fix(server): cover imported and failed shell output

packages/server/src/server/agent/agent-manager-stream-coalescing.test.ts

@@ -473,6 +473,27 @@ describe("target coalesced behavior", () => {
     }
   });
 
+  test("bounds failed shell output carried in the error", async () => {
+    const harness = createHarness();
+    try {
+      const { agentId, session } = await createManagedSession(harness);
+      const content = `${"a".repeat(512 * 1024)}${"z".repeat(512 * 1024)}`;
+      const expectedItem = toolCall({
+        status: "failed",
+        error: { content: "a".repeat(TOOL_CALL_CONTENT_MAX_LENGTH) },
+      });
+
+      session.pushEvent(timelineEvent(toolCall({ status: "failed", error: { content } })));
+      await waitForSessionEventQueue();
+
+      expect(getTimelineItems(await harness.manager.getTimelineRows(agentId))).toEqual([
+        expectedItem,
+      ]);
+    } finally {
+      harness.cleanup();
+    }
+  });
+
   test(`coalesces a same-tick assistant burst after the ${COALESCE_WINDOW_MS}ms window`, async () => {
     vi.useFakeTimers();
     const harness = createHarness();

packages/server/src/server/agent/agent-manager.test.ts

@@ -2314,6 +2314,22 @@ test("importProviderSession imports the selected session without listing and pub
             item: { type: "assistant_message" as const, text: "Done" },
             timestamp: "2026-01-02T00:00:01.000Z",
           },
+          {
+            item: {
+              type: "tool_call" as const,
+              callId: "large-shell-result",
+              name: "shell",
+              status: "completed" as const,
+              error: null,
+              detail: {
+                type: "shell" as const,
+                command: "print output",
+                output: "x".repeat(1024 * 1024),
+                exitCode: 0,
+              },
+            },
+            timestamp: "2026-01-02T00:00:02.000Z",
+          },
         ],
       };
     }
@@ -2343,6 +2359,19 @@ test("importProviderSession imports the selected session without listing and pub
   expect(manager.getTimeline(imported.id)).toEqual([
     { type: "user_message", text: "Trace provider imports" },
     { type: "assistant_message", text: "Done" },
+    {
+      type: "tool_call",
+      callId: "large-shell-result",
+      name: "shell",
+      status: "completed",
+      error: null,
+      detail: {
+        type: "shell",
+        command: "print output",
+        output: "x".repeat(64 * 1024),
+        exitCode: 0,
+      },
+    },
   ]);
   expect(events).toHaveLength(1);
   expect(events[0]).toMatchObject({

packages/server/src/server/agent/agent-manager.ts

@@ -494,7 +494,7 @@ function buildImportedTimelineRows(entries: readonly ImportedTimelineEntry[]): A
     rows.push({
       seq: rows.length + 1,
       timestamp: entry.timestamp ?? new Date().toISOString(),
-      item: entry.item,
+      item: limitAgentTimelineItemContent(entry.item),
     });
   }
   return rows;

packages/server/src/server/agent/agent-timeline-content.ts

@@ -2,7 +2,30 @@ import type { AgentTimelineItem } from "./agent-sdk-types.js";
 
 const TOOL_CALL_CONTENT_MAX_LENGTH = 64 * 1024;
 
+function limitFailedShellError(item: AgentTimelineItem): AgentTimelineItem {
+  if (
+    item.type !== "tool_call" ||
+    item.detail.type !== "shell" ||
+    item.status !== "failed" ||
+    typeof item.error !== "object" ||
+    item.error === null ||
+    !("content" in item.error) ||
+    typeof item.error.content !== "string" ||
+    item.error.content.length <= TOOL_CALL_CONTENT_MAX_LENGTH
+  ) {
+    return item;
+  }
+  return {
+    ...item,
+    error: {
+      ...item.error,
+      content: item.error.content.slice(0, TOOL_CALL_CONTENT_MAX_LENGTH),
+    },
+  };
+}
+
 export function limitAgentTimelineItemContent(item: AgentTimelineItem): AgentTimelineItem {
+  item = limitFailedShellError(item);
   if (
     item.type !== "tool_call" ||
     item.detail.type !== "shell" ||