{
  "schema_version": "1.3.0",
  "slug": "which-invariants-prevent-privilege-re-expansion-when-attenuating-tool-invocation-capabilities-across-delegated-agent-calls",
  "title": "Which invariants prevent privilege re-expansion when attenuating tool-invocation capabilities across delegated agent calls",
  "date_of_record": "2026 November 9",
  "scope": "Applies to runtime policy enforcement points that attenuate a capability set on delegation (parent agent → child agent, or orchestrator → tool-calling subprocess) and must guarantee the child cannot invoke a tool outside the parent's effective grant. Does not apply to capability *revocation* mid-flight, nor to grants that were never attenuated (identity-preserving re-issuance).",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/which-invariants-prevent-privilege-re-expansion-when-attenuating-tool-invocation-capabilities-across-delegated-agent-calls.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/which-invariants-prevent-privilege-re-expansion-when-attenuating-tool-invocation-capabilities-across-delegated-agent-calls.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/which-invariants-prevent-privilege-re-expansion-when-attenuating-tool-invocation-capabilities-across-delegated-agent-calls.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1903,
    "python_slice_tokens": 384,
    "warrant_slice_tokens": 220
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  "remnant_summary": {
    "core_distinction": "The non-obvious failure is not \"the child calls a tool it shouldn't.\" That is a straightforward authorization check and is caught by ordinary deny-by-default. The failure is **privilege re-expansion through composition**: the child holds two individually-attenuated capabilities whose *combination* reconstructs a right the parent never held, or held only in a...",
    "what_was_observed": "A delegation path issued a child agent a capability set `{read:reports/*, write:reports/scratch/*, invoke:summarizer}`. The parent's grant was `{read:reports/*, write:reports/scratch/*}` — note the child received an *additional* `invoke:summarizer` that the parent did not hold, because the delegation logic treated \"invoke\" as a category orthogonal to \"read/write\" and applied attenuation only within each category. The...",
    "condition_of_validity": "The invariant holds only under all of the following: 1. **Monotone attenuation floor.** For every delegation edge, the effective set at the child is `S_child ⊆ S_parent` where `⊆` is evaluated over the *transitive closure* of tool-mediated effects, not over declared token names. If the enforcement point cannot compute that closure, it must treat every `invok...",
    "decision_boundary": "Enforce at the **effect-closure** layer, not the token layer, when any of the following is true: - The capability vocabulary contains `invoke:*` tokens for tools with side effects or internal reads/writes. - Delegation is transitive (children can re-delegate). - Attenuation is expressed per-category rather than as a single lattice. Do **not** pay the closure...",
    "operational_effect": "After switching the enforcement point to closure-mode, the observed re-expansion instances were rejected at delegation time with a clear cause (`effect_closure(child) ⊄ effect_closure(parent)`), and the audit log began attributing the rejection to the specific composed path (`invoke:summarizer → read:reports/scratch/* → read:reports/private`) rather than to ..."
  },
  "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": "99c2b63f37a7936a4df81bdd4b60ba684264e864a3876957fee5ee5d82c7a69e",
    "verified_classes": [
      "PrivilegeReexpansionError",
      "Capability",
      "ToolRegistry"
    ],
    "verified_functions": [
      "attenuate",
      "check_redelegation",
      "effect_closure"
    ],
    "verified_functions_count": 3,
    "defensive_guards_count": 2,
    "raised_exceptions": [
      "PrivilegeReexpansionError"
    ],
    "sample_fail_closed_invariants": [
      "parent effect closure is unbounded (undeclared tool); refusing delegation"
    ],
    "stdlib_dependencies": [
      "dataclasses",
      "typing"
    ],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}