A third built-in preset: the standard coding agent plus the self-referential
Cordis toolset, a persona that explains the two-plane split, and a skill
teaching composition authoring. It exists so a person can ask an agent to
author another agent.
The skill ships INSIDE the preset directory rather than in the user's skill
root, and the root is derived from the preset's own `baseUrl` — the loader
evaluates `!!js` with `with (ctx)`, so a composition can locate itself. A
preset is the unit that gets copied and edited, so its documentation should
travel with it.
The skill leads with the rule that actually bites: a row publishing a service
may not sit loose in a preset, whether a row publishes one is not visible from
its name (`tool-bash` provides `bashEnv`), and a consumer left outside its
provider's isolate group resolves the host registry and then contributes
nothing — the quietest failure this design has.
Writing the test surfaced a consequence worth stating: an entry-local realm
makes the service invisible to the agent's own scope too, not just to the host.
Only rows inside that group resolve it, which is precisely what makes
`tool-skill` this agent's own rather than a shared one. The test asserts what
is actually observable from outside instead of reaching for the isolated
service.
TRUST: `cordis_mount` evaluates model-written JavaScript against the live
runtime, and a composition this agent writes becomes a preset other sessions
mount. Both the preset header and the toolset's own documentation say to treat
this as shell access. The tools stay opt-in per session — a test pins that they
are absent from every other preset.
Two consequences of moving the agent plane behind presets, both invisible
until the host plane stopped carrying model-facing rows.
`sessions.fork` built its child with a bare `installTarget` and a `meta`
without `agentPreset`. That was harmless while every tool sat in the host
plane — the child inherited them for free. It now comes up with an EMPTY
tool set. The child composes the parent's preset instead, for the same
reason a resumed session keeps its own: the seeded history was produced
under those tools.
`bashEnv` lives in its own `dsh-bash-env` row rather than inside
`tool-bash`, so a preset that isolates the realm must compose the provider
beside its consumer; the host row is disabled here like every other
model-facing one. Nothing outside the agent plane injects `bashEnv`, so it
stays per-session.
`session.create` takes an optional `agentPreset`, and the host resolves it,
mounts it during pre-publication setup, and records the resolved id on the
session header so a later resume rebuilds the same agent.
Resolution happens BEFORE the session exists, not inside setup: the session
boundary snapshots `meta` before asynchronous setup begins, so an id discovered
during setup could never reach the header. Mounting still happens in setup,
where a failure rolls the whole creation back rather than publishing a session
whose capabilities are half-installed.
Resume ignores whatever the request names and rebuilds from the stored id. A
resumed session's history was produced under that composition; restoring a
different one would replay tool calls the model can no longer make.
`dsh-agent-presets` now throws `UnknownPresetError` / `PresetMountError` so
the host can tell a bad request from a broken preset — they become
`agent-preset-not-found` and `agent-preset-invalid`.
Ships the two built-in compositions (`standard`, `core-web`) and the persona
row that lets them differ in identity. Nothing mounts them yet: no roster is
configured, so `composeAgent` finds no service and every session keeps the host
composition. Wiring the roster and moving base's agent-plane rows behind it is
the next commit, so the switch happens atomically with a real-composition test.
