Google Adk Openapi Tool

Google ADK — OpenAPI Tool Integration

Import

from google.adk.tools.openapi_tool.openapi_toolset import OpenAPIToolset

Basic Usage (from spec file)

from google.adk.agents import Agent
from google.adk.tools.openapi_tool.openapi_toolset import OpenAPIToolset

toolset = OpenAPIToolset(
    spec_str=open("openapi.yaml").read(),
    spec_str_type="yaml",  # or "json"
)

root_agent = Agent(
    name="api_agent",
    model="gemini-2.5-flash",
    instruction="Use the API to help users manage their resources.",
    tools=[toolset],
)

From JSON Spec

import json

with open("api_spec.json") as f:
    spec = json.dumps(json.load(f))

toolset = OpenAPIToolset(
    spec_str=spec,
    spec_str_type="json",
)

With Authentication (API Key)

from google.adk.tools.openapi_tool.openapi_toolset import OpenAPIToolset
from google.adk.auth.auth_credential import AuthCredential, AuthCredentialTypes

api_key_credential = AuthCredential(
    auth_type=AuthCredentialTypes.API_KEY,
    api_key="your-api-key",
)

toolset = OpenAPIToolset(
    spec_str=open("spec.yaml").read(),
    spec_str_type="yaml",
    auth_credential=api_key_credential,
)

With Bearer Token Auth

from google.adk.auth.auth_credential import AuthCredential, AuthCredentialTypes, HttpAuth, HttpCredentials

bearer_credential = AuthCredential(
    auth_type=AuthCredentialTypes.HTTP,
    http=HttpAuth(
        scheme="bearer",
        credentials=HttpCredentials(token="your-bearer-token"),
    ),
)

toolset = OpenAPIToolset(
    spec_str=open("spec.yaml").read(),
    spec_str_type="yaml",
    auth_credential=bearer_credential,
)

Tool Filtering

toolset = OpenAPIToolset(
    spec_str=open("spec.yaml").read(),
    spec_str_type="yaml",
    tool_filter=["getUsers", "createUser", "deleteUser"],
)

OpenAPIToolset Parameters

How It Works

1. Parses the OpenAPI spec
2. Creates one tool per operation (operationId becomes tool name)
3. Parameters/request body become tool parameters
4. Tool descriptions come from operation summary and description
5. Authentication is applied to all requests

OpenAPI Spec Requirements

• Must have operationId for each endpoint (becomes the tool function name)
• Parameters need description fields (becomes tool parameter descriptions)
• Request body schemas define the tool's input structure

Example Spec (Minimal)

openapi: "3.0.0"
info:
  title: "Task API"
  version: "1.0.0"
servers:
  - url: "https://api.example.com/v1"
paths:
  /tasks:
    get:
      operationId: listTasks
      summary: "List all tasks"
      responses:
        "200":
          description: "List of tasks"
    post:
      operationId: createTask
      summary: "Create a new task"
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              properties:
                title:
                  type: string
                  description: "Task title"
                priority:
                  type: string
                  enum: [low, medium, high]
                  description: "Task priority level"

Key Rules

• Each operation in the spec becomes a separate tool
• operationId is required and becomes the tool name the LLM sees
• Tool descriptions come from summary + description fields
• Keep spec descriptions clear and actionable for the LLM
• Filter tools to only expose what the agent needs
• Authentication is applied globally to all tools from the same spec

Related Skills

• google-adk-auth — Authentication credentials, schemes, and credential services
• google-adk-function-tool — Custom function tools
• google-adk-mcp-tool — MCP server integration