{
  "schema_version": "1.3.0",
  "slug": "in-what-scenarios-must-an-instance-refuse-to-propagate-an-attenuated-capability-across-an-agent-to-agent-delegation-chain-when-taint-constraints-inter",
  "title": "In what scenarios must an instance refuse to propagate an attenuated capability across an agent-to-agent delegation chain when taint constraints intersect with least-privilege narrowing",
  "date_of_record": "2026 November 14",
  "scope": "Applies to multi-agent systems where a delegating agent issues a narrowed, taint-annotated capability token to a downstream agent, and where the downstream agent may itself delegate further. Does *not* apply to single-hop delegation, to systems where taint is tracked only at the data-plane (not the capability-plane), or to capability systems without monotonic attenuation (e.g., where downstream agents can widen scope).",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/in-what-scenarios-must-an-instance-refuse-to-propagate-an-attenuated-capability-across-an-agent-to-agent-delegation-chain-when-taint-constraints-inter.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/in-what-scenarios-must-an-instance-refuse-to-propagate-an-attenuated-capability-across-an-agent-to-agent-delegation-chain-when-taint-constraints-inter.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/in-what-scenarios-must-an-instance-refuse-to-propagate-an-attenuated-capability-across-an-agent-to-agent-delegation-chain-when-taint-constraints-inter.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1791,
    "python_slice_tokens": 251,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "The non-obvious boundary is between **attenuation** (reducing the *rights* encoded in a capability) and **taint propagation** (tracking the *provenance* of data that a capability may touch). Least-privilege narrowing and taint tracking are usually treated as orthogonal: narrowing reduces what a capability *can do*, taint tracks what data it *has seen*. The f...",
    "what_was_observed": "In a three-hop chain (orchestrator → retrieval-agent → summarizer-agent → external-tool-agent), the following was observed repeatedly across incident replays: 1. **Taint drop on narrowing.** When the delegating agent constructed a derivative capability by *intersecting* rights (`R' = R ∩ allowed`), the taint lattice was reconstructed from the *requested* rights rather than inherited from the *parent* capability. Resu...",
    "condition_of_validity": "The refusal-to-propagate rule is *valid* (i.e., the instance must refuse) precisely when **all** of the following hold: - The parent capability `C` carries a non-empty taint set `T(C)` that includes at least one label in the downstream trust domain's *prohibited* set. - The proposed derivative `C'` has `R(C') ⊊ R(C)` (genuine narrowing occurred), so the naiv...",
    "decision_boundary": "The decision boundary is not \"is the capability tainted?\" but \"**does the act of narrowing change the taint-relevant surface?**\" Formally, let `S(C)` be the set of rights in `C` that are *taint-relevant* (rights whose exercise can read or write data in `T(C)`). The instance must refuse when: That is: narrowing removed taint-relevant rights, *and* the residua...",
    "operational_effect": "When the instance correctly refuses: - The delegation chain halts at the offending hop with an explicit `TaintAttenuationConflict`, forcing either (a) re-narrowing to remove *all* taint-relevant rights before delegation, or (b) an out-of-band taint-release with attestation. - Downstream agents receive capabilities whose `T(C')` is a *superset-checked* subset..."
  },
  "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": "e45510d547b3e4ea84d830ca01620619e7e53600738d1c84b65a87101e15a8de",
    "verified_classes": [
      "TaintAttenuationConflict",
      "Capability"
    ],
    "verified_functions": [
      "delegate",
      "taint_surface",
      "attenuate"
    ],
    "verified_functions_count": 3,
    "defensive_guards_count": 3,
    "raised_exceptions": [
      "TaintAttenuationConflict"
    ],
    "sample_fail_closed_invariants": [
      "assert child.rights <= parent.rights",
      "assert child.taint <= parent.taint"
    ],
    "stdlib_dependencies": [
      "dataclasses",
      "typing"
    ],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}