# Hub access profile 1.0.0 — implementation candidate

HUB-WP-0012 source implementation, 2026-09-28. Owner review and live acceptance
remain open. This profile does not grant platform access or enable public exposure.

## Runtime behavior

`HUB_CORE_ACCESS_MODE=auto` enables enforcement whenever `HUB_CORE_ENV` is not
`development` or `test`. `enforce` also enables it locally. `development` is
rejected in other environments. **Do not deploy this candidate as a routine
upgrade:** the default production factory has no admitted owner adapters yet and
returns 401 for missing credentials and 503 for credential-bearing requests.
The current deployed image and its release configuration have not been changed.

Without explicit browser composition, only exact `GET /healthz` is public, returning `{"status":"ok"}`. The shared
ASGI boundary protects docs, readiness, native ports, projections, compatibility
aliases and subsequently attached routes. Unknown method/route/handler combinations,
WebSockets, mounts without admission, and slash redirects without catalog entries
fail closed. Clients must use exact paths. Catalog admission does not override
compatibility feature flags or single-writer/read-only gates. Legacy bearer checks
remain in the development lane; production enforcement never falls back to them.

`hub_core/security/routes.json` is the candidate action catalog. It names each
runtime method, path template and handler, with a stable action per handler/method.
It is packaged in the wheel and tested against actual route construction. Source
inventory generation does **not** auto-admit a new route. Duplicate docs handlers
remain separately inventoried; the boundary selects the first effective route.
These technical action names require flex-auth/owner review before policy delivery.
Optional browser composition adds four exact `/auth/*` protocol routes and the
`hub.browser.session` action; login initiation is public, callback state is
browser-bound, and session access requires current root authority. See the
[browser integration contract](owner-access-integration.md#browser-composition-source-candidate).

## Composition and trust

A host composes `create_app(access_controller=AccessController(...))` with:

- `OIDCVerifier`: an explicitly trusted HTTPS issuer and Hub audience, an owned
  `httpx.AsyncClient`, RS256 discovery/JWKS, token and assurance lifetime at most
  300 seconds, a 60-second key cache, and unknown-key rotation refresh (rate limited
  to once per second). Access tokens require `at+jwt` or the KeyCape `typ: Bearer`
  payload marker. ID tokens, local issuers/profiles, weak keys, AAL0 and delegated
  agents are refused. Strict integer NumericDates and assurance time are required.
- `FactSource.resolve`: an **owner implementation still owed** that queries
  authoritative account, root entitlement, actor tenant and target tenant state.
  Its result binds issuer, subject, actor tenant, evidence reference and permitted
  producer addresses; its age may not exceed five seconds, including after policy
  and audit finish. No token role or incoming tenant/identity header supplies facts.
- `FlexPolicy`: a dedicated HTTPS Hub PDP, exact admitted ServiceAccount principal,
  a rotating projected caller-token file and an owner-delivered trusted public-key
  set. The token is reread on every call and is separate from the end-user token.
  Remote `/v1/keys` responses never establish their own trust. Current/previous keys
  can coexist in the mounted trust file; removing a key takes effect next call.
- `AuditCoreSink`: implemented against the owner
  [eight-field ingestion contract](../../audit-core/docs/event-envelope.md), returning
  only after an operational-custody probe and explicit durable acceptance. Every allow must reach this sink before handler execution;
  a failed sink blocks reads as well as writes. Authorization receipts say
  `authorized`, not “operation completed.” Domain commit/outcome audit remains a
  separate requirement; this source seam does not claim transactional audit.
- The root's existing immutable issuer and subject, supplied after owner resolution.
  No username, email, first-login promotion or generic role establishes root.

Do not implement these missing adapters as a constant allow, in-memory audit sink,
or an assertion copied from token claims. Tests use synthetic owners explicitly.
The current CLI deliberately provides no fixture adapter or production bypass.
An explicit `SecuritySettings`/owner-facts composition now owns the HTTP client
and closes it with the runtime. Audit custody is probed per append. Real owner-facts
admission and additional owner dependency probes remain T02–T04 work; see the
[owner integration review](owner-access-integration.md).

For this candidate all Hub resources are explicitly **platform-owned**. Other
target tenants are refused. Root requires AAL2/3, active account and tenants,
current root entitlement, and a fresh policy allow for every action. Workloads
receive no root shortcut: a policy grant and current authoritative facts are always
required. Real workload admission remains unproven. Cross-tenant owner administration
and Phase 2 storage/query isolation are not implemented by this classification.

## Policy interoperability and failure handling

The PDP request carries actor, target tenant, action, concrete resource path,
assurance, root entitlement, authoritative evidence reference, and a digest of
HTTP method/path/query/body. Client bodies and bearer tokens are not sent to the
PDP or audit sink. Body size is bounded at 1 MiB with a ten-second receive deadline. The controller's identity/facts/
policy/audit chain has a ten-second timeout; individual HTTP calls have three seconds.
A separate refusal-audit attempt is bounded at three seconds.

The verifier requires Ed25519 signing, the submitted request digest, matching
request ID and structured actor/action/resource/tenant/context, enforced caller
provenance, policy version/digest, a decision age at most 30 seconds and a valid
allow lifetime. It never caches decisions. Every unimplemented obligation and
non-allow/non-deny effect fails closed; approval requirements cannot be waived.
A malformed/untrusted/unavailable decision returns 503, a verified denial 403,
and invalid authentication 401. Responses are `no-store` and do not expose backend
exceptions. There is no local allow fallback.

Interoperability tests retain flex-auth's real Go-signed fixture, tampered pair,
public test key and original submitted request. Go `encoding/json` emits struct
fields in declaration order and map keys in sorted order. The verifier retains
wire order and HTML escaping for signatures and reproduces the request structs
for `submitted_request_digest`. This is **not** RFC 8785. Duplicate JSON keys and
non-integer decision numbers are outside this candidate profile and fail closed;
a reordered envelope also fails signature verification. Agree broader canonical
encoding with flex-auth before expanding this profile.

## Producers, MCP and embedded hosts

`from_address`, `from_agent` and `author`, when present in a top-level JSON command,
must match the live owner's producer-address set. Native events get a reserved
`payload._hub_access` record containing verified actor/tenant/correlation identity;
client assertions under that key are overwritten. Domain `subject_refs` remain
business data, never proof of origin. Compatibility event implementations and
external publishers still need owner acceptance of equivalent attribution.

Embedded hosts can install `AccessBoundary` and an explicit host route catalog.
Tests prove the common seam on an embedded host; each real host's mounted paths,
features and routers still require inventory and admission. Do not treat the
standalone runtime catalog as admission for every embedded API.

MCP hosts may supply `token_provider`, a callable resolving a **Hub-audience**
credential from the current invocation, with `require_credentials=True`. Credentials
are never retained on the server; requests do not follow redirects when carrying
one. `trailing_slash=False` targets the standalone runtime's native paths. The
standalone production MCP has no human flow/provider yet and fails closed.
Many legacy tools target APIs the standalone Hub does not implement. They remain
unsupported, not silently translated or authorized. Cross-audience delegation,
browser PKCE sessions/logout and real MCP root login remain open.

## Remaining release gates

1. T01: cross-owner contract review, concrete policy vocabulary, effective host and
   service-route expansion; the 250-object snapshot is not full route discovery.
2. T02: immutable root binding, registered audience/redirects, PKCE/MFA/recovery,
   admitted live facts adapters, attended login/logout and revocation receipts.
3. T03: dedicated Hub policy and fact provenance review; authenticated deployment,
   credential/key custody, real Audit Core sender admission and native rotation probes.
4. T04–T05: deploy the admitted composition, complete dependency health probes and all client/extension
   migrations, domain outcome audit, legacy lane rollback and full root journeys.
5. T06–T08: every platform/Railiance receipt, separate public-enable approval and
   later role/delegation/tenant isolation. No milestone is closed by local fixtures.