conference

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name: conference description: Twilio Conference development guide. Use when building call orchestration with hold/mute, warm transfers, coaching/whisper/barge, or any call flow needing Conference or Participants API. allowed-tools: mcp__twilio__*, Read, Grep, Glob

Conference Development Skill

Comprehensive decision-making guide for Twilio Conference. Load this skill when building call flows that need hold, mute, warm transfer, coaching, or any multi-party orchestration.

WARNING: Conference REST API state can be misleading. The REST API may report a conference as in-progress with participants muted: false when audio is actually muted (all participants have startConferenceOnEnter=false). Do not trust API state alone for audio-level verification. Use Conference Insights for authoritative post-call state. See Gotcha #2.

Evidence date: 2026-03-24 | Account: ACxx...xx | Intelligence Service: GA7d01ec... (conference-validation)

What Conference Cannot Do

Explicit list of things developers commonly assume work but don't:

• Cannot use <Gather> inside a conference — DTMF goes into the audio mix, not a handler
• Cannot rely on speaker events for app logic — fire too frequently to be actionable
• Cannot get post-flight participant data from REST API — completed conferences return empty; Insights is the only source
• Cannot verify coaching via conference recording — coach audio is NOT in the conference mix recording; only REST API and Insights events confirm coaching [Evidence: GT6e8b15..., 2026-03-24]
• Cannot filter Insights list endpoint by processing_state — must fetch by SID directly
• Cannot use PII in friendlyName — compliance requirement, not just a suggestion
• Cannot create a conference with 0 call legs and get Insights data — Insights requires ≥1 participant call attempt
• Cannot poll Insights immediately after conference end — takes 15-30+ minutes even for in_progress state
• Cannot do CRM screen pops — Conference provides call events; displaying caller context in a CRM is your application's JavaScript (Voice SDK call event → extract caller info → open CRM URL). Flex has built-in CRM panels; custom contact centers must build this.
• Cannot compute EWT — Conference and TaskRouter provide queue statistics but not Estimated Wait Time calculations or announcements. You must poll queue stats, compute estimates, and serve them via a custom waitUrl handler.