AssemblyAI transcription for media-production agents

Use AssemblyAI when the production job needs reliable transcript artifacts from recorded or live speech, especially when the transcript must drive captions, clip selection, speaker turns, show notes, chaptering, translation, moderation, or compliance review.

Treat this as a provider skill, not a generic ASR primer. Check the live AssemblyAI docs before implementing code in production because model names, pricing, add-ons, rate limits, and data-retention settings are volatile. The facts below were verified against official AssemblyAI documentation on 2026-07-10.

Pick the product surface first

AssemblyAI exposes several surfaces that look similar but serve different production needs.

Documented facts:

• Pre-recorded STT is the main batch/async API for media files. Submit audio_url or upload a local file first, then poll GET /v2/transcript/{id} or use webhooks until the transcript is completed or error. The returned transcript includes text, metadata, words with millisecond timestamps, and optional feature outputs. Source: https://www.assemblyai.com/docs/pre-recorded-audio/getting-started/transcribe-an-audio-file
• Sync STT is for short clips in a single HTTP request, with no polling or session management. Official docs describe it as accepting audio clips from 80 ms to 120 s. Use it for short voice-agent turns, quick QC snippets, or small app interactions, not long podcasts or interviews. Sources: https://www.assemblyai.com/docs/sync-stt/getting-started/transcribe-a-short-audio-file and https://www.assemblyai.com/docs/sync-stt/audio-requirements
• Real-time STT streams audio over WebSocket (wss://streaming.assemblyai.com/v3/ws) and emits Begin, repeated Turn, and Termination events. Use it for live captioning, voice agents, live meeting assistants, or real-time production monitors. Word timings are in milliseconds. Source: https://www.assemblyai.com/docs/streaming/getting-started/transcribe-streaming-audio
• Streaming is billed for the duration the WebSocket is open, not the amount of audio sent. Unclosed sessions auto-close after 3 hours and can bill for the full session duration. Source: https://www.assemblyai.com/docs/billing-and-pricing
• Use temporary streaming tokens for browser clients; never expose the account API key in client-side code. Source: https://www.assemblyai.com/docs/streaming/getting-started/transcribe-streaming-audio

Production heuristic: