Content
# callbay
https://call4.me
Your coding agent (Claude Code, Codex, Claude Desktop, ChatGPT) gets one new tool: make a phone call.
Prepaid credits from $10 via Stripe Checkout, reloading monthly by default; one MCP URL with the key in it.
## How a call works
```
agent ──MCP──▶ worker ──POST /v2/calls──▶ Telnyx ──PSTN──▶ business
▲ │ media stream (PCMU, bidirectional RTP)
│ webhooks ▼
└──────────────── CallSession (Durable Object) ◀──WS──▶ GPT-Live (gpt-live-1, audio/pcmu 8k)
└─ back office (Responses model):
end_call · ask_user · press_digits
```
- `src/server/voice/prompt.ts`: what the caller is told. The product lives here: no opening disclosure,
no recording notice, no end-of-call read-back; honest if sincerely asked whether it's an AI.
- `src/server/voice/session.ts`: the audio relay and back-office functions.
- `src/server/services/dialer.ts`: placing calls, per-account numbers, answering callbacks.
- `src/server/mcp/server.ts`: the MCP tools.
The app does not request recording when dialing or answering. Existing recordings stored by Telnyx
can be retrieved after a call ends using `callbay_get_recordings({ call_id })` over MCP, or
`GET /api/calls/{call_id}/recordings` with a callbay API key or OAuth token in the Bearer header.
Both check account ownership before contacting Telnyx and return fresh download links without
storing them. Empty results can mean processing is pending or no recording was saved. Links may
expire and should only be shared with the account owner.
Trunk recordings use call leg IDs. A separate provider ID table receives these from verified
webhooks; existing calls resolve them from an exact control ID match in Telnyx webhook history.
The app never guesses a match from phone numbers or timestamps. If provider history has expired
and no mapping was saved, only recordings directly associated with the control ID can be found.
The recording lookup never contacts the voice session or changes prompts, live tools, audio,
or Telnyx recording settings. Existing call status and transcript responses are unchanged.
The recording API's OpenAPI document is served at `/api/openapi.json`. Run
`npm run openapi:generate` to regenerate `openapi.json` from the shared MCP and HTTP schemas.
CI checks the generated artifact for drift. Run `npm test`, `npm run check`, `npm run lint`,
and `npx wrangler deploy --dry-run` before deploying through git.
## Setup
1. Telnyx: a Call Control application (its id is `TELNYX_CONNECTION_ID`) with webhook URL
`https://<host>/webhooks/telnyx`, an API key, and the account's webhook public key.
Each account's number is bought on its first call and attached to that application.
2. OpenAI: an API key with GPT-Live access.
3. Stripe: webhook endpoint `https://<host>/webhooks/stripe` for `checkout.session.completed`,
`checkout.session.async_payment_succeeded`, `invoice.paid`, `customer.subscription.updated`,
`customer.subscription.deleted`, `charge.refunded`. The blog's supporter subscriptions arrive on
the same endpoint, tagged `app=callbay, kind=supporter` (see `src/server/services/supporters.ts`).
## Credits
Everything is prepaid. Loads start at $10 and, by default, the same amount reloads monthly (a Stripe
subscription; `invoice.paid` adds the credits). A call holds its maximum cost before it dials, in one
conditional insert so parallel calls can't overspend, and settles to the real talk time when it ends.
4. Secrets (`wrangler secret put`): see `src/server/env.d.ts`.
## Blog
`/blog` is markdown files in `src/content/blog` (one per post, listed in `index.ts`, headline image at
`public/static/blog/<slug>.svg`), with an Atom feed, likes, comments, an email newsletter (sent from
`/admin/blog`, for the `ADMIN_EMAILS` accounts), and paid posts for monthly supporters.
## Self-hosting
Fork it, create your own D1 database (`wrangler d1 create callbay`) and put its id and your own hostname in `wrangler.jsonc`.
Local: `npm run db:migrate:local && npm run dev` with a `.dev.vars` holding the same secrets.
## License
MIT
MCP Store