ds-review-bot round 2. The workspace UI never consulted the advertised
directoryPicker kind: under a browse (or merge-added) backend it still
rendered 'Open local folder…' and called pickDirectory(), which the host
answers with directory-picker-unavailable. The create flow now reads
directoryPickerKind() per menu open and renders the dialog affordance only
under 'dialog' — browse (until its in-app browser UI lands) and unknown
kinds hide the entry, realizing the seam's documented default; a keyless
workspace-flow snapshot pins the hidden entry over the browse fixture.
The browse backend also resolved wire paths, silently rebasing '' or
relative parents under the host process cwd; both primitives now reject
non-absolute explicit paths with their business codes, and the seam JSDoc
carries the contract.
ds-review-bot round 1: the seam documented a merge-extensible union but
shipped a closed alias, and the gateway schema rejected any kind beyond
dialog/browse — a third backend could neither implement the seam nor be
advertised. The union now derives from an augmentable DirectoryPickerCapabilities
map, host.describe.directoryPicker preserves unknown wire kinds, and the
browse fixture applies listDirectory's root special case so creating under
'/' no longer mints a '//name' identity.
Fetch-Metadata and Origin are only attached to trustworthy destinations, so
over plain HTTP a rebound page's same-origin GET (EventSource, images,
navigations) arrives with no browser markers and a readable response. Remove
the marker shortcut; non-browser clients pass the same fence via loopback,
the CLI-derived LAN IP literals, or a declared authority.
A dangling colon (harness.internal:) or zero-padded port parses cleanly while
WHATWG silently rewrites it, turning an intended exact-port grant into an
any-port grant. Replace the character blacklist with a round-trip check: an
entry must read back from parsing exactly as written (case aside), refusing
the whole rewrite class at load.
The full-suite coverage gate found the new listDirectory/createDirectory
client methods and handler routes unexecuted: the implementation and
schema layers were tested directly, but nothing crossed the wire form.
One round trip through InProcessApiClient covers both arrows on each
side.
WHATWG trimming strips stray whitespace before parsing, so 'host:port ' passed
the load assert while the raw-string port regex read it as port-less —
broadening an exact-port grant to every port on that hostname. The explicit-
port judgment now reads URL parses under both special schemes (:80/:443 stay
explicit), and the load assert refuses whitespace outright.
WHATWG parsing would quietly read a hostname out of harness.internal/path or
user@harness.internal, authorizing the typo's hostname; other typos would sit
silently ignored until requests 403. Refuse every URL part beyond host[:port]
at plugin load.
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
Markerless requests pass on any Host (a non-browser sender is the principal
and forges headers anyway); browser Host matching gains port-less entries and
WHATWG normalization; dsh derives LAN IP-literal authorities for an
all-interfaces bind and web grows --trusted-host for named ones.
Both web-GUI groups shipped without the group README that the packages
table names as each group's canonical package/ctx-key map, and without
rows in that table. Adds both bilingual pairs, the two table rows
(ceiling 835→870: two genuinely new product groups joined the canonical
table at minimal row width), and fixes webserver README drift
(WebServerService/ctx.webServer → HttpServerService/ctx.httpServer,
matching src/index.ts).
The only browser-trust guard covered host.pickDirectory, while the
consequential methods (session.prompt drives bash) accepted any Host —
open to DNS rebinding, where a rebound page reads and writes the API as
if same-origin and only the Host header betrays the attacker's domain.
The pickDirectory-specific loopback guard becomes a prefix-wide fence:
Host must be loopback or an exact host[:port] from the new trustedHosts
config, an attached Origin must equal that authority, and explicit
cross-site markers are refused; requests without browser markers (curl,
tests, native clients) pass, because without a browser there is no
confused deputy. The loopback-socket check is dropped — binding policy
expresses reachability, and the fence is not an auth layer. The Agent
Note records the full threat model and the alternatives.
Browsers send "simple" POSTs (text/plain, form encodings) without a CORS
preflight, so a malicious page could execute side-effectful RPCs blind —
the response stays unreadable cross-origin, but session.prompt would
still run. The carrier now answers 415 unless the declared media type is
application/json, forcing every cross-site attempt into a preflight this
server never answers. Raw-fetch specs gain the header; a new handler case
proves the fence rejects before the impl runs.
