Agent Channels in OIDC-A

• Agent Channels are secure, claims-driven communication links that enable LLM-based agents to act on behalf of users via auditable authorization and authentication pathways.
• They leverage standardized agent-specific claims, ordered delegation chains, and cryptographic attestation to maintain integrity and enforce fine-grained access controls.
• The framework integrates with OAuth 2.0/OIDC to support dynamic capability control and secure access in distributed systems while ensuring interoperability.

OpenID Connect for Agents (OIDC-A) 1.0 formally extends the OAuth 2.0 and OpenID Connect (OIDC) protocols to define secure, verifiable agent channels for LLM-based autonomous agents operating in distributed systems. An agent channel, in this context, is a formally auditable authorization and authentication pathway, with explicit identity, delegation, attestation, and capability constraints at each link. The OIDC-A framework codifies the creation, validation, and governance of these agent channels by introducing agent-specific claims, structured delegation chains, cryptographically enforced attestation, and capability-based access policies, all within standard-compliant OIDC infrastructure.

1. Foundations of Agent Channels in OIDC-A

Agent channels are the secure, claims- and constraint-driven communication and authorization links by which agents (LLM-based or otherwise) act on behalf of users or other agents to obtain access to protected resources. A channel may traverse multiple agents and delegation steps, with each step cryptographically asserted, explicitly scoped, and attested via OIDC-A protocol mechanisms.

OIDC-A agent channels integrate:

• Agent identity attributes (model, provider, instance)
• Explicit, ordered delegation structures (delegation chains)
• Attestation of agent origin, integrity, and operational conditions
• Policy- and capability-aware access control

OIDC-A's technical specifications define how these are encoded in ID Tokens (JWTs), endpoints, and standardized claims, ensuring interoperability with existing OAuth 2.0/OIDC deployments.

2. Agent Identity Representation and Standard Claims

OIDC-A augments OpenID Connect's identity layer with agent-centric claims, enabling precise, machine-verifiable representation of agent attributes. Standard agent claims include:

Claim Name	Type	Description	Requirement
agent_type	string	Agent class ("assistant", "coding", etc.)	REQUIRED
agent_model	string	LLM identifier (e.g., "gpt-4")	REQUIRED
agent_version	string	Model version info	RECOMMENDED
agent_provider	string	Organization/service provider	REQUIRED
agent_instance_id	string	Unique agent instance ID	REQUIRED

These claims are included in issued ID tokens as part of the agent's subject claim, forming the bedrock of agent identity. Custom types or extensions are namespaced to ensure uniqueness.

Example JWT agent claim excerpt:

{ "agent_type": "assistant", "agent_model": "gpt-4", "agent_version": "2025-03", "agent_provider": "openai.com", "agent_instance_id": "agent_instance_789" }

3. Delegation Chain Structure and Validation

OIDC-A structures the authority transfer between users, agents, and downstream agents as an ordered, auditable delegation_chain, codified in each issued agent token. Each step in the chain is a JSON object with key fields:

• iss: Authorizing server (issuer)
• sub: Delegator (“from”)
• aud: Delegatee (“to”)
• delegated_at: Unix timestamp of the delegation
• scope: Set of authorized actions/resources (scope subset enforced)
• purpose: Human-readable or machine-parsable reason (optional)
• constraints: Programmatic usage restrictions (optional)
• jti: Optional JWT ID

Validation of the delegation chain for an agent channel requires:

1. Chronological order of delegated_at timestamps
2. Trust in issuers (iss) per local security policy
3. Strict audience chaining: aud of step N equals sub of step N+1
4. Scope reduction at each step:

$\text{scope}_{N+1} \subseteq \text{scope}_{N}$

1. Constraint and policy compliance (resource, time, contextual limits)
2. Cryptographic signature verification (when chain steps are signed)
3. Chain length and complexity control per deployment policy

Example two-step delegation:

"delegation_chain": [ { "iss": "https://auth.example.com", "sub": "user_456", "aud": "agent_instance_789", "delegated_at": 1714348800, "scope": "email calendar", "purpose": "Manage emails/calendar" }, { "iss": "https://auth.example.com", "sub": "agent_instance_789", "aud": "agent_instance_101", "delegated_at": 1714348830, "scope": "calendar:view", "purpose": "Analyze schedule" } ]

This guarantees traceability and containment of every active agent channel.

4. Attestation, Capabilities, and Authorization

OIDC-A mandates cryptographically-verifiable evidence (“attestation”) of agent integrity, origin, and runtime properties to support robust trust and fine-grained security postures.

The agent_attestation claim object encapsulates:

• format: Attestation type (e.g., "urn:ietf:params:oauth:token-type:eat")
• token: Raw (or referenced) JWT/EAT with evidence
• timestamp: NumericDate UNIX timestamp

Example:

"agent_attestation": { "format": "urn:ietf:params:oauth:token-type:eat", "token": "eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9...", "timestamp": 1714348800 }

Verification steps include cryptographic signature validation (using keys announced via attestation_verification_keys_endpoint), comparison with attested measurements, and checks for freshness and nonce inclusion.

Capabilities and access boundaries are asserted in agent_capabilities and delegation_constraints claims:

Claim	Content	Enforced By
agent_capabilities	array	Relying party
agent_trust_level	string	Relying party
delegation_constraints	object	Relying party

For all agents $A_0 \to A_1 \to \dots \to A_N$, the effective privileges are the intersection of all delegated scopes and constraints across the delegation chain: $$\text{Granted Capabilities} = \bigcap_{i=1}^N \text{capabilities}_i$$

5. Protocols, Endpoints, and Security Flows

OIDC-A introduces extensions to standard OAuth 2.0/OIDC flows to establish, maintain, and govern agent channels:

• Client Registration: Agents register, advertising provider, supported models, and capabilities.
• Authorization: Requests with explicit agent scopes and optionally a delegation_context.
• Token Issuance: Agent identity, full delegation chain, attestation, and capabilities are embedded as JWT claims.
• Validation and Enforcement: Relying parties validate all claims (ID token, delegation, attestation), enforcing constraints and revoking stale or over-privileged channels.

OIDC-A endpoints:

• agent_attestation_endpoint: Online attestation verification.
• agent_capabilities_endpoint: Capability discovery and lookup.
• attestation_verification_keys_endpoint: Fetch keys for attestation checking.

Authentication leverages JWT client authentication or Mutual TLS for strong proof-of-possession semantics. Scopes are strictly reduced in chains; tokens are short-lived and optionally JWE-encrypted for additional confidentiality.

6. Agent Channel Structure: Mathematical Formalism

Formally, an OIDC-A agent channel can be represented as: $$\mathcal{C} = (A_0 \xrightarrow{S_1, P_1, C_1} A_1 \xrightarrow{S_2, P_2, C_2} \dots \xrightarrow{S_N, P_N, C_N} A_N)$$ where for each delegation step:

• $A_i$: Delegator or intermediate agent
• $S_i$: Scope granted
• $P_i$: Purpose
• $C_i$: Constraints (resource, temporal, contextual)

The channel is instantiated as a validated delegation_chain with attached attestation and capability claims.

7. Backward Compatibility, Maintenance, and Security Properties

OIDC-A maintains backward compatibility: extensions are opt-in, with client and server roles interoperating with legacy OAuth 2.0/OIDC infrastructure. Agent-specific functionality is activated only when advanced agent mediation is required.

Channels are maintained by token expiry, re-attestation cycles, consistent validation of the delegation chain and capabilities, and cryptographic revocation as needed. Agent channels are strongly authenticated, auditable, and resistant to common threats (impersonation, privilege escalation, and replay), by construction.

8. Summary Table: OIDC-A Agent Channel Mechanisms

Mechanism	OIDC-A Feature	Details
Agent identity	Standard claims	Model, version, provider, instance
Delegation chain	Ordered claim array	Multi-step auditable delegation
Attestation	Attestation claims	Cryptographically verifiable evidence
Capabilities	Capabilities claims	Intersection across the chain
Protocol/flow	Extended OIDC flows	Registration, authorization, token, endpoints
Security	JWS/JWE, mTLS, revocation	Policy enforcement, signature checks

9. Conclusion

OIDC-A 1.0 defines and governs agent channels as a network of authenticated, authorizable, and attestable trust links from users through (possibly multiple) agents to backend services, instantiated as structured OIDC flows with explicit claims and cryptographic evidence at each step. This enables precise, secure agent-mediated access in distributed systems, accommodating delegation, fine-grained capability control, and auditable, revocable operation, fully compatible with the OAuth 2.0 ecosystem.