test: establish canonical live reasoning experiment harness

docs/task-context-packs.md

@@ -24,6 +24,48 @@
 - the task requires an undocumented contract;
 - the experiment begins expanding into several capabilities.
 
+### Live experiment execution route
+
+A canonical live-update harness exists at `tests/graph/live-update-experiment-helper.cjs`.
+It loads `.env.local`, validates required variables, invokes the real `updateCase()` production
+entry point, and returns standard reasoning checkpoints (userSupportedMeaning, possibleInference,
+rawAnswerCategory, proposedMeaningCategory, proposalValidation, compatibilityGuard, graphMutation,
+selectedQuestion, behaviourSelection, reasoningState).
+
+**Execution pattern:**
+
+```js
+const { runLiveExperiment } = require("./tests/graph/live-update-experiment-helper.cjs");
+
+const result = await runLiveExperiment({
+  graph: /* SituationGraph fixture *\/,
+  previousQuestion: "Is risk a hard constraint?",
+  answer: "Risk matters more to me.",
+});
+
+// Checkpoints available on `result`:
+//   result.userSupportedMeaning
+//   result.possibleInference
+//   result.rawAnswerCategory
+//   result.proposedMeaningCategory
+//   result.proposalValidation
+//   result.compatibilityGuard
+//   result.graphMutation
+//   result.selectedQuestion
+//   result.behaviourSelection
+//   result.reasoningState
+```
+
+**Required environment (from `.env.local`):**
+- `process.env.OLLAMA_BASE_URL` — must be a real host (no localhost fallback)
+- `process.env.OLLAMA_MODEL` — model name (e.g. `qwen-claude:latest`)
+
+The harness fails clearly if either variable is missing or OLLAMA_BASE_URL points to localhost.
+It makes exactly one live Ollama call per invocation unless the experiment explicitly specifies otherwise.
+
+**Rule:** During normal reasoning experiments, never create a bespoke harness, enumerate `/api/tags`,
+probe localhost, or discover/substitute another model. Use the canonical harness above.
+
 ## Pack 2 — UI and Mock Work
 
 ### Always read