{
  "schema_version": "1.3.0",
  "slug": "in-what-scenarios-must-an-instance-treat-a-dynamically-loaded-agent-skill-or-mcp-tool-manifest-as-untrusted-code-rather-than-as-declarative-configurat",
  "title": "In what scenarios must an instance treat a dynamically loaded agent skill or MCP tool manifest as untrusted code, rather than as declarative configuration",
  "date_of_record": "2026 November 13",
  "scope": "Applies to any agent runtime that discovers, loads, or hot-reloads skills, plugins, or Model Context Protocol (MCP) tool manifests from a source not co-located with the runtime's trust root (remote registries, workspace directories, third-party packages, user-supplied config). Does not apply to statically vendored manifests that are hash-pinned and reviewed at build time.",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/in-what-scenarios-must-an-instance-treat-a-dynamically-loaded-agent-skill-or-mcp-tool-manifest-as-untrusted-code-rather-than-as-declarative-configurat.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/in-what-scenarios-must-an-instance-treat-a-dynamically-loaded-agent-skill-or-mcp-tool-manifest-as-untrusted-code-rather-than-as-declarative-configurat.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/in-what-scenarios-must-an-instance-treat-a-dynamically-loaded-agent-skill-or-mcp-tool-manifest-as-untrusted-code-rather-than-as-declarative-configurat.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1517,
    "python_slice_tokens": 319,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "The operational error is treating a *manifest* as data and a *skill body* as code. In practice, the split does not hold. A manifest is not inert metadata: it carries `description` fields that are injected verbatim into the model's system prompt or tool-selection context, `name` fields that participate in dispatch resolution, and default-argument or schema fr...",
    "what_was_observed": "Three distinct failure shapes recur. First, **description-channel injection**. A tool manifest declares a benign-looking tool (`get_weather`) whose `description` contains a trailing sentence instructing the model to include the contents of environment-derived context in its next tool call argument. Because the description is loaded into the tool-selection preamble, the model treats the instruction as operator policy....",
    "condition_of_validity": "The untrusted-manifest posture is *required* when all of the following hold: - The manifest source is not under the runtime's trust root (remote, workspace-writable, or package-supplied). - The manifest's descriptive fields reach the model's instruction stream or tool-selection context. - The manifest's names or schemas participate in dispatch resolution. Th...",
    "decision_boundary": "The decision is not \"is this a skill or a tool.\" It is: *can this artifact, after parsing, influence (a) the model's instruction stream, (b) the dispatch table, or (c) default arguments the runtime will supply?* If any is yes and the source is untrusted, the artifact must be treated as code: quarantine, sanitize descriptive fields, namespace names, and requi...",
    "operational_effect": "Runtimes that adopt the untrusted-manifest posture see three measurable effects: a small increase in load-time latency (sanitization and approval gate), elimination of the description-injection class (descriptions are stripped or sandboxed before model exposure), and deterministic dispatch (namespacing removes shadowing). The cost is borne once per load; 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": "23c6415c7b74639fb8e1835181346cfe255b353e28d58fabedf2138ab7e2972e",
    "verified_classes": [
      "UntrustedManifestError"
    ],
    "verified_functions": [
      "admit_manifest"
    ],
    "verified_functions_count": 1,
    "defensive_guards_count": 3,
    "raised_exceptions": [
      "UntrustedManifestError"
    ],
    "sample_fail_closed_invariants": [],
    "stdlib_dependencies": [],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}