batch4.1-5.1: dedup audit, archive 400 fix, sidebar Delete, landing-page enrichment, auto-name tool-call fix

- Fastify global empty-JSON-body parser fixes archive/unarchive/stop 400s
- Removed redundant local sessionEvents.emit at all 5+2 sites with server-side WS publishers; added dedupe guards in useSidebar/Workspace/Project handlers
- Sidebar session right-click adds Delete (destructive) with confirm Dialog
- Session.tsx navigates away on session_deleted/session_archived for the active session
- SessionLandingPage chat rows show message_count, effective_context_tokens, last_message_preview via LATERAL joins on GET /api/sessions/:id/chats
- Workspace.tsx pane drag-to-reorder using native HTML5 events (no new deps)
- CompactCard: Copy toast, Send-to-chat with target chat name, empty-state in share popover, Re-run button
- auto_name.ts: filter count gate and assistant-fetch by content <> '' so tool-call assistant rows don't trip the once-and-only-once guard
- Adds CLAUDE.md and apps/web/src/lib/format.ts

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

CLAUDE.md

@@ -0,0 +1,106 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## What is BooCode
+
+Self-hosted single-user developer chat app. AI assistant with read-only file tools (view_file, list_dir, grep, find_files) running against a local llama-swap inference server. Sessions organized by project, with a multi-pane workspace (chat + file browser side by side).
+
+## Commands
+
+```bash
+# Development (run in separate terminals)
+pnpm dev:server          # tsx watch, port 3000
+pnpm dev:web             # Vite dev server, port 5173 (proxies /api to :3000)
+
+# Build
+pnpm build               # builds web then server
+pnpm -C apps/server build  # server only (tsc + copy schema.sql)
+pnpm -C apps/web build     # web only (vite)
+
+# Type checking (no emit)
+npx tsc --noEmit                              # project references (root)
+npx tsc -p apps/web/tsconfig.app.json --noEmit  # web app specifically
+
+# IMPORTANT: root tsc --noEmit uses project references and can miss errors
+# that the per-app tsconfig catches. Always verify with the per-app command
+# when editing web code. The server build (pnpm -C apps/server build) is
+# authoritative for server code.
+
+# Production
+docker compose build --no-cache boocode && docker compose up -d
+```
+
+There are no tests or linters configured.
+
+## Architecture
+
+**Monorepo**: pnpm workspaces with `apps/server` (Fastify + postgres) and `apps/web` (React + Vite).
+
+### Server (`apps/server/src/`)
+
+- **Fastify** with `@fastify/websocket` and `@fastify/static` (serves built frontend)
+- **postgres** (porsager/postgres) with tagged-template SQL — no ORM. Schema in `schema.sql`, applied on startup. LSP may false-positive on `sql<Type[]>\`...\`` generics; CLI `tsc` / `pnpm build` is authoritative.
+- **Zod** for request validation and config parsing.
+
+Key services:
+- **`services/inference.ts`** — Streams LLM responses, executes tool loops (max 5 depth), flushes to DB every 500ms. Publishes `InferenceFrame` events through the broker.
+- **`services/broker.ts`** — In-memory pub/sub with two channel types: per-session (message streaming) and per-user (sidebar updates). No persistence; clients reconnect on restart.
+- **`services/tools.ts`** — Four read-only file tools exposed as OpenAI function-calling schemas. All file access goes through `path_guard.ts` which resolves against project root.
+- **`services/file_ops.ts`** — Shared file operation implementations used by both inference tools and HTTP routes.
+- **`services/auto_name.ts`** — Non-streaming LLM call to generate 4-word session titles after first assistant reply.
+
+Route registration: all routes registered in `index.ts` via `register*Routes(app, sql, ...)` functions. Routes are in `routes/*.ts`.
+
+### Frontend (`apps/web/src/`)
+
+- **React 18** + React Router v6 + **Tailwind v4** + shadcn/radix-ui primitives.
+- **Shiki** for syntax highlighting (async `codeToHtml` in `CodeBlock.tsx` and `FileViewer` in `FileBrowserPane.tsx`).
+- Path alias: `@/` maps to `src/`.
+
+Key patterns:
+- **`hooks/sessionEvents.ts`** — Module-singleton event bus (Set of listeners). Used for cross-component communication: session renames, file-open events, attachment dispatch. 9 event types in the discriminated union. When adding a new event type to the `SessionEvent` union, you must also add a case to the `applyEvent` switch in `useSidebar.ts` (even if it's a no-op `return prev`).
+- **`hooks/useSessionStream.ts`** — WebSocket per session, `applyFrame` reducer builds message list from streaming frames.
+- **`hooks/useUserEvents.ts`** — Single app-level WS to `/api/ws/user` with exponential backoff reconnect. Forwards frames onto the sessionEvents bus.
+- **`hooks/usePanes.ts`** — Per-session pane CRUD with 300ms debounced state PATCH (Map-based coalescing for last-write-wins).
+- **`hooks/useSidebar.ts`** — Module-singleton with Set<setState> subscriber pattern. Handles all sessionEvent types to keep sidebar in sync.
+- **`api/client.ts`** — Centralized typed fetch wrapper. All endpoints under `api.*` namespace.
+
+### Data flow for chat
+
+1. User sends message → POST `/api/sessions/:id/messages` creates user + assistant (status=streaming) rows
+2. `inference.enqueue()` starts async streaming loop
+3. LLM deltas published via `broker.publish(sessionId, frame)`
+4. Client's `useSessionStream` WS receives frames, `applyFrame` reducer updates message list
+5. Tool calls: inference executes tools server-side, publishes tool_call/tool_result frames, loops back to LLM
+6. Terminal states (complete/error): DB updated with final content + token counts, `session_updated` frame published on user channel
+
+### Multi-pane workspace
+
+Sessions hold 1–5 panes (chat or file_browser). `Workspace.tsx` renders tab strip + CSS grid layout. Pane state persisted in `session_panes` table (position + JSONB state). Tab reorder via native HTML5 drag events.
+
+## Database
+
+PostgreSQL 16. Tables: `projects`, `sessions`, `messages`, `settings`, `session_panes`. Schema applied idempotently on startup via `applySchema()`. Use `clock_timestamp()` (not `NOW()`) inside transactions for accurate per-statement timestamps.
+
+Position-shift pattern for panes: negate-and-restore to avoid UNIQUE(session_id, position) collisions during reorder/insert/delete. Sentinel value -100 for the moving pane.
+
+## Environment
+
+Required: `DATABASE_URL`, `LLAMA_SWAP_URL`. Optional: `PORT` (3000), `HOST` (0.0.0.0), `PROJECT_ROOT_WHITELIST` (/opt), `DEFAULT_MODEL`, `LOG_LEVEL`.
+
+## Workflow
+
+- Sam reviews all diffs and commits manually. Do not commit unless explicitly asked.
+- Deploy: `cd /opt/boocode && docker compose build --no-cache boocode && docker compose up -d`
+- Don't accumulate `.bak-*` files. Clean them up in the same batch or immediately after merge.
+
+## Conventions
+
+- `overflowWrap` not `wordWrap` — TypeScript's CSSStyleDeclaration marks `wordWrap` as deprecated (error 6385).
+- No app-layer auth. Authelia handles auth at the reverse proxy. All `broker.publishUser`/`subscribeUser` calls use `'default'` as the user key.
+- TypeScript strict mode. Both apps share `tsconfig.base.json`.
+- Server uses NodeNext module resolution (`.js` extensions in imports).
+- Discriminated unions for type narrowing: `Pane` (by `kind`), `SessionEvent` (by `type`), `InferenceFrame` (by `type`).
+- shadcn primitives live in `components/ui/`. Don't modify them unless adding a new primitive.
+- `inferLanguage()` from `lib/attachments.ts` is the canonical file-extension-to-language map. `CodeBlock.tsx` keeps its own `LANG_MAP` because it also resolves markdown fence names.

apps/server/src/index.ts

@@ -24,6 +24,22 @@ async function main() {
     logger: { level: config.LOG_LEVEL },
   });
 
+  // Allow empty JSON bodies on POSTs that don't take a body (archive, unarchive, stop, etc.).
+  // Default Fastify parser throws FST_ERR_CTP_EMPTY_JSON_BODY on empty string.
+  app.removeContentTypeParser(['application/json']);
+  app.addContentTypeParser('application/json', { parseAs: 'string' }, (_req, body, done) => {
+    const str = (body as string) ?? '';
+    if (str.trim().length === 0) {
+      done(null, {});
+      return;
+    }
+    try {
+      done(null, JSON.parse(str));
+    } catch (err) {
+      done(err as Error, undefined);
+    }
+  });
+
   const sql = getSql(config);
   await applySchema(sql);
   app.log.info('database schema applied');

apps/server/src/routes/chats.ts

@@ -26,11 +26,37 @@ export function registerChatRoutes(
         reply.code(404);
         return { error: 'session not found' };
       }
+      // Enriched list: computed per-chat fields via LATERAL joins.
+      // `effective_context_tokens` = ctx_used (prompt tokens) on the most
+      // recent complete assistant message — represents the current context
+      // window consumption post-compact.
       const rows = await sql<Chat[]>`
-        SELECT id, session_id, name, status, created_at, updated_at
-        FROM chats
-        WHERE session_id = ${req.params.id}
-        ORDER BY updated_at DESC
+        SELECT
+          c.id, c.session_id, c.name, c.status, c.created_at, c.updated_at,
+          COALESCE(mc.cnt, 0)::int AS message_count,
+          lp.preview AS last_message_preview,
+          ec.tokens AS effective_context_tokens
+        FROM chats c
+        LEFT JOIN LATERAL (
+          SELECT COUNT(*) AS cnt FROM messages WHERE chat_id = c.id
+        ) mc ON TRUE
+        LEFT JOIN LATERAL (
+          SELECT LEFT(BTRIM(REGEXP_REPLACE(content, E'[\\n\\r]+', ' ', 'g')), 80) AS preview
+          FROM messages
+          WHERE chat_id = c.id AND kind = 'message' AND content <> ''
+          ORDER BY created_at DESC
+          LIMIT 1
+        ) lp ON TRUE
+        LEFT JOIN LATERAL (
+          SELECT ctx_used AS tokens
+          FROM messages
+          WHERE chat_id = c.id AND kind = 'message' AND role = 'assistant'
+            AND status = 'complete' AND ctx_used IS NOT NULL
+          ORDER BY created_at DESC
+          LIMIT 1
+        ) ec ON TRUE
+        WHERE c.session_id = ${req.params.id}
+        ORDER BY c.updated_at DESC
       `;
       return rows;
     }

apps/server/src/services/auto_name.ts

@@ -51,6 +51,7 @@ export async function maybeAutoNameChat(
     WHERE chat_id = ${chatId}
       AND role = 'assistant'
       AND status = 'complete'
+      AND content <> ''
   `;
   if (counts[0]?.n !== 1) return;
 
@@ -80,6 +81,7 @@ export async function maybeAutoNameChat(
     WHERE chat_id = ${chatId}
       AND role = 'assistant'
       AND status = 'complete'
+      AND content <> ''
     ORDER BY created_at ASC
     LIMIT 1
   `;

apps/server/src/types/api.ts

@@ -33,6 +33,10 @@ export interface Chat {
   status: ChatStatus;
   created_at: string;
   updated_at: string;
+  // Populated by GET /api/sessions/:id/chats only.
+  message_count?: number;
+  last_message_preview?: string | null;
+  effective_context_tokens?: number | null;
 }
 
 // KEEP IN SYNC: apps/server/src/schema.sql messages_role_chk / messages_status_chk

apps/web/src/api/types.ts

@@ -33,6 +33,10 @@ export interface Chat {
   status: ChatStatus;
   created_at: string;
   updated_at: string;
+  // Populated by GET /api/sessions/:id/chats only.
+  message_count?: number;
+  last_message_preview?: string | null;
+  effective_context_tokens?: number | null;
 }
 
 export type MessageRole = 'user' | 'assistant' | 'tool' | 'system';

apps/web/src/components/AddProjectModal.tsx

@@ -1,7 +1,6 @@
 import { useEffect, useState } from 'react';
 import { api } from '@/api/client';
 import type { AvailableProject } from '@/api/types';
-import { sessionEvents } from '@/hooks/sessionEvents';
 import { Button } from '@/components/ui/button';
 import {
   Dialog,
@@ -43,8 +42,8 @@ export function AddProjectModal({ open, onOpenChange, onAdded }: Props) {
     setBusy(true);
     setError(null);
     try {
-      const created = await api.projects.add({ path });
-      sessionEvents.emit({ type: 'project_created', project: created });
+      await api.projects.add({ path });
+      // Server publishes project_created via WS; let useUserEvents deliver it.
       onAdded();
       onOpenChange(false);
     } catch (err) {

apps/web/src/components/MessageBubble.tsx

@@ -2,7 +2,7 @@ import { Children, cloneElement, isValidElement, useState } from 'react';
 import type { ReactElement, ReactNode } from 'react';
 import Markdown from 'react-markdown';
 import remarkGfm from 'remark-gfm';
-import { ChevronDown, ChevronRight, Copy, RefreshCw, Check, Share2 } from 'lucide-react';
+import { ChevronDown, ChevronRight, Copy, RefreshCw, Check, Share2, RotateCw } from 'lucide-react';
 import { toast } from 'sonner';
 import type { Chat, Message } from '@/api/types';
 import { api } from '@/api/client';
@@ -255,6 +255,7 @@ function CompactCard({ message, sessionChats }: { message: Message; sessionChats
   const [expanded, setExpanded] = useState(false);
   const [copied, setCopied] = useState(false);
   const [shareOpen, setShareOpen] = useState(false);
+  const [rerunning, setRerunning] = useState(false);
 
   const headerMatch = message.content.match(/^\[Context compacted — (\d+) messages summarized\]/);
   const headerText = headerMatch ? headerMatch[0] : 'Context compacted';
@@ -267,21 +268,34 @@ function CompactCard({ message, sessionChats }: { message: Message; sessionChats
       await navigator.clipboard.writeText(summaryText);
       setCopied(true);
       setTimeout(() => setCopied(false), 1200);
+      toast.success('Summary copied to clipboard');
     } catch {
       toast.error('Copy failed');
     }
   }
 
-  async function handleShareToChat(chatId: string) {
+  async function handleShareToChat(chat: Chat) {
     try {
-      await api.messages.send(chatId, summaryText);
-      toast.success('Summary sent to chat');
+      await api.messages.send(chat.id, summaryText);
+      toast.success(`Summary sent to ${chat.name ?? 'New chat'}`);
       setShareOpen(false);
     } catch (err) {
       toast.error(err instanceof Error ? err.message : 'Failed to share');
     }
   }
 
+  async function handleRerun() {
+    if (rerunning) return;
+    setRerunning(true);
+    try {
+      await api.chats.compact(message.chat_id);
+    } catch (err) {
+      toast.error(err instanceof Error ? err.message : 'Re-run failed');
+    } finally {
+      setRerunning(false);
+    }
+  }
+
   const otherChats = (sessionChats ?? []).filter(
     (c) => c.id !== message.chat_id && c.status === 'open'
   );
@@ -302,35 +316,51 @@ function CompactCard({ message, sessionChats }: { message: Message; sessionChats
           onClick={() => void handleCopy()}
           className="p-1 rounded hover:bg-muted text-muted-foreground"
           aria-label="Copy summary"
+          title="Copy summary"
         >
           {copied ? <Check size={12} /> : <Copy size={12} />}
         </button>
-        {otherChats.length > 0 && (
-          <div className="relative">
-            <button
-              type="button"
-              onClick={() => setShareOpen(!shareOpen)}
-              className="p-1 rounded hover:bg-muted text-muted-foreground"
-              aria-label="Send to chat"
-            >
-              <Share2 size={12} />
-            </button>
-            {shareOpen && (
-              <div className="absolute right-0 top-full mt-1 z-50 bg-popover border rounded-md shadow-md min-w-[160px] py-1">
-                {otherChats.map((c) => (
+        <div className="relative">
+          <button
+            type="button"
+            onClick={() => setShareOpen(!shareOpen)}
+            className="p-1 rounded hover:bg-muted text-muted-foreground"
+            aria-label="Send to chat"
+            title="Send to chat"
+          >
+            <Share2 size={12} />
+          </button>
+          {shareOpen && (
+            <div className="absolute right-0 top-full mt-1 z-50 bg-popover border rounded-md shadow-md min-w-[180px] py-1">
+              {otherChats.length === 0 ? (
+                <div className="px-3 py-1.5 text-xs text-muted-foreground">
+                  No other chats in this session
+                </div>
+              ) : (
+                otherChats.map((c) => (
                   <button
                     key={c.id}
                     type="button"
-                    onClick={() => void handleShareToChat(c.id)}
+                    onClick={() => void handleShareToChat(c)}
                     className="w-full text-left px-3 py-1.5 text-xs hover:bg-accent truncate"
                   >
                     {c.name ?? 'New chat'}
                   </button>
-                ))}
-              </div>
-            )}
-          </div>
-        )}
+                ))
+              )}
+            </div>
+          )}
+        </div>
+        <button
+          type="button"
+          onClick={() => void handleRerun()}
+          disabled={rerunning}
+          className="p-1 rounded hover:bg-muted text-muted-foreground disabled:opacity-40"
+          aria-label="Re-run compact"
+          title="Re-run compact"
+        >
+          <RotateCw size={12} className={rerunning ? 'animate-spin' : ''} />
+        </button>
       </div>
       {expanded && (
         <div className="px-3 pb-3 text-xs leading-relaxed text-muted-foreground whitespace-pre-wrap border-t pt-2">

apps/web/src/components/ProjectSidebar.tsx

@@ -16,6 +16,13 @@ import {
   ContextMenuSeparator,
   ContextMenuTrigger,
 } from '@/components/ui/context-menu';
+import {
+  Dialog,
+  DialogContent,
+  DialogHeader,
+  DialogTitle,
+  DialogDescription,
+} from '@/components/ui/dialog';
 import { AddProjectModal } from './AddProjectModal';
 import { api } from '@/api/client';
 import { sessionEvents } from '@/hooks/sessionEvents';
@@ -100,6 +107,7 @@ export function ProjectSidebar() {
   const [expanded, setExpanded] = useState<Set<string>>(() => readExpanded());
   const [renamingSession, setRenamingSession] = useState<string | null>(null);
   const [renameValue, setRenameValue] = useState('');
+  const [deleteConfirm, setDeleteConfirm] = useState<{ id: string; name: string } | null>(null);
   const navigate = useNavigate();
   const location = useLocation();
   const lastToastedError = useRef<string | null>(null);
@@ -135,7 +143,7 @@ export function ProjectSidebar() {
   async function handleRemove(id: string) {
     try {
       await api.projects.remove(id);
-      sessionEvents.emit({ type: 'project_deleted', project_id: id });
+      // Server publishes project_deleted via WS; useUserEvents delivers it.
       navigate('/');
     } catch (err) {
       toast.error(err instanceof Error ? err.message : 'failed to remove project');
@@ -145,13 +153,23 @@ export function ProjectSidebar() {
   async function handleArchiveSession(sessionId: string, projectId: string) {
     try {
       await api.sessions.archive(sessionId);
-      sessionEvents.emit({ type: 'session_archived', session_id: sessionId, project_id: projectId });
+      // Server publishes session_archived via WS; useUserEvents delivers it.
       if (activeSession === sessionId) navigate(`/project/${projectId}`);
     } catch (err) {
       toast.error(err instanceof Error ? err.message : 'failed to archive session');
     }
   }
 
+  async function handleDeleteSession(sessionId: string, projectId: string) {
+    try {
+      await api.sessions.remove(sessionId);
+      // Server publishes session_deleted via WS; useUserEvents delivers it.
+      if (activeSession === sessionId) navigate(`/project/${projectId}`);
+    } catch (err) {
+      toast.error(err instanceof Error ? err.message : 'failed to delete session');
+    }
+  }
+
   async function handleRenameSession(sessionId: string) {
     const trimmed = renameValue.trim();
     setRenamingSession(null);
@@ -293,10 +311,16 @@ export function ProjectSidebar() {
                           }}>
                             Rename
                           </ContextMenuItem>
-                          <ContextMenuSeparator />
                           <ContextMenuItem onSelect={() => void handleArchiveSession(s.id, p.id)}>
                             Archive
                           </ContextMenuItem>
+                          <ContextMenuSeparator />
+                          <ContextMenuItem
+                            variant="destructive"
+                            onSelect={() => setDeleteConfirm({ id: s.id, name: s.name })}
+                          >
+                            Delete
+                          </ContextMenuItem>
                         </ContextMenuContent>
                       </ContextMenu>
                     ))}
@@ -316,6 +340,36 @@ export function ProjectSidebar() {
       </nav>
 
       <AddProjectModal open={addOpen} onOpenChange={setAddOpen} onAdded={() => {}} />
+
+      <Dialog open={deleteConfirm !== null} onOpenChange={(open) => { if (!open) setDeleteConfirm(null); }}>
+        <DialogContent>
+          <DialogHeader>
+            <DialogTitle>Delete session?</DialogTitle>
+            <DialogDescription>
+              This will permanently delete {deleteConfirm ? `"${deleteConfirm.name}"` : 'this session'} and all its chats and messages. This cannot be undone.
+            </DialogDescription>
+          </DialogHeader>
+          <div className="flex gap-2 justify-end pt-2">
+            <Button variant="outline" onClick={() => setDeleteConfirm(null)}>
+              Cancel
+            </Button>
+            <Button
+              variant="destructive"
+              onClick={() => {
+                if (deleteConfirm) {
+                  const projectId = projects.find((p) =>
+                    p.recent_sessions.some((s) => s.id === deleteConfirm.id)
+                  )?.id;
+                  if (projectId) void handleDeleteSession(deleteConfirm.id, projectId);
+                }
+                setDeleteConfirm(null);
+              }}
+            >
+              Delete
+            </Button>
+          </div>
+        </DialogContent>
+      </Dialog>
     </aside>
   );
 }

apps/web/src/components/SessionLandingPage.tsx

@@ -3,6 +3,7 @@ import { MessageSquare, Send, ChevronDown, ChevronRight } from 'lucide-react';
 import type { Chat } from '@/api/types';
 import { Button } from '@/components/ui/button';
 import { Textarea } from '@/components/ui/textarea';
+import { formatTokens } from '@/lib/format';
 
 interface Props {
   sessionId: string;
@@ -27,6 +28,51 @@ function relTime(iso: string): string {
   return `${day}d ago`;
 }
 
+function ChatRow({
+  chat,
+  onClick,
+  dimmed,
+  trailing,
+}: {
+  chat: Chat;
+  onClick: () => void;
+  dimmed?: boolean;
+  trailing?: string;
+}) {
+  const meta: string[] = [relTime(chat.updated_at)];
+  if (chat.message_count !== undefined && chat.message_count > 0) {
+    meta.push(`${chat.message_count} msg`);
+  }
+  const tokens = formatTokens(chat.effective_context_tokens);
+  if (tokens) meta.push(tokens);
+  const preview = chat.last_message_preview;
+  return (
+    <button
+      type="button"
+      onClick={onClick}
+      className="w-full flex flex-col gap-0.5 px-3 py-2 hover:bg-muted/50 text-left"
+    >
+      <div className="flex items-center gap-2 min-w-0">
+        <MessageSquare className={`size-3.5 shrink-0 ${dimmed ? 'opacity-40' : 'opacity-70'}`} />
+        <span className={`truncate text-sm flex-1 ${dimmed ? 'text-muted-foreground' : ''}`}>
+          {chat.name ?? 'New chat'}
+        </span>
+        {trailing && (
+          <span className="text-xs text-muted-foreground shrink-0">{trailing}</span>
+        )}
+      </div>
+      <div className="ml-5 text-xs text-muted-foreground tabular-nums">
+        {meta.join(' · ')}
+      </div>
+      {preview && (
+        <div className="ml-5 text-xs italic text-muted-foreground truncate">
+          {preview}
+        </div>
+      )}
+    </button>
+  );
+}
+
 export function SessionLandingPage({
   chats,
   onOpenChat,
@@ -50,6 +96,10 @@ export function SessionLandingPage({
     setComposerValue('');
   }
 
+  // TODO: Landing page chat counts are a snapshot at mount. New messages in
+  // visible chats won't update the per-row stats until next mount/navigation.
+  // Wiring WS reactivity through here is deferred (rare use case: user is in
+  // a pane when messages stream, not on the landing page).
   return (
     <div className="flex flex-col h-full min-h-0">
       <div className="flex-1 overflow-y-auto px-6 py-4 space-y-6">
@@ -60,19 +110,7 @@ export function SessionLandingPage({
             <ul className="divide-y rounded-md border">
               {openChats.map((chat) => (
                 <li key={chat.id}>
-                  <button
-                    type="button"
-                    onClick={() => onOpenChat(chat.id)}
-                    className="w-full flex items-center gap-2 px-3 py-2 hover:bg-muted/50 text-left"
-                  >
-                    <MessageSquare className="size-3.5 opacity-70 shrink-0" />
-                    <span className="truncate text-sm flex-1">
-                      {chat.name ?? 'New chat'}
-                    </span>
-                    <span className="text-xs text-muted-foreground shrink-0 tabular-nums">
-                      {relTime(chat.updated_at)}
-                    </span>
-                  </button>
+                  <ChatRow chat={chat} onClick={() => onOpenChat(chat.id)} />
                 </li>
               ))}
             </ul>
@@ -94,19 +132,12 @@ export function SessionLandingPage({
               <ul className="divide-y rounded-md border">
                 {closedChats.map((chat) => (
                   <li key={chat.id}>
-                    <button
-                      type="button"
+                    <ChatRow
+                      chat={chat}
                       onClick={() => void onReopenChat(chat.id)}
-                      className="w-full flex items-center gap-2 px-3 py-2 hover:bg-muted/50 text-left"
-                    >
-                      <MessageSquare className="size-3.5 opacity-40 shrink-0" />
-                      <span className="truncate text-sm flex-1 text-muted-foreground">
-                        {chat.name ?? 'New chat'}
-                      </span>
-                      <span className="text-xs text-muted-foreground shrink-0">
-                        Reopen
-                      </span>
-                    </button>
+                      dimmed
+                      trailing="Reopen"
+                    />
                   </li>
                 ))}
               </ul>

apps/web/src/components/Workspace.tsx

@@ -1,4 +1,5 @@
 import { useCallback, useEffect, useRef, useState } from 'react';
+import type { DragEvent } from 'react';
 import { PanelRight, MessageSquare, Terminal, Bot } from 'lucide-react';
 import { toast } from 'sonner';
 import { api } from '@/api/client';
@@ -61,6 +62,8 @@ export function Workspace({ sessionId, projectId }: Props) {
   const [chats, setChats] = useState<Chat[]>([]);
   const chatsRef = useRef<Chat[]>([]);
   chatsRef.current = chats;
+  const draggingIdxRef = useRef<number | null>(null);
+  const [dragOverIdx, setDragOverIdx] = useState<number | null>(null);
 
   useEffect(() => {
     let cancelled = false;
@@ -87,7 +90,10 @@ export function Workspace({ sessionId, projectId }: Props) {
   useEffect(() => {
     return sessionEvents.subscribe((event) => {
       if (event.type === 'chat_created' && event.session_id === sessionId) {
-        setChats((prev) => [event.chat, ...prev]);
+        setChats((prev) => {
+          if (prev.some((c) => c.id === event.chat.id)) return prev;
+          return [event.chat, ...prev];
+        });
       }
       if (event.type === 'chat_updated') {
         setChats((prev) => prev.map((c) =>
@@ -177,8 +183,11 @@ export function Workspace({ sessionId, projectId }: Props) {
   const createChat = useCallback(async (paneIdx: number) => {
     try {
       const chat = await api.chats.create(sessionId);
-      setChats((prev) => [chat, ...prev]);
-      sessionEvents.emit({ type: 'chat_created', chat, session_id: sessionId });
+      // Optimistic local insert; the WS chat_created echo will be deduped by id.
+      setChats((prev) => {
+        if (prev.some((c) => c.id === chat.id)) return prev;
+        return [chat, ...prev];
+      });
       openChatInPane(paneIdx, chat.id);
     } catch (err) {
       toast.error(err instanceof Error ? err.message : 'Failed to create chat');
@@ -256,11 +265,61 @@ export function Workspace({ sessionId, projectId }: Props) {
     });
   }, []);
 
+  const handlePaneDragStart = useCallback(
+    (idx: number) => (e: DragEvent<HTMLDivElement>) => {
+      draggingIdxRef.current = idx;
+      e.dataTransfer.effectAllowed = 'move';
+      e.dataTransfer.setData('text/plain', String(idx));
+    },
+    []
+  );
+
+  const handlePaneDragOver = useCallback(
+    (idx: number) => (e: DragEvent<HTMLDivElement>) => {
+      if (draggingIdxRef.current === null) return;
+      e.preventDefault();
+      e.dataTransfer.dropEffect = 'move';
+      if (dragOverIdx !== idx) setDragOverIdx(idx);
+    },
+    [dragOverIdx]
+  );
+
+  const handlePaneDragLeave = useCallback(() => {
+    setDragOverIdx(null);
+  }, []);
+
+  const handlePaneDrop = useCallback(
+    (targetIdx: number) => (e: DragEvent<HTMLDivElement>) => {
+      e.preventDefault();
+      const fromIdx = draggingIdxRef.current;
+      draggingIdxRef.current = null;
+      setDragOverIdx(null);
+      if (fromIdx === null || fromIdx === targetIdx) return;
+      setPanes((prev) => {
+        const next = [...prev];
+        const [moved] = next.splice(fromIdx, 1);
+        if (!moved) return prev;
+        next.splice(targetIdx, 0, moved);
+        // Keep active selection on the same logical pane (the one being dragged).
+        setActivePaneIdx(targetIdx);
+        return next;
+      });
+    },
+    []
+  );
+
+  const handlePaneDragEnd = useCallback(() => {
+    draggingIdxRef.current = null;
+    setDragOverIdx(null);
+  }, []);
+
   const handleLandingSend = useCallback(async (paneIdx: number, content: string) => {
     try {
       const chat = await api.chats.create(sessionId);
-      setChats((prev) => [chat, ...prev]);
-      sessionEvents.emit({ type: 'chat_created', chat, session_id: sessionId });
+      setChats((prev) => {
+        if (prev.some((c) => c.id === chat.id)) return prev;
+        return [chat, ...prev];
+      });
       openChatInPane(paneIdx, chat.id);
       await api.messages.send(chat.id, content);
     } catch (err) {
@@ -315,23 +374,34 @@ export function Workspace({ sessionId, projectId }: Props) {
           <div
             key={pane.id}
             className={cn(
-              'flex flex-col h-full min-h-0 border-r border-border last:border-r-0',
-              idx === activePaneIdx && 'ring-1 ring-inset ring-ring/20'
+              'flex flex-col h-full min-h-0 border-r border-border last:border-r-0 relative',
+              idx === activePaneIdx && 'ring-1 ring-inset ring-ring/20',
+              dragOverIdx === idx && draggingIdxRef.current !== idx &&
+                'before:absolute before:inset-y-0 before:left-0 before:w-0.5 before:bg-primary before:z-10'
             )}
             onClick={() => setActivePaneIdx(idx)}
+            onDragOver={panes.length > 1 ? handlePaneDragOver(idx) : undefined}
+            onDragLeave={panes.length > 1 ? handlePaneDragLeave : undefined}
+            onDrop={panes.length > 1 ? handlePaneDrop(idx) : undefined}
           >
-            <ChatTabBar
-              pane={pane}
-              tabs={chatsForPane(pane)}
-              onSwitchTab={(tabIdx) => switchTab(idx, tabIdx)}
-              onRemoveTab={(chatId) => removeTab(idx, chatId)}
-              onNewChat={() => void createChat(idx)}
-              onShowHistory={() => showLandingPage(idx)}
-              onRename={renameChat}
-              onClose={closeChat}
-              onDelete={deleteChat}
-              onRemovePane={panes.length > 1 ? () => removePane(idx) : undefined}
-            />
+            <div
+              draggable={panes.length > 1}
+              onDragStart={panes.length > 1 ? handlePaneDragStart(idx) : undefined}
+              onDragEnd={panes.length > 1 ? handlePaneDragEnd : undefined}
+            >
+              <ChatTabBar
+                pane={pane}
+                tabs={chatsForPane(pane)}
+                onSwitchTab={(tabIdx) => switchTab(idx, tabIdx)}
+                onRemoveTab={(chatId) => removeTab(idx, chatId)}
+                onNewChat={() => void createChat(idx)}
+                onShowHistory={() => showLandingPage(idx)}
+                onRename={renameChat}
+                onClose={closeChat}
+                onDelete={deleteChat}
+                onRemovePane={panes.length > 1 ? () => removePane(idx) : undefined}
+              />
+            </div>
 
             <div className="flex-1 min-h-0 overflow-hidden">
               {pane.kind === 'chat' && pane.chatId ? (

apps/web/src/hooks/useSidebar.ts

@@ -52,6 +52,7 @@ function load(): Promise<void> {
 function applyEvent(prev: SidebarResponse, event: import('./sessionEvents').SessionEvent): SidebarResponse {
   switch (event.type) {
     case 'project_created': {
+      if (prev.projects.some((p) => p.id === event.project.id)) return prev;
       const fresh: SidebarProject = {
         id: event.project.id,
         name: event.project.name,
@@ -69,6 +70,7 @@ function applyEvent(prev: SidebarResponse, event: import('./sessionEvents').Sess
       let changed = false;
       const projects = prev.projects.map((p) => {
         if (p.id !== event.project_id) return p;
+        if (p.recent_sessions.some((s) => s.id === event.session.id)) return p;
         changed = true;
         const fresh: SidebarSession = {
           id: event.session.id,
@@ -89,8 +91,10 @@ function applyEvent(prev: SidebarResponse, event: import('./sessionEvents').Sess
       let changed = false;
       const projects = prev.projects.map((p) => {
         if (p.id !== event.project_id) return p;
-        changed = true;
         const recent = p.recent_sessions.filter((s) => s.id !== event.session_id);
+        const wasPresent = recent.length !== p.recent_sessions.length;
+        if (!wasPresent) return p;
+        changed = true;
         return {
           ...p,
           recent_sessions: recent,

apps/web/src/lib/format.ts

@@ -0,0 +1,5 @@
+export function formatTokens(n: number | null | undefined): string | null {
+  if (n === null || n === undefined) return null;
+  if (n < 1000) return `${n} tok`;
+  return `${(n / 1000).toFixed(1)}k tok`;
+}

apps/web/src/pages/Project.tsx

@@ -37,11 +37,17 @@ export function Project() {
       if (event.type === 'session_archived' && event.project_id === id) {
         setArchivedSessions((prev) => {
           if (!prev) return prev;
+          if (prev.some((s) => s.id === event.session_id)) return prev;
           const session = sessions?.find((s) => s.id === event.session_id);
           if (!session) return prev;
           return [{ ...session, status: 'archived' as const }, ...prev];
         });
       }
+      if (event.type === 'session_deleted' && event.project_id === id) {
+        setArchivedSessions((prev) =>
+          prev ? prev.filter((s) => s.id !== event.session_id) : prev
+        );
+      }
     });
   }, [id, sessions]);
 
@@ -50,7 +56,7 @@ export function Project() {
     setCreating(true);
     try {
       const s = await create({});
-      sessionEvents.emit({ type: 'session_created', session: s, project_id: id });
+      // Server publishes session_created via WS; let useUserEvents deliver it.
       navigate(`/session/${s.id}`);
     } finally {
       setCreating(false);
@@ -112,11 +118,7 @@ export function Project() {
                   onClick={async () => {
                     try {
                       await remove(s.id);
-                      sessionEvents.emit({
-                        type: 'session_deleted',
-                        session_id: s.id,
-                        project_id: id!,
-                      });
+                      // Server publishes session_deleted via WS.
                     } catch (err) {
                       toast.error(
                         err instanceof Error ? err.message : 'failed to delete session'

apps/web/src/pages/Session.tsx

@@ -1,5 +1,5 @@
 import { useEffect, useState } from 'react';
-import { Link, useParams } from 'react-router-dom';
+import { Link, useNavigate, useParams } from 'react-router-dom';
 import { ChevronLeft } from 'lucide-react';
 import { api } from '@/api/client';
 import type { Session as SessionType } from '@/api/types';
@@ -9,6 +9,7 @@ import { ModelPicker } from '@/components/ModelPicker';
 
 export function Session() {
   const { id } = useParams<{ id: string }>();
+  const navigate = useNavigate();
   const [session, setSession] = useState<SessionType | null>(null);
   const [name, setName] = useState('');
   const [editingName, setEditingName] = useState(false);
@@ -43,12 +44,19 @@ export function Session() {
   useEffect(() => {
     if (!id) return;
     return sessionEvents.subscribe((event) => {
-      if (event.type !== 'session_renamed') return;
-      if (event.session_id !== id) return;
-      setSession((prev) => (prev ? { ...prev, name: event.name } : prev));
-      setName((prev) => (editingName ? prev : event.name));
+      if (event.type === 'session_renamed' && event.session_id === id) {
+        setSession((prev) => (prev ? { ...prev, name: event.name } : prev));
+        setName((prev) => (editingName ? prev : event.name));
+        return;
+      }
+      if (
+        (event.type === 'session_deleted' || event.type === 'session_archived') &&
+        event.session_id === id
+      ) {
+        navigate(`/project/${event.project_id}`);
+      }
     });
-  }, [id, editingName]);
+  }, [id, editingName, navigate]);
 
   async function saveName() {
     if (!id || !session) return;