kandev/apps/web/AGENTS.md

Frontend (Vite/React SPA) — architecture and conventions

Scoped guidance for apps/web/. Repo-wide rules (commit format, code-quality limits, etc.) live in the root AGENTS.md.

Plugin authoring

For plugin UI work, begin with the canonical plugin authoring guide. Follow: choose recipe → edit manifest.yaml → implement → validate → package → smoke test. The frontend contract pair is ../../docs/plans/plugins/PLUGIN-API.md plus lib/plugins/types.ts; concrete shared Host UI exports are in lib/plugins/host-api.ts, and registration/cleanup behavior is in lib/plugins/registry.ts and lib/plugins/host.ts. Treat that pair as the source of truth for which hooks exist, and extend it in the same change rather than shipping a signature it does not declare.

UI Components

Shadcn Components: Import from @kandev/ui package:

import { Badge } from "@kandev/ui/badge";
import { Button } from "@kandev/ui/button";
import { Dialog } from "@kandev/ui/dialog";
// etc...

Do NOT import from @/components/ui/* - always use @kandev/ui package.

• Always prefer native shadcn components over custom implementations.
• Check apps/packages/ui/src/ for available components (pagination, table, dialog, etc.).
• For data tables, use @kandev/ui/table with TanStack Table; use shadcn Pagination components.
• Only create custom components when shadcn doesn't provide what's needed.

Responsive and touch surfaces

• Use hooks/use-responsive-breakpoint.ts for application layout decisions. Its mobile boundary matches the sidebar's 768px md boundary, and it also models tablet, compact desktop, full desktop, and pointer precision; do not substitute the UI package's generic useIsMobile hook. Tablet is a coarse-pointer fallback between md and lg, so no fine-pointer width reports it — a spec that needs the tablet layout has to emulate touch.
• When a Tailwind visibility class gates the same surface the hook picks, both must use the same boundary. A sm: class paired with a hook-driven mobile branch leaves 640-767px in a state neither side renders.
• Use useTouchDrawer when a hover/popover disclosure needs a coarse-pointer Drawer alternative. Width-based phone composition and pointer-based disclosure behavior are related but not interchangeable.
• Existing Radix DropdownMenu and ContextMenu surfaces receive inset, safe-area-aware bottom-sheet treatment below 640px in app/globals.css. Reuse those primitives for contextual actions and add focused coverage for long or nested menus instead of creating a parallel mobile menu.
• Mobile capability parity does not require desktop layout parity. Load /mobile-parity for the Kandev surface decision guide, mobile design contract, and verification requirements.

Data Flow Pattern (Critical)

Go Boot Payload -> Hydrate Store -> Components Read Store -> Hooks Subscribe

Never fetch data directly in components.

Browser capability boundaries

• Use generateUUID() for client-only non-security IDs, not crypto.randomUUID(); use copyToClipboard() for copy actions, not navigator.clipboard.writeText(). Keep fallbacks non-security; test missing or rejected capabilities with an rg audit.

Store Structure (Domain Slices)

lib/state/
├── store.ts                        # Root composition
├── default-state.ts                # Default state + initial state merge
├── slices/                         # Domain slices
│   ├── kanban/                    # boards, tasks, columns
│   ├── session/                   # sessions, messages, turns, worktrees
│   ├── session-runtime/           # shell, processes, git, context
│   ├── workspace/                 # workspaces, repos, branches
│   ├── settings/                  # executors, agents, editors, prompts (incl. userSettings)
│   ├── comments/                  # code review diff comments
│   ├── github/                    # GitHub PRs, reviews
│   ├── gitlab/                    # GitLab MRs, watches, MR automation options
│   └── ui/                        # preview, connection, active state, sidebar views
├── hydration/                     # SSR merge strategies

hooks/domains/{kanban,session,workspace,settings,comments,github,gitlab}/  # Domain-organized hooks
lib/api/domains/                    # API clients
├── kanban-api, session-api, workspace-api, settings-api, process-api
├── plan-api, queue-api, workflow-api, stats-api, github-api
├── user-shell-api, debug-api, secrets-api, sprites-api, vscode-api
├── health-api, utility-api

Key State Paths:

• messages.bySession[sessionId], shell.outputs[sessionId], gitStatus.bySessionId[sessionId]
• tasks.activeTaskId, tasks.activeSessionId, workspaces.activeId
• repositories.byWorkspace, repositoryBranches.byRepository

Quick Chat stores server conversations in quickChat.sessions and browser-local terminals in quickChat.terminalTabs; activeKind and terminal IDs track selection. quick-terminal-actions.ts owns lifecycle/fallback; terminal descriptors never enter conversation APIs or get lost in reconciliation.

Hydration: Go injects window.__KANDEV_BOOT_PAYLOAD__ into the SPA shell before React mounts. lib/state/hydration/merge-strategies.ts has deepMerge(), mergeSessionMap(), mergeLoadingState() to avoid overwriting live client state. Pass activeSessionId to protect active sessions.

For rebasing or finishing PRs written against the old Next.js runtime, follow docs/nextjs-spa-migration.md.

Hooks Pattern: Hooks in hooks/domains/ encapsulate WS subscription + store selection. WS client deduplicates subscriptions automatically.

WebSockets

Format: {id, type, action, payload, timestamp}.

Use subscription hooks only; the WS client auto-deduplicates.

Task overview vs. session detail: Shared task rows read Task.statusSummary and task.status_summary.updated; rich streams stay session-detail-only. Extend the bounded projection per the spec and ADR.

Branch-scoped task state: For live worktree/session state plus task_prs, key by (repository, checked-out branch), not task/repository alone. branch_switched invalidates prior status/commits; reject late results with a generation/identity guard and preserve siblings. Historical PRs affect Changes only when repository_id and normalized head_branch match; Review/PR history may still show them. Test single/multi-repo cases and desktop/mobile Changes behavior. HTTP/WS cache races: When HTTP hydrates a cache also updated by WebSockets, guard responses with per-scope revision and request/workspace generation; discard or refresh stale responses and cover deferred responses. useEnsureTaskSession re-fires session.ensure when an open task page sees zero sessions after a prior ensure, so deleting the last session from that page spawns a replacement; test zero-session states through the backend/API instead.

When changing task lifecycle WS handlers (task.updated, task.deleted, task.state_changed), check both kanban and Office surfaces. Archive/delete events may need to update kanban caches, tasks.activeTaskId / session pin state, recent/sidebar prefs, Office refetch triggers such as setOfficeRefetchTrigger("tasks"), and route redirects for /t/:id, /tasks/:id, and /office/tasks/:id. Add focused tests for every affected surface.

Component conventions

• Framework adapters during Next removal: Client components should import links, router hooks, dynamic imports, images, and theme hooks from the local adapter modules (components/routing/*, lib/routing/*, components/theme/app-theme) instead of importing next/* or next-themes directly. The routing/image/dynamic adapters now provide browser-native behavior for the Vite SPA while legacy Next entrypoints are phased out.
• Components: <200 lines, extract to domain components, composition over props.
• Hooks: domain-organized in hooks/domains/, encapsulate subscription + selection.
• Interactivity: all buttons and links with actions must have cursor-pointer class.
• Self-documenting settings: every setting must explain in visible, plain-language copy what changes, when the setting applies, and when the user should choose each non-obvious option. State important exclusions, precedence, cost, or destructive consequences next to the control when they can affect the decision. Do not rely on tooltips, external documentation, or implementation terms alone to teach the setting.
• Settings save coordination: settings surfaces with local unsaved state must register a contributor with useSettingsSaveContributor (or use SettingsPageTemplate) so the shared floating Save changes control, navigation guard, and discard flow own persistence. Do not add page-local Save/Cancel controls. Contributor save callbacks must reject on failure so the coordinator can report an error; discard must restore the contributor's authoritative baseline.
• Dialog Enter-to-confirm: the base @kandev/ui DialogContent / AlertDialogContent activate the dialog's semantic action on plain Enter (packages/ui/src/lib/dialog-default-action.ts), so per-dialog "submit on Enter" input handlers are unnecessary — let the base own it. Resolution: AlertDialogAction → an explicit data-dialog-default-action button → the single primary (type="submit" or data-variant="default"|"destructive") button in DialogFooter. More than one primary candidate (counting disabled ones), a disabled resolved action, or one inside a hidden/aria-hidden subtree → no-op (never guesses). Left alone: textarea/contenteditable, Shift/Cmd/Ctrl/Alt+Enter, event.repeat auto-repeat, mid-IME composition (isComposing or keyCode 229), already-preventDefaulted events, and Enter fired from a focused interactive control that owns Enter (any action button — including outline/secondary like Copy/Back — <select>, combobox, or a listbox option / menu item). Only a slot-marked alert-dialog-cancel / dialog-close is treated as a dismiss control and overridden (the Radix-focuses-Cancel case). A plain single-line <input> is not exempt — type-to-confirm dialogs rely on Enter firing the primary. Pass enterConfirms={false} to opt a dialog out; mark the intended button with data-dialog-default-action when a footer has several action buttons.
• Radix tooltip on disabled buttons: disabled buttons do not receive pointer/focus events, so wrap the disabled Button in a focusable span and put TooltipTrigger asChild on that span:

  <Tooltip>
    <TooltipTrigger asChild>
      <span tabIndex={disabled ? 0 : -1} className="inline-flex">
        <Button disabled={disabled}>Run</Button>
      </span>
    </TooltipTrigger>
    <TooltipContent>{disabledReason}</TooltipContent>
  </Tooltip>
  

  Keep the wrapper focusable only while disabled; when enabled, the button itself owns focus.
• Interactive help inside Radix tooltips: do not nest a Tooltip root inside another TooltipContent when the inner trigger must remain interactive. Tooltip roots under one provider coordinate open state, so the inner tooltip can close and unmount its parent before the pointer reaches it. Render the secondary help inline in the existing content or use a disclosure primitive with independent open state. Touch-pinned help must close on a second trigger tap, outside interaction, and Escape; verify desktop pointer and mobile-sized touch flows.
• Renaming a data-testid: use data-legacy-testid for the old id while migrating specs; JSX and Playwright only support one data-testid attribute.
• Dockview session activation: audit pointer/keyboard tabs, shortcuts, reopen/menu actions, and close controls; combine store state with api.isActive, clear same-session intent, and treat default-tab close as delete rather than session switching.
• Conditional review panels: show pr-detail only for active tasks with a linked PR/MR; default layouts only provide preferred placement. Hydrated review loss removes canonical panels, while restoration/maximized and offered/dismissed markers suppress insertion; existing panels sync identity without moving.
• Dockview environment switching: reconcile ephemeral panels before restoring views; correlate ID-less groups by stable ID or position. Treat chat/session:* as semantic only with a non-null activeSessionId.
• GitHub PR status UI: use the shared pr-task-icon.tsx display helpers and isPRReadyToMerge; aggregate counts are display-only and cannot enable merges. Update pr-task-icon.test.ts and pr-status-chip.test.tsx with behavior changes.
• GitHub PR associations: retain terminal/merged siblings for tabs/unlink; derive openPRs only for aggregate status/automation and test desktop/mobile terminal unlink plus two-to-one collapse/focus.
• Task repository labels: user-facing task/card repo chips should display a stable repo slug or name (owner/repo when known, otherwise the repo name), not a local filesystem path. Local clone paths or folder paths belong in hover/title/tooltip metadata. Tasks with no repository, or only a non-repo local folder, should not render a repo chip.

Internationalization (i18n)

Externalization is complete. #2367 localized app/office, the last un-migrated area. A hardcoded user-facing literal is now a regression, not leftover migration work. New copy must go through t() / <Trans> wherever you write it.

User-facing strings are localized with i18next + react-i18next, keyed as namespace:key. Add the English text to src/locales/en/<namespace>.json, then reference it with t("settings:deleteExecutor") (useTranslation() in components, the module-level t from @/lib/i18n in plain helpers). Use <Trans i18nKey=... values={...}> only for copy containing markup — and never a t() call inside its children, which shifts the message's tag indices.

Never translate user/domain data, code identifiers, data-testid, or a literal that is also compared with ===, used as a map key, or typed as a string-literal union. When a prop is both display copy and logic (label: "Reviewers" | "Assignees"), split it into a kind/origin discriminant plus a translated label rather than translating in place.

lib/i18n/provider.tsx initializes i18next at module load. Do not remove that call: react-i18next suspends on an uninitialized instance and there is no Suspense boundary above the root, so the app renders a blank page with no error of any kind. Unit tests cannot catch it — vitest.setup.ts pre-initializes.

Never write a plural ending yourself: use t(key, { count }) with _one/_other keys. Passing the morpheme as a value ({ s: n === 1 ? "" : "s" }) is untranslatable — the plural rule ends up at the call site.

Never assign t() to a module-level constant. It resolves at import, before a locale is active, and never updates on a switch — and the pseudo-locale cannot see it, because the text is translated, just frozen. Store the key and resolve at render, or make the value a component. check-module-scope-t.mjs enforces it.

UI punctuation: avoid Unicode em dash (U+2014) in user-facing copy and locale values. pnpm run i18n:check enforces periods, colons, commas, semicolons, and parentheses.

pnpm lint fails on hardcoded UI strings (i18next/no-literal-string is an error), but only on the i18nGuardFiles allowlist in eslint.i18n.options.mjs, which covers every area the migration touched. It stays an allowlist because a repo-wide error breaks every unrelated PR that adds a label — what made the first attempt unmergeable. Append a path in the same PR that adds it or externalizes it (lib/sidebar is one still off the list). Never delete an entry to make a build pass; check-guard-allowlist.mjs rejects that unless the file is gone. Use pnpm run lint:i18n <path> to preview the guard on a path not yet on the list.

Separately, pnpm run i18n:ratchet (pre-commit + CI) guards new code everywhere, regardless of the allowlist: a file you added must be clean outright, and a file you modified is judged on the lines you touched. Untouched literals are never reported, so it cannot ask you to migrate code you did not write — the same contract as golangci-lint --new-from-rev for Go.

The rule sees JSX literals but misses confirm() and plain .ts helper copy; it also skips SCREAMING_CASE constants, so review config tables by eye. i18n:check gates key/catalog drift, <Trans> indices, inline plurals, module-scope t(), and the pseudo-locale (Settings → General → Appearance) completeness check. It needs Node 24. Full guide: docs/i18n.md; spec: docs/specs/platform/i18n.md.

Markdown safety

Any renderer that enables embedded raw HTML must pair rehype-raw immediately with rehype-sanitize, and enable that combination only on the intended surface. Do not broaden raw-HTML support to chat, comments, or other renderers without a separate security decision. Add regression coverage for permitted README markup and for stripping executable HTML and unsafe URLs.

Code-quality limits

Enforced by apps/web/eslint.config.mjs (warnings, will become errors):

• Files: ≤600 lines · Functions: ≤100 lines
• Cyclomatic complexity: ≤15 · Cognitive complexity: ≤20
• Nesting depth: ≤4 · Parameters: ≤5
• No duplicated strings (≥4 occurrences) · No identical functions · No unused imports
• No nested ternaries

When you hit a limit, extract a helper function, custom hook, or sub-component. Prefer composition over growing a single function.

Plugin system

The frozen frontend contract is docs/plans/plugins/PLUGIN-API.md; lib/plugins/types.ts is its TS mirror — the two must change together. lib/plugins/registry.ts is the reactive singleton PluginRegistry; every register* call there needs a matching cleanup entry in unregisterPlugin and totalCount(), or a disabled/uninstalled plugin leaks a stale registration.

• Task panels (registerTaskPanel): one generic dockview component, "plugin-panel", shared by every plugin — identity lives in params: { pluginId, panelKey } (id helpers in lib/state/layout-manager/plugin-panels.ts). renderPanel in dockview-shared.tsx and dockview-panel-content.tsx each get exactly one "plugin-panel" case (lookup tables, not switches). PluginTaskPanel (components/task/) resolves the registration behind a PluginErrorBoundary; mobileEnabled: true also renders it via the phone bottom nav (session-mobile-bottom-nav.tsx) with presentation: "mobile".
• Kanban card contributions: registerTaskMenuAction({ group: "edit", ... }) turns the flat Edit item into an Edit submenu (kanban-card-edit-submenu.tsx); registerComponent("task-card-indicators", ...) renders beside PRTaskIcon via <PluginSlot/>; task-card-tags renders in its own row below the badges (for contributions too wide for the title-row indicators spot, e.g. tag chips).
• host.storage: authenticated per-user key/value storage (lib/plugins/host-api.ts), backed by /api/plugins/{id}/user-state/... (docs/decisions/2026-08-01-per-user-plugin-storage.md). subscribe (lib/plugins/user-state-sync.ts) wraps registerWsHandler with own-plugin filtering and own-tab echo suppression via a per-tab writerId.
• host.ui.RichTextEditor/RichTextReadOnly (components/editors/tiptap/rich-text-editor.tsx): narrow Plan-panel-tiptap wrappers; update PLUGIN-API.md before widening props beyond { taskId, value, onChange, placeholder, className, testId } / { value, className, testId }.

Testing notes

• jsdom secure cookies need cookie-setter interception; Radix Tooltip tests use keyboard focus, while Playwright covers pointer hover with locator.hover().
• Scope terminal selectors to the active panel/container; mobile and dockview may mount multiple instances, so shared helpers must not use global selectors.