reasoning: preserve evidence versus clarification distinction

lib/graph/question-formulator.js

@@ -123,6 +123,49 @@ function buildEvidenceFallbackQuestion(meaning) {
   return `What evidence would confirm or rule out ${stripTrailingPunctuation(meaning)}?`;
 }
 
+function extractConstraintClarificationSubject(node) {
+  const label = stripTrailingPunctuation(node?.label || "");
+  const description = String(node?.description || "");
+  const combined = `${label} ${description}`;
+
+  const labelMatch = label.match(
+    /^Whether\s+(.+)\s+is\s+a\s+hard constraint$/i,
+  );
+  if (labelMatch?.[1]) {
+    return labelMatch[1].trim();
+  }
+
+  const descriptionMatch = combined.match(
+    /whether\s+(.+?)\s+is\s+a\s+hard constraint\s+or\s+a\s+preference(?:\/|-|\s)trade(?:\/|-|\s)?off/i,
+  );
+  if (descriptionMatch?.[1]) {
+    return descriptionMatch[1].trim();
+  }
+
+  return null;
+}
+
+function buildUserMeaningClarificationQuestion(node) {
+  const subject = extractConstraintClarificationSubject(node);
+
+  if (subject) {
+    return `Is ${subject} a hard constraint or a preference/trade-off?`;
+  }
+
+  return buildNeutralClarificationQuestion(extractMeaning(node));
+}
+
+function isUserOwnedMeaningBoundaryUnknown(node) {
+  const text = normaliseText(`${node?.label || ""} ${node?.description || ""}`);
+  return (
+    text.includes("hard constraint") &&
+    (text.includes("preference trade off") ||
+      text.includes("preference/trade-off") ||
+      text.includes("preference or trade off") ||
+      text.includes("preference or trade-off"))
+  );
+}
+
 function collectObservationNodes(graph) {
   return (graph?.nodes || []).filter(
     (node) => node.kind === "observation" && node.status === "supported",
@@ -1726,6 +1769,34 @@ export function formulateQuestion({ node, graph, context = {} }) {
   const rejectedQuestionFamilies = rejectedQuestionFamiliesForPattern(
     reasoningPatternSelection.pattern,
   );
+
+  if (isUserOwnedMeaningBoundaryUnknown(node)) {
+    const question = sanitizeQuestionText(
+      buildUserMeaningClarificationQuestion(node),
+    );
+    const questionComplexity = assessQuestionComplexity({
+      question,
+      selectedUnknown: node,
+      graph,
+    });
+
+    return {
+      question,
+      reason:
+        "Formulated as a user-clarification question because this unresolved distinction depends on the user's own meaning rather than external evidence.",
+      strategy: null,
+      investigationStrategy: null,
+      reasoningPattern: reasoningPatternSelection.pattern,
+      reasoningPatternReason: reasoningPatternSelection.reason,
+      questionFamily: "prioritisation",
+      allowedQuestionFamilies,
+      rejectedQuestionFamilies,
+      selectedQuestionTemplate: "user_meaning_clarification",
+      questionComplexity,
+      plainLanguageNormalisations: [],
+    };
+  }
+
   const foundationalDirectQuestion = buildFoundationalDirectQuestion(node);
   if (
     foundationalDirectQuestion &&
@@ -1794,7 +1865,7 @@ export function formulateQuestion({ node, graph, context = {} }) {
     )
   ) {
     question = sanitizeQuestionText(
-      investigationStrategy &&
+      (investigationStrategy &&
         isClaimLikeUnknown(
           node,
           normaliseText(
@@ -1807,7 +1878,8 @@ export function formulateQuestion({ node, graph, context = {} }) {
               .filter(Boolean)
               .join(" "),
           ),
-        )
+        )) ||
+        reasoningPatternSelection.pattern === "diagnosis"
         ? buildEvidenceFallbackQuestion(fallbackMeaning)
         : buildNeutralClarificationQuestion(fallbackMeaning),
     );

tests/graph/question-formulator.test.js

@@ -280,12 +280,12 @@ describe("formulateQuestion", () => {
     expect(result.pattern).toBe("comparison");
   });
 
-  it("constraint unknown uses evidence-gathering within the fixed strategy set", () => {
+  it("user-owned constraint ambiguity produces a clarification question rather than an evidence request", () => {
     const unknown = makeNode({
       id: "n-constraint",
-      label: "Budget constraint",
+      label: "Whether avoiding additional risk is a hard constraint",
       description:
-        "Need the main budget constraint because it limits the available options.",
+        "Need to know whether avoiding additional risk is a hard constraint or a preference/trade-off.",
       kind: "unknown",
       status: "unknown",
       confidence: "medium",
@@ -296,8 +296,33 @@ describe("formulateQuestion", () => {
       graph: makeGraphFor(unknown),
     });
 
-    expect(result.strategy).toBe("evidence_gathering");
+    expect(result.strategy).toBeNull();
+    expect(result.question).toBe(
+      "Is avoiding additional risk a hard constraint or a preference/trade-off?",
+    );
+  });
+
+  it("evidence-resolvable competing-cause unknown stays on an evidence route rather than neutral clarification", () => {
+    const unknown = makeNode({
+      id: "n-delivery-cause",
+      label: "Possible causes of the delivery delay",
+      description:
+        "Need to determine whether staff capacity or supplier lead times are responsible for the delivery delay.",
+      kind: "unknown",
+      status: "unknown",
+      confidence: "medium",
+    });
+
+    const result = formulateQuestion({
+      node: unknown,
+      graph: makeGraphFor(unknown, {
+        centralStatement: "Delivery is delayed and the cause is still unknown.",
+      }),
+    });
+
+    expect(result.reasoningPattern).toBe("diagnosis");
     expect(result.question).toContain("What evidence");
+    expect(result.question).not.toContain("What would clarify");
   });
 
   it("the same unknown can produce different questions when paired with different strategies", () => {