Hmbown/CodeWhale · error

{err}

Error message

{err}

What it means

The Anthropic SSE reader decodes only complete lines and decodes them strictly: a line containing bytes that are not valid UTF-8 produces this error instead of silently substituting U+FFFD replacement characters (a deliberate contract, tracked as #5374). `take_sse_line` splits on `\n`, strips a trailing `\r`, then runs `std::str::from_utf8`; on failure the `InvalidSseUtf8` error (with `valid_up_to`/`error_len`) is surfaced and the stream terminates.

Source

Thrown at crates/tui/src/client/anthropic.rs:344

                            stream_idle_timeout,
                            bytes_received,
                            stream_start.elapsed(),
                            last_chunk_at.elapsed(),
                        )));
                        return;
                    }
                };

                bytes_received += chunk.len();
                last_chunk_at = std::time::Instant::now();
                buffer.extend_from_slice(&chunk);

                loop {
                    let line = match super::take_sse_line(&mut buffer) {
                        Ok(Some(line)) => line,
                        Ok(None) => break,
                        Err(err) => {
                            yield Err(anyhow::anyhow!("{err}"));
                            return;
                        }
                    };

                    // `event:` lines are redundant (the data payload carries
                    // `type`) and comment/heartbeat lines are ignorable.
                    let Some(data) = super::extract_sse_data_value(&line) else {
                        continue;
                    };

                    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;
                        }

View on GitHub (pinned to 8880682c63)

Solutions

1. Bypass the intermediary: connect directly to the API endpoint without the SSL-inspecting proxy/VPN and retry.
2. Fix proxy configuration: disable response buffering/transcoding for `text/event-stream` and ensure compression is applied once.
3. If you control the server, audit what is written into the stream — the error means raw invalid bytes on a complete line.
4. Report persistent occurrences to the provider with a timestamp; strict rejection here is intentional so corruption is visible rather than silently mangled.

fn is_invalid_sse_utf8_error(e: &anyhow::Error) -> bool {
    e.to_string().contains("invalid UTF-8") || e.to_string().contains("valid up to")
}

// The stream terminates on invalid UTF-8 by design; surface the cause,
// do not swallow it into replacement characters.
match stream.next().await {
    Some(Err(e)) if is_invalid_sse_utf8_error(&e) => {
        log::error!("SSE stream corrupted (invalid UTF-8) — bypass SSL-inspecting proxies");
        return Err(e); // keep corruption visible instead of mangling output
    }
    other => handle(other),
}

When it happens

Trigger: A gateway/MITM proxy re-encoding or corrupting the event stream (e.g. broken chunked-compression, charset transcoding); a provider bug emitting binary garbage inside a `data:` line; a misbehaving cache layer serving mixed-encoding fragments. Because line splitting happens on `\n` bytes, normal multi-byte text split across reads is NOT a cause — only genuinely invalid byte sequences trigger it.

Common situations: Antivirus/SSL-inspection appliances rewriting SSE bodies; reverse proxies mis-applying gzip twice; self-hosted anthropic-compatible servers writing log bytes into the stream; extremely rare provider-side serialization bugs.

Related errors

• {err}
• Stream read error: {e}
• SSE stream idle timeout after {}s — no data received (bytes_
• Anthropic stream error ({error_type}): {message}
• invalid SSE JSON: {e}

AI-assisted analysis of Hmbown/CodeWhale@8880682c63 (2026-08-16). Data as JSON: /api/errors/17d420e74c3fbd44. Report an issue: GitHub.