spring-projects/spring-ai · error · AnthropicIoException

Failed to write request body

Error message

Failed to write request body

What it means

The custom OkHttp RequestBody created by toHttpRequestBody writes its content to the network sink via source.writeTo(sink). If an IOException occurs while streaming bytes to the output stream, it is wrapped in AnthropicIoException 'Failed to write request body'.

Source

Thrown at models/spring-ai-anthropic/src/main/java/org/springframework/ai/anthropic/http/okhttp/SpringAiAnthropicHttpClient.java:427

			@Override
			public long contentLength() {
				return length;
			}

			@Override
			public boolean repeatable() {
				return !isOneShot;
			}

			@Override
			public void writeTo(OutputStream outputStream) {
				BufferedSink sink = Okio.buffer(Okio.sink(outputStream));
				try {
					source.writeTo(sink);
					sink.flush();
				}
				catch (IOException e) {
					throw new AnthropicIoException("Failed to write request body", e);
				}
			}

			@Override
			public void close() {
			}
		};
	}

	private static Headers toAnthropicHeaders(okhttp3.Headers okHttpHeaders) {
		Headers.Builder builder = Headers.builder();
		for (int i = 0, n = okHttpHeaders.size(); i < n; i++) {
			builder.put(okHttpHeaders.name(i), okHttpHeaders.value(i));
		}
		return builder.build();
	}

	/**

View on GitHub (pinned to 98a7beda4f)

Solutions

1. Retry the request; transient write failures on uploads are usually recoverable.
2. Reduce payload size or enable compression before upload.
3. Increase OkHttp writeTimeout/callTimeout for large request bodies.
4. Check network stability/proxy configuration and inspect the wrapped cause.

Example fix

// before
client.upload(bigFile); // fails on flaky network
// after
try {
    client.upload(bigFile);
} catch (AnthropicIoException e) {
    retryWithBackoff(() -> client.upload(bigFile), 3);
}

static void assertUploadSizeWithin(long bytes, long maxBytes) {
    if (bytes > maxBytes) throw new IllegalStateException("Upload too large: " + bytes);
}

try {
    return client.sendRequest(request);
} catch (AnthropicIoException e) {
    if (e.getCause() instanceof IOException) return retryWithBackoff(...); // transient write failure
    throw e;
}

When it happens

Trigger: The connection breaks while the request body is being uploaded (large uploads), the source content itself throws while reading, or the socket write times out during writeTo.

Common situations: Uploading large payloads over unstable networks; request timeouts set shorter than upload duration; proxy or load balancer cutting the connection mid-upload.

Related errors

• Request failed
• Failed to read audio speech response
• Request failed
• Failed to write request body
• Failed to cache the resource:

AI-assisted analysis of spring-projects/spring-ai@98a7beda4f (2026-09-11). Data as JSON: /api/errors/45efdff33d0d62ae. Report an issue: GitHub.