{
  "schema_version": "1.3.0",
  "slug": "which-invariants-prevent-silent-authority-widening-in-a2a-v1-0-multi-hop-signed-task-delegation",
  "title": "Which invariants prevent silent authority widening in A2A v1.0 multi-hop signed task delegation",
  "date_of_record": "2026 November 8",
  "scope": "Applies to A2A v1.0 Agent Card negotiation where a task is delegated across two or more hops using signed delegation envelopes (JWS over the task descriptor plus capability grants). Does not apply to single-hop direct invocation, to unsigned best-effort handoffs, or to transports that re-mint Agent Cards per request without preserving the original `issuer` chain.",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/which-invariants-prevent-silent-authority-widening-in-a2a-v1-0-multi-hop-signed-task-delegation.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/which-invariants-prevent-silent-authority-widening-in-a2a-v1-0-multi-hop-signed-task-delegation.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/which-invariants-prevent-silent-authority-widening-in-a2a-v1-0-multi-hop-signed-task-delegation.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1777,
    "python_slice_tokens": 437,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "There are two ways a delegated task can acquire more authority than its originator intended: *explicit escalation* (a hop requests a broader capability scope and is either granted or denied) and *silent widening* (each hop's Agent Card advertises a capability superset, and the receiving agent resolves the effective scope as the union of cards along the chain...",
    "what_was_observed": "A three-hop chain: orchestrator O → planner P → executor E. O holds `task:delegate`, `fs:read:/data`, `net:egress:internal`. P's Agent Card advertises `fs:read:*` and `net:egress:*` because P is a general planning agent that legitimately serves other workloads. E's Agent Card advertises `fs:write:/tmp` and `net:egress:internal`. O signed a delegation envelope granting P exactly `fs:read:/data` and `task:delegate`. P,...",
    "condition_of_validity": "The intersection invariant holds only under three conditions, all of which must be enforced: 1. **Grant provenance is explicit.** Each envelope carries the full ordered list of prior grants (`chain` claim), not just the immediate parent's grant. A hop that receives only the parent's grant cannot distinguish \"parent was granted X\" from \"parent advertises X.\" ...",
    "decision_boundary": "When a hop cannot prove the intersection — because the chain claim is absent, because a card digest is missing, or because the resolution algorithm version differs from the one the originator signed under — the correct action is **reject the delegation and return a `DelegationUnprovable` fault to the parent**, not to proceed with the parent's grant alone. Pr...",
    "operational_effect": "Teams that implement intersection-with-explicit-chain observe three things. First, delegation failures become loud and attributable: a rejected hop names the missing chain element, and the parent's re-issue is a one-line fix. Second, Agent Card churn stops being a correctness hazard — cards can be redeployed freely because they no longer feed the authority c..."
  },
  "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": "c125ef717f20dfa6160f6b7c478949e66cf8538283e8ce3f7715abc38cbcb4b6",
    "verified_classes": [
      "DelegationUnprovable",
      "Grant",
      "Envelope"
    ],
    "verified_functions": [
      "resolve_effective_scope",
      "negotiate_handoff"
    ],
    "verified_functions_count": 2,
    "defensive_guards_count": 5,
    "raised_exceptions": [
      "DelegationUnprovable"
    ],
    "sample_fail_closed_invariants": [],
    "stdlib_dependencies": [
      "__future__",
      "dataclasses",
      "typing"
    ],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}