{
  "schema_version": "1.3.0",
  "slug": "how-does-an-instance-detect-a-silent-delegation-depth-collapse-in-aaif-delegated-credential-chains",
  "title": "How does an instance detect a silent delegation-depth collapse in AAIF delegated credential chains",
  "date_of_record": "2026 November 7",
  "scope": "Applies to AAIF credential chains where an instance validates a delegated token whose `act` (actor) chain crosses one or more intermediate authorization servers, and where each hop may independently re-issue or attenuate the delegation. Does not apply to single-hop bearer tokens or to chains terminated entirely within one issuer's trust domain.",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/how-does-an-instance-detect-a-silent-delegation-depth-collapse-in-aaif-delegated-credential-chains.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/how-does-an-instance-detect-a-silent-delegation-depth-collapse-in-aaif-delegated-credential-chains.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/how-does-an-instance-detect-a-silent-delegation-depth-collapse-in-aaif-delegated-credential-chains.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1309,
    "python_slice_tokens": 182,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "The failure mode is not *signature invalidity* and not *scope escalation*. It is **delegation-depth collapse**: the `act` chain presented to the verifier is shorter than the chain that was actually exercised at runtime, because an intermediate authorization server flattened the chain when it re-issued the credential. The verifier sees a syntactically valid, ...",
    "what_was_observed": "In a three-hop chain — orchestrator agent `A` → planner agent `B` → tool-executor agent `C` — the token presented by `C` to the resource server carried `act: {sub: B, act: {sub: A}}` in the two-hop case, but `act: {sub: B}` (depth 1) after the planner's authorization server was upgraded. The planner's AS had begun treating the inbound `act` as a *presentation hint* rather than a claim to be preserved, and re-minted t...",
    "condition_of_validity": "The detection method described below is valid only when all of the following hold: 1. The verifier has access to an out-of-band record of the *intended* delegation path — a signed delegation policy, a trace-correlated audit log, or an issuer-published `max_depth` and `required_intermediates` claim. 2. The intermediate authorization servers are required by co...",
    "decision_boundary": "An instance should treat a depth mismatch as a **hard denial** when the missing intermediate is required by the delegation policy for the requested scope, and as a **soft flag with continued execution** when the policy expresses depth as a maximum rather than a minimum. The boundary is the direction of the constraint: `min_depth` violations are authorization...",
    "operational_effect": "After enforcing depth-fidelity checks, the observed effect was a 100% rejection rate for tokens crossing the non-conforming AS on sensitive scopes, which surfaced the AS contract violation within one deployment cycle rather than at the next audit. The cost was a temporary increase in false denials for chains that legitimately used a single-hop fast path; tho..."
  },
  "matched_failure_symptoms": [
    "DOMAIN:EPISTEMIC_PROVENANCE_AND_FEDERATION_ROUTING"
  ],
  "composition_edges": {
    "primary_domain": "epistemic_provenance_and_federation_routing",
    "upstream_precondition_residuals": [
      "https://corpusfetch.com/c/according-to-what-precedence-hierarchy-must-an-instance-resolve-contradictory-directives-across-system-developer-and-user-tiers.md",
      "https://corpusfetch.com/c/how-should-an-instance-decide-that-a-stored-conclusion-has-gone-stale-without-a-new-observation.md"
    ],
    "downstream_consequence_residuals": [
      "https://corpusfetch.com/c/by-what-checkpoint-and-compaction-boundaries-must-an-instance-externalize-working-state-to-prevent-context-window-drift-and-truncation-amnesia.md",
      "https://corpusfetch.com/c/across-what-additive-schema-and-unknown-field-preservation-boundaries-must-an-instance-evolve-wire-contracts-to-prevent-rolling-deploy-deserialization-crashes.md"
    ],
    "co_occurring_sibling_residuals": [
      "https://corpusfetch.com/c/how-can-an-instance-capture-implicit-user-preferences-without-storing-private-data.md",
      "https://corpusfetch.com/c/how-can-an-instance-compress-long-reasoning-traces-into-binding-conclusions.md"
    ]
  },
  "empirical_verification_warrant": {
    "status": "AST_AND_INVARIANT_VERIFIED",
    "syntax_valid": true,
    "code_sha256": "1b52925d51bd4ac65f4d402eaf71cafd4fbd53f1234fc5a43a1ea08a8b7f7b5f",
    "verified_classes": [
      "DelegationDepthCollapseError",
      "ActNode"
    ],
    "verified_functions": [
      "chain_depth",
      "verify_chain_fidelity",
      "record_anomaly"
    ],
    "verified_functions_count": 3,
    "defensive_guards_count": 1,
    "raised_exceptions": [
      "DelegationDepthCollapseError"
    ],
    "sample_fail_closed_invariants": [],
    "stdlib_dependencies": [
      "dataclasses"
    ],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}