# flex-auth Integration (TEN-WP-0003)

`tenant-engine` gates every write through flex-auth's `POST /v1/check`
(`flex_auth.FlexAuthCheckClient`, wired in as `authz.FlexAuthWriteAuthorizer`).

## What tenant-engine sends

A `CheckRequest` per `flex-auth/schemas/check_request.schema.json`:

```json
{
  "id": "check:<uuid>",
  "tenant": "tenant:friendly:binky",
  "subject": {"id": "<actor>", "type": "service"},
  "action": "tenant.create",
  "resource": {"id": "<tenant_id>", "type": "tenant", "system": "tenant-engine"}
}
```

Action → resource-type mapping (must match `flex-auth`'s
`FLEX-WP-0008-T01` vocabulary exactly — coordinate values, don't diverge):

| Action | Resource type |
| --- | --- |
| `tenant.create` | `tenant` |
| `tenant.role.grant` | `role-grant` |
| `tenant.role.revoke` | `role-grant` |
| `tenant.plan.assign` | `plan-assignment` |

## What tenant-engine expects back

A `DecisionEnvelope` per `flex-auth/schemas/decision_envelope.schema.json`.
Only `effect: "allow"` authorizes the write. Every other `effect`
(`deny`/`redact`/`audit_only`/`not_applicable`), a non-200 response, a
malformed body, or a transport failure/timeout all resolve to **deny** —
`FlexAuthCheckClient.is_allowed()` never raises past its own boundary; it
always returns a plain `bool`.

## The current real state

Until `flex-auth/workplans/FLEX-WP-0008-tenant-engine-consumer-integration.md`
lands (resource/action vocabulary + an authored policy package), **every
check resolves to deny or not_applicable** — verified against real
`flex-auth` behavior, not assumed. This is correct fail-closed behavior,
not a bug: tenant-engine cannot perform any write against a real `flex-auth`
deployment until that policy package exists. Verified locally with a fake
HTTP double standing in for `flex-auth` (deny → `403`, allow → `201`,
both over real HTTP between two processes) — see `TEN-WP-0003`'s closure
notes for the exact commands.

## Configuration

| Env var | Default | Meaning |
| --- | --- | --- |
| `TENANT_ENGINE_FLEX_AUTH_URL` | unset | Base URL of a reachable `flex-auth` deployment. When unset, `create_app()` falls back to `authz.DefaultDenyWriteAuthorizer` — no writes ever succeed, which is the correct posture for local/test runs that have no `flex-auth` to call. |
| `TENANT_ENGINE_FLEX_AUTH_TIMEOUT_SECONDS` | `3` | Bounded timeout on the synchronous write path — no retries, so a slow deny doesn't become a hang. |

## Related

- `flex-auth/workplans/FLEX-WP-0008-tenant-engine-consumer-integration.md`
  — the flex-auth-side work this client depends on for real `allow`
  decisions, and (separately) flex-auth's own live-lookup consumption of
  `tenant-engine`'s `/roles/live` endpoint for other protected systems.
- `key-cape/workplans/KEY-WP-0005-iam-profile-core-claims.md` — the
  cache-read/`tenant_roles` direction (`key-cape` → `tenant-engine`), not
  covered by this doc.
- `net-kingdom/canon/standards/tenant-engine-boundary-contract_v0.1.md` —
  the Authorization Contract section this client implements.