fix(agents): apply truncation cap to structured tool-result fallback (#97267)

zw-xysk · zw-xysk · commit 3c7be77cf084 · 2026-06-28T00:52:01.000+08:00
Preserve the existing TOOL_RESULT_MAX_CHARS truncation invariant
in the new structured-block JSON serialization fallback path.
ClawSweeper review noted the path was added without cap coverage.
diff --git a/src/agents/embedded-agent-subscribe.tools.test.ts b/src/agents/embedded-agent-subscribe.tools.test.ts
@@ -441,4 +441,14 @@ describe("extractToolResultText", () => {
     expect(withoutText).toBeDefined();
     expect(withoutText).toContain("resource");
   });
+
+  it("truncates large structured fallback output to TOOL_RESULT_MAX_CHARS (#97267)", () => {
+    const bigData = "x".repeat(10_000);
+    const text = extractToolResultText({
+      content: [{ type: "resource", resource: { data: bigData } }],
+    });
+    expect(text).toBeDefined();
+    expect(text!.length).toBeLessThanOrEqual(8100);
+    expect(text).toContain("(truncated)");
+  });
 });
diff --git a/src/agents/embedded-agent-subscribe.tools.ts b/src/agents/embedded-agent-subscribe.tools.ts
@@ -303,7 +303,8 @@ export function extractToolResultText(result: unknown): string | undefined {
       }
     }
     if (fallbackParts.length > 0) {
-      return fallbackParts.join("\n");
+      const joined = fallbackParts.join("\n");
+      return truncateToolText(joined);
     }
   }
 

Original file line number	Diff line number	Diff line change
`@@ -303,7 +303,8 @@ export function extractToolResultText(result: unknown): string \| undefined {`
`303`	`303`	`}`
`304`	`304`	`}`
`305`	`305`	`if (fallbackParts.length > 0) {`
`306`		`- return fallbackParts.join("\n");`
	`306`	`+ const joined = fallbackParts.join("\n");`
	`307`	`+ return truncateToolText(joined);`
`307`	`308`	`}`
`308`	`309`	`}`
`309`	`310`