# a2a-n8n-adapter

An A2A facade in front of an n8n workflow. One image, one instance per agent,
configured entirely by environment.

The repo's notes proposed serving this from the gateway instead — a static Agent
Card and a route to the webhook, no new component. That does not reach. A2A is
not request/response: a caller gets a `Task` with an id, a context and a state
that can be `input-required` or `failed`, and none of that can be synthesised
from a webhook's single reply by a proxy. Templating the whole lifecycle in
gateway configuration is an adapter, written in the wrong language.

So: the alternative those same notes anticipated, written once for both agents.

## It owns the protocol and nothing else

It holds no Keycloak client and no credentials. It forwards the end user's token
to the workflow in `X-Subject-Token` — a header rather than the body, so a
workflow that logs its input does not log the token with it — and the workflow
exchanges it, because the component that can mint tokens should be the one that
uses them.

The workflow answers `{"answer": "...", "escalate": false}`. Anything else is
returned as raw text rather than guessed at: a workflow that has drifted from
the contract should look wrong, not be quietly reinterpreted.

`escalate: true` fails the task rather than completing it. An autonomous agent
that meets a rule needing approval must hand it back, never decide, and a
completed task is the wrong shape for "a human has to look at this".

## Configuration

| | |
|---|---|
| `ADAPTER_AGENT_NAME` | `approvisionnement` |
| `ADAPTER_AGENT_DESCRIPTION` | what the card says it is |
| `ADAPTER_SKILL_ID` | `check_availability` |
| `ADAPTER_SKILL_NAME`, `_DESCRIPTION`, `_EXAMPLES` | the card's one skill; examples are newline-separated |
| `ADAPTER_WEBHOOK_URL` | the workflow's production webhook |
| `ADAPTER_PUBLIC_URL` | what callers dial — the Service DNS name, not the bind address |
| `ADAPTER_CA_BUNDLE` | the lab CA, so TLS is verified rather than disabled |

One skill per instance, deliberately. A second one is a card change, which is
the moment to ask whether the agent has quietly become a data proxy.