ruvnet--RuView/docs/adr/ADR-271-cognitum-oauth-resource-server.md

ADR-271: RuView as a Cognitum OAuth resource server

• Status: accepted
• Date: 2026-07-22
• Deciders: RuView maintainers
• Tags: auth, oauth, cognitum, security, sensing-server
• Related: ADR-055 (integrated sensing server), ADR-102 (edge module registry), ADR-066 (ESP32 seed pairing), cognitum-one/dashboard ADR-060 (OAuth scopes beyond inference), cognitum-one/meta-llm ADR-045 (Bearer at completions)

Context

/api/v1/* on wifi-densepose-sensing-server is gated by RUVIEW_API_TOKEN (bearer_auth.rs): a single shared secret, compared in constant time, with no expiry, no rotation and no per-user attribution. homecore-api has a second, unrelated scheme (LongLivedTokenStore over HOMECORE_TOKENS) whose own doc comment describes it as "no expiry, no rotation, no per-user attribution yet".

That is proportionate for the ADR-055 topology — server bundled in the desktop app, spawned as a child, localhost only. It is not proportionate for the other deployment RuView actually has: a sensing server on a Pi or hub, reachable on a LAN, potentially serving more than one person, exposing live presence, pose, breathing and heart-rate data plus destructive operations (model training, model delete, recording delete).

Cognitum operates a live OAuth 2.1 authorization server at auth.cognitum.one. Users of RuView are already Cognitum account holders. The obvious question is whether RuView can accept that identity instead of a shared string.

The direction of the integration is the thing most likely to be misread

Every existing Cognitum OAuth integration in the org — meta-proxy, musica, metaharness, the dashboard CLI — is an OAuth client: it obtains a token so the application can call a Cognitum service (the completions plane).

RuView is the opposite. It makes no authenticated calls to any Cognitum API. Its only outbound Cognitum dependency is the ADR-102 registry fetch, which is an anonymous GET against a public GCS bucket. What RuView wants is to be a resource server: a user signs in to their own RuView instance with their Cognitum identity, and RuView verifies the token they present.

So the client-side prior art in the org, while useful for a future ruview login command, addresses a plane RuView does not have. The only relevant precedent is meta-llm/src/auth/oauthBearer.ts (ADR-045) — the org's sole resource-server-side verifier of these tokens. It is TypeScript; RuView is the first Rust one.

Facts about the tokens, verified against a live production token

• ES256 JWT, signed by a single P-256 key published at https://auth.cognitum.one/.well-known/jwks.json.
• 15-minute lifetime, with an opaque refresh token that rotates with reuse detection (presenting a spent one ends the session).
• Claims: typ, sub, account_id, org_id, workspace_id, client_id, scope, family_id, jti, iat, exp, setup, workload.
• No aud claim. No /oauth/introspect. No /userinfo. It is an OAuth 2.1 authorization server, not an OpenID Provider, deliberately.

Decision

Verify Cognitum access tokens offline, in a new ruview-auth crate, and gate RuView's own API surface on the scope they carry.

1. Offline verification is a requirement, not an optimisation

RuView runs on Pi-class hardware that loses WAN, and there is no introspection endpoint to call even when the network is up. Verification is therefore an ES256 signature check against a kid-indexed JWKS cache. Two consequences we accept explicitly:

• Revocation window = token lifetime. A compromised access token stays usable until exp. This is the same position meta-llm takes, for the same reason, and it is why §3 refuses long-lived credentials.
• A JWKS refetch failure is survivable while a key set is cached. A key that verified a minute ago has not stopped being valid because the network blipped; failing closed there would log every user out of their own sensing server whenever their internet wobbled. We fail closed in exactly one case: no key set has ever been fetched.

2. The accept-rule is ported from meta-llm, not designed

typ == "access"  AND  NOT setup  AND  NOT workload
AND account_id is a non-empty string
AND exp is in the future
AND iss matches the configured issuer verbatim
AND the scope required by the route is held

Divergence from oauthBearer.ts would be a bug rather than a preference: a token meta-llm rejects must not be one RuView accepts. The algorithm is fixed to ES256 by our code — the header's alg is only ever compared against that allowlist, never used to select an algorithm.

3. Long-lived setup and workload credentials are refused outright

Identity also issues 365-day setup and machine workload credentials. Their revocation state lives in identity's oauth_setup_tokens table. RuView — like meta-llm — has no database and no way to check it, so accepting one would mean honouring a credential that may already have been revoked. A 15-minute token needs no revocation round-trip because it expires faster than revocation propagates; a 365-day one does.

4. Scope is the capability boundary, because nothing else can be

Tokens carry no aud, so RuView cannot verify a token was minted for RuView. client_id cannot substitute: clients borrow each other's registrations when their own has not been deployed (musica ships DEFAULT_CLIENT_ID = "meta-proxy").

This is not a defect to route around. Cross-product identity is intended — one Cognitum account, every Cognitum product. Cross-product capability is not, and scope is what carries the difference.

RuView registers two scopes (dashboard ADR-060, identity migration 0016):

Scope	Grants
sensing:read	sensing/pose streams, one-shot inference, reading model and recording metadata
sensing:admin	POST /api/v1/train/*, DELETE /api/v1/models/{id}, DELETE /api/v1/recording/{id}

No hierarchy: sensing:admin does not imply sensing:read. Consent means exactly what it said, and a token needing both must have consented to both. client_id is retained on the principal for logging and attribution only — never as an authorization input.

5. Additive and fail-closed, never a silent downgrade

RUVIEW_API_TOKEN and HOMECORE_TOKENS deployments keep working unchanged. OAuth is opt-in; with it unconfigured, behaviour is byte-identical to today. When OAuth is configured but unusable (JWKS unreachable at boot, required scope not registered), the server must refuse to serve /api/v1/* rather than fall through to an open or single-secret state.

6. ureq, and a transport seam

wifi-densepose-sensing-server deliberately chose ureq as "the smallest" HTTP client. Introducing reqwest for a JWKS fetch would silently reverse that for the whole dependency graph. The fetch sits behind a JwksFetcher trait — the ureq implementation is a default-on feature, and a host may supply its own and take no HTTP dependency at all.

Consequences

• Requests become attributable: sub, account_id, org_id, workspace_id, jti. This closes the gap homecore-api's tokens.rs has been deferring as "P3", using claims rather than new RuView machinery.
• Destructive operations can be separated from observation for the first time.
• The 15-minute lifetime is the main operational cost. A long-running client must refresh, and because refresh tokens rotate with reuse detection, a concurrent or naively retried refresh ends the session — single-flight is a correctness requirement, not an optimisation. This lands with the login flow, not this crate.
• Hosts without a battery-backed clock will fail exp/iat until NTP lands. The verifier reports that distinguishably so it is diagnosable rather than presenting as a generic 401.
• A new dependency, jsonwebtoken — the same crate, same major version, that identity itself uses to sign these tokens.

Alternatives considered

Keep RUVIEW_API_TOKEN only. Zero work, and adequate for a single-user localhost install. Rejected because it cannot express who did what, cannot be revoked without a restart, and cannot separate "watch the stream" from "delete the model" — all of which matter the moment the server is on a LAN.

Exchange the OAuth token for a cog_ key. The pattern ADR-316 (meta-proxy) and ADR-119 (metaharness) originally described. Rejected: it cannot work. /v1/me/keys requires a Firebase ID token, not an OAuth token — meta-proxy hit the resulting 401 in production, replaced the approach with Bearer-direct under ADR-045, and deleted mint.rs as dead code.

Call identity to introspect each token. Rejected: no introspection endpoint exists, and a network round-trip per request would be wrong for an edge sensing server regardless.

Wait for an aud claim before shipping. Rejected as sequencing. aud would touch every issued token and every verifier in the org; scope is additive and independently correct. Tracked separately; adding aud later strengthens this design rather than invalidating it.

Use OAuth for the ESP32 device plane too. Rejected as a category error. Devices have no browser, no user and no human present; they already pair with a seed_token bearer (ADR-066) plus a device-bound PSK. Cognitum OAuth is for the API plane only.

Implementation

v2/crates/ruview-auth — jwks (fetch, TTL cache, kid index, one rate-limited forced refetch on an unknown kid so rotation is picked up without waiting out the TTL), verify (the §2 accept-rule), principal (the verified caller and its scopes).

41 tests pass under both cargo test --no-default-features (the repo's canonical gate) and default features. The matrix signs real ES256 tokens with a runtime-generated key — no key material is committed — and covers alg:none, forged signatures, spliced payloads, unknown kid, expiry on both sides of the leeway, issuer mismatch including a trailing-slash-only difference, typ confusion, setup/workload smuggled onto a typ=access token, missing and empty account_id, and scope escalation.

The load-bearing case is g2_a_genuinely_valid_token_from_another_cognitum_product_cannot_reach_the_sensing_surface: a correctly signed, unexpired, right-issuer, right-typ token bearing client_id=meta-proxy and scope=inference is rejected. Nothing about its signature or identity claims distinguishes it — only scope does. A naive verifier accepts it, and an inference token becomes a key to someone's home sensor.

Not in this crate: WebSocket authentication (ADR-272) and any outbound Cognitum call.

Amendment, 2026-07-22 — the login flow lives here after all, behind a feature

The paragraph above originally also excluded the login flow. That was written to keep the sensing server lean, which is the right goal but not a reason to put the code somewhere else: the Tauri desktop app needs the same flow, and a second copy of a PKCE + rotating-refresh implementation is exactly the kind of duplication that drifts apart and then disagrees about something subtle.

So login is a non-default feature of this crate. A server built with default features gets the verifier and nothing more — no reqwest, no tokio networking, no browser launcher. The CLI opts in with features = ["login"], and the desktop app can do the same.

Shipped as wifi-densepose login / logout / whoami. Two properties worth restating because they are easy to get wrong:

• Refresh is serialised and never retried. Identity rotates refresh tokens with reuse detection, so a concurrent refresh looks like replay and a retry is replay — either revokes the session family. Session::ensure_fresh holds an async mutex across the network call, re-checks expiry after acquiring it, and persists the rotated token before returning it.
• Least scope by default. login requests sensing:read; --admin is an explicit escalation and requests both scopes, since there is no hierarchy server-side.