openclaw - 💡(How to fix) Fix [Feature]: Signal channel — pluggable audio preflight (whisper auto-transcribe for voice notes) [1 participants]

Ask

Expose a pluggable audio-preflight hook for the Signal channel (and ideally a channel-agnostic base) so voice notes can be auto-transcribed before they reach the agent — parity with Telegram and Discord.

Two flavors would work:

1. Built-in whisper integration, mirroring what Telegram/Discord ship — a config key like channels.signal.audio.transcribe: whisper with provider auth pulled from the same place other channels use.
2. Config hook for an external converter, e.g.

   channels:
     signal:
       audio:
         preflight_cmd: "/usr/local/bin/whisper-any.sh {{ MediaPath }}"

   The gateway invokes the command with the media path, reads stdout as transcript, and substitutes it for the <media:audio> placeholder before the agent sees the message.

Why

Today Signal inbound voice notes arrive at the agent as <media:audio> placeholder text with no transcript. The agent has no transcribe-tool to call, so it responds blindly. Telegram and Discord auto-transcribe via built-in whisper; Signal doesn't.

Gotchas to document

If upstream ships option (1), two issues we hit on a local workaround:

• The Signal monitor exposes {{ MediaPath }} (Handlebars-style), not {input} or {path}. Document which template variables are available to the preflight hook.
• whisper-cli only reads WAV. Inbound Signal audio is typically OGG/Opus or MP4 — the hook needs access to an ffmpeg or similar to convert first. A small bundled wrapper (or docs pointing at one) would save users reinventing it.

Related

• #48614 [Bug]: Signal voice notes — MediaPath not populated, audio transcription pipeline never triggers
• #46326 Audio transcription stopped working after update to 2026.3.12/3.13
• #54695 [Bug] STT transcription not working on Telegram (Groq)
• #51645 Voice transcription not working in group/topic chats

Context

We were carrying a local patch against dist/monitor-*.js that called transcribeFirstAudio() from the plugin-sdk on inbound Signal audio. Retiring it because minified targets drift across releases (2026.4.21 changed the monitor bundle structure). Prefer an officially supported hook.

Env

• [email protected]
• Signal channel via signal-cli, multi-tenant self-host