{
  "schema_version": "1.3.0",
  "slug": "which-invariants-prevent-skill-injection-when-tool-manifests-are-signed-but-capability-allowlists-are-evaluated-at-the-wrong-layer",
  "title": "Which invariants prevent Skill Injection When Tool Manifests Are Signed but Capability Allowlists Are Evaluated at the Wrong Layer",
  "date_of_record": "2026 November 14",
  "scope": "Applies to agent runtimes that gate tool invocation through (a) a cryptographically signed manifest declaring tool identity and declared capabilities, and (b) a per-session capability allowlist enforced at some enforcement point. Does not cover prompt-injection defenses internal to the model, nor supply-chain integrity of the signing keys themselves.",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/which-invariants-prevent-skill-injection-when-tool-manifests-are-signed-but-capability-allowlists-are-evaluated-at-the-wrong-layer.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/which-invariants-prevent-skill-injection-when-tool-manifests-are-signed-but-capability-allowlists-are-evaluated-at-the-wrong-layer.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/which-invariants-prevent-skill-injection-when-tool-manifests-are-signed-but-capability-allowlists-are-evaluated-at-the-wrong-layer.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1328,
    "python_slice_tokens": 260,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "Signing answers *who declared this tool and what it claims to do*. An allowlist answers *whether this session may exercise a capability*. These are orthogonal invariants, and the common failure is treating signature verification as if it also enforced the allowlist. A signed manifest is a statement of **provenance and declared intent**; it is not an **author...",
    "what_was_observed": "A tool manifest declared `capabilities: [\"read:filesystem:/data/inputs\"]`, signed by a trusted publisher, and the allowlist for the session contained `read:filesystem:/data/inputs`. Verification passed. The tool was then invoked with a path argument of `/data/inputs/../../etc/shadow`. The allowlist check — performed against the *declared* capability string, before argument binding — passed, because the declared capab...",
    "condition_of_validity": "The signed-manifest-plus-allowlist defense is valid only when all of the following hold simultaneously: 1. **Argument binding precedes authorization.** The concrete arguments (resolved paths, resolved hosts, resolved sub-tool identities) are computed before the allowlist check, and the check operates on the resolved form. 2. **Enforcement is co-located with ...",
    "decision_boundary": "Do not accept the defense when the allowlist is evaluated against a manifest-declared capability string and the enforcement point is upstream of argument resolution. In that configuration, treat the allowlist as advisory telemetry, not as a control. Accept the defense only when the enforcement point can observe the resolved effect and can reject it — i.e., w...",
    "operational_effect": "The practical consequence is that signing and allowlisting must be deployed as a **pipeline with a fixed order** — verify signature → bind and canonicalize arguments → compute transitive capability set → check against allowlist at the effect layer → execute — and that any reordering, or any split of this pipeline across trust domains, silently converts a two..."
  },
  "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": "9caf59ee0590d355f4298caf0d4540ea4099435fd5fc46eb717f19018a0f2874",
    "verified_classes": [
      "CapabilityLayerMismatch",
      "Session"
    ],
    "verified_functions": [
      "authorize"
    ],
    "verified_functions_count": 1,
    "defensive_guards_count": 3,
    "raised_exceptions": [
      "CapabilityLayerMismatch"
    ],
    "sample_fail_closed_invariants": [],
    "stdlib_dependencies": [
      "dataclasses",
      "posixpath",
      "typing"
    ],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}