> ## Documentation Index > Fetch the complete documentation index at: https://docs.voice.wixzel.com/llms.txt > Use this file to discover all available pages before exploring further. # Connect an OAuth MCP server > Starts signing in to a server whose `auth.type` is `oauth`. Open `authorization_url` in a browser; when the provider sends the browser back, the server is connected and its tools are read. The link is single-use and expires after ten minutes. Any stored sign-in is replaced. Requires `mcp_servers:write`. ## OpenAPI ````yaml /openapi.json post /v1/mcp-servers/{id}/oauth/start openapi: 3.1.0 info: title: Wixzel Voice API version: '2026-09-01' description: >- APIs for agentic telephony. One API key, one balance, every voice engine. ## Authentication Send your key as `Authorization: Bearer wv_live_...`. Keys are scoped: grant only what an integration needs. There is no admin scope. ## Versioning The `/v1` prefix covers additive changes. Behavioural changes ship behind a dated `Wixzel-Version` header, and existing keys keep the behaviour they were created with. ## Money Amounts are integer **micro-USD** (1,000,000 = $1.00). Voice usage is billed per second, per token and per character, so a float dollar figure cannot represent it without disagreeing with the ledger. ## Errors Every error carries a stable `code` and a `request_id`. Match on `code`; the `message` is for humans and may change. contact: name: Wixzel Voice url: https://voice.wixzel.com servers: - url: https://api.voice.wixzel.com description: Production security: [] tags: - name: Calls description: Place calls and read what happened on them. - name: Realtime description: Talk to an agent from a browser or app, with no phone line. - name: Agents description: The prompt, voice and behaviour of a caller. - name: Leads description: People to call, and data to merge into prompts. - name: Campaigns description: Call a list of leads with one agent. - name: Knowledge bases description: Facts an agent can draw on mid-call. - name: Phone numbers description: Numbers on your SIP trunks. - name: SIP trunks description: Your carrier connections. - name: Appointments description: Bookings, including ones agents make on calls. - name: Usage description: Itemised billing lines. - name: Billing description: Balance, ledger and top-ups. - name: API keys description: Create, scope and rotate keys. - name: Engines description: What the platform can serve, and what it costs. - name: Webhooks description: Where events are sent, and what happened when they got there. - name: MCP servers description: Other apps’ tools, for agents to use while they are on a call. paths: /v1/mcp-servers/{id}/oauth/start: post: tags: - MCP servers summary: Connect an OAuth MCP server description: >- Starts signing in to a server whose `auth.type` is `oauth`. Open `authorization_url` in a browser; when the provider sends the browser back, the server is connected and its tools are read. The link is single-use and expires after ten minutes. Any stored sign-in is replaced. Requires `mcp_servers:write`. parameters: - schema: type: string pattern: ^[0-9a-f]{24}$ example: 6a96a3ead6e886d42462dd3e required: true name: id in: path responses: '200': description: Where to sign in content: application/json: schema: $ref: '#/components/schemas/McpServerOAuthStart' '400': description: Invalid request content: application/json: schema: $ref: '#/components/schemas/Error' '401': description: Missing or invalid API key content: application/json: schema: $ref: '#/components/schemas/Error' '403': description: Key lacks the required scope content: application/json: schema: $ref: '#/components/schemas/Error' '404': description: No such record content: application/json: schema: $ref: '#/components/schemas/Error' '429': description: Rate limited. Retry after the interval in `Retry-After`. content: application/json: schema: $ref: '#/components/schemas/Error' security: - bearerAuth: [] components: schemas: McpServerOAuthStart: type: object properties: object: type: string enum: - mcp_server_oauth authorization_url: type: string description: >- Open this in a browser and sign in. The server is connected when the browser comes back. redirect_uri: type: string description: >- Where the provider sends the browser back to. Register this if you supply your own client_id. expires_at: type: string format: date-time description: ISO 8601, always UTC. example: '2026-09-01T12:00:00.000Z' required: - object - authorization_url - redirect_uri - expires_at Error: type: object properties: error: type: object properties: type: type: string enum: - invalid_request_error - authentication_error - permission_error - rate_limit_error - insufficient_credits - not_found_error - conflict_error - api_error code: type: string description: Stable machine-readable code. example: agent_not_found message: type: string description: >- Human-readable explanation. Do not match on this — match on code. param: type: string description: Which field caused the failure, when applicable. doc_url: type: string request_id: type: string description: Quote this when asking for help. example: req_01HXYZ... required: - type - code - message - request_id required: - error securitySchemes: bearerAuth: type: http scheme: bearer description: >- Your Wixzel Voice API key: `Authorization: Bearer wv_live_...`. Keys are scoped; grant only what the integration needs. ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.