Route muse lanes through T3's Muse driver on a T3 parent #283

Current scope

On a T3 parent, muse:* lanes always take the external runner, even when T3 has an enabled Muse provider. The driverKind table in the T3 host section of plugins/pstack/skills/poteto-mode/references/provider-dispatch.md has no muse row. That conflicts with the rule quoted in #253: "any lane for which there is a delegate provider available and configured should go through that delegate provider, otherwise it should go through the external runners."

Live evidence: orchestrator_capabilities on studio1 (T3 0.1.7, 2026-11-08) shows these instances:

• muse_pool: driverKind: muse, enabled, canRunChildTask and canRunCrossProviderChildTask true. It lists muse-wonder-1.0, muse-spark-1.3 and others, with a reasoningEffort option.
• muse: driverKind: muse, disabled.
• codex: also lists Muse model IDs. Muse rejects every call made through the Codex driver ("Recursive JSON schemas are not currently supported"), so a Muse lane must never match the codex instance. Matching on driverKind already prevents that.

T3 0.1.7 has no Amp driver, so amp correctly has no row.

Acceptance

1. The driverKind table maps pstack muse to T3 muse.
2. The T3 route says which instance a lane uses when more than one instance shares the lane's driverKind, as muse and muse_pool do here. Pick the rule that needs no operator config, for example the only instance that meets every route condition, with a named dropout when several meet them.
3. The effort-option bullet names Muse's key (reasoningEffort, as the capabilities show).
4. The T3 route covers unregistered pairs. Muse has no model-matrix rows, so every muse:* descriptor is an unregistered pair. The "Model catalog" section says such a pair runs unchanged only on an external route and on Codex's native route.
5. Live gate: one delegate_task lane on a Muse model from a T3 parent, judged by the T3 host completion rules. This is the cheapest case, so it needs no setup run.

Source: review of #175 against the T3 support from #272 (1.19.0), 2026-11-08.