---
id: HARN.1
status: ratified
ratified: 2026-09-01 (Jason Woltje; PRD rev1 ratification PR)
---

# HARN.1 — Harness configuration

A harness is an installed agent runtime (claude, pi, codex, opencode, …).
Shared contracts speak capability language; harness commands, model IDs,
hooks, and settings live in runtime adapters (register OD-38).

## Harness configuration surface (WebUI page + CLI)

| Control | Notes |
|---|---|
| install harness | single button push; installer runs server-side through official tooling |
| enable / disable | disabled harnesses are not selectable on any seat page |
| available models | an **allowlist** a seat may select from — not a selection. Whether `enabledModels` is role policy or harness/seat preference is open: [[GOV.5-open-questions]] Q-H1 |
| reasoning level defaults | |
| provider | which provider(s) back this harness ([[PROV.1-providers]]) |
| linked auth accounts | which accounts may drive this harness ([[AUTHN.1-auth-accounts]]) |

Enable/disable and install are runtime state (Postgres-owned) projected into
whatever flat state the launcher needs ([[DATA.1-record-authority]]).
## Runtime adapter contract (pulled 2026-08-31 from adapter-contract draft)

Every harness adapter binds a required capability set or **fails closed**:
repository ops via wrapper capability, scoped file/command execution,
structured reasoning, shared-memory capture/search/recall, inter-seat
messaging/wake, checkpoint persistence + mechanical telemetry, a `mosaic coord`
client that cannot mutate Kanban state or deploy seats directly, and credential
resolution through the seat's own slot. Rules:

- An unavailable capability is a **named blocker**, never silent degradation.
  **"Prompt adherence is not an enforcement mechanism"** — a harness that
  cannot persist checkpoints, emit telemetry, or honor fencing does not run
  workflows that need them.
- Each adapter publishes a capability→binding table (capability, binding
  surface, config source, verification check) and proves its bindings at
  session start; verification failure is a named blocker.
- Adapters bind capabilities but **never redefine role authority, delivery
  policy, gate outcomes, or review independence** — a harness whose native
  workflow conflicts with shared policy keeps the shared policy and records the
  conflict as an adapter limitation.

## E2 inputs (triage 2026-08-31; see [[GOV.2-docs-inventory]])

**Canonical ground truth**: the `fleet/` book — `concepts/desired-vs-observed-state.md`
(roster-v2 sole writable authority), `concepts/generated-env-launch-chain.md` +
`reference/generated-env-boundary.md`, `reference/roster-v2-fields.md`,
`operations/reconcile-and-recover.md` (lock/generation semantics),
`NORTH_STAR.md`/`FLEET-DOCTRINE.md` (delivery-fleet north star, subordinate to
this PRD per rev0 §10).
**Pending pulls**: brain `docs/guides/proposed/runtime/adapter-contract.md`
(the register-OD-38 runtime-adapter capability contract this section cites).

## enabledModels ruling (Q-D4, Jason 2026-09-01)

The Role Revision defines the allowed model set — a policy ceiling. The seat
records model preferences within that set. Effective models = the
intersection, consistent with the L2-D39 authority-intersection chain. A seat
preference outside the role ceiling is refused, not silently clamped.