A2A between agents, tools inside each one
The planner, the client agent, sends SendMessage over A2A to three remote agents: test-runner on port 41241 with skill run-tests, code-reviewer on port 41242 with skills review-diff and answer-question, and deployer on port 41243 with skill deploy. The planner sees only these cards and endpoints. Below a dashed line, hidden from the planner, each agent runs its own logic and calls its own systems as tools: Git and a CI runner for test-runner, Git for code-reviewer, and a deploy API for deployer.
CLIENT AGENT
planner
delivers payments-api: tests, review, deploy
A2A ยท WHAT THE PLANNER SEES
HIDDEN FROM THE PLANNER
The kit simulates these systems in Python. A real agent calls them through MCP or any API.
SendMessage
test-runner :41241
run-tests
SendMessage
code-reviewer :41242
review-diff
answer-question
SendMessage
deployer :41243
deploy
its own logic
model and code
its own logic
model and code
its own logic
model and code
tool call
Git, CI runner
check out, run the suite
tool call
Git
fetch the base branch
tool call
deploy API
roll out to staging