For the complete documentation index, see llms.txt. Markdown versions of all docs pages are available by appending .md to any docs URL.

Responses

Send requests through agentgateway using the OpenAI Responses API.

The OpenAI Responses API (/v1/responses) is OpenAI’s interface for stateful, multi-step model interactions.

About

The OpenAI Responses API is a unified interface that supports text and multimodal generation, built-in tools, and multi-turn conversation state. Agentgateway proxies these requests to your configured providers while providing token usage tracking, observability metrics, and policy enforcement.

Route type configuration

In the simplified llm configuration, agentgateway automatically maps /v1/responses requests to the responses route type, so no explicit route configuration is required.

# yaml-language-server: $schema=https://agentgateway.dev/schema/config
llm:
  models:
  - name: "*"
    provider: openAI
    params:
      apiKey: "$OPENAI_API_KEY"

To configure the route type explicitly, use the binds/listeners/routes format and set the responses route type in the policies.ai.routes map.

# yaml-language-server: $schema=https://agentgateway.dev/schema/config
binds:
- port: 4000
  listeners:
  - routes:
    - backends:
      - ai:
          name: openai
          provider:
            openAI: {}
      policies:
        ai:
          routes:
            "/v1/responses": "responses"
        backendAuth:
          key: "$OPENAI_API_KEY"

Using the API

Using the Responses API works exactly the same as consuming OpenAI directly, with only a change to the base URL. This allows you to continue using existing code and SDKs.

curl 'http://localhost:4000/v1/responses' \
--header 'Content-Type: application/json' \
--data '{
  "model": "gpt-4o-mini",
  "input": "Tell me a story"
}'

import openai

client = openai.OpenAI(
    api_key="anything",
    base_url="http://localhost:4000"
)

response = client.responses.create(
    model="gpt-4o-mini",
    input="this is a test request, write a short poem"
)

print(response)

import OpenAI from "openai";

const openai = new OpenAI({
  apiKey: "anything",
  baseURL: "http://localhost:4000",
});

const response = await openai.responses.create({
  model: "gpt-4o-mini",
  input: "this is a test request, write a short poem"
});

console.log(response);

Token usage tracking

After sending Responses requests, verify that agentgateway recorded token usage metrics.

1. Open the agentgateway metrics endpoint.
2. Look for the agentgateway_gen_ai_client_token_usage metric. The metric includes labels for the token type (input or output) and the model used.

For more information about LLM metrics and observability, see Observe traffic.