Voice Call (plugin)

Voice calls for ThinkFleet via a plugin. Supports outbound notifications and multi-turn conversations with inbound policies.

Current providers:

• twilio (Programmable Voice + Media Streams)
• telnyx (Call Control v2)
• plivo (Voice API + XML transfer + GetInput speech)
• mock (dev/no network)

Quick mental model:

• Install plugin
• Restart Gateway
• Configure under plugins.entries.voice-call.config
• Use thinkfleetbot voicecall ... or the voice_call tool

Where it runs (local vs remote)

The Voice Call plugin runs inside the Gateway process.

If you use a remote Gateway, install/configure the plugin on the machine running the Gateway, then restart the Gateway to load it.

Install

Option A: install from npm (recommended)

thinkfleetbot plugins install @thinkfleetbot/voice-call

Restart the Gateway afterwards.

Option B: install from a local folder (dev, no copying)

thinkfleetbot plugins install ./extensions/voice-call
cd ./extensions/voice-call && pnpm install

Restart the Gateway afterwards.

Config

Set config under plugins.entries.voice-call.config:

{
  plugins: {
    entries: {
      "voice-call": {
        enabled: true,
        config: {
          provider: "twilio", // or "telnyx" | "plivo" | "mock"
          fromNumber: "+15550001234",
          toNumber: "+15550005678",

          twilio: {
            accountSid: "ACxxxxxxxx",
            authToken: "..."
          },

          plivo: {
            authId: "MAxxxxxxxxxxxxxxxxxxxx",
            authToken: "..."
          },

          // Webhook server
          serve: {
            port: 3334,
            path: "/voice/webhook"
          },

          // Public exposure (pick one)
          // publicUrl: "https://example.ngrok.app/voice/webhook",
          // tunnel: { provider: "ngrok" },
          // tailscale: { mode: "funnel", path: "/voice/webhook" }

          outbound: {
            defaultMode: "notify" // notify | conversation
          },

          streaming: {
            enabled: true,
            streamPath: "/voice/stream"
          }
        }
      }
    }
  }
}

Notes:

• Twilio/Telnyx require a publicly reachable webhook URL.
• Plivo requires a publicly reachable webhook URL.
• mock is a local dev provider (no network calls).
• skipSignatureVerification is for local testing only.
• If you use ngrok free tier, set publicUrl to the exact ngrok URL; signature verification is always enforced.
• tunnel.allowNgrokFreeTierLoopbackBypass: true allows Twilio webhooks with invalid signatures only when tunnel.provider="ngrok" and serve.bind is loopback (ngrok local agent). Use for local dev only.
• Ngrok free tier URLs can change or add interstitial behavior; if publicUrl drifts, Twilio signatures will fail. For production, prefer a stable domain or Tailscale funnel.

TTS for calls

Voice Call uses the core messages.tts configuration (OpenAI or ElevenLabs) for streaming speech on calls. You can override it under the plugin config with the same shape — it deep‑merges with messages.tts.

{
  tts: {
    provider: "elevenlabs",
    elevenlabs: {
      voiceId: "pMsXgVXv3BLzUgSXRplE",
      modelId: "eleven_multilingual_v2"
    }
  }
}

Notes:

• Edge TTS is ignored for voice calls (telephony audio needs PCM; Edge output is unreliable).
• Core TTS is used when Twilio media streaming is enabled; otherwise calls fall back to provider native voices.

More examples

Use core TTS only (no override):

{
  messages: {
    tts: {
      provider: "openai",
      openai: { voice: "alloy" }
    }
  }
}

Override to ElevenLabs just for calls (keep core default elsewhere):

{
  plugins: {
    entries: {
      "voice-call": {
        config: {
          tts: {
            provider: "elevenlabs",
            elevenlabs: {
              apiKey: "elevenlabs_key",
              voiceId: "pMsXgVXv3BLzUgSXRplE",
              modelId: "eleven_multilingual_v2"
            }
          }
        }
      }
    }
  }
}

Override only the OpenAI model for calls (deep‑merge example):

{
  plugins: {
    entries: {
      "voice-call": {
        config: {
          tts: {
            openai: {
              model: "gpt-4o-mini-tts",
              voice: "marin"
            }
          }
        }
      }
    }
  }
}

Inbound calls

Inbound policy defaults to disabled. To enable inbound calls, set:

{
  inboundPolicy: "allowlist",
  allowFrom: ["+15550001234"],
  inboundGreeting: "Hello! How can I help?"
}

Auto-responses use the agent system. Tune with:

• responseModel
• responseSystemPrompt
• responseTimeoutMs

CLI

thinkfleetbot voicecall call --to "+15555550123" --message "Hello from ThinkFleetBot"
thinkfleetbot voicecall continue --call-id <id> --message "Any questions?"
thinkfleetbot voicecall speak --call-id <id> --message "One moment"
thinkfleetbot voicecall end --call-id <id>
thinkfleetbot voicecall status --call-id <id>
thinkfleetbot voicecall tail
thinkfleetbot voicecall expose --mode funnel

Agent tool

Tool name: voice_call

Actions:

• initiate_call (message, to?, mode?)
• continue_call (callId, message)
• speak_to_user (callId, message)
• end_call (callId)
• get_status (callId)

This repo ships a matching skill doc at skills/voice-call/SKILL.md.

Gateway RPC

• voicecall.initiate (to?, message, mode?)
• voicecall.continue (callId, message)
• voicecall.speak (callId, message)
• voicecall.end (callId)
• voicecall.status (callId)