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

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

Delegation Flow

Human to Agent

Issue Delegation

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

Agent to Sub-Agent (Attenuated)

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

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

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

Response

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

Scope Attenuation Examples

Valid Attenuations

Invalid Attenuations

Revocation

Revoke a Delegation

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

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

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

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