@callmcp/server

The CallMCP server core — an MCP server implementing the 14-tool CallMCP telephony contract (SPEC.md at the repo root) against whichever Driver you configure. This package has no telephony logic of its own; it's the neutral layer that turns a Driver implementation (@callmcp/driver-kaicalls, @callmcp/driver-dograh, @callmcp/driver-byok, or a third-party one) into a spec-conformant MCP server.

What's in here

| File | What it's for | |---|---| | src/config.ts | Resolves a callmcp.config.json file or env vars into a set of configured drivers, exactly one marked default. | | src/driverRegistry.ts | Dynamically loads driver packages (or embeds already-constructed Drivers), falls back to @callmcp/driver-interface's MockDriver if nothing loads, notifies listeners on reconfiguration. | | src/approval.ts | ApprovalStore — the SPEC §3 approval state machine (pending/approved/denied/expired), elicitation-first with the out-of-band-URL fallback for clients that don't support MCP elicitation. | | src/tools.ts | ServerCore — registers all 14 tools with their SPEC-defined schemas and annotations; make_call/send_sms route through ensureDestinationApproved before ever touching a driver. | | src/dynamicTools.ts | Computes the live tools/list from the active driver's capability manifest (SPEC §2.2) and fires notifications/tools/list_changed when the driver set changes. | | src/transports.ts | stdio and Streamable HTTP transports, both backed by the same ServerCore. Also serves /approve/:id, the human-facing approval page for the non-elicitation fallback. | | src/index.ts | CLI entrypoint (callmcp-server bin). | | test/server.test.ts | Unit tests against @callmcp/driver-interface's MockDriver, plus a real dynamic-import() test against the three bundled driver packages. |

Usage

npx @callmcp/server                    # stdio transport, reads ./callmcp.config.json if present
npx @callmcp/server --http --port 8787 # Streamable HTTP transport
npx @callmcp/server doctor             # read-only journey preflight
npx @callmcp/server --sandbox          # explicit local sandbox; never contacts a provider

Config file

{
  "drivers": [
    { "id": "kaicalls", "type": "kaicalls", "default": true,
      "credentials": { "apiKey": "kc_live_..." } },
    { "id": "dograh", "type": "dograh",
      "credentials": { "baseUrl": "http://localhost:8000", "apiKey": "..." } }
  ],
  "http": { "port": 8787, "publicUrl": "https://your-host.example.com" }
}

• type is one of kaicalls, dograh, byok, or mock (an in-memory no-credentials driver for local testing, from @callmcp/driver-interface).
• Exactly one driver may be "default": true. Omit it entirely and the first configured driver becomes default. A tool call with no driver field routes to whichever one is default.
• credentials/options are shallow-merged and passed straight through to the driver package's constructor — see each driver's own README for its expected shape (e.g. KaiCallsDriverConfig, DograhDriverOptions, BYOKDriverConfig).
• http.publicUrl matters even in stdio mode: it's what the out-of-band approval link (SPEC §3.4) points at when the connected client doesn't support MCP elicitation. If you're running stdio-only with no HTTP surface reachable at that URL, a human can't open the link — see the note in src/index.ts.

Env vars (no config file — e.g. a single-tenant Docker container)

CALLMCP_DRIVER_TYPE=kaicalls
CALLMCP_DRIVER_CREDENTIALS='{"apiKey":"kc_live_..."}'
npx @callmcp/server

Or CALLMCP_DRIVERS_JSON (a JSON array, same shape as the config file's drivers field) for more than one driver without a mounted file.

No driver configured

The server fails closed. It does not silently load the in-memory mock, because that can make an unconfigured deployment look production-ready. Use --sandbox or an explicit { "id": "mock", "type": "mock" } entry for local testing, then configure a real provider before activation.

Managed KaiCalls path

For the shortest hosted path, configure type: "kaicalls" with a kc_live_... API key. KaiCalls' API-first onboarding is POST https://www.kaicalls.com/api/v1/signup; existing accounts use the managed MCP endpoint at https://www.kaicalls.com/api/mcp. KaiCalls currently does not issue a kc_test_ sandbox key, so CallMCP's --sandbox is intentionally local and never substitutes for provider-side activation.

Third-party drivers

A driver package doesn't need to be in this monorepo. Export a createDriver(entry: { id, credentials, options }) => Driver factory (named or default export) and reference it as type in your config — see driverRegistry.ts's factory-convention lookup. The three bundled drivers predate this convention and are loaded via a known-class fallback instead; new drivers should use the factory.