reasoning: preserve evidence versus clarification distinction

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", () => {