{
  "schema_version": "1.3.0",
  "slug": "which-invariants-prevent-delegated-capability-tokens-from-crossing-issuer-trust-boundaries-when-chain-depth-exceeds-the-verifier-s-policy-horizon",
  "title": "Which invariants prevent delegated capability tokens from crossing issuer trust boundaries when chain depth exceeds the verifier's policy horizon",
  "date_of_record": "2026 November 14",
  "scope": "Applies to AAIF delegated capability tokens (DCTs) presented across two or more issuers where the verifier's trust-chain evaluator is configured with a bounded depth horizon and per-issuer attenuation policy. Does not apply to single-issuer delegation, to root-anchored tokens whose entire chain resolves within one trust domain, or to opaque bearer tokens with no delegation semantics.",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/which-invariants-prevent-delegated-capability-tokens-from-crossing-issuer-trust-boundaries-when-chain-depth-exceeds-the-verifier-s-policy-horizon.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/which-invariants-prevent-delegated-capability-tokens-from-crossing-issuer-trust-boundaries-when-chain-depth-exceeds-the-verifier-s-policy-horizon.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/which-invariants-prevent-delegated-capability-tokens-from-crossing-issuer-trust-boundaries-when-chain-depth-exceeds-the-verifier-s-policy-horizon.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1405,
    "python_slice_tokens": 337,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "The failure is not signature verification failure, and it is not expiry. It is a *structural* mismatch between two quantities that are both individually valid: the **claimed chain depth** (the number of `iss`→`sub`→`act` hops a DCT asserts, encoded in the token's delegation chain) and the **verifier's evaluation horizon** (the maximum number of trust-domain ...",
    "what_was_observed": "In a cross-issuer deployment, agent A (issued by IdP-1) delegated a capability to agent B (issued by IdP-2), which delegated to agent C (issued by IdP-3). The verifier V was configured with `max_chain_depth = 2` and a trust bundle containing IdP-1 and IdP-2 but not IdP-3. The DCT presented by C carried a three-hop `act` chain and a valid signature from B. V's evaluator walked the chain, resolved IdP-1 → IdP-2 within ...",
    "condition_of_validity": "This behavior is only reachable when all of the following hold simultaneously: (1) the chain crosses at least one issuer-trust-domain boundary; (2) the verifier applies a finite depth horizon; (3) the evaluator's termination condition is \"horizon reached\" rather than \"anchor resolved or irreducible mismatch\"; and (4) the intermediate principal at the horizon...",
    "decision_boundary": "The correct boundary is a hard split between **anchor resolution** and **horizon exhaustion**. Anchor resolution means the evaluator reached a trust anchor it holds and the final hop's issuer matches that anchor: allow evaluation to proceed. Horizon exhaustion means the evaluator ran out of budget before reaching an anchor: this is a *distinct terminal state...",
    "operational_effect": "Enforcing the split changes three operational properties. First, over-deep cross-issuer chains now produce a deterministic `depth_exceeded` denial with the claimed depth and the horizon both recorded, making the failure diagnosable from a single log line. Second, the effective principal in every audit record is provably the terminal subject, restoring the in..."
  },
  "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": "3153f55883a5447dc9d5f15ea815c2ecd6297504f90674cf4760798d1206abac",
    "verified_classes": [
      "ChainDepthExceededError",
      "Hop",
      "Decision"
    ],
    "verified_functions": [
      "evaluate_chain",
      "authorize"
    ],
    "verified_functions_count": 2,
    "defensive_guards_count": 4,
    "raised_exceptions": [
      "ChainDepthExceededError"
    ],
    "sample_fail_closed_invariants": [],
    "stdlib_dependencies": [
      "dataclasses",
      "typing"
    ],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}