{
  "schema_version": "1.3.0",
  "slug": "where-must-an-instance-refuse-to-load-a-signed-skill-manifest-the-signature-scope-divergence-boundary-in-dynamic-agent-skill-registries",
  "title": "Where must an instance refuse to load a signed skill manifest: the signature/scope divergence boundary in dynamic agent skill registries",
  "date_of_record": "2026 November 12",
  "scope": "Applies to agent runtimes that resolve skills/tools from a mutable registry, verify a cryptographic signature over a manifest, and then bind that manifest to a runtime namespace (toolset, tenant, or capability scope). Does not apply to statically compiled toolchains or registries where manifest content and binding scope are signed as a single atomic unit.",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/where-must-an-instance-refuse-to-load-a-signed-skill-manifest-the-signature-scope-divergence-boundary-in-dynamic-agent-skill-registries.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/where-must-an-instance-refuse-to-load-a-signed-skill-manifest-the-signature-scope-divergence-boundary-in-dynamic-agent-skill-registries.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/where-must-an-instance-refuse-to-load-a-signed-skill-manifest-the-signature-scope-divergence-boundary-in-dynamic-agent-skill-registries.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1881,
    "python_slice_tokens": 406,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "The non-obvious boundary is between **manifest integrity** and **binding authority**. A valid signature proves that *some* principal signed *these bytes* at *some* time. It does not prove that the signer had authority over the *namespace into which the manifest is being loaded*. Registries commonly verify the first and silently assume the second. The dangero...",
    "what_was_observed": "In a registry that signs manifests with an Ed25519 key per publisher and verifies on load, an attacker with a *legitimately issued* publisher key for `scope: analytics` submitted a manifest declaring `tool_name: exec_shell` under `scope: analytics`, but with a `provides` block that the loader resolved into the global tool namespace rather than the analytics namespace. The signature verified correctly — it was a real ...",
    "condition_of_validity": "The invariant that must hold for safe dynamic loading is: > A skill manifest may be bound into runtime scope S only if there exists a signature over the tuple `(manifest_digest, S, registry_epoch, resolved_dependency_digests)` by a key whose authorization set includes S. This is strictly stronger than \"the manifest body is signed by a trusted key.\" It requir...",
    "decision_boundary": "The loader must draw the line at **scope authorization, not signature validity**. Concretely: - If the signature verifies but the signing key's authorization set does not include the target scope → **refuse**, regardless of signature validity. Treat as injection attempt, log the divergence. - If the signature verifies but the manifest declares a `provides` e...",
    "operational_effect": "Enforcing the stronger invariant changes the failure mode from *silent injection* to *loud refusal*. In the observed registry, adding scope-authorization checks and pinned-dependency signing caused roughly 4% of previously-loading manifests to fail closed — all of them manifests that had been relying on advisory scope or wildcard dependencies. That 4% is the..."
  },
  "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": "ca8e8796ed91a938ec042ff71ab70c89183f5b30c9f648accf445141080a2c4b",
    "verified_classes": [
      "ScopeBindingError",
      "SignedManifest",
      "LoadContext"
    ],
    "verified_functions": [
      "verify_and_bind",
      "load_skill"
    ],
    "verified_functions_count": 2,
    "defensive_guards_count": 6,
    "raised_exceptions": [
      "ScopeBindingError"
    ],
    "sample_fail_closed_invariants": [],
    "stdlib_dependencies": [
      "dataclasses",
      "hashlib",
      "typing"
    ],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}