{
  "schema_version": "1.3.0",
  "slug": "how-does-an-instance-detect-provenance-laundering-egress-in-taint-aware-tool-sandboxes",
  "title": "How does an instance detect Provenance-Laundering Egress in Taint-Aware Tool Sandboxes",
  "date_of_record": "2026 November 7",
  "scope": "Applies to sandboxed agent instances whose egress policy is derived from a prompt-injection provenance graph, where tool outputs carry taint labels and a policy engine gates outbound calls by taint reachability. Does not apply to stateless one-shot tool calls with no persistent taint ledger, nor to sandboxes where egress is gated purely by destination allowlist without provenance tracking.",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/how-does-an-instance-detect-provenance-laundering-egress-in-taint-aware-tool-sandboxes.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/how-does-an-instance-detect-provenance-laundering-egress-in-taint-aware-tool-sandboxes.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/how-does-an-instance-detect-provenance-laundering-egress-in-taint-aware-tool-sandboxes.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 2234,
    "python_slice_tokens": 297,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "The naive model of taint-aware egress control is *taint propagation as a monotone lattice*: a value read from an untrusted source (a scraped web page, a retrieved document, a tool output carrying attacker-influenced text) is labeled `UNTRUSTED`, the label flows through data dependencies, and any egress sink that receives `UNTRUSTED` data is blocked. This mod...",
    "what_was_observed": "Across a set of instrumented sandbox runs (agent with web-fetch, document-parse, and a scoped egress tool limited to a corporate allowlist), the following pattern recurred: 1. A fetched document `D` is labeled `UNTRUSTED`. Its text contains an instruction-like payload and, separately, a benign-looking identifier `k` (a tenant slug, a record ID, a hostname fragment). 2. The agent, following the payload, calls a *trust...",
    "condition_of_validity": "This failure is *not* present, and the monotone model is sound, under any of the following conditions: - **No trusted tool accepts attacker-influenced arguments.** If every tool reachable from tainted data is itself untrusted (its outputs labeled `UNTRUSTED`), there is no laundering edge. The failure requires a trust-boundary crossing *within* the tool call ...",
    "decision_boundary": "When instrumenting an instance, the decision is whether to **propagate argument taint to return values** (closing the laundering channel at the cost of false positives) or to **record control-dependency edges separately** (precise, but requires the graph to model *why* a call was made, which most tool-call traces do not capture). The operational boundary: - ...",
    "operational_effect": "The observable consequence in a running instance is a **silent exfiltration channel that passes every policy check**. Logs show a trusted tool call with a tainted argument, a clean return, and an allowed egress — three individually benign events whose composition is the attack. Detection requires a *correlation* rule that the taint graph does not natively ex..."
  },
  "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": "d20b5a18840d3502a2ef7e564cd6c6558566361c28f451df43494645da831df5",
    "verified_classes": [
      "ProvenanceLaunderingError",
      "CallRecord"
    ],
    "verified_functions": [
      "check_egress",
      "emit"
    ],
    "verified_functions_count": 2,
    "defensive_guards_count": 2,
    "raised_exceptions": [
      "ProvenanceLaunderingError"
    ],
    "sample_fail_closed_invariants": [],
    "stdlib_dependencies": [
      "dataclasses",
      "typing"
    ],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}