capability binding: not "can access Google Drive" but "can read file X in folder Y until time T." RFC 9396 provides the structural mechanism but no agent-specific vocabulary or attenuation rules.

  5. No synchronous revocation cascade. Revoking a root delegation must immediately invalidate all derived delegations. UCAN revocation is gossip-based. RFC 8693 explicitly defers revocation to implementations. No existing standard provides sub-second cascading revocation for a delegation tree.

  6. No asynchronous consent. Agent-initiated flows require user approval without a redirect URI. CIBA [OIDC-CIBA] provides the mechanism but is not profiled for agent delegation scenarios, and CIBA + DPoP interaction is underspecified.

  7. No delegation audit chain. No standard defines an immutable, portable audit trail for "Agent A used User B's credential C to perform operation D at time T via delegation chain E."

This document profiles existing standards to address all seven gaps.

1.2. Relationship to Existing Work

The IETF landscape for agent authorization moved quickly during 2026. The OAuth Working Group was rechartered in June 2026 with agents acting on behalf of users explicitly in scope. The WIMSE Working Group held an interim meeting on June 3, 2026 dedicated to AI agent authentication and authorization and is discussing adoption of that work. Several dozen individual drafts now address some slice of agent identity or delegation. This section positions this protocol against the working group documents and the individual drafts closest to its mechanics. It is not a survey.

1.2.1. Frameworks and Working Group Documents

draft-klrc-aiagent-auth ([KLRC-AIAGENT]): A framework for AI agent authentication and authorization, at -02 with -03 in preparation, and the subject of the WIMSE adoption discussion noted above. The framework identifies the need for concrete delegation mechanics and defers them to OAuth flows. This document supplies those mechanics and is designed as a companion, not a replacement.

draft-ietf-wimse-arch ([WIMSE-ARCH]): Defines the trust domain model and terminology assumed here for WIMSE deployments. The Delegation Server is a service within a trust domain, and Agent identities established per Section 4 are compatible with WIMSE workload identifiers.

draft-ietf-wimse-wpt ([WIMSE-WPT]): Defines the Workload Proof Token (WPT), a proof-of-possession mechanism for workloads. This protocol binds Delegation Tokens with DPoP [RFC9449] instead: DTs are exercised over plain HTTP by ephemeral agents that may sit outside any WIMSE trust domain, the deployment shape DPoP already serves. A future revision may profile WPT for DS-to-resource-server hops inside WIMSE trust domains.

draft-ni-wimse-ai-agent-identity ([WIMSE-AGENT]): Addresses agent identity within WIMSE. The did:key model used here is compatible. This document adds credential wrapping, revocation, consent gating, and chain verification.

draft-reece-wimse-cross-org-delegation ([CROSS-ORG-REQS]): A problem statement and requirements catalogue for cross-organizational delegation, used on the WIMSE list as a common frame for evaluating delegation proposals. A future revision of this document will map the protocol against those requirements.

1.2.2. Delegation Chain Mechanics

draft-ietf-oauth-identity-chaining ([OAUTH-CHAINING]): Approved for publication in 2026. Chains identity and authorization across trust domains by exchanging a token in one domain for a JWT assertion accepted in another. It preserves identity across hops but does not constrain what each hop may do. This protocol adds structural attenuation and receipt-based chain verification on the same RFC 8693 substrate. The two compose.

draft-niyikiza-oauth-attenuating-agent-tokens ([AAT]): Defines tokens a holder can attenuate offline, in the macaroon tradition. Same goal as Section 5.3, different trust model: AAT verification relies on the root issuer key and offline derivation, while this protocol keeps the Delegation Server in the loop at every hop in exchange for synchronous revocation (Section 7) and server-checked strict-subset validation.

draft-gco-oauth-delegate-sd-jwt ([DELEGATE-SD-JWT]): Delegates SD-JWT credentials holder-to-holder by allowing a Key Binding JWT to act as an SD-JWT. It operates at the credential format layer; this protocol operates at the delegation service layer. A DS could issue capability attestations as Delegate SD-JWTs without changing the mechanics defined here.

draft-zhu-oauth-async-delegation ([ASYNC-DELEG]): Defines delegated refresh tokens so agents can act while the user is offline. This protocol answers the same need by keeping refresh tokens in the Credential Vault and giving agents only short-lived DTs. The two are alternative positions on whether agents may hold long-lived credentials at all.

draft-oauth-ai-agents-on-behalf-of-user ([OBO-USER]; expired February 2026): Introduced requested_actor and actor_token parameters binding the acting agent into the authorization code exchange. That closes the same actor-binding weakness this protocol closes with prf receipts, but only for the first hop and only at the authorization server. See Section 9.2.

1.2.3. Credential Intermediation

draft-hartman-credential-broker-4-agents ([CB4A]): Specifies a credential vaulting broker that mediates agent API access through short-lived, narrowly scoped proxy credentials. Architecturally the closest work to the Delegation Server and Credential Vault defined here. CB4A defines the broker; this document additionally defines the delegation chain (attenuation, receipts, sub-delegation), the consent flow, and the revocation cascade such a broker must enforce.

draft-araut-oauth-transaction-tokens-for-agents ([TXN-AGENTS]): Extends transaction tokens to carry agent context in the act claim for intra-domain call chains. Complementary: transaction tokens propagate context within a domain after authorization exists; this protocol governs how the authorization comes to exist.

draft-schwenkschuster-wimse-credential-exchange ([WIMSE-CRED-X]; expired): Despite the similar name, addresses a workload exchanging its own credential for a different format or trust domain. This document addresses human-to-agent delegation over stored credentials that are never issued to the requesting party.

1.3. Design Principles

Compose, don't invent. Every mechanism reuses an existing standard. New concepts appear only where the gaps identified in Section 1.1 are confirmed.

Attenuation is structural. Agents cannot widen authority at any delegation hop. This is enforced by the Delegation Server, not by trusting agents. Inspired by UCAN attenuation semantics and the object-capability model [MILLER-2006].

Credentials are never possessed. Agents receive and exercise delegated authority through the Delegation Server. Raw credentials never cross the boundary to the agent host. This architecturally eliminates the confused deputy attack surface for credential theft [CONFUSED-DEPUTY].

Revocation is synchronous. A user revoking delegation takes effect within the SLA defined in Section 7. Eventual consistency is not acceptable for credential revocation in adversarially-promptable systems.

Capability-shaped, not identity-scoped. Delegation tokens authorize specific operations on specific resources with specific constraints, not "Agent X can access Service Y." Follows the NORA (designation = authority) principle from capability security.

Chain integrity is cryptographic. Each delegation hop produces a signed receipt. The chain is verifiable end-to-end without trusting intermediate agents, addressing the RFC 8693 delegation chain splicing vulnerability.

2. Terminology

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.

Delegation Server (DS):

A service that issues, manages, and revokes Delegation Tokens on behalf of Subjects. The DS maintains the Credential Vault and enforces delegation policies. It acts as an intermediary between Agents and upstream OAuth authorization servers.

Agent:

An autonomous software entity that performs actions on behalf of a Subject across one or more service providers. An Agent authenticates to the DS using an ephemeral key pair and receives Delegation Tokens authorizing specific operations. An Agent MUST NOT possess or have access to the underlying credentials stored in the Credential Vault.

Subject:

The human user who authorizes credential delegation. The Subject authenticates to the DS, deposits credentials into the Credential Vault, defines delegation policies, and approves or denies consent-gated delegation requests.

Delegation Token (DT):

A signed JWT issued by the DS that authorizes an Agent to perform specified operations on specified resources via the DS. A DT contains capability claims structured per [RFC9396], a DPoP key binding for proof-of-possession verification, and an opaque credential handle. Delegation Tokens MUST NOT contain raw OAuth tokens or credentials.

Credential Vault:

Server-side secure storage maintained by the DS that holds OAuth tokens and credentials deposited by Subjects. Credentials are referenced by opaque handles and exercised exclusively by the DS on behalf of Agents presenting valid Delegation Tokens.

Capability:

A structured authorization grant specifying a permitted operation, a target resource, and optional constraints (time bounds, rate limits, argument restrictions). Expressed using the authorization_details object defined in [RFC9396] and bound to a specific Delegation Token.

Attenuation:

The process by which a Capability is further constrained when delegated from one entity to another. An attenuated Capability MUST be a strict subset of its parent. Authority can only narrow at each delegation hop; it can never widen.

Delegation Chain:

An ordered sequence of Delegation Tokens from Subject to Agent_1 to Agent_2 ... to Agent_N, where each link attenuates the authority of the previous. The chain is verifiable from any link back to the root consent event via signed delegation receipts.

Credential Exercise:

The act of the DS using a stored credential on behalf of an Agent. The Agent presents a valid DT and DPoP proof to the DS, which validates the DT, retrieves the credential from the Vault, calls the resource server, and returns only the API response.

3. Architecture Overview

+------------------------------------------------------+
|                    SUBJECT (User)                    |
|  1. Connects services (OAuth)                        |
|  2. Sets delegation policies                         |
|  3. Approves consent requests (CIBA)                 |
+--------------------------+---------------------------+
                           |
                           v
+------------------------------------------------------+
|              DELEGATION SERVER (DS)                  |
|                                                      |
|  +-------------+  +------------+  +--------------+   |
|  | Credential  |  | Delegation |  |   Consent    |   |
|  |   Vault     |  |   Engine   |  |   Manager    |   |
|  |             |  |            |  |   (CIBA)     |   |
|  | OAuth tokens|  | DT issue   |  |              |   |
|  | API keys    |  | Attenuation|  | Approve/Deny |   |
|  | Refresh tkns|  | Chain vrfy |  | Policy eval  |   |
|  +------+------+  +------------+  +--------------+   |
|         |                                            |
|  +------+---------------------------------------+    |
|  |               Exercise Proxy                 |    |
|  |  Validates DT -> Retrieves cred -> Calls RS  |    |
|  |  Returns API response (never raw credential) |    |
|  +----------------------------------------------+    |
|                                                      |
|  +----------------------------------------------+    |
|  |           Revocation & Audit                 |    |
|  |  Synchronous cascade | Tamper-evident log    |    |
|  +----------------------------------------------+    |
+--------------------------+---------------------------+
                           |
                           v
+------------------------------------------------------+
|                      AGENT                           |
|                                                      |
|  1. Generates ephemeral did:key                      |
|  2. Authenticates via JWT Bearer (RFC 7523)          |
|  3. Requests delegation (capabilities + constraints) |
|  4. Receives DT (DPoP-bound, capability-shaped)      |
|  5. Exercises credentials via DS /exercise endpoint  |
|  6. Sub-delegates via attenuation (optional)         |
|                                                      |
|  TRUST BOUNDARY: Agent sees DT + API responses only  |
|  Agent NEVER sees: raw tokens, refresh tokens, keys  |
+------------------------------------------------------+
Figure 1: Protocol Architecture

Critical architectural property: The Agent's trust boundary extends only to the network interface of the Delegation Server. The Agent never crosses into the Vault. This eliminates credential theft as an attack surface: there is nothing for a compromised agent to exfiltrate.

3.1. Protocol Version Negotiation

The canonical protocol version for this draft is 0.1.0.

HTTP protocol clients MUST advertise the highest Cred Protocol version they support for a request using the Cred-Protocol-Version request header. The header value MUST be a single semantic-version string in MAJOR.MINOR.PATCH form. Delegation Servers MUST set Cred-Protocol-Version on every protocol response, including error responses, to the version selected by the server for that response.

Each implementation MUST maintain:

  • a supported-version set, ordered from newest to oldest

  • a configured version floor, below which requests are rejected

For this draft, the supported-version set is ["0.1.0"] and the default version floor is 0.1.0.

A Delegation Server MUST reject a request that advertises a version lower than the configured floor or a version outside the supported-version set. The server MUST return HTTP 426 with a JSON body containing:

{
  "error": "protocol_version_unsupported",
  "message": "Cred Protocol version 0.0.9 is not supported",
  "requested_version": "0.0.9",
  "supported_versions": ["0.1.0"],
  "minimum_version": "0.1.0",
  "current_version": "0.1.0"
}

The response MUST also include Cred-Protocol-Version set to the server's current version so clients can distinguish protocol drift from authentication, authorization, or policy failures.

During the 0.1.0 compatibility window, a missing Cred-Protocol-Version request header MAY be treated as 0.1.0. This allowance exists only because there is no earlier wire version to downgrade to. Implementations that raise the version floor above 0.1.0 MUST reject missing protocol-version headers with protocol_version_unsupported.

4. Agent Identity

4.1. Ephemeral Key Pairs

An Agent MUST generate an Ed25519 or P-256 key pair at instantiation. The DID is derived deterministically from the public key using the did:key method [DID-KEY], a DID method conforming to [DID-CORE]. No pre-registration is required. The DS MUST NOT reject a DID it has not seen before.

4.2. Agent Authentication

The Agent authenticates to the DS using a JWT Bearer assertion [RFC7523] signed with the private key corresponding to its did:key. Required claims:

Table 1: Required authentication claims
Claim Value Notes
iss Agent DID did:key:z...
sub Agent DID Same as iss
aud DS endpoint URL  
iat Current time  
exp iat + max 300s 5-minute maximum
jti Unique nonce Prevents replay

Optional claims:

Table 2: Optional authentication claims
Claim Value Notes
agent_model Model identifier Vendor-prefixed, e.g., "vendor:model-id"
agent_operator Operator DID or URL Organization running the agent
agent_checksum SHA-256 hash Intent binding per [AGENTIC-JWT]; advisory only due to IPR

4.3. Agent Lifecycle

Agents SHOULD generate a new key pair per session. The DS MAY require Subject pre-authorization of specific agent DIDs or agent operators before issuing Delegation Tokens. When an agent terminates, the DS SHOULD invalidate any active Delegation Tokens bound to that agent's DPoP key within the revocation SLA.

5. Delegation Token Format

A Delegation Token is a DPoP-bound JWT [RFC9449] issued by the Delegation Server.

5.1. Required Claims

Table 3: Required Delegation Token claims
Claim Value Specification
iss DS identifier  
sub Subject identifier User on whose behalf delegation occurs
act {"sub": "<Agent DID>"} Per RFC 8693, Section 4.1
authorization_details Capability array Per RFC 9396
cnf {"jkt": "<DPoP thumbprint>"} Per RFC 9449
iat Issuance time  
exp Expiry time Max 1 hour; 15 minutes RECOMMENDED
jti Unique identifier  
consent_id Consent record ID Traceable to root consent event
credential_handle Opaque string References Vault entry; MUST NOT be the credential itself

5.2. Capability Structure

Capabilities are expressed as RFC 9396 authorization_details objects:

{
  "type": "cred_delegation",
  "provider": "google",
  "operations": ["drive.files.get", "drive.files.list"],
  "resources": ["folder:abc123"],
  "constraints": {
    "expires": "2026-07-28T22:00:00Z",
    "max_calls": 10,
    "max_response_size": "10MB"
  }
}

The DS MUST validate that capabilities in a sub-delegation request are a strict subset of the parent DT's capabilities. Validation is the DS's responsibility, not the requesting agent's.

5.3. Delegation Chain Integrity

To address the delegation chain splicing vulnerability in Sections 2.1-2.2 of [RFC8693], each delegation hop MUST produce a signed delegation receipt containing: the parent DT's jti, the child DT's jti, the delegating agent's DID, the receiving agent's DID, and the attenuated capability set. The receipt is signed by the DS and included in the child DT as the prf claim (an array of receipt content identifiers). Chain verification traces prf links back to the root consent event.

6. Credential Wrapping

6.1. Exercise Flow

The Agent presents a valid DT and DPoP proof to the DS's /exercise endpoint. The DS:

  1. Validates the DT signature and expiry

  2. Verifies the DPoP binding (htm, htu, nonce)

  3. Checks that the requested operation is within the DT's authorization_details

  4. Retrieves the credential from the Vault using the opaque credential_handle

  5. Performs the authorized API call against the resource server using the stored credential

  6. Returns only the API response

The raw credential MUST NOT appear in any agent-facing response.

6.2. Proxy Semantics

For resource servers that accept standard OAuth Bearer tokens: the DS acts as a reverse proxy, performing the actual API call with the stored credential. The Agent's HTTP request to /exercise specifies the operation and parameters; the DS maps these to the upstream API call.

6.3. Native Resource Server Support (Future)

For resource servers that natively support this protocol: the DS performs RFC 8693 token exchange, issuing a scoped access token containing the DT's act claim and authorization_details for direct presentation at the resource server. This eliminates the proxy step for participating services.

7. Revocation

When a Subject revokes a delegation (root or any subtree node), the DS MUST:

  1. Invalidate the specified DT within 1 second

  2. Cascade revocation to all descendant DTs within 5 seconds

  3. Return HTTP 401 with error: delegation_revoked for any in-flight /exercise request using a revoked DT

  4. Write an immutable revocation event to the audit log with a revocation_time claim

Revocation endpoint: DELETE /delegation/{jti}

The response MUST include a revoked_count field indicating the number of tokens invalidated in the cascade.

9. Security Considerations

9.1. Confused Deputy Mitigation

Capability-shaped tokens eliminate ambient authority. An adversarially-prompted agent cannot widen its own capabilities since attenuation is DS-enforced. OAuth access tokens are ambient authority: any code holding the token exercises its full scope. For adversarially-promptable agents, this is a structural exploit vector. Cred delegation tokens are operation-bound, resource-specific, and constraint-bearing, following the principle that designation should equal authority [CONFUSED-DEPUTY].

9.2. Delegation Chain Splicing

The mandatory prf chain with DS-signed receipts addresses the vulnerability in Sections 2.1-2.2 of [RFC8693] disclosed to the OAuth WG on February 26, 2026 [OAUTH-SPLICING]. Each receipt cross-references parent and child DT jti values along with both agent DIDs, preventing presentation of tokens from mismatched delegation contexts. The requested_actor/actor_token binding proposed in [OBO-USER] mitigates the same class of attack at the authorization server for the first delegation hop; the prf chain extends equivalent protection across every subsequent hop (see Section 1.2). The two can compose: a DS can accept an actor-bound access token issued under [OBO-USER] as the credential it wraps, then produce prf receipts for every sub-delegation beyond that first hop.

9.3. DPoP Binding

DPoP [RFC9449] prevents Delegation Token theft and replay by requiring cryptographic proof of private key possession on every /exercise request. The proof is bound to the htm (HTTP method) and htu (URI) of the specific request, preventing re-use across operations.

9.4. Prompt Injection Containment

Because credentials never reach the agent host, a successful prompt injection attack cannot exfiltrate credentials. The agent can only exercise capabilities already granted in its DT, and only via the DS /exercise endpoint. The blast radius of a compromised agent is bounded by its current DT's authorization_details.

9.5. Chain Depth Limits

Implementations SHOULD enforce a maximum delegation chain depth of 5. Unbounded sub-delegation creates exponential revocation cascades and audit complexity.

9.6. Token Lifetime

The default DT lifetime of 15 minutes limits the blast radius of any single token compromise. Implementations MUST NOT issue DTs with a lifetime exceeding 1 hour.

9.7. Model Identity and Substitution

The agent_model and agent_checksum claims are self-asserted. A credential valid for an agent remains valid if the operator substitutes the underlying model, a threat class raised against the klrc framework in March 2026. Verifying model identity requires attestation of the agent runtime and is out of scope for this document. Deployments that need it should treat these claims as advisory policy input, not proof, and look to remote attestation work in the RATS WG.

10. IANA Considerations

This document requests registration of:

11. References

11.1. Normative References

[DID-CORE]
Sporny, M., Longley, D., and D. Chadwick, "Decentralized Identifiers (DIDs) v1.0", W3C Recommendation, , <https://www.w3.org/TR/did-core/>.
[DID-KEY]
Longley, D., "The did:key Method v0.7", W3C CCG Draft, <https://w3c-ccg.github.io/did-method-key/>.
[OIDC-CIBA]
OpenID Foundation, "OpenID Connect Client-Initiated Backchannel Authentication Flow - Core 1.0", , <https://openid.net/specs/openid-client-initiated-backchannel-authentication-core-1_0.html>.
[RFC2119]
Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <https://www.rfc-editor.org/rfc/rfc2119>.
[RFC6749]
Hardt, D., Ed., "The OAuth 2.0 Authorization Framework", RFC 6749, DOI 10.17487/RFC6749, , <https://www.rfc-editor.org/rfc/rfc6749>.
[RFC7523]
Jones, M., Campbell, B., and C. Mortimore, "JSON Web Token (JWT) Profile for OAuth 2.0 Client Authentication and Authorization Grants", RFC 7523, DOI 10.17487/RFC7523, , <https://www.rfc-editor.org/rfc/rfc7523>.
[RFC8174]
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <https://www.rfc-editor.org/rfc/rfc8174>.
[RFC8693]
Jones, M., Nadalin, A., Campbell, B., Ed., Bradley, J., and C. Mortimore, "OAuth 2.0 Token Exchange", RFC 8693, DOI 10.17487/RFC8693, , <https://www.rfc-editor.org/rfc/rfc8693>.
[RFC9396]
Lodderstedt, T., Richer, J., and B. Campbell, "OAuth 2.0 Rich Authorization Requests", RFC 9396, DOI 10.17487/RFC9396, , <https://www.rfc-editor.org/rfc/rfc9396>.
[RFC9449]
Fett, D., Campbell, B., Bradley, J., Lodderstedt, T., Jones, M., and D. Waite, "OAuth 2.0 Demonstrating Proof of Possession (DPoP)", RFC 9449, DOI 10.17487/RFC9449, , <https://www.rfc-editor.org/rfc/rfc9449>.

11.2. Informative References

[AAT]
Aimable, N., "Attenuating Authorization Tokens for Agentic Delegation Chains", Work in Progress, draft-niyikiza-oauth-attenuating-agent-tokens-01, , <https://datatracker.ietf.org/doc/draft-niyikiza-oauth-attenuating-agent-tokens/>.
[AGENTIC-JWT]
Goswami, A., "Secure Intent Protocol for Agentic Systems", Work in Progress (expired July 2026), draft-goswami-agentic-jwt-00, , <https://datatracker.ietf.org/doc/draft-goswami-agentic-jwt/>.
[ASYNC-DELEG]
Zhu, L., "Delegated Refresh Tokens for OAuth 2.0 Token Exchange", Work in Progress, draft-zhu-oauth-async-delegation-04, , <https://datatracker.ietf.org/doc/draft-zhu-oauth-async-delegation/>.
[CB4A]
Hartman, K., "Credential Broker for Agents (CB4A)", Work in Progress, draft-hartman-credential-broker-4-agents-00, , <https://datatracker.ietf.org/doc/draft-hartman-credential-broker-4-agents/>.
[CONFUSED-DEPUTY]
Hardy, N., "The Confused Deputy (or Why Capabilities Might Have Been Invented)", ACM SIGOPS Operating Systems Review, .
[CROSS-ORG-REQS]
Reece, M., "Cross-Organizational Delegation for Workload and Agent Identity", Work in Progress, draft-reece-wimse-cross-org-delegation-00, , <https://datatracker.ietf.org/doc/draft-reece-wimse-cross-org-delegation/>.
[DELEG-RECEIPTS]
Nelson, R., "Delegation Receipt Protocol for AI Agent Authorization", Work in Progress, draft-nelson-agent-delegation-receipts-05, , <https://datatracker.ietf.org/doc/draft-nelson-agent-delegation-receipts/>.
[DELEGATE-SD-JWT]
Oliver, G., "Delegate SD-JWT", Work in Progress, draft-gco-oauth-delegate-sd-jwt-00, , <https://datatracker.ietf.org/doc/draft-gco-oauth-delegate-sd-jwt/>.
[ECT]
Nennemann, C., "Execution Context Tokens", Work in Progress, draft-nennemann-wimse-ect-00, , <https://datatracker.ietf.org/doc/draft-nennemann-wimse-ect/>.
[KLRC-AIAGENT]
Kasselman, P., Lombardo, J., Rosomakho, Y., Campbell, B., and N. Steele, "AI Agent Authentication and Authorization", Work in Progress, draft-klrc-aiagent-auth-02, , <https://datatracker.ietf.org/doc/draft-klrc-aiagent-auth/>.
[MANDATE-PS]
Yossif, M., "Problem Statement on Verifiable Human Mandates for Autonomous Agent Actions", Work in Progress, draft-yossif-agent-mandate-problem-00, , <https://datatracker.ietf.org/doc/draft-yossif-agent-mandate-problem/>.
[MILLER-2006]
Miller, M. S., "Robust Composition: Towards a Unified Approach to Access Control and Concurrency Control", PhD thesis, Johns Hopkins University, .
[NIST-AGENT-ID]
NIST NCCoE, "Accelerating the Adoption of Software and AI Agent Identity and Authorization", , <https://www.nccoe.nist.gov/>.
[OAUTH-CHAINING]
IETF OAuth Working Group, "OAuth Identity and Authorization Chaining Across Domains", draft-ietf-oauth-identity-chaining-15, approved for publication, , <https://datatracker.ietf.org/doc/draft-ietf-oauth-identity-chaining/>.
[OAUTH-SPLICING]
OAuth Working Group mailing list, "Security Consideration: Delegation Chain Splicing in RFC 8693 Token Exchange", , <https://mailarchive.ietf.org/arch/browse/oauth/>.
[OBO-USER]
Dissanayaka, T. and A. Dissanayaka, "OAuth 2.0 Extension: On-Behalf-Of User Authorization for AI Agents", Work in Progress (expired), draft-oauth-ai-agents-on-behalf-of-user-02, , <https://datatracker.ietf.org/doc/draft-oauth-ai-agents-on-behalf-of-user/>.
[OWASP-AGENTIC]
OWASP, "Top 10 for Agentic Applications v1.0", , <https://owasp.org/>.
[TXN-AGENTS]
Raut, A., "Transaction Tokens for Agents", Work in Progress, draft-araut-oauth-transaction-tokens-for-agents, , <https://datatracker.ietf.org/doc/draft-araut-oauth-transaction-tokens-for-agents/>.
[UCAN-SPEC]
Zelenka, B., "UCAN Delegation", RC v1.0, <https://github.com/ucan-wg/delegation>.
[WIMSE-AGENT]
Ni, Y. and P. Liu, "WIMSE Applicability for AI Agents", Work in Progress, draft-ni-wimse-ai-agent-identity-02, , <https://datatracker.ietf.org/doc/draft-ni-wimse-ai-agent-identity/>.
[WIMSE-ARCH]
IETF WIMSE Working Group, "Workload Identity in a Multi System Environment (WIMSE) Architecture", Work in Progress, draft-ietf-wimse-arch-08, , <https://datatracker.ietf.org/doc/draft-ietf-wimse-arch/>.
[WIMSE-CRED-X]
Schwenkschuster, A., "WIMSE Credential Exchange", Work in Progress (expired), draft-schwenkschuster-wimse-credential-exchange-03, , <https://datatracker.ietf.org/doc/draft-schwenkschuster-wimse-credential-exchange/>.
[WIMSE-WPT]
IETF WIMSE Working Group, "WIMSE Workload Proof Token", Work in Progress, draft-ietf-wimse-wpt-01, , <https://datatracker.ietf.org/doc/draft-ietf-wimse-wpt/>.

Acknowledgments

The design of this protocol draws on UCAN attenuation semantics [UCAN-SPEC], the object-capability literature, and ongoing work in the IETF WIMSE and OAuth working groups. Threat modeling was informed by [OWASP-AGENTIC] and [NIST-AGENT-ID].

Author's Address

Kieran Sweeney