fix(ai): fix bedrock throttling misidentification (#2699)

- Add NON_OVERFLOW_PATTERNS to explicitly exclude known non-overflow errors
- Consolidate Cerebras 400/413 no-body check into OVERFLOW_PATTERNS
- Format Bedrock errors as ${error.name}: ${error.message} for pattern matching

packages/ai/test/overflow.test.ts

@@ -39,4 +39,26 @@ describe("isContextOverflow", () => {
 		const message = createErrorMessage("500 `model runner crashed unexpectedly`");
 		expect(isContextOverflow(message, 32768)).toBe(false);
 	});
+
+	it("does not treat Bedrock throttling 'Too many tokens' as overflow", () => {
+		// Bedrock returns this for HTTP 429 rate limiting, NOT context overflow.
+		// formatBedrockError uses a human-readable prefix for ThrottlingException.
+		const message = createErrorMessage("Throttling error: Too many tokens, please wait before trying again.");
+		expect(isContextOverflow(message, 200000)).toBe(false);
+	});
+
+	it("does not treat Bedrock service unavailable as overflow", () => {
+		const message = createErrorMessage("Service unavailable: The service is temporarily unavailable.");
+		expect(isContextOverflow(message, 200000)).toBe(false);
+	});
+
+	it("does not treat generic rate limit errors as overflow", () => {
+		const message = createErrorMessage("Rate limit exceeded, please retry after 30 seconds.");
+		expect(isContextOverflow(message, 200000)).toBe(false);
+	});
+
+	it("does not treat HTTP 429 style errors as overflow", () => {
+		const message = createErrorMessage("Too many requests. Please slow down.");
+		expect(isContextOverflow(message, 200000)).toBe(false);
+	});
 });