chenhg5/cc-connect · error

synthesize: %w

Error message

synthesize: %w

What it means

cc-connect wraps any failure from the configured TTS engine's Synthesize call (which converts reply text into audio data) with the 'synthesize: %w' prefix. The error is a pass-through wrapper: the underlying cause (network, auth, quota, unsupported text) is preserved via %w and should be inspected with errors.Unwrap or errors.As. It is thrown in the engine's TTS reply path before any audio is sent to the platform.

Source

Thrown at core/engine.go:15889

	if e.tts.TTS == nil {
		return fmt.Errorf("tts provider is not configured")
	}
	if e.tts.MaxTextLen > 0 && utf8.RuneCountInString(text) > e.tts.MaxTextLen {
		return fmt.Errorf("text exceeds max_text_len (%d > %d)", utf8.RuneCountInString(text), e.tts.MaxTextLen)
	}
	as, ok := p.(AudioSender)
	if !ok {
		return fmt.Errorf("platform %s does not support audio sending", p.Name())
	}
	slog.Info("tts: starting synthesis", "voice", e.tts.Voice, "speed", e.tts.Speed, "text_len", len(text))
	opts := TTSSynthesisOpts{
		Voice:        e.tts.Voice,
		LanguageType: e.tts.LanguageType,
		Speed:        e.tts.Speed,
	}
	audioData, format, err := e.tts.TTS.Synthesize(e.ctx, StripMarkdown(text), opts)
	if err != nil {
		return fmt.Errorf("synthesize: %w", err)
	}
	slog.Info("tts: synthesis successful", "format", format, "audio_size", len(audioData))
	if err := as.SendAudio(e.ctx, replyCtx, audioData, format); err != nil {
		return fmt.Errorf("send audio: %w", err)
	}
	slog.Info("tts: audio sent successfully", "platform", p.Name())
	return nil
}

// ──────────────────────────────────────────────────────────────
// Bot-to-bot relay
// ──────────────────────────────────────────────────────────────

type platformNameOnly struct {
	name string
}

func (p platformNameOnly) Name() string                           { return p.name }

View on GitHub (pinned to 4000b2338a)

Solutions

1. Check the wrapped cause with errors.Unwrap(err) or %v of the error to see the provider-specific failure
2. Verify TTS provider credentials/endpoint in the [tts] section of config.toml
3. Test the TTS provider directly (curl / SDK sample) to rule out outage or quota limits
4. Check network egress/proxy settings on the host running cc-connect
5. Retry — transient network or rate-limit failures resolve on their own

Example fix

// before
if err != nil {
    return fmt.Errorf("synthesize: %w", err)
}
// after
if err != nil {
    if errors.Is(err, context.Canceled) {
        return err // don't log user-initiated cancellation as failure
    }
    slog.Warn("tts: synthesis failed, falling back to text reply", "error", err)
    return fmt.Errorf("synthesize: %w", err)
}

// before enabling TTS, verify provider works
if e.tts != nil && e.tts.TTS != nil {
    if _, _, err := e.tts.TTS.Synthesize(ctx, "ping", opts); err != nil {
        slog.Warn("tts provider unavailable, disabling TTS", "error", err)
    }
}

func ttsAvailable(e *Engine) bool {
    return e != nil && e.tts != nil && e.tts.TTS != nil
}

if err != nil {
    var ctxErr error
    switch {
    case errors.Is(err, context.Canceled), errors.Is(err, context.DeadlineExceeded):
        return err // expected during shutdown
    default:
        slog.Error("tts synthesize failed", "cause", errors.Unwrap(err))
        return fmt.Errorf("synthesize: %w", err)
    }
    _ = ctxErr
}

When it happens

Trigger: A message reply triggers text-to-speech (e.tts configured) and e.tts.TTS.Synthesize(e.ctx, StripMarkdown(text), opts) returns a non-nil error — e.g. the TTS provider API is unreachable, credentials are invalid, the text exceeds provider limits, or the context is cancelled mid-request.

Common situations: Misconfigured TTS provider credentials in config.toml; TTS service outage or rate limiting; text length exceeding the provider's max input; network egress blocked in the deployment environment; e.ctx cancelled because the user stopped the bot.

Related errors

• platform %s does not support audio sending
• send audio: %w
• openai tts: create request: %w
• openai tts: request: %w
• openai tts API %d: %s

AI-assisted analysis of chenhg5/cc-connect@4000b2338a (2026-09-06). Data as JSON: /api/errors/4c8b64b176d4ff1f. Report an issue: GitHub.