> ## Documentation Index
> Fetch the complete documentation index at: https://www.voiceflow.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Execute MCP tool

> Calls one MCP tool on its server with the arguments in the body, using the server's saved URL, headers, and authorization. No conversation is involved.



## OpenAPI

````yaml /specs-prettified/realtime/openapi.stable.json post /v1/stable/mcp-tool/{toolID}/execute
openapi: 3.0.0
info:
  title: Realtime
  description: Realtime gateway API service
  version: 1.0.0
  contact: {}
servers:
  - url: https://realtime-api.voiceflow.com
security: []
tags: []
paths:
  /v1/stable/mcp-tool/{toolID}/execute:
    post:
      tags:
        - MCP Tool
      summary: Execute MCP tool
      description: Calls one MCP tool on its server with the arguments in the body,
        using the server's saved URL, headers, and authorization. No
        conversation is involved.
      operationId: StableMCPToolController_execute
      parameters:
        - name: toolID
          required: true
          in: path
          schema:
            type: string
          x-vf-doc:
            description: The ID of the MCP tool to execute.
          description: The ID of the MCP tool to execute.
        - name: projectID
          required: true
          in: query
          schema:
            type: string
            description: The ID of the project to operate on.
        - name: environmentAlias
          required: true
          in: query
          schema:
            type: string
            description: The alias of the environment to operate on (e.g. `main`).
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: "#/components/schemas/StableMCPToolExecuteRequest"
      responses:
        "200":
          description: Returns what the MCP server answered, with success, latencyMs, and
            error fields. Secret values read [secret] wherever they appear.
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/StableMCPToolExecuteResponse"
          x-vf-doc:
            description: Returns what the MCP server answered, with success, latencyMs, and
              error fields. Secret values read [secret] wherever they appear.
      security:
        - token: []
components:
  schemas:
    StableMCPToolExecuteRequest:
      type: object
      properties:
        inputs:
          default: {}
          description: "The tool's arguments, keyed by argument name and typed as its JSON
            Schema says; see get_schema. A top-level string value follows the
            ExecuteInputString rules, so {secret_name} inserts a project secret.
            Secrets work only at the top level: inside a nested object or array,
            {secret_name} is sent as written and no secret is filled in."
          type: object
          additionalProperties: {}
      additionalProperties: false
    StableMCPToolExecuteResponse:
      type: object
      properties:
        success:
          type: boolean
          description: Whether the tool ran and reported no error.
        latencyMs:
          type: number
          description: How long the run took, in milliseconds, measured by this API around
            the call.
        error:
          nullable: true
          description: Why the run failed when `success` is false, otherwise null. Secret
            values read `[secret]`.
          type: string
        truncated:
          type: boolean
          description: Whether a returned payload was over 64 KB and was cut to its first
            64 KB of JSON text, which then arrives as a string.
        output:
          description: "What the MCP server returned. A result with `isError: true` fails
            the run and keeps this output. Null when the call itself failed or
            did not answer in time. Secret values read `[secret]`."
      required:
        - success
        - latencyMs
        - error
        - truncated
        - output
  securitySchemes:
    token:
      scheme: bearer
      bearerFormat: JWT
      type: http
      description: Voiceflow bearer token
````