github/copilot-sdk · error

failed to log message

Error message

failed to log message: %w

What it means

Session's logging path builds a log request from LogOptions (including optional ephemeral flag) and calls s.RPC.Log. This error wraps any failure of that RPC — the runtime rejected the log level/options or the transport failed.

Solutions

1. Check the wrapped error for the runtime's specific rejection
2. Verify the session is still connected before logging
3. Validate LogOptions (level, ephemeral) against the runtime version
4. Make logging non-fatal: log-and-continue instead of propagating

Example fix

// before
if err := session.Log(ctx, LevelInfo, msg, opts); err != nil { return err }
// after
if err := session.Log(ctx, LevelInfo, msg, opts); err != nil {
    log.Printf("session log dropped: %v", err) // keep app running
}

if session == nil || session.SessionID == "" {
    return errors.New("cannot log: session not connected")
}

if err := session.Log(ctx, level, msg, opts); err != nil {
    log.Printf("session log failed (dropped): %v", err)
    // do not propagate; logging must not break the app
}

When it happens

Trigger: Calling the session Log API (with LogOptions) when the `Log` RPC fails: invalid level/options for the runtime, dead connection, or unknown session.

Common situations: Emitting logs after the session/runtime was torn down; using a log option not supported by the running runtime; logging from a goroutine racing session disconnect.

Understand the failure class

Background: "API request failed": what wrapped HTTP errors from external APIs mean and how to find the real cause — this error's family across 29 libraries.

Related errors

• unknown error
• failed to get events
• failed to disconnect session
• failed to abort session
• No session found for sessionId

AI-assisted analysis of github/copilot-sdk@cd8cf15dc3 (2026-09-09). Data as JSON: /api/errors/ebc9a8757b801504. Report an issue: GitHub.

Appendix: source

Thrown at go/session.go:2087

//	session.Log(ctx, "Rate limit approaching", &copilot.LogOptions{Level: rpc.SessionLogLevelWarning})
//
//	// Ephemeral message (not persisted)
//	session.Log(ctx, "Working...", &copilot.LogOptions{Ephemeral: copilot.Bool(true)})
func (s *Session) Log(ctx context.Context, message string, opts *LogOptions) error {
	params := &rpc.LogRequest{Message: message}

	if opts != nil {
		if opts.Level != "" {
			params.Level = &opts.Level
		}
		if opts.Ephemeral != nil {
			params.Ephemeral = opts.Ephemeral
		}
	}

	_, err := s.RPC.Log(ctx, params)
	if err != nil {
		return fmt.Errorf("failed to log message: %w", err)
	}

	return nil
}

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