Hmbown/CodeWhale · error

Failed to parse Anthropic SSE event: {e}

Error message

Failed to parse Anthropic SSE event: {e}

What it means

In the Anthropic SSE stream handler, convert_anthropic_sse_data failing to parse an event's data payload yields Err("Failed to parse Anthropic SSE event: {e}") into the stream, terminating it. This fires when the upstream returns malformed or unexpected JSON on the SSE channel (proxy truncation, protocol drift, non-event body on a 200 stream) — the stream surfaces it as a normal error result for the turn rather than panicking.

Source

Thrown at crates/tui/src/client/anthropic.rs:374

                    };

                    match convert_anthropic_sse_data(data) {
                        Some(Ok(StreamEvent::Error { error })) => {
                            let (error_type, message) = anthropic_error_fields(&error);
                            yield Err(anyhow::anyhow!(
                                "Anthropic stream error ({error_type}): {message}"
                            ));
                            return;
                        }
                        Some(Ok(event)) => {
                            let is_stop = matches!(event, StreamEvent::MessageStop);
                            yield Ok(event);
                            if is_stop {
                                return;
                            }
                        }
                        Some(Err(e)) => {
                            logging::warn(format!("Failed to parse Anthropic SSE event: {e}"));
                        }
                        None => {}
                    }
                }

                if ended {
                    break;
                }
            }
        };

        Ok(Box::pin(stream))
    }

    /// Handle a non-streaming Messages API request.
    pub(super) async fn handle_anthropic_message(
        &self,
        prepared: &super::PreparedOutboundRequest,

View on GitHub (pinned to 0c42157ee5)

Solutions

1. Retry the request; transient proxy truncation is the most common cause
2. Capture the raw SSE body (debug logging) if the error repeats to check for API protocol changes
3. Confirm no auth/error HTML page is being streamed in place of SSE events

When it happens

Trigger: Thrown at crates/tui/src/client/anthropic.rs:374 when the library encounters an invalid state.

Common situations: See trigger scenarios.

Understand the failure class

• Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

AI-assisted analysis of Hmbown/CodeWhale@0c42157ee5 (2026-08-20). Data as JSON: /api/errors/f676468b41d9f3e2. Report an issue: GitHub.