Telemost Recorder — production verification of Zoom and Yandex Telemost
Telemost Recorder — production verification of Zoom and Yandex Telemost
Operational snapshot recorded after production incident investigation and live acceptance testing on 2026-09-29.
Confirmed platform status
- Zoom works in production. A real Zoom meeting
99262276704was recorded. Telegram stop initiated graceful leave; original audio was uploaded to Yandex Disk; two audio tracks were transcribed through AssemblyAI; transcript, AI summary, MongoDB record, and raw LLM Wiki ingest were produced. - Yandex Telemost works in production. A real acceptance meeting
77647324350820was used after deploying the safety and stop fixes. The bot joined successfully, confirmed microphone and camera off before and after joining, detected the canonical stop lock, shut down with recorder exit code0, uploaded the original audio to Yandex Disk, transcribed the spoken channel, and discarded an empty channel.
Incident and root causes
During an earlier real Telemost meeting, participants heard unwanted sounds from the recorder bot. The recorder launched headless Chromium with a fake media device, generated a private-join URL with mic=on and camera=on, disabled noise cancellation, and skipped the UI mute block in headless mode. No user had requested audio output, camera, screen sharing, or visual presentation from the bot.
The Telegram stop button also failed for a Telemost URL containing ?from=.... Telegram used the canonical meeting ID, while the recorder derived its stop filename from the entire final URL segment, including a sanitized query string. Therefore button and monitor referred to different lock filenames.
Applied fixes
Commits:
6605ff7—fix: make Telemost recording receive-only and stoppable38f72e0—fix: initialize Telemost shutdown guard before meeting loop
Implemented controls:
1. Telemost private join defaults to mic=off, camera=off, noise cancellation enabled. 2. Fake media device removed from Telemost Chromium launch. 3. UI state is checked across frames before and after joining; unsafe or unconfirmed state fails closed. 4. A WebRTC-level guard disables/stops/removes local audio/video senders and changes sending transceivers to receive-only. 5. Canonical meeting ID is obtained through detectPlatform; query parameters never enter stop filenames. 6. Telegram stop delivers both a canonical lock file and a signal to the registered process. 7. Graceful shutdown is idempotent; stale stop locks are removed. 8. MediaRecorder stop events and pending final chunk writes are awaited before browser close. 9. Telegram status distinguishes command delivery from completion; processed output is the completion proof. 10. Cyrillic wake-word matching was corrected; production recorder contract tests now target the actual Telemost implementation.
Verification evidence
- Full host test suite after fixes: 73 tests passed, 0 failed.
- Full test suite inside the rebuilt production container before the final regression fix: 72 passed, 0 failed; the added shutdown ordering regression test raises the final suite to 73.
- Production container rebuilt and restarted successfully.
- First live Telemost test exposed a temporal-dead-zone bug in the idempotent shutdown guard. The test correctly prevented a false declaration of success. The guard was moved before the top-level meeting loop and covered by a regression test.
- Second live Telemost test completed cleanly with exit code
0; stop lock was consumed and removed; output WebM and per-track artifacts were produced; upload and transcription ran.
Current operational conclusion
As of this verification, both Zoom and Yandex Telemost are working platform paths in Telemost Recorder. Telemost is explicitly receive-only: it records incoming media and must not speak, publish microphone audio, publish camera video, or show visuals unless a future separately designed and explicitly requested interactive-agent mode is enabled.