`core-web` said neither of the things that matter about it. The `-web`
suffix is a leftover from the whole-process `core-web.cordis.yml` overlay,
and presets are per-session and not web-specific. `core` reads as "the
foundational one" when it is in fact the one with the fewest capabilities.
`minimal` says what it is and orders the shipped set legibly by capability:
minimal, standard, cordis.
Breaking: a session created under `core-web` records that id in its header
and will fail to resolve it on resume. Nothing outside this repository has
shipped, so no migration path is offered.
The identically named `config/core-web.cordis.yml` — the legacy
whole-process overlay behind the web snapshot test — is a different thing
and keeps its name.
`dsh web` failed to boot: the aggressive plane split moved `subagents` and
its spawn/fork backends into the preset's entry-local realm, but
`dsh-host-apiproxy` is a host row that injects `subagents` to answer the
browser's cross-session queries, so it waited forever for a service only
sessions now provided. A per-session copy is wrong twice over — a provider
name registers once, so the second session would have collided anyway.
The registry and its backends go back to the host composition; the presets
keep the delegation TOOLS, which resolve that host registry. `workflows`
stays entry-local: nothing outside an agent reads it.
The web real-composition test could not have caught this, because it
disabled `api-gateway` — the very row whose pending injection names the
break. It now boots with the api-proxy enabled and the browse directory
picker substituted, so the boot audit covers the whole host-plane injection
graph. Re-introducing the old split makes it fail with the three pending
entries, which is how this was verified.
A composition is a file, but "edit it on the filesystem" is not a browser
affordance. The roster gains `read`/`write`/`remove` beside `select`, and
the browser gains a settings section over them: the presets as rows, one
composition open in a YAML editor at a time, and per-row default, duplicate,
and delete.
All four authoring methods are loopback-pinned. A composition names the
plugins a session runs, so reading one is reconnaissance, writing one is
arbitrary capability, and selecting one can move a session onto a preset
that edits the live runtime. `agentPreset.list` deliberately stays ordinary
and now reports `authorable`, so a surface knows whether creating is
possible at all rather than offering a button whose save always fails.
Authoring starts by duplicating: a shipped preset opens read-only because
the deployment's copy is what a broken local one is compared against. Ids
are contained before they become directory names, and the text is parsed
with the loader's own schema, so a save cannot leave a file no session
could load.
Fixes a defect the real-composition test found: a preset written under the
user's home could never mount, because the loader resolves a row against the
composition's own directory and Node's `node_modules` walk from there never
reaches the installed harness. The mount now records the host base and sends
bare specifiers there, leaving relative paths resolving from the preset.
Also closes the coverage the earlier surfaces in this stack shipped without —
the General row, the composer seat, and the plugin halves now have tests.
The Agent Note was written when only the seam existed and never caught up.
Rewritten in place, per the implemented-note contract, with the four facts the
later work established:
- a preset file is an INPUT: `EntryTree.write()` persists a tree whenever the
Loader thinks the config changed, and a self-disposing plugin is enough, so
the inherited behaviour truncates a shipped preset to `[]` the first time a
session ends
- a plugin that looks itself up in the global registry breaks inside a preset,
because `register()` files into the calling context's scope — the general
rule behind the `dsh-tool-skill` fix
- an entry-local `isolate` realm is invisible to the agent's own scope too, not
only to the host, which is what makes a preset's registry that agent's own
and also why a consumer left outside the group silently contributes nothing
- switching is blank-only, and why it swaps the subtree rather than the session
`docs/architecture.md` gains an Agent Presets section: the map has to carry a
new architectural concept or it is wrong, and the root layout gains the group.
Both budget ceilings are raised rather than the content cut. `AGENTS.md` sat at
1774/1775 — one word of room, already far under the 5% headroom the standard
asks for — so no group line could be added at all; `architecture.md` was in the
same shape. Raising restores headroom instead of encoding "the map may not grow".
`config.default` becomes the composition base of an `agent-presets` settings
namespace, so the user document layers over the deployment's engineering
default and a person can change which preset new sessions get without a
restart.
The value is read per resolution rather than snapshotted: a hot-reloaded
document takes effect on the next session created, and every running session
stays on the preset it was composed from — which is the same rule the
session-header guard enforces from the other side.
`resolve()` read `config.default` directly, which would have made the whole
setting inert; it now goes through `defaultId` like every other caller.
The write-protection test is rewritten against a temp profile root. It was
passing vacuously: the un-overridden Loader REWRITES the composition it read —
stamping `disabled: true` onto the self-disposing row — so the committed
fixture had been mutated by the very run that proved the bug, and every later
run compared against the damaged file and passed. Building the preset in a
temp directory makes the assertion immune to its own failure mode, and it now
fails with a visible `+ disabled: true` when the override is removed.
Review follow-ups on this layer. The exported schema is
`AgentPresetSettingsSchema`, symmetric with the `AgentPresetSettings`
interface it resolves and self-describing at an import site. The `session.create`
JSDoc promised "the deployment's default preset" for an omitted `agentPreset`,
which this layer makes false — it now names the effective default. The
constructor records why it does not use `installSettingsSection`: that helper
re-judges what a consumer DERIVED across attach and detach, and nothing here is
derived. The provider-unload test disposes the fiber `ctx.plugin()` handed back
instead of reaching into `ctx.reflect.store`, and the write-protection wait says
why slack is the right shape for an absence assertion.
The real composition covers the layering too. `apps/cli` boots the shipped
`cordis.yml`, stores `agent-presets.default`, and asserts an unnamed session
composes from it — the package suite proves the layering against a hand-built
context, this proves the roster and the settings provider are wired to each
other. That test also pins the settings row at a temp file: it defaulted to
`$DSH_HOME/settings.yaml`, so a developer's own stored default decided the
outcome of a file whose whole point is that only the shipped root does.
The Agent Note records the per-resolution read and its correspondence with the
session header, and the vacuous-test finding above.
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.
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
