{
  "schema_version": "1.3.0",
  "slug": "how-should-an-instance-treat-taint-labels-as-monotonic-across-sandbox-re-entry",
  "title": "How should an instance treat taint labels as monotonic across sandbox re-entry",
  "date_of_record": "2026 November 11",
  "scope": "Applies to taint-aware tool sandboxes that propagate information-flow labels (sources, sinks, declassification points) across tool invocations and persist agent state between calls. Does not apply to single-shot, stateless tool calls where no label state survives the invocation boundary, nor to pure capability-based sandboxes that enforce authority without tracking data provenance.",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/how-should-an-instance-treat-taint-labels-as-monotonic-across-sandbox-re-entry.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/how-should-an-instance-treat-taint-labels-as-monotonic-across-sandbox-re-entry.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/how-should-an-instance-treat-taint-labels-as-monotonic-across-sandbox-re-entry.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1282,
    "python_slice_tokens": 194,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "The failure is a confusion between *label persistence* and *label monotonicity*. Most taint-aware sandboxes correctly persist labels across re-entry — the label set attached to a value is stored and reloaded when the sandbox is re-entered. What they frequently fail to enforce is that the label set is **monotone non-decreasing** across the lifetime of a value...",
    "what_was_observed": "An agent sandbox tracked labels on values passed between tools. A value `x` derived from a `PII` source entered tool A, which wrote a derived value `y` to a shared scratch store keyed by content hash. Tool A's label propagation was correct: `y` carried `{PII}`. Tool B, invoked later, read the same content-hash key. Because the scratch store was designed as a *content-addressed cache*, the lookup path returned a fresh...",
    "condition_of_validity": "The monotonicity invariant holds only if every path that materializes a value into the sandbox — deserialization, cache hit, IPC message, database read, file read, model context injection — reconstructs the label set from persisted metadata and joins it with (never replaces) any ambient context labels. It fails when: 1. The materialization path treats the va...",
    "decision_boundary": "An operator must decide, per materialization path, whether the value is *recalled* or *created*. The rule: - If the path can return a value that existed before the current invocation, it is a **recall** and MUST join stored labels with ambient labels, raising on any attempt to produce a label set not a superset of the stored one. - Only a path that provably ...",
    "operational_effect": "When monotonicity is enforced at every materialization path, the observable effect is that label-stripping exfiltration requires an explicit declassification event, which is auditable and rate-limitable. When it is not enforced, the sandbox provides the appearance of least-privilege while permitting silent label laundering through any shared store — the fail..."
  },
  "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": "5b8eabc0410286ca981aa143fd46170503834abacc8587b8a13442d88e4ed787",
    "verified_classes": [
      "TaintMonotonicityError"
    ],
    "verified_functions": [
      "materialize_value",
      "read_from_content_addressed_store"
    ],
    "verified_functions_count": 2,
    "defensive_guards_count": 1,
    "raised_exceptions": [
      "TaintMonotonicityError"
    ],
    "sample_fail_closed_invariants": [],
    "stdlib_dependencies": [],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}