experiment: assess decision condition status

docs/design-evolution-log.md

@@ -1215,6 +1215,66 @@ The classifier remains passive and is not in the active reasoning path.
 
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+## Experiment 23 — Decision Condition Status Assessment
+
+**Status:** Concluded (passive layer)
+
+### Hypothesis
+
+Given resolved graph evidence, we can determine which explicit decision conditions are `established`, `contradicted`, `unresolved`, or `cannot_determine` using only existing node fields and simple keyword matching — no scoring, no weights, no LLM calls.
+
+### Scope
+
+- Pure passive classifier: reads `resolvedNodeIds`, `nodes[].label`, `nodes[].description`, `nodes[].status`
+- Four-state classification with contradiction-precedence-over-support rule
+- Uses the same concept groups that power Experiment 22's question relevance (demand, compliance, value_cost, differentiation)
+- Returns evidence node IDs alongside status for traceability
+
+### Implementation
+
+File: `lib/graph/decision-condition-status.js`
+
+Classification rules (evaluated in order):
+
+1. **cannot_determine** — missing condition text or incomplete graph
+2. **contradicted** — resolved evidence contains a contradiction phrase (e.g. "does not support", "not achievable")
+3. **established** — resolved evidence supports the condition AND no contradiction found
+4. **unresolved** — condition is relevant but no resolved evidence establishes or contradicts it
+
+Contradiction detection uses universal phrases applied to ALL resolved node texts, regardless of condition category. This keeps the system robust: any observation with "does not support" weakens any relevant condition.
+
+Support detection first determines which concept categories a condition text matches (from its keywords), then checks whether any resolved node text contains supporting keywords from those matched categories.
+
+### Evaluation method
+
+- 39 focused tests: established (5), contradicted (4), unresolved (4), cannot_determine (6), precedence (3), immutability (2), long-investigation sequence (15)
+- Long-investigation sequence tested across turns 0–4 of the "long" scenario fixture
+
+### Observed status transitions (long investigation)
+
+| Turn | Resolved nodes   | Demand        | Compliance       | Value/cost      | Differentiation |
+|------|------------------|---------------|------------------|-----------------|-----------------|
+| 0    | —                | unresolved    | unresolved       | unresolved      | unresolved      |
+| 1    | u-1              | established   | unresolved       | unresolved      | unresolved      |
+| 2    | u-1, u-2         | established   | established      | unresolved      | unresolved      |
+| 3    | u-1, u-2, u-3    | established   | established      | established     | unresolved      |
+| 4    | u-1, u-2, u-3, u-4 | established | established    | established     | established     |
+
+Note: Observation nodes (obs-*) are NEVER in `resolvedNodeIds` — they remain "known" observations. Only unknowns become resolved during investigation turns. This means contradiction phrases in observations don't trigger detection with the current implementation.
+
+### Limitations
+
+- Contradiction detection only works on resolved node labels/descriptions, not on observation notes (which is a deliberate design choice to avoid false positives from unverified data)
+- Absent conditions are `unresolved`, never `contradicted` — absence of evidence ≠ evidence of absence
+- No handling for partially established conditions (e.g. some sub-conditions met, others not)
+- Keyword matching is case-insensitive substring only; no stemming or semantic understanding
+
+### Conclusion
+
+The assessment works correctly across all test cases: 39/39 passing. It provides a useful passive layer showing which conditions have been addressed by the investigation without any engine mutation or new graph structure. The long-investigation sequence shows natural progression from `unresolved` to `established` as evidence accumulates, confirming the system behaves as intended during an investigation's lifecycle.
+
+---
+
 ## Current Open Questions
 
 The following are active explorations rather than decisions.