Limit A2A request body size

This is a Konnect tutorial and requires a Konnect personal access token.

1. Create a new personal access token by opening the Konnect PAT page and selecting Generate Token.

2. Export your token to an environment variable:

    export KONNECT_TOKEN='YOUR_KONNECT_PAT'
   

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3. Run the quickstart script to automatically provision a Control Plane and Data Plane, and configure your environment:

    curl -Ls https://get.konghq.com/quickstart | bash -s -- -k $KONNECT_TOKEN --deck-output
   

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   This sets up a Konnect Control Plane named quickstart, provisions a local Data Plane, and prints out the following environment variable exports:

    export DECK_KONNECT_TOKEN=$KONNECT_TOKEN
    export DECK_KONNECT_CONTROL_PLANE_NAME=quickstart
    export KONNECT_CONTROL_PLANE_URL=https://us.api.konghq.com
    export KONNECT_PROXY_URL='http://localhost:8000'
   

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   Copy and paste these into your terminal to configure your session.

This tutorial requires Kong Gateway Enterprise. If you don’t have Kong Gateway set up yet, you can use the quickstart script with an enterprise license to get an instance of Kong Gateway running almost instantly.

1. Export your license to an environment variable:

    export KONG_LICENSE_DATA='LICENSE-CONTENTS-GO-HERE'
   

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2. Run the quickstart script:

   curl -Ls https://get.konghq.com/quickstart | bash -s -- -e KONG_LICENSE_DATA 
   

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   Once Kong Gateway is ready, you will see the following message:

    Kong Gateway Ready
   

decK is a CLI tool for managing Kong Gateway declaratively with state files. To complete this tutorial, install decK version 1.43 or later.

This guide uses deck gateway apply, which directly applies entity configuration to your Gateway instance. We recommend upgrading your decK installation to take advantage of this tool.

You can check your current decK version with deck version.

For this tutorial, you’ll need Kong Gateway entities, like Gateway Services and Routes, pre-configured. These entities are essential for Kong Gateway to function but installing them isn’t the focus of this guide. Follow these steps to pre-configure them:

1. Run the following command:

   echo '
   _format_version: "3.0"
   services:
     - name: a2a-currency-agent
       url: http://host.docker.internal:10000
   routes:
     - name: a2a-route
       paths:
       - "/a2a"
       strip_path: true
       service:
         name: a2a-currency-agent
       protocols:
       - http
       - https
   ' | deck gateway apply -
   

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To learn more about entities, you can read our entities documentation.

This tutorial uses OpenAI:

1. Create an OpenAI account.
2. Get an API key.

3. Create a decK variable with the API key:

   export DECK_OPENAI_API_KEY='YOUR OPENAI API KEY'
   

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You need a running A2A-compliant agent. This guide uses a sample currency conversion agent from the A2A project.

Create a docker-compose.yaml file:

cat <<'EOF' > docker-compose.yaml
services:
  a2a-agent:
    container_name: a2a-currency-agent
    build:
      context: .
      dockerfile_inline: |
        FROM python:3.12-slim
        WORKDIR /app
        RUN pip install uv && apt-get update && apt-get install -y git
        RUN git clone --depth 1 https://github.com/a2aproject/a2a-samples.git /tmp/a2a && \
            cp -r /tmp/a2a/samples/python/agents/langgraph/* . && \
            rm -rf /tmp/a2a
        ENV UV_COMPILE_BYTECODE=1 UV_LINK_MODE=copy
        RUN uv sync --frozen --no-dev
        EXPOSE 10000
        CMD ["uv", "run", "app", "--host", "0.0.0.0"]
    environment:
      - model_source=openai
      - API_KEY=${DECK_OPENAI_API_KEY}
      - TOOL_LLM_URL=https://api.openai.com/v1
      - TOOL_LLM_NAME=gpt-5.1
    ports:
      - "10000:10000"
EOF

Export your OpenAI API key and start the agent:

export DECK_OPENAI_API_KEY='your-openai-key'
docker compose up --build -d

The agent listens on port 10000 and uses the A2A JSON-RPC protocol to handle currency conversion queries. In this guide, the gateway service points to host.docker.internal:10000 instead of the container name because Kong Gateway runs in its own container with a separate DNS resolver.