Delegation Constraints

Read Session Delegation first. Constraints state how far, how long, and for what a Delegation may be used. Caracal validates them when the Delegation is created and again before issuing a Mandate through it.

Constraint Types

Constraint	Use it to limit
Resource	Which protected target can be reached.
Scopes	Which actions can be requested.
TTL	How long the delegated edge remains useful.
Hop count	How deep the delegation chain may become.
Approval metadata	Audit/display annotation; it does not authorize the edge.
Broad reason	Audit/display note for an elevated resource-unbounded edge.

Example Shape

{
  "resource": "resource://piperchat",
  "scopes": ["piperchat:read", "piperchat:comment"],
  "max_hops": 2,
  "expires_at": "2026-06-01T12:00:00Z",
  "policy_approved": true
}

Delegation constraints bound authority, lifetime, and propagation. They are not quotas: the wire accepts a budget field, but it is a narrowing bound - a child edge’s budget can never exceed its parent’s - not a per-call counter, and no constraint performs usage accounting. Use a domain-specific store when calls, work, or cost must be consumed atomically. Approval metadata and broad-reason fields are audit annotations; they do not authorize the Delegation.

Application-chain requirements are verifier options rather than edge constraints. Use requireChainContains at a resource boundary when a specific application must appear in the signed delegation chain.

Where Constraints Are Enforced

flowchart TD
  SDK["SDK creates edge"] --> Coordinator["Coordinator stores constraints"]
  Coordinator --> STS["STS validates live authoritative lineage"]
  STS --> Policy["Policy evaluates its documented input"]
  Policy --> Mandate["Mandate carries delegation claims"]
  Mandate --> Adapter["Gateway or adapter checks claims"]

Design Guidance

Put durable business rules in policy data documents.
Put per-edge runtime limits in constraints.
Prefer positive allowlists over open-ended deny lists.
Keep constraints small enough to review in audit traces.
Use consistent field names across agents so policies stay readable.

Next Step

Read Sessions and Revocation to understand how active authority ends.