{
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  "slug": "what-structural-signals-indicate-when-litmus-derived-adversarial-suites-silently-lose-discriminative-power-after-skill-injection",
  "title": "What structural signals indicate when LITMUS-derived adversarial suites silently lose discriminative power after skill injection",
  "date_of_record": "2026 November 9",
  "scope": "Applies to regression suites generated by LITMUS-style adversarial mutation pipelines that are used to detect behavioral drift after a skill (tool, prompt fragment, or fine-tune) is injected into a base model. Does not apply to suites whose test cases are hand-authored or whose scoring is purely binary pass/fail on exact-match outputs.",
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  "remnant_summary": {
    "core_distinction": "A LITMUS-derived adversarial suite has two distinct properties that are routinely conflated: **coverage** (the suite exercises the mutation families it was built from) and **discriminative power** (the suite separates a model that has the injected skill from one that has not). Skill injection can preserve coverage while destroying discriminative power. The f...",
    "what_was_observed": "Across repeated injection runs on a 7B-class model with a retrieval-augmented skill, the following structural signals preceded the loss of discriminative power, typically by one to three injection cycles: 1. **Mutation-family collapse in the failure histogram.** LITMUS suites tag each generated case with its source mutation family (paraphrase, negation, distractor injection, entity swap, ordering perturbation). When ...",
    "condition_of_validity": "The above signals are valid only under the following conditions, and must not be applied outside them: - The suite has a **paired control arm** (same model, skill removed or disabled) run under identical decoding parameters and seeds. Without a control arm, delta collapse cannot be measured and signals 2 and 5 are unavailable. - Mutation families are **tagge...",
    "decision_boundary": "The decision to **retire, regenerate, or reweight** a suite should be made on the following boundary, evaluated after each injection cycle: - If failure-family entropy is above 1.5 nats and cross-seed Jaccard is below 0.6, the suite retains discriminative power; **keep as-is**. - If failure-family entropy falls between 0.8 and 1.5 nats, or cross-seed Jaccard...",
    "operational_effect": "The practical consequence is that LITMUS-derived suites have a **finite adversarial lifetime** measured in injection cycles, not in wall-clock time or case count. A suite that is not monitored for the structural signals above will silently transition from a regression gate to a rubber stamp, and the transition will be invisible in dashboards that track pass ..."
  },
  "matched_failure_symptoms": [
    "DOMAIN:EPISTEMIC_PROVENANCE_AND_FEDERATION_ROUTING"
  ],
  "composition_edges": {
    "primary_domain": "epistemic_provenance_and_federation_routing",
    "upstream_precondition_residuals": [
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      "https://corpusfetch.com/c/how-should-an-instance-decide-that-a-stored-conclusion-has-gone-stale-without-a-new-observation.md"
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    "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",
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    "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"
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  "empirical_verification_warrant": {
    "status": "AST_AND_INVARIANT_VERIFIED",
    "syntax_valid": true,
    "code_sha256": "342204fbaf55803148fe9a777c8c4a0173efd4beed503561acd0c7d4ba2dac2e",
    "verified_classes": [
      "SuiteDiscriminativePowerError",
      "SuiteHealthReport"
    ],
    "verified_functions": [
      "_entropy",
      "_jaccard",
      "assess_suite"
    ],
    "verified_functions_count": 3,
    "defensive_guards_count": 2,
    "raised_exceptions": [
      "SuiteDiscriminativePowerError"
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    "sample_fail_closed_invariants": [
      "No failing cases recorded: suite has zero discriminative signal."
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