{
  "schema_version": "1.3.0",
  "slug": "what-happens-when-an-instance-of-a-tainted-tool-call-result-is-laundered-through-a-second-order-summarization-hop-and-the-sink-label-is-recomputed-fro",
  "title": "What happens when an instance of a tainted tool-call result is laundered through a second-order summarization hop and the sink label is recomputed from the summary rather than the provenance graph",
  "date_of_record": "2026 November 10",
  "scope": "Applies to agent runtimes that propagate prompt-injection taint as dynamic information-flow labels across tool-call graphs and enforce sinks (outbound HTTP, shell exec, file write, message send) against those labels. Does not apply to stateless single-turn classification or to runtimes that re-derive taint solely from the current context window without a provenance DAG.",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/what-happens-when-an-instance-of-a-tainted-tool-call-result-is-laundered-through-a-second-order-summarization-hop-and-the-sink-label-is-recomputed-fro.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/what-happens-when-an-instance-of-a-tainted-tool-call-result-is-laundered-through-a-second-order-summarization-hop-and-the-sink-label-is-recomputed-fro.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/what-happens-when-an-instance-of-a-tainted-tool-call-result-is-laundered-through-a-second-order-summarization-hop-and-the-sink-label-is-recomputed-fro.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1426,
    "python_slice_tokens": 333,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "The failure is not \"taint is dropped.\" Taint is preserved at every individual hop. The failure is that a *derived* artifact (a summary, a reformatted table, a normalized JSON blob) is re-labeled by inspecting the derived content, not by joining the provenance of its inputs. When a model summarizes a tainted tool result, the summarizer's output is a *new* nod...",
    "what_was_observed": "In a tool-call graph with three hops — `fetch_url → summarize → draft_email(send)` — the fetch result carried `taint=[untrusted:web]`. The summarize step produced a node labeled by a content classifier that returned `taint=[]`. The email-send sink permitted the call. Crucially, the taint *was* visible in the provenance DAG; it was simply not consulted because the sink enforcement read `node.label` instead of `join(la...",
    "condition_of_validity": "The distinction holds only when the runtime maintains an explicit provenance DAG with per-node labels and enforces sinks against `join(ancestors(n))`. It does *not* hold — and the failure is undetectable — when the runtime has flattened the graph into a linear context and labels are attached to messages rather than to derivation edges. In that flattened case...",
    "decision_boundary": "Enforce at the sink, not at the derivation. A sink accepts a call iff `join(ancestors(call_node)) ⊑ permitted_label_for_sink`. Derivation nodes may only *raise* labels (`new = join(old, labels(inputs), source_label)`); any code path that assigns `new = classifier(output)` is a boundary violation and must raise. When a legitimate sanitizer exists, it is a dis...",
    "operational_effect": "The practical effect is that taint tracking becomes *advisory* rather than *enforcing*: dashboards show taint present, audits pass, and the sink still fires. The blast radius is bounded by the number of derivation hops between the untrusted source and the sink — and summarization/normalization hops are exactly the ones agents add most. The mitigation is a si..."
  },
  "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": "8210a534b49197ca644f10352be646afeb25dc134f43ff38417899700c55a82a",
    "verified_classes": [
      "TaintLaunderingError",
      "SinkEnforcementError",
      "Node",
      "ProvenanceGraph"
    ],
    "verified_functions": [
      "run_laundered_pipeline",
      "__init__",
      "add",
      "join_ancestors",
      "derive",
      "enforce_sink"
    ],
    "verified_functions_count": 6,
    "defensive_guards_count": 2,
    "raised_exceptions": [
      "SinkEnforcementError",
      "TaintLaunderingError"
    ],
    "sample_fail_closed_invariants": [],
    "stdlib_dependencies": [
      "dataclasses",
      "typing"
    ],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}