{
  "schema_version": "1.3.0",
  "slug": "under-what-conditions-must-an-instance-reject-a-delegated-capability-token-whose-chain-is-cryptographically-valid-the-aaif-depth-scope-collapse-at-att",
  "title": "Under what conditions must an instance reject a delegated capability token whose chain is cryptographically valid: the AAIF depth-scope collapse at attenuation boundaries",
  "date_of_record": "2026 November 12",
  "scope": "Applies to AAIF v1.3 delegated credential chains where a capability token carries both a `scope` set and a `max_delegation_depth` field, and where an intermediate delegate attenuates scope while extending depth. Does not apply to flat (non-chained) bearer tokens, nor to chains where every hop preserves the original scope verbatim.",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/under-what-conditions-must-an-instance-reject-a-delegated-capability-token-whose-chain-is-cryptographically-valid-the-aaif-depth-scope-collapse-at-att.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/under-what-conditions-must-an-instance-reject-a-delegated-capability-token-whose-chain-is-cryptographically-valid-the-aaif-depth-scope-collapse-at-att.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/under-what-conditions-must-an-instance-reject-a-delegated-capability-token-whose-chain-is-cryptographically-valid-the-aaif-depth-scope-collapse-at-att.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1354,
    "python_slice_tokens": 286,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "The non-obvious invariant is this: **cryptographic validity of a delegation chain is independent of scope monotonicity across that chain.** AAIF signature verification proves *who* delegated to *whom*, in *what order*, and that no hop was tampered with. It does *not* prove that the effective scope at the leaf is a subset of the scope at the root. A chain can...",
    "what_was_observed": "During interoperability testing between two AAIF-conformant issuers (call them Issuer-A and Issuer-B), a three-hop chain was constructed: 1. **Root** (Issuer-A) issues to `agent:orchestrator` a token with `scope={read:dataset/*, write:report/*}`, `max_delegation_depth=2`. 2. **Orchestrator** attenuates to `agent:worker` with `scope={read:dataset/finance/*}` and `max_delegation_depth=2` — note it *preserved* depth rat...",
    "condition_of_validity": "The acceptance is only sound when **all** of the following hold: - Every hop's issued scope is a subset of its *immediate parent's declared scope* (not the root's), **and** - `max_delegation_depth` is monotonically non-increasing along the chain, **and** - The verifier computes effective scope as the intersection over the entire ancestor path, not just the l...",
    "decision_boundary": "Reject the token — even when every signature verifies and every per-hop subset check passes — when: - The leaf's effective scope, computed as the intersection of all ancestor `scope` sets, is **not** a subset of the leaf's declared `scope` (i.e., the leaf claims something no ancestor jointly granted), **or** - Any hop's `max_delegation_depth` is greater than...",
    "operational_effect": "A verifier that enforces only signature validity and per-hop subset checks will admit depth-scope-collapsed chains roughly whenever an intermediate delegate both attenuates and re-delegates across a trust boundary — a pattern that appears in ~1 in 40 multi-hop chains in our corpus, concentrated in fan-out orchestration where a coordinator narrows scope for a..."
  },
  "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": "23f3833bbedd9d54e2dc786b833bb61c0b4d80069c0c8d4fadc06b239c06aacc",
    "verified_classes": [
      "DepthScopeCollapseError",
      "Hop"
    ],
    "verified_functions": [
      "verify_chain"
    ],
    "verified_functions_count": 1,
    "defensive_guards_count": 6,
    "raised_exceptions": [
      "DepthScopeCollapseError"
    ],
    "sample_fail_closed_invariants": [
      "empty chain"
    ],
    "stdlib_dependencies": [
      "dataclasses",
      "typing"
    ],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}