railiance-platform/docs/credential-lane-designs/secrets-engine-service-jwt.md

# Secrets-engine service JWT login

Status: proposed, not provisioned. Owner: railiance-platform, RPF-WP-0035-T02 (design origin RPF-WP-0032).
Demand: State Hub message `38b47122-07eb-4a7f-a5df-13a38f50e110`.

## Contract and ownership

KeyCape's accepted provider contract is
`../key-cape/docs/openbao-service-auth-contract.md`. The consumer implementation
is `../secrets-engine/src/secrets_engine/engine_auth.py`; the existing coding
agent role is `openbao/auth/coding-agent-jwt-role.json`. The service must have
its own role and identity. It must not acquire the coding-agent role or an
operator's policy set.

Propose an isolated JWT auth mount `keycape-services`, role
`secrets-engine-openbao`, and policy `secrets-engine-login-self`. Survey first:
if an equivalent service mount already exists, the owner may select it in the
approved contract instead. Do not reconfigure the browser `netkingdom` mount
or the coding-agent mount to introduce this service.

| Setting | Proposed value / evidence required |
| --- | --- |
| Verification | RS256 only; issuer `https://kc.coulomb.social`, JWKS `https://kc.coulomb.social/jwks`; public discovery rechecked 2026-09-27; live registration remains unverified |
| Role type / user claim | `jwt` / `sub` |
| Audience | `secrets-engine-openbao` |
| Subject | `service:secrets-engine` |
| Bound claims, string matching | `principal_type=service`, `tenant=tenant:platform`, required `roles=secrets-engine`, `scope=openbao:login` |
| Token policy | `secrets-engine-login-self` only; no default policy |
| Token bounds | service token, TTL/max/explicit max `5m`, 8 uses, no periodic token; budget must include cleanup |
| Logging | verbose OIDC logging disabled; no JWT claim dump or token/accessor in receipts |

The self policy permits only `auth/token/lookup-self` read,
`sys/capabilities-self` update, and `auth/token/revoke-self` update. These
explicit self endpoints are necessary because default policy is disabled.
No KV read, policy/auth mutation, SecretID minting, child-token creation or
renewal is granted. Verify the token's effective identity policies too: disabling
default policy alone does not prove that aliases/groups add no permissions.

This is an identity login contract. It is intentionally insufficient to apply
native lanes. `../secrets-engine/docs/native-lane-cutover.md` still requires
canonical ActionAuthorization, successful approval-engine consume, scoped
attended production authority and consumer verification per lane. Granting this
service standing wildcard ACL/role-write privileges would let a raw OpenBao
token bypass those application checks. Any future execution entitlement needs
a separate reviewed CCR type and backend-enforced scope. The current
`workload-kv-read` schema cannot encode this JWT administrative authority.

## Publication and custody

After live verification, publish a separate non-secret consumer file with
exactly these fields (the template below is deliberately invalid until filled):

```yaml
mount: keycape-services
role: secrets-engine-openbao
bound_issuer: null # required exact HTTPS KeyCape issuer; do not guess
```

Point `SECRETS_ENGINE_OPENBAO_JWT_LOGIN` only at the approved final file. The
consumer requires its issuer to equal `SECRETS_ENGINE_KEYCAPE_ISSUER`. The client
secret remains in the separately approved KeyCape client custody lane, mounted
as a protected file; the JWT exchange and OpenBao login remain in memory or
private temporary input with cleanup. This design does not establish that client
secret's live path or provision it. `--auth service-jwt` is the explicit pilot;
failure must never fall back to bootstrap/env authentication.

KeyCape bounds JWT lifetime to 15 minutes and provides no refresh token. OpenBao
login is not a one-time consumption guarantee for that JWT: it may be replayed
while valid. Disabling issuance does not recall already issued JWTs or OpenBao
tokens. In an incident, disable the exact role/client and revoke issued service
tokens through owner custody; do not disable a shared mount. Without active
revocation, residual access can extend by the OpenBao token TTL after the last
accepted JWT login. Renew by a fresh exchange; always self-revoke after use.

## Approval and acceptance

KeyCape confirms issuer, verification endpoint, registration and claim types;
platform approves the exact mount/config/role/policy and effective policy set;
secrets-engine accepts the five-minute token/use budget and login-only scope.
The installed OpenBao version must support the reviewed parameters. A metadata
survey must show no conflicting role before any write.

Prove correct-service login, exact policy set, expiry/use exhaustion and cleanup.
Reject wrong issuer/audience/subject/tenant/principal/role/scope, invalid or
expired signatures, and coding-agent credentials. Prove KV read, policy write,
SecretID issuance and child-token creation are denied. Separately prove a
failed login never consults bootstrap/env providers. Retain only timestamps,
public contract revision, capability outcomes and boolean cleanup evidence.
First-lane apply remains gated on SECRETS-WP-0007-T04 and its own exact approval.

Rollback disables the role and revokes its tokens; removing an exclusively
owned empty mount is a later review. Existing ESO lanes and interim proxies
remain available. The login contract is withdrawn until verification is green.

OpenBao's [JWT documentation](https://openbao.org/docs/auth/jwt/) describes
signature verification and claim binding; its [role API](https://openbao.org/docs/2.4.x/api/auth/jwt/)
defines token TTL/use limits and the explicit maximum. These are mechanism
references, not evidence of this cluster's installed configuration.

## Prepared source return — 2026-09-27

The exact proposed bundle is `openbao/auth/keycape-services-config.json`,
`openbao/auth/secrets-engine-jwt-role.json` and
`openbao/policies/secrets-engine-login-self.hcl`. These files are non-secret
inputs for the existing attended platform procedure, not an applied receipt.
The discovery document advertises `/token` and `client_credentials`.

The operator clarified that platform infrastructure belongs to tenant zero,
`tenant:platform`. Coulomb is a workload tenant; its DNS domain is not ownership.
The former `tenant:coulomb` service registration and consumer preflight were
consistent but incorrectly scoped. The corrected source uses `tenant:platform`
for both OpenBao infrastructure clients and the existing approval clients.

Before writing: survey mounts/roles, confirm exact live client registration and
protected client-side custody, review this bundle and obtain the scoped attended
window via `warden access openbao-platform-admin-login --exec -- <reviewed-command>`.
Do not execute a placeholder command. The reviewed child must install only this
isolated mount/config, self policy and role, compare effective policy metadata,
then perform the positive/negative/expiry/use-limit/revocation checks above.
Do not print login responses. Publish the consumer contract only after those
checks pass. A conflicting existing mount/role requires review, not overwrite.
No service-client secret is created, moved or requested by this source return.