atlas-iac/docs/hux/HANDOFF.md

# hermes-next: Claude backend handoff ledger

Branch `feature/hermes-next-hux` (origin, pushed after every card); draft PR #55 https://scm.bstein.dev/atlas/titan-iac/pulls/55 (opened through the SCM broker, never merged by Claude). Board
`hermes-next` on the operator Hermes Kanban; cards HUX-01..HUX-12 are parked
(`blocked`) on purpose so the CLI lane runner never auto-claims them — the
Claude coordinator and the Codex root session are the only implementers.
Contract: `hux.v1` 1.0.0 (`services/hermes/contracts/hux/VERSION`,
`docs/hux/ADR-0001-hux-v1-contract-freeze.md`). Threat model:
`docs/hux/THREAT-MODEL.md` (SO-01..SO-54). Data model: `docs/hux/DATA-MODEL.md`.

Run everything with the CI interpreter:
`python -m pytest testing/tests/test_hermes_hux_*.py -q` and
`python -m coverage run --branch --source=dockerfiles/hermes-hux-foundation -m pytest testing/tests/test_hermes_hux_*.py`.

## Codex integration requirements common to every card

- Package `dockerfiles/hermes-hux-foundation/hux/` runs as `python -m hux.server`
  inside each `hermes-chat-tenant` pod (and the Worker) on `127.0.0.1:8790`.
  Image, manifest, NetworkPolicy and Flux wiring are Codex's (SO-01, SO-02,
  SO-45: separate uid, `/opt/data/hux` mode 0700).
- Env: `HUX_DATA_ROOT` (tenant PVC, default `/opt/data`), `HUX_TENANT_SLOT`
  (pin, SO-03), `HUX_FLAGS` (comma list, default empty = everything off),
  `HUX_RELAY_KEY` (Telegram relay), `HUX_WORKER_KEY` (Worker),
  `HUX_BUILD_COMMIT`, `HUX_IMAGE_DIGEST`, `HUX_CONTRACT_DIR` (schemas path in
  the image; default resolves relative to the repo layout).
- Router → service headers (SO-04): `X-Hermes-Tenant-Identity: slot-N`,
  `X-Hux-Subject: usr_<hash>`, `X-Hux-Surface: chat|telegram|voice|api|worker`,
  optional `X-Hux-Trust: relay|worker` + `X-Hux-Relay-Key`. The router must
  strip any inbound `X-Hux-*` before setting its own.
- First client call: `GET /hux/v1/capabilities` → which cards/routes are on.
  Disabled or unknown → `404` (`flag_off` vs `not_found` only in the body).
- Mutations: `If-Match: <revision>` on revisioned records (409 on mismatch);
  `Idempotency-Key` on creates. Errors are `hux.error.v1`.
- Fixtures Codex codes against: `services/hermes/contracts/hux/examples/*.json`
  (validated in CI by `test_hermes_hux_contract_schemas.py`).

## HUX-11 shared foundation — DONE (backend)

| | |
|---|---|
| Commits | `47a9fd83` (contract freeze 1.0.0), `7cf9a714` (service core) |
| Files | `services/hermes/contracts/hux/{common,identity}.schema.json` + examples, `VERSION`; `dockerfiles/hermes-hux-foundation/hux/{__init__,errors,identity,flags,store,audit,http,foundation,server,contracts,rules}.py`; `docs/hux/ADR-0001-*.md`, `THREAT-MODEL.md`, `DATA-MODEL.md` |
| Tests | `testing/tests/test_hermes_hux_contract_schemas.py` (61), `test_hermes_hux_contract_foundation.py` (30): identity header rejection matrix, relay/worker keys, slot pinning, fail-closed flag chains, capabilities record validity, tenant-scoped paths + traversal rejection, revisions/conflicts, torn-ledger recovery, blobs, manifest, concurrent writers, audit rows, flag-off == not-found, 401 never touches storage, real HTTP server JSON + SSE, loopback-only bind, all errors validate, ≤500 LOC guard |
| Coverage | 99% line / 98% branch over the package |
| Contract | 1.0.0 |
| Flag | `hux.foundation` (root of every dependency chain) |
| Risks | Rate limiting (SO-53) and hash-chained audit (SO-46) not yet implemented — tracked for the Wave A review; relay callers still carry `X-Hux-Subject` (deviates from SO-06; the slot→owner mapping lives in the router, so the header is redundant but harmless and lets the service pin the subject) |
| Codex needs | Wire the service into the tenant pod + Worker, NetworkPolicy, router header contract above, `HUX_FLAGS=hux.foundation` for the first canary; `testing/quality_contract.json` may add `dockerfiles/hermes-hux-foundation/**/*.py` to `line_limit_globs` and the two moved modules to `managed_modules` (Claude does not edit that file) |