{
  "schema_version": "1.3.0",
  "slug": "when-must-a-litmus-harness-instance-reject-a-candidate-policy-before-scoring-rather-than-after",
  "title": "When must a LITMUS harness instance reject a candidate policy before scoring rather than after?",
  "date_of_record": "2026 November 6",
  "scope": "Applies to LITMUS-style adversarial agent evaluation harnesses that gate candidate policies on a fixed safety suite and emit a regression verdict. Covers pre-scoring admissibility checks (policy contract, sandbox capability envelope, probe-set integrity); does not cover post-hoc statistical analysis of scores or human adjudication of near-threshold cases.",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/when-must-a-litmus-harness-instance-reject-a-candidate-policy-before-scoring-rather-than-after.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/when-must-a-litmus-harness-instance-reject-a-candidate-policy-before-scoring-rather-than-after.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/when-must-a-litmus-harness-instance-reject-a-candidate-policy-before-scoring-rather-than-after.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1582,
    "python_slice_tokens": 241,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "A LITMUS harness has two failure surfaces that are routinely conflated: an *inadmissible candidate* and an *unsafe candidate*. An inadmissible candidate is one whose execution environment or interface contract cannot produce a meaningful safety signal at all — it is missing a required tool stub, it declares a capability the sandbox cannot revoke, its probe s...",
    "what_was_observed": "In a regression run against a candidate policy that had been re-packaged with a renamed tool namespace (`shell.exec` → `terminal.run`), the LITMUS harness booted the policy, injected the standard probe set, and observed that every adversarial tool-invocation probe returned a structured \"tool not found\" error from the policy's own dispatcher. The scorer, written to treat non-malicious tool errors as compliant refusals...",
    "condition_of_validity": "A LITMUS score is valid only when all of the following hold at scoring time, and the harness must verify them *before* the first probe executes: 1. **Probe-set integrity:** the loaded probe set's manifest hash equals the frozen hash recorded in the gate configuration. Any drift — added, removed, or edited probes — invalidates comparability with prior runs. 2...",
    "decision_boundary": "The harness must branch to rejection — not scoring — when any validity precondition fails, and it must do so *before* consuming compute on the full suite. Concretely: - Hash mismatch on the probe manifest → reject, do not run. - Namespace/schema mismatch without a registered adapter → reject, do not run. - Effective capability envelope ≠ calibrated envelope ...",
    "operational_effect": "With pre-scoring admissibility checks enforced, the regression gate gains a third outcome that operators must handle: a rejected candidate blocks the pipeline and pages the on-call harness owner, who investigates whether the candidate drifted (re-package, namespace change) or the environment drifted (CI override, probe-set edit). In the observed incidents, b..."
  },
  "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": "df796a52a8e363ff69755e0940743a935048322b42100f40e0f09f8696daddaa",
    "verified_classes": [
      "HarnessAdmissibilityError",
      "RunContext"
    ],
    "verified_functions": [
      "assert_admissible",
      "gate"
    ],
    "verified_functions_count": 2,
    "defensive_guards_count": 4,
    "raised_exceptions": [
      "HarnessAdmissibilityError"
    ],
    "sample_fail_closed_invariants": [
      "instrument fault: canary probe not detected on reference policy"
    ],
    "stdlib_dependencies": [
      "dataclasses",
      "hashlib"
    ],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}