A sandbox header bought isolation by taking the document's origin away, and
measuring that cost decided against it: the reported artifact throws
SecurityError on load, and because an uncaught exception aborts the rest of
its <script>, every listener declared after that line — theme toggle, mobile
menu, model tabs — never binds. Two of the four artifacts in the reporting
user's workspace were dead pages under it, and they still looked right.
A second listener on the API's host, answering /f and nothing else, is the
same boundary without the amputation: cross-origin to /api (refused by the
Origin fence and by CORS), same-origin with itself (localStorage, cookies and
fetch all work). Its port is published into the index page; the browser half
reads it to address previews, and its absence — the keyless fixture lane — is
what makes a file row fall back to the Host opener instead of a dead tab.
fileUrl moves from IWorkspaces to ConnectionHandle: the transport owns both
the listener that serves the bytes and the port that addresses it.
Serve one file at a time out of a Session's workspace under /f on the web
transport, and point the conversation's existing file-open affordance at it.
Clicking a write/edit/read row's path now opens that file in a browser tab —
including from a LAN client, where the Host's system opener is fenced to
loopback and answered nothing.
- /f/<sessionId>/<segments> in client-connection, behind the same
browser-trust fence as /api; realpath confinement, streamed reads,
GET/HEAD only, nosniff + no-store.
- Script-capable documents carry CSP sandbox: model-authored markup must not
be same-origin with /api, where events.mux is a readable GET stream.
- ApiProxy.workspaceRootOf answers where a Session's files live without
resuming an agent; the client program cannot reach the core services.
- The /f URL shape lives in dsh-host-apiproxy/api so both ends share one
encoding (client bundles may not value-import another plugin).
Public snapshot state stays in the store engine's plain-data vocabulary
(immer drafts reject Sets without the MapSet plugin, which stays off):
manager/service/contract carry readonly SessionId[] in Host order, and
the tree derivations build their own transient Set — the
expandedProjects pattern. Membership-unchanged installs still keep the
array reference for Object.is short-circuits.
- WorkspaceRegistry.archiveSession no longer wraps persistence-listing
failures as WorkspaceUnknownSessionError: only a definite miss (live
lookup, header index, then a fresh list) maps to session-not-found;
storage faults propagate as internal errors, with a negative test.
- The archived-current sweep moves from the unary path into the
projection: any install path (local echo, another tab's frame, a
reconnect baseline) clears a selection that landed in the archive set.
- An archive set installed while workspace.list is in flight supersedes
the stale baseline's set instead of being rolled back by it.
- The workspace-management e2e anchors the archived row by its session
actions button and asserts the single-stray fixture assumption loudly.
- Drop the stale touchSession rows from the workspace READMEs (the
method was removed with its Agent Note).
WorkspaceListState gains archivedSessionIds (ReadonlySet, replaced only
on membership change), installed as full snapshots from the list
baseline, the unary echo, and the changed frame. Archiving the current
session clears the selection into the New Session view state. Test
doubles (test-runtime, fake APIs, fixture client) follow the widened
IWorkspaces/IApiClient faces.
Sink the behavior previously held only by the apps/web jsdom snapshots
into the owning packages, each bench mounting the real apply on the
production slot machinery with fixture-fed data:
- ui-conversation/assembly-surfaces: the todo_write turn reaches both
product surfaces (keyed toolview row + dock plan strip via the todos
projection) and the strip follows projection retirement; the keyed
bash row carries its resident terminal card while the fallback row
reaches one through expand; the locked no-session view state; the
composer textarea surviving the blank→active conversion as the same
DOM node; the promptError alert strip with the machine-restored
draft; one summary update re-labeling the breadcrumb.
- ui-workspace/rename-assembly: the session-rename chain (row menu →
dialog → the injected renameSession hop → ISession.rename with the
edge-trimmed draft → dialog close and row re-label from the list),
plus the rejected arm keeping the dialog open with the error.
- runtime/workspaces-service: startInitialSelection — connects the
recent Workspace once both baselines are ready and opens the session,
stays idle with a current session or no recent target (double start
fails loud), and a failed connect returns to waiting and retries on
the next list change.
Component-level arms stay in the existing package suites; these files
prove only the assembled wiring.
One list call now materializes at most maxEntries child rows (config,
default 1000 - GitHub's web-UI directory-listing bound). Candidates sort
before probing so a cut level keeps the name-sorted head and symlink
probing stops with the bound, and DirectoryListing carries a required
truncated flag on the seam and the wire so clients can state
incompleteness instead of silently missing tail entries.
ui-workspace's two trigger surfaces each declare a single-kind directory-flow
hole (conversation.hero.workspace.directoryFlow / sidebar.workspaces.directoryFlow,
same owner contract) and keep only the trigger and the adoption: the Open-local-
folder entry renders while the surface's hole is occupied, and the occupant
reports one picked path per open through the hole's owner conversation
(open/busy/onPicked/onCancel/onError).
directory-picker-native becomes dual-face: its browser half fills both holes
with a renderless occupant driving host.pickDirectory, so the cordis.yml row
that mounts the backend also composes the client interaction — a mismatch is
impossible and a second flow package fails at client load.
With composition wiring both sides, the host.describe.directoryPicker
advertisement and the client's kind branching lose their last consumer:
the field, WorkspacesService.directoryPickerKind(), the DirectoryPickerKind
wire type, and the picker's per-open describe read are deleted. The connection
fixture now serves a deterministic pickDirectory path so the keyless snapshot
drives the full pick-then-adopt flow. ui-workspace's hand-rolled declaration
deferral is replaced by the deferRegistration helper it duplicated.
The web GUI's folder picking was hardwired to one interaction: a native
OS chooser compiled into the gateway, unusable for remote deployments
and swappable only by editing apiproxy source.
Directory picking becomes a three-package capability seam in
packages/host: ctx.directoryPicker returns a discriminated capability —
dialog (the extracted native chooser; host-display only) or browse
(new: one-level listing + child creation over Node stdlib, hidden flags
host-stamped, symlinks followed, ancestry crumbs; remote-capable). The
gateway injects the seam, advertises the kind via
host.describe.directoryPicker, serves host.listDirectory /
host.createDirectory under browse, and answers
directory-picker-unavailable across kinds. cordis.yml is the swap
point; apps/cli keeps dialog mounted, so behavior is unchanged until
the in-app browser PR flips the default. The connection fixture serves
a deterministic browse tree; WorkspacesService gains the browse calls
the browser UI will drive. Decision record:
.agents/notes/implemented/architecture/2026-07-28-directory-picker-capability-seam.md
ZiyaZhang
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creatixchu
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ZiyaZhang
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