One unit definition already serves every session — its cells are keyed by
`Session` — but registrants became per-session when agent presets started
mounting tool packages per agent. N sessions on one preset register the
same key N times.
The first registration won and owned the only disposer, so ending one
session stripped `goal`, `todos`, `plan`, `tokenUsage` and
`contextPressure` from every other live session's snapshot. Measured
against the shipped `standard` preset: two concurrent sessions each had
eight projection keys, and disposing the first left the second with three
— the ones host rows register.
Count the registrants instead and remove the key when the last one goes.
A differing `stateVersion` still refuses to share: it is the one
incompatibility a runtime comparison can name, since everything else
about a definition is functions.
The Loader writes a tree back to its source whenever it decides the
config changed, and a row disposing its own fiber is enough to decide
that. The mounted subtree overrides `write()` as a no-op for that
reason — a fact that lived only in a PR description, so nothing in the
repo said why the override exists or what removing it would cost.
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.
The Web overlay disables base's 32 agent-plane rows and mounts the preset
roster instead, so each session composes its own tools and prompt rather than
sharing one process-wide set. The TUI keeps base unchanged: it is single-session
and composing its agent process-wide is correct there.
`roots` is patched in by AppCLIEntry, like `distIndex`: the shipped presets sit
beside the composition that names them and the user's live under the Harness
home, neither of which a config author chooses.
A session's preset is fixed at creation. Naming a different one for an existing
identity is `agent-preset-conflict` rather than a switch, because that
session's history was produced under the first preset's tools. The guard sits
after `await creation`, beside the cwd check, so it covers every path that
yields a live agent — freshly created, adopted live, resumed, or recovered by
the concurrent-creation catch. A request naming no preset adopts the session as
it is, keeping reconnect and retry ordinary.
Two bugs the real-composition test caught, both invisible to unit tests:
`PresetTree` now refuses to write. The Loader persists a tree whose plugin
self-disposed, and tearing an agent down disposes its whole subtree — inherited,
that rewrote the shipped composition, truncating a 241-line preset to `[]` the
first time a session ended.
`dsh-tool-skill` compared against a lookup of its own name in the global layer,
so it threw inside any preset: `register()` files into the calling context's
scope. It now compares against the definition it registered, which is what the
identity check meant all along.
The `standard` catalog is asserted exactly, not spot-checked: a row that
registers into the wrong layer mounts cleanly and simply contributes nothing, so
an omission is this design's quietest failure. It matches the shipped TUI
catalog plus `glob`/`grep`, the pair that composition documents as
ripgrep-dependent.
Re-records `cordis-inspect-jsdoc`, whose rendered `SessionHeader` gains the
`agentPreset` field. `fs-glob-sampling` fails identically on pristine master
and is untouched here.
The browser e2e scaffold gains the roster fact AppCLIEntry supplies. `roots` is
resolved and patched in by the CLI entry, like `distIndex` on the webserver row,
and this lane boots the shipped tree without that entry — so it has to supply
the same fact or the roster resolves nothing and every session in the lane
composes an agent with no tools, no persona, and no token meter. Only the
shipped root: a developer's own `~/.dsh/.agent-presets` must not decide a golden. The
`cordis:group` builtin comes with it, exactly as `boot()` registers it, because
a preset resolving package names from its own directory cannot reach
`@cordisjs/plugin-group` by name.
The lane stays red through this layer and the next four for the reason stated
above — the api-proxy injects `subagents`, `workspace`, and `tools`, so
`api-gateway` cannot activate and the browser has no `/api` at all. It goes
green again in the layer that returns those registries to the host plane; this
change is what makes that layer's fix sufficient rather than partial.
`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.
`dsh-system-prompt` owns the deployment persona as its own config and registers
that section unconditionally, so a process has exactly one. An agent preset
cannot mount the prompt registry itself, which means that without a row of its
own a preset could change an agent's tools but never its identity — and a
roster of presets that all sound the same is not worth having.
The row is scope-only by construction: mounted outside an agent scope it
collides with the registry's own `deployment:persona` registration and fails
loud. That is the correct shape rather than a gap, because the unscoped slot
already has an owner and this row exists to shadow it for one agent.
Two behaviours are pinned by test because both read the other way at a glance:
an empty persona still occupies the slot (shadowing the deployment persona away
entirely, then disappearing at render), and `assemble()` keeps section text
uninterpolated — `renderPrompt()` is the stage that resolves `{{…}}`.
A composition that shares one `isolate` realm across rows needs a
`cordis:group` row, and a preset living outside this workspace — the
authored ones under the Harness home — cannot resolve
`@cordisjs/plugin-group` by name: Node's upward `node_modules` walk
never reaches the harness from there. Registering it as a loader builtin
beside `cordis:include` loads both through the ambient module pipeline
instead.
Record it in the preset Agent Note, which leans on the realm vocabulary
without saying where the group row comes from, and drop the preset
README's limitation claiming this builtin is unavailable — it described
the state this change ends.
The test's assertion had a vacuous escape: `provide` mints the root
symbol unconditionally, so the `rootKey === undefined` disjunct could
never hold and the comment claiming the root realm never learned the
name was wrong. Pin both halves — the symbol exists, nothing is stored
under it — and clean up the global the fixture writes.
Records are pruned by observation rather than by a disposal hook, for the
reason the module already states: three different owners can tear a
subtree down, and a cleared `uid` is what they share. That leaves the
pruning to whoever reads — and the only production reader is the
invariant companion, whose package is a development composition a
shipped host never loads.
So a live host pruned nothing: every session ever composed left a record
retaining its whole disposed subtree, since the fiber holds its config
and that config is the key its EntryTree is stored under.
Prune on the mount path too. Every session takes it, which bounds the
set at one generation of dead records instead of one per session.
- the cached-identity rung gains a finality gate: the identity value
carries its descriptor seq and a cached row is served only when that
seq lands in the child's own suffix, so a fork seed's replayed
ancestor identity can never outrank the authoritative refold
(stateVersion bumped for the state-shape change)
- the cold preparation validates the inspected header against the
enumerated candidate's lifecycle witness; a republished id degrades to
that child's corrupt diagnostic instead of leaking the new owner's log
- the new projection registration proves HMR disposal; companion notes
qualify the superseded decision text and record the deliberate
error-face asymmetry
subagents.history drops its session-query read: a live child serves its
in-memory events with the registry watermark snapshot, a cold child goes
through inspectServable with a detached fold, and the retired
SESSION_QUERY_* arms disappear while every wire face stays put. The
design note records the shared read source.
- the subagent projection's empty state becomes a serializable null
sentinel (undefined fields vanish in JSON push frames, leaving stale
identities in clients); consumers treat null and a missing key alike,
and cached sentinels defer to the authoritative refold
- the tool catalog generator mounts the projection registry for
list_agents; the shared unavailable-error copy goes catalog-neutral
- the design note's verification section records the new
subagent-diagnostic snapshot honestly, the 2026-07-22 note's test
inventory is rewritten to the current mechanism, and the session-store
error code is documented
Cold children consult the optional session-projection-cache checkpoint
before paying a preparation recompute: the identity is immutable once
appended, so a cached value is definitive regardless of its watermark.
The cache stays a read-only accelerator (absent service or any rung-two
fault falls through silently; verdicts stay with the authoritative
refold), and the note plus core-data-structures pages describe the
three-rung ladder.
- listChildren contains per-child projection faults on both ladder rungs
(any registered unit's fold/schema rejection maps to that child's corrupt
diagnostic) and pins the whole-enumeration listing-failure rethrow
- the base bundle mounts session-projection (web-app's own insert retired
to avoid the double mount); stale composition comment updated
- the shared projections-unavailable wire face is pinned across
list/history/prompt; retired session-query arms removed from the catalog
paths
- the design note records the unknown-parent semantics shift and the
fold-fault isolation rule
Mounting session-projection in the example compositions staled the
generated composition and module graphs; the 2026-07-22 note now
describes the retired optional-session-query spec without a live path.
The subagent API surface change staled the committed catalog artifacts;
the snapshot fixture agent is referenced only from its cordis.snapshot.yml,
so knip learns it as an entry like its siblings.
- listChildren reads the session store via strict ctx.get (property proxy
is caller-scoped), orders candidates branchlessly, narrows the cold-read
return type, and pins the cost model and store/registry composition gaps
with tests; per-file coverage restored
- acp-agent and headless-agent compositions mount session-projection; a
keyless snapshot pins the descriptor-less diagnostic row
- api-proxy cold spec pins header-origin ownership and the legacy
descriptor-only opt-out
- design note ships as implemented with its English pairing; companion
notes and core-data-structures pages synced
knip: ui-settings no longer imports react-dom (the portal moved into
OnboardingSurface), so the react-dom peer/dev dependencies and
@types/react-dom go away with the usage.
Review follow-ups: the Agent Note's Testing section now records the
held-join reload regression scenario this PR adds (both languages,
pairing re-recorded); the e2e hold gates EVERY settings.describe issued
before release instead of only the first, so a future boot-time join
consumer cannot silently collapse the widened window; the sampler's
persistence across later navigations is documented and the vacuity
wording softened to what the hold actually buys (timing independence).
A preset is a directory holding one `agent.cordis.yml`. Mounting it under an
agent's scope context during `setup(agentCtx)` gives that one session its own
tools and prompt sections while every other live session keeps its own.
No registry gains a tier. `dsh-tools` and `dsh-system-prompt` already file
registrations into the calling context's scope layer, and entry contexts chain
to the context a subtree was plugged into, so a composition mounted under
`agent.ctx` is that agent's alone and unwinds with it.
The mount audits itself because a directly-plugged subtree is absent from
`ctx.loader.entries()` and no boot audit covers it. It rejects an unscoped
target, a row that never became usable, and a row that published a service into
the root service realm — that last one is process-global rather than
per-session, and its collision with the next session surfaces as an unhandled
rejection `setup` never observes, leaving a half-composed agent that looks
healthy. The package invariant re-checks that rule on every service
notification, since a row publishing from a timer would escape a one-shot audit.
Raises the `packages/README.md` word ceiling from 920 to 980: the group table
must enumerate every group, and the new `preset/` row is necessary content.
Design: .agents/notes/implemented/architecture/2026-08-03-per-session-agent-presets.md
The settings shell painted the onboarding overlay (opaque stage, mask,
#root inert) the moment a step was registered and not locally completed,
while every step still had to load its private join before deciding
whether to show — rendering null could not suppress the shell-owned
chrome. Every reload on the hero therefore flashed a full-screen opaque
layer (white in the light palette) for one settings/credential RPC
round-trip after the session list turned ready.
The chrome now belongs to the step: a new zero-cordis OnboardingSurface
primitive (ui-primitives) renders the body-portaled overlay/mask/stage
verbatim from the former SettingsRoot stylesheet and holds #root inert
for exactly its own lifetime. WelcomeNotice and DeepSeekOnboardingDialog
wrap only their visible branch in it, so their existing null branches
paint and block nothing by construction. SettingsRoot keeps the
coordinator unchanged but renders the elected step bare, and the
settings.onboarding contract now names the surface wrap as the
registrant's obligation.
The onboarding e2e gains a held-join reload scenario pinning that a
configured world never mounts the takeover chrome or inerts the app.
