fix(agents): keep emoji / surrogate pairs intact during error observation truncation

maweibin · claude · maweibin · commit 8e1126296147 · 2026-07-07T20:06:12.000+08:00
Use truncateUtf16Safe() instead of .slice() to count full code points.

Co-Authored-By: Claude Opus 4.8 &lt;noreply@anthropic.com&gt;
diff --git a/src/agents/embedded-agent-error-observation.test.ts b/src/agents/embedded-agent-error-observation.test.ts
@@ -207,3 +207,14 @@ describe("sanitizeForConsole", () => {
     expect(sanitizeForConsole("run-1\nprovider\tmodel\rtest")).toBe("run-1 provider model test");
   });
 });
+
+describe("observation truncation", () => {
+  it("does not split surrogate pairs", async () => {
+    const { truncateUtf16Safe } = await import("@openclaw/normalization-core/utf16-slice");
+    const content = "x".repeat(77) + "🚀tail";
+    const bad = content.slice(0, 78);
+    expect(bad.endsWith("\uD83D")).toBe(true);
+    const good = truncateUtf16Safe(content, 78);
+    expect(good).toBe("x".repeat(77));
+  });
+});
diff --git a/src/agents/embedded-agent-error-observation.ts b/src/agents/embedded-agent-error-observation.ts
@@ -1,10 +1,11 @@
-/**
- * Builds structured observations for embedded-agent API/text failures.
- */
 import { normalizeOptionalString } from "@openclaw/normalization-core/string-coerce";
 import { readLoggingConfig } from "../logging/config.js";
 import { redactIdentifier } from "../logging/redact-identifier.js";
 import { getDefaultRedactPatterns, redactSensitiveText } from "../logging/redact.js";
+/**
+ * Builds structured observations for embedded-agent API/text failures.
+ */
+import { truncateUtf16Safe } from "../utils.js";
 import {
   classifyProviderRuntimeFailureKind,
   getApiErrorPayloadFingerprint,
@@ -43,7 +44,7 @@ function truncateForObservation(text: string | undefined, maxChars: number): str
   if (!trimmed) {
     return undefined;
   }
-  return trimmed.length > maxChars ? `${trimmed.slice(0, maxChars)}…` : trimmed;
+  return trimmed.length > maxChars ? `${truncateUtf16Safe(trimmed, maxChars)}…` : trimmed;
 }
 
 function boundObservationInput(text: string | undefined): string | undefined {
