sigoden/aichat · error

Invalid response data

Error message

Invalid response data: {data} (smithy_type: {smithy_type})

What it means

During Bedrock's smithy EventStream decoding, a message of type 'exception' arrives over the stream. The library base64-decodes the payload and bails with 'Invalid response data' including the payload text and its smithy_type. This is Bedrock signaling a mid-stream exception (e.g. ModelStreamErrorException, ThrottlingException) that the client surfaces verbatim.

Solutions

1. Read smithy_type and the decoded payload in the message to identify the exact Bedrock exception
2. Implement retry with exponential backoff for throttling-type exceptions
3. Reduce request size (shorter prompt / smaller max_tokens) to avoid stream timeouts
4. Check service health and quota limits in the AWS console
5. Ensure SDK/region config is correct if the exception indicates validation failure

Example fix

// before
match result { Err(e) if e.to_string().contains("Throttling") => bail!(e), ... }
// after: retry throttled stream errors
let out = loop {
    match client.chat_completions_streaming(req).await {
        Err(e) if e.to_string().contains("ThrottlingException") => { tokio::time::sleep(backoff).await; backoff *= 2; }
        other => break other,
    }
};

match result {
    Err(e) if e.to_string().contains("smithy_type: ThrottlingException") => retry_with_backoff(),
    Err(e) if e.to_string().contains("Invalid response data") => log::error!("bedrock stream exception: {e}"),
    other => other?,
}

When it happens

Trigger: chat_completions_streaming receives an event-stream message with message_type == "exception"; the decoded payload text and smithy_type are included in the error message.

Common situations: Bedrock throttles the stream mid-generation (ThrottlingException), the model stream fails internally (ModelStreamErrorException/ModelTimeoutException), or a long-running generation exceeds service limits.

Related errors

• Unrecognized message, message_type
• Invalid response data
• The model does not support network images
• {err}
• Failed to read json stream

AI-assisted analysis of sigoden/aichat@82976d349a (2026-09-09). Data as JSON: /api/errors/c697fc5068c7fa1f. Report an issue: GitHub.

Appendix: source

Thrown at src/client/bedrock.rs:291

                                }
                                let arguments: Value = function_arguments.parse().with_context(|| {
                                    format!("Tool call '{function_name}' have non-JSON arguments '{function_arguments}'")
                                })?;
                                handler.tool_call(ToolCall::new(
                                    function_name.clone(),
                                    arguments,
                                    Some(function_id.clone()),
                                ))?;
                            }
                        }
                        _ => {}
                    }
                }
                ("exception", _) => {
                    let payload = base64_decode(message.payload())?;
                    let data = String::from_utf8_lossy(&payload);

                    bail!("Invalid response data: {data} (smithy_type: {smithy_type})")
                }
                _ => {
                    bail!("Unrecognized message, message_type: {message_type}, smithy_type: {smithy_type}",);
                }
            }
        }
    }
    Ok(())
}

async fn embeddings(builder: RequestBuilder) -> Result<EmbeddingsOutput> {
    let res = builder.send().await?;
    let status = res.status();
    let data: Value = res.json().await?;

    if !status.is_success() {
        catch_error(&data, status.as_u16())?;
    }

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