@@ -78,6 +78,19 @@ describe("workEntryIndicatesToolFailure", () => {
     },
   );
 
+  it("ignores failure phrases in reasoning text", () => {
+    const entry: WorkLogPresentationEntry = {
+      ...base,
+      label: "Thinking",
+      tone: "thinking",
+      itemType: "reasoning",
+      toolLifecycleStatus: "completed",
+      detail: "That exit code 2 is just from listing the deleted directory, which is expected.",
+    };
+    expect(workEntryIndicatesToolFailure(entry)).toBe(false);
+    expect(workEntryDisplayIndicatesToolFailure(entry)).toBe(false);
+  });
+
   it("is true for error tone", () => {
     expect(
       workEntryIndicatesToolFailure({
 
@@ -365,7 +365,10 @@ function workEntryIndicatesToolFailureFromOutput(
   ) {
     return true;
   }
-  if (!workLogEntryIsToolLike(entry)) return false;
+  // Reasoning detail is the model's own prose (often tens of KB), not tool
+  // output: scanning it is slow on long threads and misreads phrases like
+  // "that exit code 2 is expected" as a failed tool.
+  if (!workLogEntryIsToolLike(entry) || entry.itemType === "reasoning") return false;
   if (
     resolveT3McpToolDefinition(workEntryToolName(entry)) &&
     t3ToolResultIndicatesFailure(workEntryToolOutput(entry))