fix(agents): skip extracting tool calls from errored assistant turns

When an assistant turn has stopReason: "error", the tool calls within
it were never completed (often contain partialJson). Inserting synthetic
tool_results for these caused Anthropic's API to reject requests with
"unexpected tool_use_id" errors, permanently breaking the session.

Now we skip extracting tool calls from assistant messages with
stopReason: "error", preventing the broken synthetic results.

Fixes #1826

Co-Authored-By: Claude <noreply@anthropic.com>

src/agents/session-transcript-repair.test.ts

@@ -109,4 +109,34 @@ describe("sanitizeToolUseResultPairing", () => {
     expect(out.some((m) => m.role === "toolResult")).toBe(false);
     expect(out.map((m) => m.role)).toEqual(["user", "assistant"]);
   });
+
+  it("does not insert synthetic tool results for errored/terminated assistant turns", () => {
+    // When an assistant turn has stopReason: "error", the tool calls within it were
+    // never completed. Inserting synthetic tool_results would cause Anthropic's API
+    // to reject requests with "unexpected tool_use_id".
+    // See: https://github.com/clawdbot/clawdbot/issues/1826
+    const input = [
+      { role: "user", content: "schedule a reminder" },
+      {
+        role: "assistant",
+        content: [
+          {
+            type: "toolCall",
+            id: "toolu_terminated",
+            name: "cron",
+            arguments: { action: "add" },
+            partialJson: '{"action": "add", "job": {"name": "test',
+          },
+        ],
+        stopReason: "error",
+        errorMessage: "terminated",
+      },
+      { role: "user", content: "what happened?" },
+    ] satisfies AgentMessage[];
+
+    const out = sanitizeToolUseResultPairing(input);
+    // Should NOT have any tool results - the errored turn's tool calls are ignored
+    expect(out.some((m) => m.role === "toolResult")).toBe(false);
+    expect(out.map((m) => m.role)).toEqual(["user", "assistant", "user"]);
+  });
 });

src/agents/session-transcript-repair.ts

@@ -8,6 +8,14 @@ type ToolCallLike = {
 function extractToolCallsFromAssistant(
   msg: Extract<AgentMessage, { role: "assistant" }>,
 ): ToolCallLike[] {
+  // Skip extracting tool calls if the assistant turn errored/terminated.
+  // Errored turns contain incomplete tool calls (often with partialJson) that
+  // were never executed. Inserting synthetic tool_results for these would cause
+  // Anthropic's API to reject subsequent requests with "unexpected tool_use_id".
+  // See: https://github.com/clawdbot/clawdbot/issues/1826
+  const stopReason = (msg as { stopReason?: unknown }).stopReason;
+  if (stopReason === "error") return [];
+
   const content = msg.content;
   if (!Array.isArray(content)) return [];