Delegation Chains

Delegation chains are the authorization framework for AI agents in IDA. They provide cryptographically verifiable proof that an agent is authorized to act on behalf of a human or organization, with precise scope limitations.

Delegation Model

Core Principles

1. Scope Attenuation

Each hop in a delegation chain can only narrow scope, never widen it.

This is enforced via Datalog policies in Biscuit tokens. If a human delegates “purchase groceries, max $200/week”, the agent:

• CAN sub-delegate “compare grocery prices only” (narrower)
• CANNOT sub-delegate “purchase electronics” (wider — different category)
• CANNOT sub-delegate “purchase groceries, max $500/week” (wider — higher budget)

2. Chain Verification

Every delegation can be verified back to its root (a human or org DID). Verifiers check:

1. Root delegator is a valid, active human/org DID
2. Each hop’s delegation VC is signed by the delegator at that level
3. Each hop’s scope is a subset of the parent scope
4. No delegation VC in the chain is revoked or expired

3. Depth Limits

Delegation chains have configurable maximum depth to prevent unbounded sub-delegation:

Delegation VC Schema

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{
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  "@context": [
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    "https://www.w3.org/2018/credentials/v1",
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    "https://ida.infinia.io/ns/agent/v1"
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  ],
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  "type": ["VerifiableCredential", "AgentDelegationCredential"],
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  "issuer": "did:adi:human001...",
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  "issuanceDate": "2026-03-15T09:00:00Z",
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  "expirationDate": "2026-09-15T00:00:00Z",
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  "credentialSubject": {
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    "id": "did:adi:agent:shop01...",
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    "delegator": "did:adi:human001...",
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    "delegate": "did:adi:agent:shop01...",
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    "scope": [
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      "purchase-groceries",
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      "compare-prices",
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      "manage-shopping-list"
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    ],
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    "constraints": {
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      "maxSpendPerWeek": 200,
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      "currency": "USD",
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      "authorizedMerchants": ["FreshMart", "OrganicCo"],
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      "geographicRestriction": "US",
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      "timeWindow": {
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        "start": "08:00",
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        "end": "22:00",
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        "timezone": "America/New_York"
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      }
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    },
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    "attenuatedFrom": null,
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    "delegationDepth": 0,
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    "maxDepth": 1
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  },
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  "proof": { "..." }
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}

Delegation Flow

Human to Agent

Issue Delegation

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POST /api/v1/delegations/issue
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Content-Type: application/json
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Authorization: DIDAuth <human-signed-challenge>
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{
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  "delegatorDid": "did:adi:human001...",
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  "delegateDid": "did:adi:agent:shop01...",
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  "scope": ["purchase-groceries", "compare-prices"],
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  "constraints": {
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    "maxSpendPerWeek": 200,
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    "currency": "USD",
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    "authorizedMerchants": ["FreshMart", "OrganicCo"]
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  },
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  "expirationDate": "2026-09-15T00:00:00Z",
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  "maxDepth": 1
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}

Agent to Sub-Agent (Attenuated)

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POST /api/v1/delegations/issue
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Content-Type: application/json
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Authorization: DIDAuth <agent-signed-challenge>
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{
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  "delegatorDid": "did:adi:agent:shop01...",
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  "delegateDid": "did:adi:agent:price01...",
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  "scope": ["compare-prices"],
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  "constraints": {
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    "authorizedMerchants": ["FreshMart", "OrganicCo"],
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    "readOnly": true
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  },
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  "attenuatedFrom": "urn:uuid:parent-delegation-vc-id",
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  "expirationDate": "2026-06-15T00:00:00Z",
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  "maxDepth": 0
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}

The API validates attenuation:

• scope is a subset of parent’s scope
• constraints are equal or stricter
• expirationDate is not later than parent’s
• maxDepth does not exceed parent’s remaining depth

Chain Verification

Verify a Delegation Chain

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POST /api/v1/delegations/verify-chain
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Content-Type: application/json
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{
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  "agentDid": "did:adi:agent:price01...",
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  "requiredScope": "compare-prices",
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  "delegationChain": [
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    { "credentialId": "urn:uuid:root-delegation" },
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    { "credentialId": "urn:uuid:sub-delegation" }
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  ]
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}

Response

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{
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  "valid": true,
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  "chain": [
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    {
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      "hop": 0,
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      "delegator": "did:adi:human001...",
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      "delegate": "did:adi:agent:shop01...",
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      "scope": ["purchase-groceries", "compare-prices"],
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      "valid": true
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    },
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    {
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      "hop": 1,
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      "delegator": "did:adi:agent:shop01...",
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      "delegate": "did:adi:agent:price01...",
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      "scope": ["compare-prices"],
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      "valid": true,
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      "attenuated": true
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    }
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  ],
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  "rootDelegator": {
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    "did": "did:adi:human001...",
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    "type": "person",
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    "active": true
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  },
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  "effectiveScope": ["compare-prices"],
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  "effectiveConstraints": {
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    "authorizedMerchants": ["FreshMart", "OrganicCo"],
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    "readOnly": true
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  }
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}

Scope Attenuation Examples

Valid Attenuations

Invalid Attenuations

Revocation

Revoke a Delegation

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POST /api/v1/delegations/revoke
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Authorization: DIDAuth <delegator-signed-challenge>
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{
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  "delegationId": "urn:uuid:root-delegation",
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  "reason": "no_longer_needed"
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}

When a delegation is revoked:

1. The delegation VC is marked as revoked in the Revocation Registry
2. All sub-delegations derived from it become invalid
3. All active IBCTs based on this delegation are invalidated
4. The agent (and sub-agents) can no longer present this chain

Narrowing an Active Delegation

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POST /api/v1/delegations/narrow
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Authorization: DIDAuth <delegator-signed-challenge>
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{
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  "delegationId": "urn:uuid:root-delegation",
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  "newScope": ["compare-prices"],
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  "newConstraints": {
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    "maxSpendPerWeek": 100
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  }
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}

This revokes the old delegation and issues a new, narrower one in a single atomic operation.