Testing your Agents

Before you deploy your agent, you should test it to ensure that it is working as intended. The easiest way to test your agent in your development environment is to use the ADK API server.

PythonJava

adk api_server

Make sure to update the port number.

mvn compile exec:java \
     -Dexec.args="--adk.agents.source-dir=src/main/java/agents --server.port=8080"

In Java, both the Dev UI and the API server are bundled together.

This command will launch a local web server, where you can run cURL commands or send API requests to test your agent.

Advanced Usage and Debugging

For a complete reference on all available endpoints, request/response formats, and tips for debugging (including how to use the interactive API documentation), see the ADK API Server Guide below.

Local testing

Local testing involves launching a local web server, creating a session, and sending queries to your agent. First, ensure you are in the correct working directory:

parent_folder/
└── my_sample_agent/
    └── agent.py (or Agent.java)

Launch the Local Server

Next, launch the local server using the commands listed above.

The output should appear similar to:

PythonJava

INFO:     Started server process [12345]
INFO:     Waiting for application startup.
INFO:     Application startup complete.
INFO:     Uvicorn running on http://localhost:8000 (Press CTRL+C to quit)

2025-05-13T23:32:08.972-06:00  INFO 37864 --- [ebServer.main()] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port 8080 (http) with context path '/'
2025-05-13T23:32:08.980-06:00  INFO 37864 --- [ebServer.main()] com.google.adk.web.AdkWebServer          : Started AdkWebServer in 1.15 seconds (process running for 2.877)
2025-05-13T23:32:08.981-06:00  INFO 37864 --- [ebServer.main()] com.google.adk.web.AdkWebServer          : AdkWebServer application started successfully.

Your server is now running locally. Ensure you use the correct port number in all the subsequent commands.

Create a new session

With the API server still running, open a new terminal window or tab and create a new session with the agent using:

curl -X POST http://localhost:8000/apps/my_sample_agent/users/u_123/sessions/s_123 \
  -H "Content-Type: application/json" \
  -d '{"state": {"key1": "value1", "key2": 42}}'

Let's break down what's happening:

• http://localhost:8000/apps/my_sample_agent/users/u_123/sessions/s_123: This creates a new session for your agent my_sample_agent, which is the name of the agent folder, for a user ID (u_123) and for a session ID (s_123). You can replace my_sample_agent with the name of your agent folder. You can replace u_123 with a specific user ID, and s_123 with a specific session ID.
• {"state": {"key1": "value1", "key2": 42}}: This is optional. You can use this to customize the agent's pre-existing state (dict) when creating the session.

This should return the session information if it was created successfully. The output should appear similar to:

{"id":"s_123","appName":"my_sample_agent","userId":"u_123","state":{"key1":"value1","key2":42},"events":[],"lastUpdateTime":1743711430.022186}

Info

You cannot create multiple sessions with exactly the same user ID and session ID. If you try to, you may see a response, like: {"detail":"Session already exists: s_123"}. To fix this, you can either delete that session (e.g., s_123), or choose a different session ID.

Send a query

There are two ways to send queries via POST to your agent, via the /run or /run_sse routes.

• POST http://localhost:8000/run: collects all events as a list and returns the list all at once. Suitable for most users (if you are unsure, we recommend using this one).
• POST http://localhost:8000/run_sse: returns as Server-Sent-Events, which is a stream of event objects. Suitable for those who want to be notified as soon as the event is available. With /run_sse, you can also set streaming to true to enable token-level streaming.

Using /run

curl -X POST http://localhost:8000/run \
-H "Content-Type: application/json" \
-d '{
"app_name": "my_sample_agent",
"user_id": "u_123",
"session_id": "s_123",
"new_message": {
    "role": "user",
    "parts": [{
    "text": "Hey whats the weather in new york today"
    }]
}
}'

If using /run, you will see the full output of events at the same time, as a list, which should appear similar to:

[{"content":{"parts":[{"functionCall":{"id":"af-e75e946d-c02a-4aad-931e-49e4ab859838","args":{"city":"new york"},"name":"get_weather"}}],"role":"model"},"invocationId":"e-71353f1e-aea1-4821-aa4b-46874a766853","author":"weather_time_agent","actions":{"stateDelta":{},"artifactDelta":{},"requestedAuthConfigs":{}},"longRunningToolIds":[],"id":"2Btee6zW","timestamp":1743712220.385936},{"content":{"parts":[{"functionResponse":{"id":"af-e75e946d-c02a-4aad-931e-49e4ab859838","name":"get_weather","response":{"status":"success","report":"The weather in New York is sunny with a temperature of 25 degrees Celsius (41 degrees Fahrenheit)."}}}],"role":"user"},"invocationId":"e-71353f1e-aea1-4821-aa4b-46874a766853","author":"weather_time_agent","actions":{"stateDelta":{},"artifactDelta":{},"requestedAuthConfigs":{}},"id":"PmWibL2m","timestamp":1743712221.895042},{"content":{"parts":[{"text":"OK. The weather in New York is sunny with a temperature of 25 degrees Celsius (41 degrees Fahrenheit).\n"}],"role":"model"},"invocationId":"e-71353f1e-aea1-4821-aa4b-46874a766853","author":"weather_time_agent","actions":{"stateDelta":{},"artifactDelta":{},"requestedAuthConfigs":{}},"id":"sYT42eVC","timestamp":1743712221.899018}]

Using /run_sse

curl -X POST http://localhost:8000/run_sse \
-H "Content-Type: application/json" \
-d '{
"app_name": "my_sample_agent",
"user_id": "u_123",
"session_id": "s_123",
"new_message": {
    "role": "user",
    "parts": [{
    "text": "Hey whats the weather in new york today"
    }]
},
"streaming": false
}'

You can set streaming to true to enable token-level streaming, which means the response will be returned to you in multiple chunks and the output should appear similar to:

data: {"content":{"parts":[{"functionCall":{"id":"af-f83f8af9-f732-46b6-8cb5-7b5b73bbf13d","args":{"city":"new york"},"name":"get_weather"}}],"role":"model"},"invocationId":"e-3f6d7765-5287-419e-9991-5fffa1a75565","author":"weather_time_agent","actions":{"stateDelta":{},"artifactDelta":{},"requestedAuthConfigs":{}},"longRunningToolIds":[],"id":"ptcjaZBa","timestamp":1743712255.313043}

data: {"content":{"parts":[{"functionResponse":{"id":"af-f83f8af9-f732-46b6-8cb5-7b5b73bbf13d","name":"get_weather","response":{"status":"success","report":"The weather in New York is sunny with a temperature of 25 degrees Celsius (41 degrees Fahrenheit)."}}}],"role":"user"},"invocationId":"e-3f6d7765-5287-419e-9991-5fffa1a75565","author":"weather_time_agent","actions":{"stateDelta":{},"artifactDelta":{},"requestedAuthConfigs":{}},"id":"5aocxjaq","timestamp":1743712257.387306}

data: {"content":{"parts":[{"text":"OK. The weather in New York is sunny with a temperature of 25 degrees Celsius (41 degrees Fahrenheit).\n"}],"role":"model"},"invocationId":"e-3f6d7765-5287-419e-9991-5fffa1a75565","author":"weather_time_agent","actions":{"stateDelta":{},"artifactDelta":{},"requestedAuthConfigs":{}},"id":"rAnWGSiV","timestamp":1743712257.391317}

Info

If you are using /run_sse, you should see each event as soon as it becomes available.

Integrations

ADK uses Callbacks to integrate with third-party observability tools. These integrations capture detailed traces of agent calls and interactions, which are crucial for understanding behavior, debugging issues, and evaluating performance.

• Comet Opik is an open-source LLM observability and evaluation platform that natively supports ADK.

Deploying your agent

Now that you've verified the local operation of your agent, you're ready to move on to deploying your agent! Here are some ways you can deploy your agent:

• Deploy to Agent Engine, the easiest way to deploy your ADK agents to a managed service in Vertex AI on Google Cloud.
• Deploy to Cloud Run and have full control over how you scale and manage your agents using serverless architecture on Google Cloud.

The ADK API Server

The ADK API Server is a pre-packaged FastAPI web server that exposes your agents through a RESTful API. It is the primary tool for local testing and development, allowing you to interact with your agents programmatically before deploying them.

Running the Server

To start the server, run the following command from your project's root directory:

adk api_server

By default, the server runs on http://localhost:8000. You will see output confirming that the server has started:

INFO:     Uvicorn running on http://localhost:8000 (Press CTRL+C to quit)

Debugging with Interactive API Docs

The API server automatically generates interactive API documentation using Swagger UI. This is an invaluable tool for exploring endpoints, understanding request formats, and testing your agent directly from your browser.

To access the interactive docs, start the API server and navigate to http://localhost:8000/docs in your web browser.

You will see a complete, interactive list of all available API endpoints, which you can expand to see detailed information about parameters, request bodies, and response schemas. You can even click "Try it out" to send live requests to your running agents.

API Endpoints

The following sections detail the primary endpoints for interacting with your agents.

JSON Naming Convention

• Request bodies must use snake_case for field names (e.g., "app_name").
• Response bodies will use camelCase for field names (e.g., "appName").

Utility Endpoints

List Available Agents

Returns a list of all agent applications discovered by the server.

• Method: GET
• Path: /list-apps

Example Request

curl -X GET http://localhost:8000/list-apps

Example Response

["my_sample_agent", "another_agent"]

---

Session Management

Sessions store the state and event history for a specific user's interaction with an agent.

Create or Update a Session

Creates a new session or updates an existing one. If a session with the given IDs already exists, its state will be overwritten with the new state provided.

• Method: POST
• Path: /apps/{app_name}/users/{user_id}/sessions/{session_id}

Request Body

{
  "state": {
    "key1": "value1",
    "key2": 42
  }
}

Example Request

curl -X POST http://localhost:8000/apps/my_sample_agent/users/u_123/sessions/s_abc \
  -H "Content-Type: application/json" \
  -d '{"state": {"visit_count": 5}}'

Example Response

{"id":"s_abc","appName":"my_sample_agent","userId":"u_123","state":{"visit_count":5},"events":[],"lastUpdateTime":1743711430.022186}

Get a Session

Retrieves the details of a specific session, including its current state and all associated events.

• Method: GET
• Path: /apps/{app_name}/users/{user_id}/sessions/{session_id}

Example Request

curl -X GET http://localhost:8000/apps/my_sample_agent/users/u_123/sessions/s_abc

Example Response

{"id":"s_abc","appName":"my_sample_agent","userId":"u_123","state":{"visit_count":5},"events":[...],"lastUpdateTime":1743711430.022186}

Delete a Session

Deletes a session and all of its associated data.

• Method: DELETE
• Path: /apps/{app_name}/users/{user_id}/sessions/{session_id}

Example Request

curl -X DELETE http://localhost:8000/apps/my_sample_agent/users/u_123/sessions/s_abc

Example Response A successful deletion returns an empty response with a 204 No Content status code.

---

Agent Execution

These endpoints are used to send a new message to an agent and get a response.

Run Agent (Single Response)

Executes the agent and returns all generated events in a single JSON array after the run is complete.

• Method: POST
• Path: /run

Request Body

{
  "app_name": "my_sample_agent",
  "user_id": "u_123",
  "session_id": "s_abc",
  "new_message": {
    "role": "user",
    "parts": [
      { "text": "What is the capital of France?" }
    ]
  }
}

Example Request

curl -X POST http://localhost:8000/run \
  -H "Content-Type: application/json" \
  -d '{
    "app_name": "my_sample_agent",
    "user_id": "u_123",
    "session_id": "s_abc",
    "new_message": {
      "role": "user",
      "parts": [{"text": "What is the capital of France?"}]
    }
  }'

Run Agent (Streaming)

Executes the agent and streams events back to the client as they are generated using Server-Sent Events (SSE).

• Method: POST
• Path: /run_sse

Request Body The request body is the same as for /run, with an additional optional streaming flag.

{
  "app_name": "my_sample_agent",
  "user_id": "u_123",
  "session_id": "s_abc",
  "new_message": {
    "role": "user",
    "parts": [
      { "text": "What is the weather in New York?" }
    ]
  },
  "streaming": true
}

- streaming: (Optional) Set to true to enable token-level streaming for model responses. Defaults to false.

Example Request

curl -X POST http://localhost:8000/run_sse \
  -H "Content-Type: application/json" \
  -d '{
    "app_name": "my_sample_agent",
    "user_id": "u_123",
    "session_id": "s_abc",
    "new_message": {
      "role": "user",
      "parts": [{"text": "What is the weather in New York?"}]
    },
    "streaming": false
  }'