fix(classifier): dedupe tool-error iteration numbers

internal/classifier/classify.go

@@ -99,8 +99,8 @@ func detectToolError(t *trace.Trace) *Classification {
 	for i, it := range t.Iterations {
 		if it.Phase == trace.PhaseError {
 			errorIters = append(errorIters, i+1)
-		}
-		if it.Verification != nil && it.Verification.Status == "fail" {
+		} else if it.Verification != nil && it.Verification.Status == "fail" {
+			// else-if: PhaseError + tool-ish verify fail must not record the same iter twice
 			output := strings.ToLower(it.Verification.Output)
 			if strings.Contains(output, "file not found") ||
 				strings.Contains(output, "permission denied") ||

internal/classifier/classify_test.go

@@ -124,3 +124,72 @@ func TestNoClassification_HealthyTrace(t *testing.T) {
 		t.Errorf("expected 0 classifications for healthy trace, got %d: %v", len(results), results)
 	}
 }
+
+func TestDetectToolError_NoDuplicateIterations(t *testing.T) {
+	// Iteration with PhaseError AND a tool-ish verify fail used to be recorded twice
+	// (e.g. "Tool errors at iterations [3, 3, 5]").
+	tr := trace.New([]trace.Iteration{
+		{Number: 1, Phase: trace.PhaseAct},
+		{Number: 2, Phase: trace.PhaseAct},
+		{
+			Number: 3,
+			Phase:  trace.PhaseError,
+			Verification: &trace.Verification{
+				Status: "fail",
+				Output: "Error: file not found: src/missing.ts",
+			},
+		},
+		{Number: 4, Phase: trace.PhaseAct},
+		{
+			Number: 5,
+			Phase:  trace.PhaseError,
+			Verification: &trace.Verification{
+				Status: "fail",
+				Output: "permission denied",
+			},
+		},
+	})
+
+	results := Classify(tr)
+	var evidence string
+	found := false
+	for _, r := range results {
+		if r.Category == CatToolError {
+			found = true
+			evidence = r.Evidence
+		}
+	}
+	if !found {
+		t.Fatal("expected tool_error classification")
+	}
+	if evidence != "Tool errors at iterations [3 5], never recovered" {
+		t.Fatalf("expected deduped iterations [3 5], got evidence %q", evidence)
+	}
+}
+
+func TestDetectToolError_VerifyFailWithoutPhaseError(t *testing.T) {
+	tr := trace.New([]trace.Iteration{
+		{
+			Number: 1,
+			Phase:  trace.PhaseVerify,
+			Verification: &trace.Verification{
+				Status: "fail",
+				Output: "command not found: foo",
+			},
+		},
+	})
+
+	results := Classify(tr)
+	found := false
+	for _, r := range results {
+		if r.Category == CatToolError {
+			found = true
+			if r.Evidence != "Tool errors at iterations [1], never recovered" {
+				t.Fatalf("unexpected evidence: %q", r.Evidence)
+			}
+		}
+	}
+	if !found {
+		t.Fatal("expected tool_error when verify fail has tool-ish output")
+	}
+}