master made `allowParallelInProgress` a required field on dsh-tool-todo, so
every composition must choose it. The base patch was updated with the field,
but the Web surface takes `tool-todo` from the mounted preset instead, and
that row carried no config — so the `standard` preset failed to mount and
every session on the Web surface died at setup.
Also make the preset tree's write test reach the override. Tearing the agent
down stops in the loader's own "tree is being disposed" case before any write;
a live row reconfiguring itself is the trigger that actually gets there.
`ui-question`'s node half called `ctx.tools.register` on the host context.
`ScopedLayers.merge()` combines the global layer with the agent's exact-scope
layer, and an unscoped registration lands in the global one — so the tool
reached every agent no matter which preset composed it. `core-web`, sold as a
two-tool benchmark surface, really presented three.
Rendering a question is a host UI capability; having the tool is an agent
capability, and only a preset decides that. The node half is now empty and the
`tool-ask-user` row moved into the preset that wants it. The TUI keeps its own
row, having no presets.
The composition tests now assert the global tool layer is EMPTY, which is the
invariant that would have caught this: any tool outside a preset reaches every
agent. The browser lane's composition, seeded-history, and hermetic-skill
assertions address their registries through a composed agent for the same
reason — those services are per session now, and the host cannot resolve an
`isolate` realm by name.
Moving the agent plane behind per-session presets took five rows with it that
the host still owns, and the Web surface stopped booting: `host-apiproxy`
injects `subagents`, so with the registry disabled here the entry never
activated and `dsh web` died at plugin-tree load.
The criterion is injection, not subject matter. A host row that injects a
service resolves it before any session exists, so there is no agent to key by:
`bash-env` (which `apps/cli/src/web.ts` injects to publish `DSH_WEB_URL`), the
`subagents` registry and its spawn/fork backends (a process singleton whose
cross-session queries the api-proxy serves, and whose provider names are
globally unique), and `tool-subagent-report` (a continuable setup on that
singleton, registered once per live session by a list that is not scope-aware)
all stay host-plane. What a preset chooses is which delegation TOOLS it sees.
The browser lane needs the second half: skill roots now resolve inside a preset,
a subtree the lane's include patches cannot reach, so the row's documented
environment fallback is pinned for the whole scaffold lifetime — presets mount
when a session is created, not at boot. Without it a developer's real
~/.dsh/skills enters replay requests and goldens while CI sees none.
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.
