v1.9: settings pane + per-project defaults + bulk archive + themes lift

Adds a singleton, ephemeral 'settings' pane kind to the workspace.
Opened via a new bottom-pinned button in ProjectSidebar (emits an
open_settings_pane event when a session is mounted; navigates to
/settings otherwise). Pane has three sections — Session, Project,
Theme — and a maximize toggle that hides sibling pane columns via
display:none on desktop only. Settings panes don't count toward
MAX_PANES and are filtered out of the localStorage persistence layer
so reload always restores a clean workspace.

Schema (additive):
- projects.default_system_prompt TEXT NOT NULL DEFAULT ''
- projects.default_web_search_enabled BOOLEAN NOT NULL DEFAULT false
- sessions.web_search_enabled BOOLEAN  (nullable; null = inherit)

Inference resolves user_prompt = session.system_prompt.trim() ||
project.default_system_prompt.trim() — empty/whitespace at either
layer means "no override". Keeps the columns NOT NULL and matches
the existing inherit semantics.

Server routes:
- GET /api/projects/:id (new; settings pane refetches on
  project_updated)
- PATCH /api/projects/:id accepts default_system_prompt,
  default_web_search_enabled
- PATCH /api/sessions/:id accepts web_search_enabled (tri-state)
- POST /api/projects/:id/sessions/archive-all + GET
  /api/projects/:id/sessions/open-count
- POST /api/sessions/:id/chats/archive-all + GET
  /api/sessions/:id/chats/open-count
- PATCH /api/sessions/:id now broadcasts session_updated on every
  successful PATCH (was rename-only). Lets SettingsPane open in
  another tab pick up edits without a refetch.

Bulk-archive publishes one session_archived / chat_archived frame
per affected id so useSidebar's existing reducer cases handle them
incrementally — no new frame type, no payload widening.

ModelPicker refactored: shared ModelList inside a responsive shell.
Desktop = labeled trigger + DropdownMenu, mobile = icon-only Cpu
button + BottomSheet. Header in Session.tsx drops the pill wrap on
mobile since the new trigger is the visual.

ChatInput gains an icon-only '+' DropdownMenu next to AgentPicker
when sessionId + webSearchEnabled props are provided. One item for
now — Web search — with a checkmark reflecting the stored value
(true), not the effective one. Click PATCHes the override; to
restore inherit-from-project the user opens SettingsPane.

ThemePicker lifted out of pages/Settings.tsx into a reusable
component. The standalone /settings route is now a thin wrapper
that mounts <ThemePicker /> with a Back button on top
(navigate(-1) with fallback to '/'); the SettingsPane Theme tab
renders the same picker bare.

Project section delete-flow removed (button + confirm dialog +
handler). Replaced with "Archive all sessions" using the same
two-step count → confirm → fire pattern as "Archive all chats" in
the Session section. api.projects.remove() stays in the client
because useProjects.ts still uses it.

Hand-rolled Switch primitive in SettingsPane (no shadcn switch in
the project; spec said no new deps). Section nav is plain buttons
(no shadcn Tabs).

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

apps/server/src/routes/chats.ts

@@ -123,6 +123,53 @@ export function registerChatRoutes(
     }
   );
 
+  // v1.9: bulk-archive every open chat in a session. Mirrors the single
+  // /chats/:id/archive shape — N chat_archived frames published, useSidebar
+  // reducer handles each via the existing case.
+  app.post<{ Params: { id: string } }>(
+    '/api/sessions/:id/chats/archive-all',
+    async (req, reply) => {
+      const session = await sql`SELECT id FROM sessions WHERE id = ${req.params.id}`;
+      if (session.length === 0) {
+        reply.code(404);
+        return { error: 'session not found' };
+      }
+      const rows = await sql<{ id: string }[]>`
+        UPDATE chats
+           SET status = 'archived', updated_at = clock_timestamp()
+         WHERE session_id = ${req.params.id} AND status = 'open'
+         RETURNING id
+      `;
+      const ids = rows.map((r) => r.id);
+      for (const id of ids) {
+        broker.publishUser('default', {
+          type: 'chat_archived',
+          chat_id: id,
+          session_id: req.params.id,
+        });
+      }
+      return { archived: ids.length, ids };
+    }
+  );
+
+  // v1.9: count helper for the confirm dialog.
+  app.get<{ Params: { id: string } }>(
+    '/api/sessions/:id/chats/open-count',
+    async (req, reply) => {
+      const session = await sql`SELECT id FROM sessions WHERE id = ${req.params.id}`;
+      if (session.length === 0) {
+        reply.code(404);
+        return { error: 'session not found' };
+      }
+      const rows = await sql<{ count: number }[]>`
+        SELECT COUNT(*)::int AS count
+          FROM chats
+         WHERE session_id = ${req.params.id} AND status = 'open'
+      `;
+      return { count: rows[0]?.count ?? 0 };
+    }
+  );
+
   app.post<{ Params: { id: string } }>(
     '/api/chats/:id/archive',
     async (req, reply) => {

apps/server/src/routes/projects.ts

@@ -22,8 +22,14 @@ const AddProjectBody = z.object({
   name: z.string().min(1).optional(),
 });
 
+// v1.9: PATCH accepts the new per-project defaults. All fields optional so
+// the existing rename-only callers keep working. Empty string on
+// default_system_prompt is the "no override" sentinel — same convention as
+// sessions.system_prompt.
 const PatchProjectBody = z.object({
-  name: z.string().min(1).max(200),
+  name: z.string().min(1).max(200).optional(),
+  default_system_prompt: z.string().max(8000).optional(),
+  default_web_search_enabled: z.boolean().optional(),
 });
 
 const CreateProjectBody = z.object({
@@ -70,7 +76,8 @@ export function registerProjectRoutes(
   app.get<{ Querystring: { status?: string } }>('/api/projects', async (req) => {
     const status = req.query.status === 'archived' ? 'archived' : 'open';
     const rows = await sql<Project[]>`
-      SELECT id, name, path, added_at, last_session_id, status, gitea_remote
+      SELECT id, name, path, added_at, last_session_id, status, gitea_remote,
+             default_system_prompt, default_web_search_enabled
       FROM projects
       WHERE status = ${status}
       ORDER BY added_at DESC
@@ -119,7 +126,8 @@ export function registerProjectRoutes(
       const [row] = await sql<Project[]>`
         INSERT INTO projects (name, path, gitea_remote)
         VALUES (${parsed.data.name}, ${bootstrap.folder_real_path}, ${bootstrap.gitea_remote_url})
-        RETURNING id, name, path, added_at, last_session_id, status, gitea_remote
+        RETURNING id, name, path, added_at, last_session_id, status, gitea_remote,
+                  default_system_prompt, default_web_search_enabled
       `;
       broker.publishUser('default', { type: 'project_created', project: row as unknown as Project });
       reply.code(201);
@@ -173,7 +181,8 @@ export function registerProjectRoutes(
       INSERT INTO projects (name, path)
       VALUES (${name}, ${resolved.real})
       ON CONFLICT (path) DO UPDATE SET status = 'open'
-      RETURNING id, name, path, added_at, last_session_id, status, gitea_remote
+      RETURNING id, name, path, added_at, last_session_id, status, gitea_remote,
+                default_system_prompt, default_web_search_enabled
     `;
 
     if (existing.length === 0) {
@@ -187,22 +196,53 @@ export function registerProjectRoutes(
     return row;
   });
 
+  // v1.9: single-project fetch so the settings pane can refetch on
+  // project_updated without pulling the whole project list.
+  app.get<{ Params: { id: string } }>('/api/projects/:id', async (req, reply) => {
+    const rows = await sql<Project[]>`
+      SELECT id, name, path, added_at, last_session_id, status, gitea_remote,
+             default_system_prompt, default_web_search_enabled
+      FROM projects WHERE id = ${req.params.id}
+    `;
+    if (rows.length === 0) {
+      reply.code(404);
+      return { error: 'not found' };
+    }
+    return rows[0];
+  });
+
   app.patch<{ Params: { id: string } }>('/api/projects/:id', async (req, reply) => {
     const parsed = PatchProjectBody.safeParse(req.body);
     if (!parsed.success) {
       reply.code(400);
       return { error: 'invalid body', details: parsed.error.flatten() };
     }
+    const { name, default_system_prompt, default_web_search_enabled } = parsed.data;
+    // v1.9: every field optional. COALESCE on the bind keeps the prior value
+    // when the caller omits it. Boolean has its own branch since COALESCE
+    // can't disambiguate "omitted" from "explicitly false" via a single
+    // nullable parameter.
+    const dwsProvided = default_web_search_enabled !== undefined;
     const rows = await sql<Project[]>`
-      UPDATE projects SET name = ${parsed.data.name}
+      UPDATE projects
+      SET
+        name = COALESCE(${name ?? null}, name),
+        default_system_prompt = COALESCE(${default_system_prompt ?? null}, default_system_prompt),
+        default_web_search_enabled = CASE WHEN ${dwsProvided}
+          THEN ${default_web_search_enabled ?? false}
+          ELSE default_web_search_enabled END
       WHERE id = ${req.params.id}
-      RETURNING id, name, path, added_at, last_session_id, status, gitea_remote
+      RETURNING id, name, path, added_at, last_session_id, status, gitea_remote,
+                default_system_prompt, default_web_search_enabled
     `;
     if (rows.length === 0) {
       reply.code(404);
       return { error: 'not found' };
     }
     const project = rows[0]!;
+    // v1.9: the project_updated frame still only carries id + name. Clients
+    // that need the new fields refetch via api.projects.list() — keeps the
+    // frame payload lean, per the locked recon decision (d).
     broker.publishUser('default', {
       type: 'project_updated',
       project_id: project.id,
@@ -229,7 +269,8 @@ export function registerProjectRoutes(
     const rows = await sql<Project[]>`
       UPDATE projects SET status = 'open'
       WHERE id = ${req.params.id} AND status = 'archived'
-      RETURNING id, name, path, added_at, last_session_id, status, gitea_remote
+      RETURNING id, name, path, added_at, last_session_id, status, gitea_remote,
+                default_system_prompt, default_web_search_enabled
     `;
     if (rows.length === 0) {
       reply.code(404);

apps/server/src/routes/sessions.ts

@@ -19,6 +19,8 @@ const PatchBody = z.object({
   model: z.string().min(1).max(200).optional(),
   system_prompt: z.string().max(8000).optional(),
   agent_id: z.string().min(1).max(200).nullable().optional(),
+  // v1.9: null = inherit from project default; true/false = explicit override.
+  web_search_enabled: z.boolean().nullable().optional(),
 });
 
 async function resolveDefaultModel(sql: Sql, config: Config): Promise<string> {
@@ -50,7 +52,7 @@ export function registerSessionRoutes(
       }
       const status = req.query.status === 'archived' ? 'archived' : 'open';
       const rows = await sql<Session[]>`
-        SELECT id, project_id, name, model, system_prompt, status, created_at, updated_at, agent_id
+        SELECT id, project_id, name, model, system_prompt, status, created_at, updated_at, agent_id, web_search_enabled
         FROM sessions
         WHERE project_id = ${req.params.id} AND status = ${status}
         ORDER BY updated_at DESC
@@ -100,7 +102,7 @@ export function registerSessionRoutes(
         const [session] = await tx<Session[]>`
           INSERT INTO sessions (project_id, name, model, system_prompt, agent_id)
           VALUES (${req.params.id}, ${name}, ${model}, ${systemPrompt}, ${agentId})
-          RETURNING id, project_id, name, model, system_prompt, status, created_at, updated_at, agent_id
+          RETURNING id, project_id, name, model, system_prompt, status, created_at, updated_at, agent_id, web_search_enabled
         `;
         await tx`
           INSERT INTO chats (session_id, name, status)
@@ -120,7 +122,7 @@ export function registerSessionRoutes(
 
   app.get<{ Params: { id: string } }>('/api/sessions/:id', async (req, reply) => {
     const rows = await sql<Session[]>`
-      SELECT id, project_id, name, model, system_prompt, status, created_at, updated_at, agent_id
+      SELECT id, project_id, name, model, system_prompt, status, created_at, updated_at, agent_id, web_search_enabled
       FROM sessions WHERE id = ${req.params.id}
     `;
     if (rows.length === 0) {
@@ -139,10 +141,13 @@ export function registerSessionRoutes(
         return { error: 'invalid body', details: parsed.error.flatten() };
       }
       const { name, model, system_prompt } = parsed.data;
-      // agent_id is tri-state on the wire: omitted = no change, null = clear,
-      // string = set. CASE WHEN inside SET handles all three atomically.
+      // agent_id and web_search_enabled are both tri-state on the wire: omitted
+      // = no change, null = clear/inherit, value = set. CASE WHEN inside SET
+      // handles all three atomically.
       const agentIdProvided = parsed.data.agent_id !== undefined;
       const newAgentId = parsed.data.agent_id ?? null;
+      const wseProvided = parsed.data.web_search_enabled !== undefined;
+      const newWse = parsed.data.web_search_enabled ?? null;
       // Read the prior name so the post-update publish can skip no-op renames
       // (PATCH { name: "Foo" } where the session is already "Foo"). The window
       // between SELECT and UPDATE is sub-millisecond in the same request handler;
@@ -159,9 +164,11 @@ export function registerSessionRoutes(
           model = COALESCE(${model ?? null}, model),
           system_prompt = COALESCE(${system_prompt ?? null}, system_prompt),
           agent_id = CASE WHEN ${agentIdProvided} THEN ${newAgentId} ELSE agent_id END,
+          web_search_enabled = CASE WHEN ${wseProvided} THEN ${newWse} ELSE web_search_enabled END,
           updated_at = clock_timestamp()
         WHERE id = ${req.params.id}
-        RETURNING id, project_id, name, model, system_prompt, status, created_at, updated_at, agent_id
+        RETURNING id, project_id, name, model, system_prompt, status, created_at, updated_at,
+                  agent_id, web_search_enabled
       `;
       if (rows.length === 0) {
         reply.code(404);
@@ -175,10 +182,69 @@ export function registerSessionRoutes(
           name: session.name,
         });
       }
+      // v1.9: any successful PATCH broadcasts session_updated so listeners
+      // (notably the SettingsPane open in another tab) can refetch and pick
+      // up the new fields. Frame stays lean (decision d) — payload is just
+      // ids + name + updated_at, the client refetches via api.sessions.get.
+      broker.publishUser('default', {
+        type: 'session_updated',
+        session_id: session.id,
+        project_id: session.project_id,
+        name: session.name,
+        updated_at: session.updated_at,
+      });
       return session;
     }
   );
 
+  // v1.9: bulk-archive every open session in a project. Mirrors the
+  // single-archive shape (same broker frame type) so the existing useSidebar
+  // reducer cases handle it without changes — just N frames instead of 1.
+  app.post<{ Params: { id: string } }>(
+    '/api/projects/:id/sessions/archive-all',
+    async (req, reply) => {
+      const project = await sql`SELECT id FROM projects WHERE id = ${req.params.id}`;
+      if (project.length === 0) {
+        reply.code(404);
+        return { error: 'project not found' };
+      }
+      const rows = await sql<{ id: string }[]>`
+        UPDATE sessions
+           SET status = 'archived', updated_at = clock_timestamp()
+         WHERE project_id = ${req.params.id} AND status = 'open'
+         RETURNING id
+      `;
+      const ids = rows.map((r) => r.id);
+      for (const id of ids) {
+        broker.publishUser('default', {
+          type: 'session_archived',
+          session_id: id,
+          project_id: req.params.id,
+        });
+      }
+      return { archived: ids.length, ids };
+    }
+  );
+
+  // v1.9: count helper for the confirm dialog. Cheap COUNT(*) — the settings
+  // pane calls it on click, not on render.
+  app.get<{ Params: { id: string } }>(
+    '/api/projects/:id/sessions/open-count',
+    async (req, reply) => {
+      const project = await sql`SELECT id FROM projects WHERE id = ${req.params.id}`;
+      if (project.length === 0) {
+        reply.code(404);
+        return { error: 'project not found' };
+      }
+      const rows = await sql<{ count: number }[]>`
+        SELECT COUNT(*)::int AS count
+          FROM sessions
+         WHERE project_id = ${req.params.id} AND status = 'open'
+      `;
+      return { count: rows[0]?.count ?? 0 };
+    }
+  );
+
   app.post<{ Params: { id: string } }>(
     '/api/sessions/:id/archive',
     async (req, reply) => {
@@ -207,7 +273,7 @@ export function registerSessionRoutes(
       const rows = await sql<Session[]>`
         UPDATE sessions SET status = 'open', updated_at = clock_timestamp()
         WHERE id = ${req.params.id} AND status = 'archived'
-        RETURNING id, project_id, name, model, system_prompt, status, created_at, updated_at, agent_id
+        RETURNING id, project_id, name, model, system_prompt, status, created_at, updated_at, agent_id, web_search_enabled
       `;
       if (rows.length === 0) {
         reply.code(404);

apps/server/src/schema.sql

@@ -171,3 +171,11 @@ ALTER TABLE messages ADD COLUMN IF NOT EXISTS metadata JSONB;
 -- not new columns. Defaults match docs/themes_v1.md: obsidian (dark).
 INSERT INTO settings (key, value) VALUES ('theme_id', '"obsidian"') ON CONFLICT (key) DO NOTHING;
 INSERT INTO settings (key, value) VALUES ('theme_mode', '"dark"') ON CONFLICT (key) DO NOTHING;
+
+-- v1.9: per-project defaults that new sessions inherit, plus a per-session
+-- web-search override. Empty string on either prompt column means "inherit"
+-- (resolved in inference.ts buildSystemPrompt). web_search_enabled is the
+-- only tri-state field: null on session = inherit from project default.
+ALTER TABLE projects ADD COLUMN IF NOT EXISTS default_system_prompt TEXT NOT NULL DEFAULT '';
+ALTER TABLE projects ADD COLUMN IF NOT EXISTS default_web_search_enabled BOOLEAN NOT NULL DEFAULT false;
+ALTER TABLE sessions ADD COLUMN IF NOT EXISTS web_search_enabled BOOLEAN;

apps/server/src/services/__tests__/inference.test.ts

@@ -22,6 +22,7 @@ function makeSession(overrides: Partial<Session> = {}): Session {
     created_at: new Date(0).toISOString(),
     updated_at: new Date(0).toISOString(),
     agent_id: null,
+    web_search_enabled: null,
     ...overrides,
   };
 }
@@ -35,6 +36,8 @@ function makeProject(overrides: Partial<Project> = {}): Project {
     last_session_id: null,
     status: 'open',
     gitea_remote: null,
+    default_system_prompt: '',
+    default_web_search_enabled: false,
     ...overrides,
   };
 }

apps/server/src/services/inference.ts

@@ -149,9 +149,11 @@ export interface InferenceContext {
   publishUser: (frame: UserStreamFrame) => void;
 }
 
-// Resolution order: base prompt < agent.system_prompt < session.system_prompt.
-// Agent prompts layer on top of the base; session prompt is the most specific
-// override and stacks last so callers can append per-session instructions.
+// Resolution order: base prompt < agent.system_prompt < user prompt, where
+// user prompt = session.system_prompt if non-empty, else project's
+// default_system_prompt if non-empty, else nothing. Empty/whitespace-only
+// counts as "no override" for both layers (v1.9 inherit semantics — keeps
+// the column non-nullable so the existing key/value store stays put).
 export function buildSystemPrompt(
   project: Project,
   session: Session,
@@ -161,8 +163,11 @@ export function buildSystemPrompt(
   if (agent && agent.system_prompt.trim().length > 0) {
     out += '\n\n' + agent.system_prompt.trim();
   }
-  if (session.system_prompt && session.system_prompt.trim().length > 0) {
-    out += '\n\n' + session.system_prompt.trim();
+  const sessionPrompt = session.system_prompt?.trim() ?? '';
+  const projectPrompt = project.default_system_prompt?.trim() ?? '';
+  const userPrompt = sessionPrompt || projectPrompt;
+  if (userPrompt.length > 0) {
+    out += '\n\n' + userPrompt;
   }
   return out;
 }
@@ -240,14 +245,16 @@ async function loadContext(
   chatId: string
 ): Promise<{ session: Session; project: Project; history: Message[] } | null> {
   const sessionRows = await sql<Session[]>`
-    SELECT id, project_id, name, model, system_prompt, status, created_at, updated_at, agent_id
+    SELECT id, project_id, name, model, system_prompt, status, created_at, updated_at,
+           agent_id, web_search_enabled
     FROM sessions WHERE id = ${sessionId}
   `;
   if (sessionRows.length === 0) return null;
   const session = sessionRows[0]!;
 
   const projectRows = await sql<Project[]>`
-    SELECT id, name, path, added_at, last_session_id
+    SELECT id, name, path, added_at, last_session_id, status, gitea_remote,
+           default_system_prompt, default_web_search_enabled
     FROM projects WHERE id = ${session.project_id}
   `;
   if (projectRows.length === 0) return null;

apps/server/src/types/api.ts

@@ -10,6 +10,12 @@ export interface Project {
   last_session_id: string | null;
   status: ProjectStatus;
   gitea_remote: string | null;
+  // v1.9: per-project defaults inherited by new sessions. Empty string on
+  // default_system_prompt means "no override" — the model gets the base
+  // BooCode system prompt only. default_web_search_enabled is the inherited
+  // value for sessions where web_search_enabled is null.
+  default_system_prompt: string;
+  default_web_search_enabled: boolean;
 }
 
 export interface AvailableProject {
@@ -29,6 +35,10 @@ export interface Session {
   created_at: string;
   updated_at: string;
   agent_id: string | null;
+  // v1.9: per-session override for web_search. null = inherit from
+  // project.default_web_search_enabled. Plumbed but inert in v1.9 — the
+  // actual web_search tool ships in Batch 8.
+  web_search_enabled: boolean | null;
 }
 
 // v1.8.1: agents come from two sources. 'global' = /data/AGENTS.md (always

apps/web/src/api/client.ts

@@ -51,15 +51,29 @@ export const api = {
         method: 'POST',
         body: JSON.stringify(body),
       }),
-    update: (id: string, body: { name: string }) =>
+    update: (
+      id: string,
+      body: Partial<Pick<Project, 'name' | 'default_system_prompt' | 'default_web_search_enabled'>>,
+    ) =>
       request<Project>(`/api/projects/${id}`, {
         method: 'PATCH',
         body: JSON.stringify(body),
       }),
+    get: (id: string) => request<Project>(`/api/projects/${id}`),
     archive: (id: string) =>
       request<void>(`/api/projects/${id}/archive`, { method: 'POST' }),
     unarchive: (id: string) =>
       request<Project>(`/api/projects/${id}/unarchive`, { method: 'POST' }),
+    // v1.9: bulk-archive every open session in this project. Server publishes
+    // one session_archived frame per affected id, so the sidebar reducer
+    // updates incrementally rather than waiting for a refetch.
+    archiveAllSessions: (id: string) =>
+      request<{ archived: number; ids: string[] }>(
+        `/api/projects/${id}/sessions/archive-all`,
+        { method: 'POST' },
+      ),
+    openSessionsCount: (id: string) =>
+      request<{ count: number }>(`/api/projects/${id}/sessions/open-count`),
     create: (body: {
       name: string;
       commit_message?: string;
@@ -106,7 +120,7 @@ export const api = {
     get: (id: string) => request<Session>(`/api/sessions/${id}`),
     update: (
       id: string,
-      body: Partial<Pick<Session, 'name' | 'model' | 'system_prompt' | 'agent_id'>>
+      body: Partial<Pick<Session, 'name' | 'model' | 'system_prompt' | 'agent_id' | 'web_search_enabled'>>
     ) =>
       request<Session>(`/api/sessions/${id}`, {
         method: 'PATCH',
@@ -118,6 +132,15 @@ export const api = {
       request<void>(`/api/sessions/${id}/archive`, { method: 'POST' }),
     unarchive: (id: string) =>
       request<Session>(`/api/sessions/${id}/unarchive`, { method: 'POST' }),
+    // v1.9: bulk-archive every open chat in this session. Same pattern as
+    // archiveAllSessions — server publishes one chat_archived per id.
+    archiveAllChats: (id: string) =>
+      request<{ archived: number; ids: string[] }>(
+        `/api/sessions/${id}/chats/archive-all`,
+        { method: 'POST' },
+      ),
+    openChatsCount: (id: string) =>
+      request<{ count: number }>(`/api/sessions/${id}/chats/open-count`),
   },
 
   chats: {

apps/web/src/api/types.ts

@@ -9,6 +9,10 @@ export interface Project {
   last_session_id: string | null;
   status: ProjectStatus;
   gitea_remote: string | null;
+  // v1.9: per-project defaults. Empty string on default_system_prompt means
+  // "no override" — inference falls through to the base system prompt.
+  default_system_prompt: string;
+  default_web_search_enabled: boolean;
 }
 
 export interface AvailableProject {
@@ -28,6 +32,8 @@ export interface Session {
   created_at: string;
   updated_at: string;
   agent_id: string | null;
+  // v1.9: null = inherit from project.default_web_search_enabled.
+  web_search_enabled: boolean | null;
 }
 
 // v1.8.1: 'global' = /data/AGENTS.md (always-on), 'project' = per-project
@@ -225,7 +231,10 @@ export interface GitMeta {
   behind: number;
 }
 
-export type WorkspacePaneKind = 'chat' | 'terminal' | 'agent' | 'empty';
+// v1.9: 'settings' is an ephemeral pane kind — never persisted, always
+// singleton per workspace. The pane hook filters it out before writing to
+// localStorage and dedupes on insertion via openOrFocusSettingsPane().
+export type WorkspacePaneKind = 'chat' | 'terminal' | 'agent' | 'empty' | 'settings';
 
 export interface WorkspacePane {
   id: string;

apps/web/src/components/ChatInput.tsx

@@ -1,8 +1,14 @@
 import { useCallback, useEffect, useRef, useState, type DragEvent, type KeyboardEvent } from 'react';
-import { Send } from 'lucide-react';
+import { Check, Plus, Send } from 'lucide-react';
 import { toast } from 'sonner';
 import { Textarea } from '@/components/ui/textarea';
 import { Button } from '@/components/ui/button';
+import {
+  DropdownMenu,
+  DropdownMenuContent,
+  DropdownMenuItem,
+  DropdownMenuTrigger,
+} from '@/components/ui/dropdown-menu';
 import {
   flattenToMessage,
   inferLanguage,
@@ -29,11 +35,18 @@ interface Props {
   // When omitted, the toolbar row is hidden entirely.
   agentId?: string | null;
   onAgentChange?: (agentId: string | null) => void | Promise<void>;
+  // v1.9: when sessionId + webSearchEnabled are both provided, the + menu
+  // renders next to the AgentPicker with a single "Web search" toggle item.
+  // The check reflects the *stored* session value (not the effective one):
+  // null counts as unchecked. Clicking PATCHes session.web_search_enabled
+  // with the inverted boolean (null → true, true → false, false → true).
+  sessionId?: string;
+  webSearchEnabled?: boolean | null;
   onSend: (content: string) => void | Promise<void>;
   onForceSend?: (content: string) => void | Promise<void>;
 }
 
-export function ChatInput({ disabled, projectId, agentId, onAgentChange, onSend, onForceSend }: Props) {
+export function ChatInput({ disabled, projectId, agentId, onAgentChange, sessionId, webSearchEnabled, onSend, onForceSend }: Props) {
   const { isMobile } = useViewport();
   const [value, setValue] = useState('');
   const [busy, setBusy] = useState(false);
@@ -425,16 +438,51 @@ export function ChatInput({ disabled, projectId, agentId, onAgentChange, onSend,
           ))}
         </div>
       )}
-      {/* Batch 9 toolbar — agent picker. Sits above the input row so it
-          doesn't compete with the send button for vertical alignment.
-          When Batch 7 lands, ModelPicker and the + button join this row. */}
-      {onAgentChange && (
+      {/* Batch 9 toolbar — agent picker. v1.9 adds the icon-only + menu next
+          to it for quick toggles (currently: Web search). When omitted at the
+          callsite the row stays collapsed so nothing else has to change. */}
+      {(onAgentChange || sessionId) && (
         <div className="px-4 pt-2 flex items-center gap-1.5">
-          <AgentPicker
-            projectId={projectId}
-            value={agentId ?? null}
-            onChange={onAgentChange}
-          />
+          {onAgentChange && (
+            <AgentPicker
+              projectId={projectId}
+              value={agentId ?? null}
+              onChange={onAgentChange}
+            />
+          )}
+          {sessionId && (
+            <DropdownMenu>
+              <DropdownMenuTrigger asChild>
+                <button
+                  type="button"
+                  aria-label="Quick toggles"
+                  title="Quick toggles"
+                  className="inline-flex items-center justify-center size-6 rounded text-muted-foreground hover:bg-muted hover:text-foreground"
+                >
+                  <Plus className="size-3.5" />
+                </button>
+              </DropdownMenuTrigger>
+              <DropdownMenuContent align="start">
+                <DropdownMenuItem
+                  onSelect={async () => {
+                    // v1.9: tri-state collapses to two on the wire when toggled
+                    // here. null (inherit) treated as off; click flips to true.
+                    // To restore "inherit" the user opens SettingsPane.
+                    const next = webSearchEnabled === true ? false : true;
+                    try {
+                      await api.sessions.update(sessionId, { web_search_enabled: next });
+                    } catch (err) {
+                      toast.error(err instanceof Error ? err.message : 'failed to toggle web search');
+                    }
+                  }}
+                  className="text-xs"
+                >
+                  <Check className={`size-3 ${webSearchEnabled === true ? 'opacity-100' : 'opacity-0'}`} />
+                  Web search
+                </DropdownMenuItem>
+              </DropdownMenuContent>
+            </DropdownMenu>
+          )}
         </div>
       )}
       <div className="px-4 py-3 flex items-end gap-2">

apps/web/src/components/MobileTabSwitcher.tsx

@@ -5,6 +5,7 @@ import {
   Edit2,
   MessageSquare,
   MoreHorizontal,
+  Settings as SettingsIcon,
   Terminal,
   X,
 } from 'lucide-react';
@@ -33,6 +34,7 @@ interface Props {
 function paneIcon(kind: WorkspacePane['kind']) {
   if (kind === 'terminal') return <Terminal size={14} />;
   if (kind === 'agent') return <Bot size={14} />;
+  if (kind === 'settings') return <SettingsIcon size={14} />;
   return <MessageSquare size={14} />;
 }
 
@@ -53,6 +55,7 @@ function paneLabel(pane: WorkspacePane, chats: Chat[]): string {
   if (pane.kind === 'chat') return 'Chat';
   if (pane.kind === 'terminal') return 'Terminal';
   if (pane.kind === 'agent') return 'Agent';
+  if (pane.kind === 'settings') return 'Settings';
   return 'Empty';
 }
 

apps/web/src/components/ModelPicker.tsx

@@ -1,5 +1,5 @@
 import { useEffect, useState } from 'react';
-import { Check, ChevronDown } from 'lucide-react';
+import { Check, ChevronDown, Cpu } from 'lucide-react';
 import { api } from '@/api/client';
 import type { ModelInfo } from '@/api/types';
 import {
@@ -8,26 +8,94 @@ import {
   DropdownMenuItem,
   DropdownMenuTrigger,
 } from '@/components/ui/dropdown-menu';
+import { BottomSheet } from '@/components/BottomSheet';
+import { useViewport } from '@/hooks/useViewport';
 
 interface Props {
   value: string;
   onChange: (model: string) => void | Promise<void>;
 }
 
+// v1.9: shared list rendered inside both shells. Lazy-fetches /api/models on
+// first open so the picker doesn't pay for a request when it's never shown.
+function ModelList({
+  models,
+  error,
+  value,
+  onPick,
+}: {
+  models: ModelInfo[] | null;
+  error: string | null;
+  value: string;
+  onPick: (id: string) => void;
+}) {
+  if (error) {
+    return <div className="px-2 py-1.5 text-xs text-destructive">{error}</div>;
+  }
+  if (models === null) {
+    return <div className="px-2 py-1.5 text-xs text-muted-foreground">Loading…</div>;
+  }
+  return (
+    <>
+      {models.map((m) => (
+        <button
+          key={m.id}
+          type="button"
+          onClick={() => onPick(m.id)}
+          className="w-full text-left flex items-center gap-2 font-mono text-xs px-2 py-1.5 hover:bg-accent rounded"
+        >
+          <Check className={`size-3 ${m.id === value ? 'opacity-100' : 'opacity-0'}`} />
+          <span className="truncate">{m.id}</span>
+        </button>
+      ))}
+    </>
+  );
+}
+
 export function ModelPicker({ value, onChange }: Props) {
+  const { isMobile } = useViewport();
   const [models, setModels] = useState<ModelInfo[] | null>(null);
   const [error, setError] = useState<string | null>(null);
   const [open, setOpen] = useState(false);
 
   useEffect(() => {
     if (!open || models !== null) return;
-    api.models()
+    api
+      .models()
       .then(setModels)
       .catch((err) =>
-        setError(err instanceof Error ? err.message : 'failed to load models')
+        setError(err instanceof Error ? err.message : 'failed to load models'),
       );
   }, [open, models]);
 
+  function handlePick(id: string) {
+    setOpen(false);
+    void onChange(id);
+  }
+
+  // v1.9: mobile = icon-only trigger + bottom-sheet shell. Desktop = labeled
+  // trigger (model name + chevron) + dropdown. Same ModelList under the hood.
+  if (isMobile) {
+    return (
+      <>
+        <button
+          type="button"
+          onClick={() => setOpen(true)}
+          aria-label={`Model: ${value}`}
+          title={value}
+          className="inline-flex items-center justify-center min-h-[44px] min-w-[44px] rounded text-muted-foreground hover:text-foreground"
+        >
+          <Cpu className="size-4" />
+        </button>
+        <BottomSheet open={open} onClose={() => setOpen(false)} title="Model">
+          <div className="px-2 py-2 space-y-1">
+            <ModelList models={models} error={error} value={value} onPick={handlePick} />
+          </div>
+        </BottomSheet>
+      </>
+    );
+  }
+
   return (
     <DropdownMenu open={open} onOpenChange={setOpen}>
       <DropdownMenuTrigger asChild>
@@ -49,7 +117,7 @@ export function ModelPicker({ value, onChange }: Props) {
         {models?.map((m) => (
           <DropdownMenuItem
             key={m.id}
-            onSelect={() => void onChange(m.id)}
+            onSelect={() => handlePick(m.id)}
             className="font-mono text-xs"
           >
             <Check

apps/web/src/components/ProjectSidebar.tsx

@@ -1,8 +1,9 @@
 import { useEffect, useMemo, useRef, useState } from 'react';
 import { NavLink, useLocation, useNavigate } from 'react-router-dom';
-import { ChevronRight, ExternalLink, Folder, MessageSquare, Plus } from 'lucide-react';
+import { ChevronRight, ExternalLink, Folder, MessageSquare, Plus, Settings as SettingsIcon } from 'lucide-react';
 import { toast } from 'sonner';
 import { Button } from '@/components/ui/button';
+import { sessionEvents } from '@/hooks/sessionEvents';
 import {
   ContextMenu,
   ContextMenuContent,
@@ -198,7 +199,7 @@ export function ProjectSidebar() {
   const rowCls = (active: boolean) =>
     active ? 'bg-sidebar-accent text-sidebar-accent-foreground' : 'hover:bg-sidebar-accent/60';
 
-  const { open: drawerOpen } = useSidebarDrawer();
+  const { open: drawerOpen, setOpen: setDrawerOpen } = useSidebarDrawer();
   const { isMobile } = useViewport();
   const pull = usePullToRefresh(() => retry(), { enabled: isMobile });
 
@@ -412,6 +413,30 @@ export function ProjectSidebar() {
           })}
       </nav>
 
+      {/* v1.9: bottom-pinned Settings button. In a session, opens/focuses the
+          workspace settings pane via the sessionEvents bus (Session.tsx owns
+          the panesHook). Outside a session there's no workspace to mount the
+          pane in, so we navigate to /settings (themes page) instead. */}
+      <div className="border-t shrink-0 p-2">
+        <button
+          type="button"
+          onClick={() => {
+            if (activeSession) {
+              sessionEvents.emit({ type: 'open_settings_pane' });
+              if (isMobile) setDrawerOpen(false);
+            } else {
+              navigate('/settings');
+              if (isMobile) setDrawerOpen(false);
+            }
+          }}
+          className="w-full flex items-center gap-2 px-2 py-1.5 rounded-md text-sm hover:bg-sidebar-accent/60 text-sidebar-foreground"
+          aria-label="Settings"
+        >
+          <SettingsIcon className="size-3.5 shrink-0 opacity-70" />
+          <span className="flex-1 text-left">Settings</span>
+        </button>
+      </div>
+
       <AddProjectModal open={addOpen} onOpenChange={setAddOpen} onAdded={() => {}} />
 
       <Dialog open={archiveProjectConfirm !== null} onOpenChange={(open) => { if (!open) setArchiveProjectConfirm(null); }}>

apps/web/src/components/ThemePicker.tsx

@@ -0,0 +1,122 @@
+import { useState } from 'react';
+import { Check } from 'lucide-react';
+import { toast } from 'sonner';
+import { Card } from '@/components/ui/card';
+import { Label } from '@/components/ui/label';
+import { RadioGroup, RadioGroupItem } from '@/components/ui/radio-group';
+import { THEMES, setTheme, useTheme, type ThemeId, type ThemeMode } from '@/lib/theme';
+import { cn } from '@/lib/utils';
+
+// v1.9: lifted out of pages/Settings.tsx so the SettingsPane Theme tab and
+// the standalone /settings route render the same picker. Theme is global —
+// not per-project, not per-session — so no contextual props are needed.
+
+const MODES: { value: ThemeMode; label: string; hint: string }[] = [
+  { value: 'dark', label: 'Dark', hint: 'Use the dark variant.' },
+  { value: 'light', label: 'Light', hint: 'Use the light variant.' },
+  { value: 'system', label: 'System', hint: 'Follow OS preference.' },
+];
+
+export function ThemePicker() {
+  const { id: currentId, mode: currentMode } = useTheme();
+  // Track the most recent in-flight pick so the picker can show a subtle
+  // "applying…" state on the targeted card while the PATCH is in flight.
+  const [pending, setPending] = useState<
+    { kind: 'theme'; id: ThemeId } | { kind: 'mode'; mode: ThemeMode } | null
+  >(null);
+
+  async function pickTheme(id: ThemeId) {
+    if (id === currentId || pending) return;
+    setPending({ kind: 'theme', id });
+    try {
+      await setTheme(id, currentMode);
+    } catch (err) {
+      toast.error(err instanceof Error ? err.message : 'failed to apply theme');
+    } finally {
+      setPending(null);
+    }
+  }
+
+  async function pickMode(mode: ThemeMode) {
+    if (mode === currentMode || pending) return;
+    setPending({ kind: 'mode', mode });
+    try {
+      await setTheme(currentId, mode);
+    } catch (err) {
+      toast.error(err instanceof Error ? err.message : 'failed to apply mode');
+    } finally {
+      setPending(null);
+    }
+  }
+
+  return (
+    <div className="space-y-8">
+      <section className="space-y-3">
+        <h2 className="text-sm font-medium">Mode</h2>
+        <RadioGroup
+          value={currentMode}
+          onValueChange={(v) => void pickMode(v as ThemeMode)}
+          className="flex flex-wrap gap-4"
+        >
+          {MODES.map((m) => (
+            <div key={m.value} className="flex items-center gap-2">
+              <RadioGroupItem id={`mode-${m.value}`} value={m.value} />
+              <Label htmlFor={`mode-${m.value}`} className="cursor-pointer">
+                <span className="font-medium">{m.label}</span>
+                <span className="ml-2 text-xs text-muted-foreground">{m.hint}</span>
+              </Label>
+            </div>
+          ))}
+        </RadioGroup>
+      </section>
+
+      <section className="space-y-3">
+        <h2 className="text-sm font-medium">Theme</h2>
+        <div className="grid grid-cols-2 md:grid-cols-3 gap-3">
+          {THEMES.map((t) => {
+            const isActive = t.id === currentId;
+            const isPending = pending?.kind === 'theme' && pending.id === t.id;
+            const isLightOnly = !t.supportsDark;
+            return (
+              <Card
+                key={t.id}
+                onClick={() => void pickTheme(t.id)}
+                className={cn(
+                  'p-3 cursor-pointer transition-colors',
+                  'hover:bg-accent/10',
+                  isActive && 'ring-2 ring-ring',
+                  isPending && 'opacity-60',
+                )}
+              >
+                <div className="flex items-center justify-between gap-2">
+                  <div className="min-w-0">
+                    <div className="font-mono text-sm truncate">{t.name}</div>
+                    <div className="text-xs text-muted-foreground">{t.family}</div>
+                  </div>
+                  {isActive && (
+                    <span className="inline-flex items-center gap-1 text-xs text-primary shrink-0">
+                      <Check className="size-3" /> Selected
+                    </span>
+                  )}
+                </div>
+                <div className="flex mt-2 rounded overflow-hidden border border-border/40">
+                  {t.anchors.map((hex, i) => (
+                    <div
+                      key={i}
+                      className="flex-1 h-6"
+                      style={{ backgroundColor: hex }}
+                      aria-hidden="true"
+                    />
+                  ))}
+                </div>
+                {isLightOnly && (
+                  <div className="mt-2 text-xs text-muted-foreground italic">Light only</div>
+                )}
+              </Card>
+            );
+          })}
+        </div>
+      </section>
+    </div>
+  );
+}

apps/web/src/components/Workspace.tsx

@@ -1,9 +1,11 @@
+import { useEffect, useState } from 'react';
 import { PanelRight, MessageSquare, Terminal, Bot } from 'lucide-react';
-import type { Chat, WorkspacePane } from '@/api/types';
+import type { Chat, Project, Session, WorkspacePane } from '@/api/types';
 import { MAX_PANES, type UseWorkspacePanesResult } from '@/hooks/useWorkspacePanes';
 import type { UseSessionChatsResult } from '@/hooks/useSessionChats';
 import { useViewport } from '@/hooks/useViewport';
 import { ChatPane } from '@/components/panes/ChatPane';
+import { SettingsPane } from '@/components/panes/SettingsPane';
 import { ChatTabBar } from '@/components/ChatTabBar';
 import { SessionLandingPage } from '@/components/SessionLandingPage';
 import {
@@ -24,6 +26,9 @@ interface Props {
   // (MobileTabSwitcher) can share state with the pane grid.
   panesHook: UseWorkspacePanesResult;
   chatsHook: UseSessionChatsResult;
+  // v1.9: passed through to SettingsPane when one is mounted in the grid.
+  session: Session;
+  project: Project | null;
 }
 
 export function Workspace({
@@ -33,6 +38,8 @@ export function Workspace({
   onAgentChange,
   panesHook,
   chatsHook,
+  session,
+  project,
 }: Props) {
   const {
     panes,
@@ -67,6 +74,28 @@ export function Workspace({
 
   const { isMobile } = useViewport();
 
+  // v1.9: workspace-level maximize state for the settings pane. CSS-only:
+  // sibling panes get display:none, the maximized pane fills the grid cell.
+  // ESC listener only mounted while maximized. Mobile is always full-width
+  // for a single pane so maximize doesn't apply.
+  const [maximized, setMaximized] = useState(false);
+  const settingsIdx = panes.findIndex((p) => p.kind === 'settings');
+
+  useEffect(() => {
+    if (!maximized) return;
+    function onKey(e: KeyboardEvent) {
+      if (e.key === 'Escape') setMaximized(false);
+    }
+    window.addEventListener('keydown', onKey);
+    return () => window.removeEventListener('keydown', onKey);
+  }, [maximized]);
+
+  // If the settings pane was closed (no longer in panes) while maximized,
+  // clear the maximize state so the grid renders normally.
+  useEffect(() => {
+    if (maximized && settingsIdx < 0) setMaximized(false);
+  }, [maximized, settingsIdx]);
+
   function chatsForPane(pane: WorkspacePane): Chat[] {
     return pane.chatIds
       .map((id) => chats.find((c) => c.id === id))
@@ -81,10 +110,12 @@ export function Workspace({
             <DropdownMenuTrigger asChild>
               <button
                 type="button"
-                disabled={panes.length >= MAX_PANES}
+                // v1.9: settings panes excluded from the MAX cap (decision c).
+                disabled={panes.filter((p) => p.kind !== 'settings').length >= MAX_PANES}
                 className={cn(
                   'flex items-center gap-1 text-xs px-2 py-1 rounded hover:bg-muted',
-                  panes.length >= MAX_PANES && 'opacity-40 cursor-not-allowed hover:bg-transparent'
+                  panes.filter((p) => p.kind !== 'settings').length >= MAX_PANES &&
+                    'opacity-40 cursor-not-allowed hover:bg-transparent'
                 )}
               >
                 <PanelRight size={14} />
@@ -114,12 +145,24 @@ export function Workspace({
         style={
           isMobile
             ? undefined
-            : { gridTemplateColumns: `repeat(${panes.length}, minmax(0, 1fr))` }
+            : maximized && settingsIdx >= 0
+              ? { gridTemplateColumns: 'minmax(0, 1fr)' }
+              : { gridTemplateColumns: `repeat(${panes.length}, minmax(0, 1fr))` }
         }
       >
         {panes.map((pane, idx) => {
-          const visible = !isMobile || idx === activePaneIdx;
-          if (!visible) return null;
+          const isSettings = pane.kind === 'settings';
+          // v1.9: when maximized, hide every pane except the settings one.
+          // display:none keeps the React tree mounted so streams / drafts
+          // survive the toggle without re-mount cost.
+          const hiddenForMaximize = !isMobile && maximized && idx !== settingsIdx;
+          const visible = (!isMobile || idx === activePaneIdx) && !hiddenForMaximize;
+          if (!visible) {
+            if (hiddenForMaximize) {
+              return <div key={pane.id} className="hidden" />;
+            }
+            return null;
+          }
           return (
           <div
             key={pane.id}
@@ -131,19 +174,19 @@ export function Workspace({
                 'before:absolute before:inset-y-0 before:left-0 before:w-0.5 before:bg-primary before:z-10'
             )}
             onClick={() => setActivePaneIdx(idx)}
-            onDragOver={!isMobile && panes.length > 1 ? handlePaneDragOver(idx) : undefined}
-            onDragLeave={!isMobile && panes.length > 1 ? handlePaneDragLeave : undefined}
-            onDrop={!isMobile && panes.length > 1 ? handlePaneDrop(idx) : undefined}
+            onDragOver={!isMobile && !isSettings && panes.length > 1 ? handlePaneDragOver(idx) : undefined}
+            onDragLeave={!isMobile && !isSettings && panes.length > 1 ? handlePaneDragLeave : undefined}
+            onDrop={!isMobile && !isSettings && panes.length > 1 ? handlePaneDrop(idx) : undefined}
           >
             <div
-              draggable={!isMobile && panes.length > 1}
-              onDragStart={!isMobile && panes.length > 1 ? handlePaneDragStart(idx) : undefined}
-              onDragEnd={!isMobile && panes.length > 1 ? handlePaneDragEnd : undefined}
+              draggable={!isMobile && !isSettings && panes.length > 1}
+              onDragStart={!isMobile && !isSettings && panes.length > 1 ? handlePaneDragStart(idx) : undefined}
+              onDragEnd={!isMobile && !isSettings && panes.length > 1 ? handlePaneDragEnd : undefined}
             >
-              {/* Hidden on mobile per v1.8: chat-within-pane navigation
-                  is not exposed on small screens; users switch panes via
-                  the header pill instead. */}
-              {!isMobile && (
+              {/* Hidden on mobile per v1.8; settings panes own their own
+                  section nav / maximize toggle so they skip ChatTabBar
+                  entirely. */}
+              {!isMobile && !isSettings && (
                 <ChatTabBar
                   pane={pane}
                   tabs={chatsForPane(pane)}
@@ -161,7 +204,15 @@ export function Workspace({
             </div>
 
             <div className="flex-1 min-h-0 overflow-hidden">
-              {pane.kind === 'chat' && pane.chatId ? (
+              {isSettings && project ? (
+                <SettingsPane
+                  session={session}
+                  project={project}
+                  maximized={maximized}
+                  onToggleMaximize={() => setMaximized((v) => !v)}
+                  isMobile={isMobile}
+                />
+              ) : pane.kind === 'chat' && pane.chatId ? (
                 <ChatPane
                   sessionId={sessionId}
                   chatId={pane.chatId}
@@ -169,6 +220,7 @@ export function Workspace({
                   agentId={agentId}
                   onAgentChange={onAgentChange}
                   sessionChats={chats}
+                  webSearchEnabled={session.web_search_enabled}
                 />
               ) : (
                 <SessionLandingPage

apps/web/src/components/panes/ChatPane.tsx

@@ -22,9 +22,13 @@ interface Props {
   agentId?: string | null;
   onAgentChange?: (agentId: string | null) => void | Promise<void>;
   sessionChats?: import('@/api/types').Chat[];
+  // v1.9: threaded down to ChatInput's + menu (Web search quick toggle).
+  // null means "inherit project default" — ChatInput PATCHes with the
+  // opposite of the effective value.
+  webSearchEnabled?: boolean | null;
 }
 
-export function ChatPane({ sessionId, chatId, projectId, agentId, onAgentChange, sessionChats }: Props) {
+export function ChatPane({ sessionId, chatId, projectId, agentId, onAgentChange, sessionChats, webSearchEnabled }: Props) {
   const stream = useSessionStream(sessionId);
   const lastErrorRef = useRef<string | null>(null);
   const [queue, setQueue] = useState<string[]>([]);
@@ -173,8 +177,10 @@ export function ChatPane({ sessionId, chatId, projectId, agentId, onAgentChange,
         <ChatInput
           disabled={false}
           projectId={projectId}
+          sessionId={sessionId}
           agentId={agentId}
           onAgentChange={onAgentChange}
+          webSearchEnabled={webSearchEnabled}
           onSend={handleSend}
           onForceSend={streaming ? handleForceSend : undefined}
         />

apps/web/src/components/panes/SettingsPane.tsx

@@ -0,0 +1,520 @@
+import { useEffect, useState } from 'react';
+import { Archive, Maximize2, Minimize2 } from 'lucide-react';
+import { toast } from 'sonner';
+import { api } from '@/api/client';
+import type { Project, Session } from '@/api/types';
+import { Button } from '@/components/ui/button';
+import { Textarea } from '@/components/ui/textarea';
+import {
+  Dialog,
+  DialogContent,
+  DialogDescription,
+  DialogFooter,
+  DialogHeader,
+  DialogTitle,
+} from '@/components/ui/dialog';
+import { ModelPicker } from '@/components/ModelPicker';
+import { ThemePicker } from '@/components/ThemePicker';
+import { cn } from '@/lib/utils';
+
+type Section = 'session' | 'project' | 'theme';
+
+interface Props {
+  session: Session;
+  project: Project;
+  maximized: boolean;
+  onToggleMaximize: () => void;
+  isMobile: boolean;
+}
+
+// v1.9: hand-rolled Switch primitive. No shadcn switch in the existing
+// ui/ set and the dispatch said don't pnpm dlx for v1.9 either. Single
+// purpose — clicking flips aria-checked + calls onCheckedChange.
+function Switch({
+  checked,
+  onCheckedChange,
+  disabled,
+  id,
+}: {
+  checked: boolean;
+  onCheckedChange: (v: boolean) => void;
+  disabled?: boolean;
+  id?: string;
+}) {
+  return (
+    <button
+      id={id}
+      type="button"
+      role="switch"
+      aria-checked={checked}
+      disabled={disabled}
+      onClick={() => onCheckedChange(!checked)}
+      className={cn(
+        'relative inline-flex h-5 w-9 shrink-0 cursor-pointer items-center rounded-full transition-colors',
+        checked ? 'bg-primary' : 'bg-muted',
+        disabled && 'opacity-50 cursor-not-allowed',
+      )}
+    >
+      <span
+        className={cn(
+          'inline-block h-4 w-4 transform rounded-full bg-background transition-transform',
+          checked ? 'translate-x-[1.125rem]' : 'translate-x-0.5',
+        )}
+      />
+    </button>
+  );
+}
+
+export function SettingsPane({ session, project, maximized, onToggleMaximize, isMobile }: Props) {
+  const [activeSection, setActiveSection] = useState<Section>('session');
+
+  return (
+    <div className="flex flex-col h-full min-h-0">
+      <div className="flex items-center gap-2 border-b border-border bg-muted/20 px-3 py-1.5 shrink-0">
+        <div className="flex items-center gap-1 flex-1 min-w-0">
+          {(['session', 'project', 'theme'] as const).map((s) => (
+            <button
+              key={s}
+              type="button"
+              onClick={() => setActiveSection(s)}
+              className={cn(
+                'text-xs px-2 py-1 rounded capitalize',
+                activeSection === s
+                  ? 'bg-background text-foreground'
+                  : 'text-muted-foreground hover:bg-muted',
+              )}
+            >
+              {s}
+            </button>
+          ))}
+        </div>
+        {!isMobile && (
+          <button
+            type="button"
+            onClick={onToggleMaximize}
+            className="inline-flex items-center justify-center p-1 rounded text-muted-foreground hover:bg-muted hover:text-foreground"
+            aria-label={maximized ? 'Restore' : 'Maximize'}
+            title={maximized ? 'Restore (Esc)' : 'Maximize'}
+          >
+            {maximized ? <Minimize2 size={14} /> : <Maximize2 size={14} />}
+          </button>
+        )}
+      </div>
+
+      <div className="flex-1 overflow-y-auto">
+        <div className="max-w-[720px] mx-auto w-full px-4 py-4 space-y-6">
+          {activeSection === 'session' && <SessionSection session={session} project={project} />}
+          {activeSection === 'project' && <ProjectSection project={project} />}
+          {activeSection === 'theme' && <ThemePicker />}
+        </div>
+      </div>
+    </div>
+  );
+}
+
+function SessionSection({ session, project }: { session: Session; project: Project }) {
+  const [name, setName] = useState(session.name);
+  const [systemPrompt, setSystemPrompt] = useState(session.system_prompt);
+  // v1.9: tri-state on the wire (null = inherit). UI surfaces a 3-way toggle
+  // via "Inherit project default" checkbox plus the override switch.
+  const [webSearch, setWebSearch] = useState<boolean | null>(session.web_search_enabled);
+  const [saving, setSaving] = useState(false);
+  // v1.9: bulk-archive chats. Two-step: openChatsCount → confirm dialog →
+  // archiveAllChats. Server publishes one chat_archived frame per id so
+  // useSidebar / chat lists update incrementally.
+  const [archiveOpen, setArchiveOpen] = useState(false);
+  const [archiveCount, setArchiveCount] = useState(0);
+  const [archiving, setArchiving] = useState(false);
+
+  useEffect(() => {
+    setName(session.name);
+    setSystemPrompt(session.system_prompt);
+    setWebSearch(session.web_search_enabled);
+  }, [session.id, session.name, session.system_prompt, session.web_search_enabled]);
+
+  const dirty =
+    name !== session.name ||
+    systemPrompt !== session.system_prompt ||
+    webSearch !== session.web_search_enabled;
+
+  const effectiveWebSearch = webSearch ?? project.default_web_search_enabled;
+  const projectPreview = project.default_system_prompt.trim().slice(0, 200);
+
+  async function save() {
+    if (saving) return;
+    setSaving(true);
+    try {
+      await api.sessions.update(session.id, {
+        name: name.trim() || session.name,
+        system_prompt: systemPrompt,
+        web_search_enabled: webSearch,
+      });
+      toast.success('Session saved');
+    } catch (err) {
+      toast.error(err instanceof Error ? err.message : 'save failed');
+    } finally {
+      setSaving(false);
+    }
+  }
+
+  async function resetSystemPrompt() {
+    if (saving) return;
+    setSaving(true);
+    try {
+      await api.sessions.update(session.id, { system_prompt: '' });
+      toast.success('Reset to project default');
+    } catch (err) {
+      toast.error(err instanceof Error ? err.message : 'reset failed');
+    } finally {
+      setSaving(false);
+    }
+  }
+
+  async function openArchiveDialog() {
+    if (archiving) return;
+    try {
+      const { count } = await api.sessions.openChatsCount(session.id);
+      if (count === 0) {
+        toast('No open chats to archive.');
+        return;
+      }
+      setArchiveCount(count);
+      setArchiveOpen(true);
+    } catch (err) {
+      toast.error(err instanceof Error ? err.message : 'failed to count chats');
+    }
+  }
+
+  async function confirmArchive() {
+    if (archiving) return;
+    setArchiving(true);
+    try {
+      const { archived } = await api.sessions.archiveAllChats(session.id);
+      toast.success(`Archived ${archived} chat${archived === 1 ? '' : 's'}`);
+      setArchiveOpen(false);
+    } catch (err) {
+      toast.error(err instanceof Error ? err.message : 'archive failed');
+    } finally {
+      setArchiving(false);
+    }
+  }
+
+  return (
+    <div className="space-y-6">
+      <div className="space-y-1.5">
+        <label className="text-xs font-medium uppercase tracking-wide text-muted-foreground">
+          Session name
+        </label>
+        <input
+          type="text"
+          value={name}
+          onChange={(e) => setName(e.target.value)}
+          className="w-full bg-background border border-border rounded px-2 py-1.5 text-sm outline-none focus:border-ring"
+        />
+      </div>
+
+      <div className="space-y-1.5">
+        <label className="text-xs font-medium uppercase tracking-wide text-muted-foreground">
+          Model
+        </label>
+        <div className="inline-flex items-center rounded-full bg-muted/40 hover:bg-muted/70 px-1">
+          <ModelPicker
+            value={session.model}
+            onChange={async (model) => {
+              try {
+                await api.sessions.update(session.id, { model });
+                toast.success('Model updated');
+              } catch (err) {
+                toast.error(err instanceof Error ? err.message : 'failed to set model');
+              }
+            }}
+          />
+        </div>
+      </div>
+
+      <div className="space-y-1.5">
+        <div className="flex items-center justify-between gap-3">
+          <label htmlFor="session-web-search" className="text-xs font-medium uppercase tracking-wide text-muted-foreground">
+            Web search
+          </label>
+          <Switch
+            id="session-web-search"
+            checked={effectiveWebSearch}
+            onCheckedChange={(v) => setWebSearch(v)}
+          />
+        </div>
+        <div className="flex items-center gap-2 text-xs text-muted-foreground">
+          <input
+            type="checkbox"
+            id="session-web-search-inherit"
+            checked={webSearch === null}
+            onChange={(e) => setWebSearch(e.target.checked ? null : project.default_web_search_enabled)}
+          />
+          <label htmlFor="session-web-search-inherit" className="cursor-pointer">
+            Inherit project default ({project.default_web_search_enabled ? 'on' : 'off'})
+          </label>
+        </div>
+        <p className="text-xs text-muted-foreground italic">
+          Plumbed for Batch 8 (web_search tool). No effect yet.
+        </p>
+      </div>
+
+      <div className="space-y-1.5">
+        <div className="flex items-center justify-between gap-3">
+          <label className="text-xs font-medium uppercase tracking-wide text-muted-foreground">
+            System prompt
+          </label>
+          <button
+            type="button"
+            onClick={() => void resetSystemPrompt()}
+            disabled={saving || session.system_prompt === ''}
+            className="text-xs text-muted-foreground hover:text-foreground disabled:opacity-40 disabled:cursor-not-allowed"
+          >
+            Reset to project default
+          </button>
+        </div>
+        <Textarea
+          value={systemPrompt}
+          onChange={(e) => setSystemPrompt(e.target.value)}
+          rows={6}
+          className="resize-y min-h-[120px] max-h-[60vh]"
+          placeholder="Per-session override (optional). Empty = inherit project default."
+        />
+        {systemPrompt.trim().length === 0 && projectPreview.length > 0 && (
+          <p className="text-xs text-muted-foreground">
+            Falls back to project default: <span className="italic">{projectPreview}{projectPreview.length === 200 ? '…' : ''}</span>
+          </p>
+        )}
+      </div>
+
+      <div className="flex justify-end gap-2">
+        <Button onClick={() => void save()} disabled={!dirty || saving}>
+          {saving ? 'Saving…' : 'Save'}
+        </Button>
+      </div>
+
+      <div className="border-t pt-4">
+        <Button
+          variant="outline"
+          onClick={() => void openArchiveDialog()}
+          disabled={archiving}
+          className="gap-1.5"
+        >
+          <Archive size={14} /> Archive all chats
+        </Button>
+      </div>
+
+      <Dialog open={archiveOpen} onOpenChange={(open) => { if (!archiving) setArchiveOpen(open); }}>
+        <DialogContent>
+          <DialogHeader>
+            <DialogTitle>Archive all chats?</DialogTitle>
+            <DialogDescription>
+              Archive {archiveCount} open chat{archiveCount === 1 ? '' : 's'} in this session?
+              Archived chats stay accessible via the archive view.
+            </DialogDescription>
+          </DialogHeader>
+          <DialogFooter>
+            <Button variant="outline" onClick={() => setArchiveOpen(false)} disabled={archiving}>
+              Cancel
+            </Button>
+            <Button onClick={() => void confirmArchive()} disabled={archiving}>
+              {archiving ? 'Archiving…' : `Archive ${archiveCount}`}
+            </Button>
+          </DialogFooter>
+        </DialogContent>
+      </Dialog>
+    </div>
+  );
+}
+
+function ProjectSection({ project }: { project: Project }) {
+  const [name, setName] = useState(project.name);
+  const [defaultPrompt, setDefaultPrompt] = useState(project.default_system_prompt);
+  const [defaultWebSearch, setDefaultWebSearch] = useState(project.default_web_search_enabled);
+  const [saving, setSaving] = useState(false);
+  // v1.9: bulk-archive sessions. Same shape as the chats-archive flow in
+  // SessionSection — count, confirm, fire.
+  const [archiveOpen, setArchiveOpen] = useState(false);
+  const [archiveCount, setArchiveCount] = useState(0);
+  const [archiving, setArchiving] = useState(false);
+
+  useEffect(() => {
+    setName(project.name);
+    setDefaultPrompt(project.default_system_prompt);
+    setDefaultWebSearch(project.default_web_search_enabled);
+  }, [
+    project.id,
+    project.name,
+    project.default_system_prompt,
+    project.default_web_search_enabled,
+  ]);
+
+  const dirty =
+    name !== project.name ||
+    defaultPrompt !== project.default_system_prompt ||
+    defaultWebSearch !== project.default_web_search_enabled;
+
+  async function save() {
+    if (saving) return;
+    setSaving(true);
+    try {
+      await api.projects.update(project.id, {
+        name: name.trim() || project.name,
+        default_system_prompt: defaultPrompt,
+        default_web_search_enabled: defaultWebSearch,
+      });
+      toast.success('Project saved');
+    } catch (err) {
+      toast.error(err instanceof Error ? err.message : 'save failed');
+    } finally {
+      setSaving(false);
+    }
+  }
+
+  async function clearDefaultPrompt() {
+    if (saving) return;
+    setSaving(true);
+    try {
+      await api.projects.update(project.id, { default_system_prompt: '' });
+      toast.success('Cleared');
+    } catch (err) {
+      toast.error(err instanceof Error ? err.message : 'clear failed');
+    } finally {
+      setSaving(false);
+    }
+  }
+
+  async function openArchiveDialog() {
+    if (archiving) return;
+    try {
+      const { count } = await api.projects.openSessionsCount(project.id);
+      if (count === 0) {
+        toast('No open sessions to archive.');
+        return;
+      }
+      setArchiveCount(count);
+      setArchiveOpen(true);
+    } catch (err) {
+      toast.error(err instanceof Error ? err.message : 'failed to count sessions');
+    }
+  }
+
+  async function confirmArchive() {
+    if (archiving) return;
+    setArchiving(true);
+    try {
+      const { archived } = await api.projects.archiveAllSessions(project.id);
+      toast.success(`Archived ${archived} session${archived === 1 ? '' : 's'}`);
+      setArchiveOpen(false);
+    } catch (err) {
+      toast.error(err instanceof Error ? err.message : 'archive failed');
+    } finally {
+      setArchiving(false);
+    }
+  }
+
+  return (
+    <div className="space-y-6">
+      <div className="space-y-1.5">
+        <label className="text-xs font-medium uppercase tracking-wide text-muted-foreground">
+          Project name
+        </label>
+        <input
+          type="text"
+          value={name}
+          onChange={(e) => setName(e.target.value)}
+          className="w-full bg-background border border-border rounded px-2 py-1.5 text-sm outline-none focus:border-ring"
+        />
+      </div>
+
+      <div className="space-y-1.5">
+        <label className="text-xs font-medium uppercase tracking-wide text-muted-foreground">
+          Root path
+        </label>
+        <div className="font-mono text-xs text-muted-foreground bg-muted/40 rounded px-2 py-1.5 select-all">
+          {project.path}
+        </div>
+      </div>
+
+      <div className="space-y-1.5">
+        <div className="flex items-center justify-between gap-3">
+          <label htmlFor="project-default-web-search" className="text-xs font-medium uppercase tracking-wide text-muted-foreground">
+            Default web search
+          </label>
+          <Switch
+            id="project-default-web-search"
+            checked={defaultWebSearch}
+            onCheckedChange={setDefaultWebSearch}
+          />
+        </div>
+        <p className="text-xs text-muted-foreground italic">
+          Applies to new sessions only. Plumbed for Batch 8.
+        </p>
+      </div>
+
+      <div className="space-y-1.5">
+        <div className="flex items-center justify-between gap-3">
+          <label className="text-xs font-medium uppercase tracking-wide text-muted-foreground">
+            Default system prompt
+          </label>
+          <button
+            type="button"
+            onClick={() => void clearDefaultPrompt()}
+            disabled={saving || project.default_system_prompt === ''}
+            className="text-xs text-muted-foreground hover:text-foreground disabled:opacity-40 disabled:cursor-not-allowed"
+          >
+            Clear
+          </button>
+        </div>
+        <Textarea
+          value={defaultPrompt}
+          onChange={(e) => setDefaultPrompt(e.target.value)}
+          rows={6}
+          className="resize-y min-h-[120px] max-h-[60vh]"
+          placeholder="Prepended to every new session's system prompt (when its own is empty). Empty = no project default."
+        />
+      </div>
+
+      <p className="text-xs text-muted-foreground">
+        Existing sessions are not affected by changes here.
+      </p>
+
+      <div className="flex justify-end gap-2">
+        <Button onClick={() => void save()} disabled={!dirty || saving}>
+          {saving ? 'Saving…' : 'Save'}
+        </Button>
+      </div>
+
+      <div className="border-t pt-4">
+        <Button
+          variant="outline"
+          onClick={() => void openArchiveDialog()}
+          disabled={archiving}
+          className="gap-1.5"
+        >
+          <Archive size={14} /> Archive all sessions
+        </Button>
+      </div>
+
+      <Dialog open={archiveOpen} onOpenChange={(open) => { if (!archiving) setArchiveOpen(open); }}>
+        <DialogContent>
+          <DialogHeader>
+            <DialogTitle>Archive all sessions?</DialogTitle>
+            <DialogDescription>
+              Archive {archiveCount} open session{archiveCount === 1 ? '' : 's'} in this project?
+              Archived sessions stay accessible via the archive view.
+            </DialogDescription>
+          </DialogHeader>
+          <DialogFooter>
+            <Button variant="outline" onClick={() => setArchiveOpen(false)} disabled={archiving}>
+              Cancel
+            </Button>
+            <Button onClick={() => void confirmArchive()} disabled={archiving}>
+              {archiving ? 'Archiving…' : `Archive ${archiveCount}`}
+            </Button>
+          </DialogFooter>
+        </DialogContent>
+      </Dialog>
+    </div>
+  );
+}

apps/web/src/hooks/sessionEvents.ts

@@ -62,6 +62,14 @@ export interface OpenChatInActivePaneEvent {
   chat_id: string;
 }
 
+// v1.9: client-side event fired by the sidebar Settings button when a
+// session is currently mounted. Session.tsx subscribes and calls
+// panesHook.openOrFocusSettingsPane(). Sidebar handles the no-session case
+// by navigating to /settings (themes page) directly.
+export interface OpenSettingsPaneEvent {
+  type: 'open_settings_pane';
+}
+
 export interface SessionArchivedEvent {
   type: 'session_archived';
   session_id: string;
@@ -139,6 +147,7 @@ export type SessionEvent =
   | OpenFileInBrowserEvent
   | AttachChatFileEvent
   | OpenChatInActivePaneEvent
+  | OpenSettingsPaneEvent
   | SessionArchivedEvent
   | ChatCreatedEvent
   | ChatUpdatedEvent

apps/web/src/hooks/useSidebar.ts

@@ -151,6 +151,10 @@ function applyEvent(prev: SidebarResponse, event: import('./sessionEvents').Sess
     case 'open_chat_in_active_pane':
       // Consumed by Workspace; sidebar has no business with pane state.
       return prev;
+    case 'open_settings_pane':
+      // v1.9: consumed by Session.tsx (calls openOrFocusSettingsPane on its
+      // panesHook). Sidebar data is untouched.
+      return prev;
     case 'session_archived': {
       let changed = false;
       const projects = prev.projects.map((p) => {

apps/web/src/hooks/useWorkspacePanes.ts

@@ -19,6 +19,26 @@ function chatPane(chatId: string): WorkspacePane {
   return { id: generateId(), kind: 'chat', chatId, chatIds: [chatId], activeChatIdx: 0 };
 }
 
+// v1.9: settings pane factory. No chats, no state beyond identity — the
+// SettingsPane component renders Session/Project sections from the
+// surrounding session/project.
+function settingsPane(): WorkspacePane {
+  return { id: generateId(), kind: 'settings', chatIds: [], activeChatIdx: -1 };
+}
+
+// v1.9: settings panes are ephemeral. Filter them out before persisting so a
+// page reload always returns to a clean workspace; the user re-opens via the
+// sidebar Settings button when needed.
+function persistablePanes(panes: WorkspacePane[]): WorkspacePane[] {
+  return panes.filter((p) => p.kind !== 'settings');
+}
+
+// v1.9: per recon decision (c), settings panes don't count toward MAX_PANES.
+// Helper used at every pane-insertion site so the rule lives in one place.
+function nonSettingsCount(panes: WorkspacePane[]): number {
+  return panes.reduce((n, p) => n + (p.kind === 'settings' ? 0 : 1), 0);
+}
+
 function loadPanes(sessionId: string): WorkspacePane[] | null {
   try {
     const raw = localStorage.getItem(`${STORAGE_KEY}.${sessionId}`);
@@ -33,7 +53,10 @@ function loadPanes(sessionId: string): WorkspacePane[] | null {
 
 function savePanes(sessionId: string, panes: WorkspacePane[]): void {
   try {
-    localStorage.setItem(`${STORAGE_KEY}.${sessionId}`, JSON.stringify(panes));
+    localStorage.setItem(
+      `${STORAGE_KEY}.${sessionId}`,
+      JSON.stringify(persistablePanes(panes)),
+    );
   } catch { /* quota or disabled */ }
 }
 
@@ -50,6 +73,10 @@ export interface UseWorkspacePanesResult {
   closeAllTabs: (paneIdx: number) => void;
   showLandingPage: (paneIdx: number) => void;
   addSplitPane: (kind: 'chat' | 'terminal' | 'agent') => void;
+  // v1.9: idempotent open-or-focus for the settings pane singleton. Appends
+  // a new settings pane if none exists, otherwise just focuses the existing
+  // one. Always succeeds — settings panes don't count toward MAX_PANES.
+  openOrFocusSettingsPane: () => void;
   removePane: (idx: number) => void;
   removeChatFromPanes: (chatId: string) => void;
   initializeFirstChatIfEmpty: (chatId: string) => void;
@@ -216,7 +243,8 @@ export function useWorkspacePanes(sessionId: string): UseWorkspacePanesResult {
       return;
     }
     setPanes((prev) => {
-      if (prev.length >= MAX_PANES) {
+      // v1.9: settings panes are excluded from the MAX cap (decision c).
+      if (nonSettingsCount(prev) >= MAX_PANES) {
         toast.error(`Maximum ${MAX_PANES} panes`);
         return prev;
       }
@@ -226,6 +254,19 @@ export function useWorkspacePanes(sessionId: string): UseWorkspacePanesResult {
     });
   }, []);
 
+  const openOrFocusSettingsPane = useCallback(() => {
+    setPanes((prev) => {
+      const existingIdx = prev.findIndex((p) => p.kind === 'settings');
+      if (existingIdx >= 0) {
+        setActivePaneIdx(existingIdx);
+        return prev;
+      }
+      const next = [...prev, settingsPane()];
+      setActivePaneIdx(next.length - 1);
+      return next;
+    });
+  }, []);
+
   const removePane = useCallback((idx: number) => {
     setPanes((prev) => {
       if (prev.length <= 1) return prev;
@@ -318,6 +359,7 @@ export function useWorkspacePanes(sessionId: string): UseWorkspacePanesResult {
     setActivePaneIdx,
     activePaneIdxRef,
     openChatInPane,
+    openOrFocusSettingsPane,
     switchTab,
     removeTab,
     closeOtherTabs,

apps/web/src/pages/Home.tsx

@@ -47,6 +47,11 @@ export function Home() {
               last_session_id: null,
               status: 'archived' as const,
               gitea_remote: fromSidebar.gitea_remote,
+              // v1.9: synthesized stub for an archived project that only the
+              // sidebar cache has — defaults match the schema NOT NULL DEFAULT
+              // values. The full row gets re-fetched on unarchive.
+              default_system_prompt: '',
+              default_web_search_enabled: false,
             },
             ...prev,
           ];

apps/web/src/pages/Session.tsx

@@ -116,9 +116,32 @@ function SessionInner({ sessionId }: { sessionId: string }) {
         event.session_id === sessionId
       ) {
         navigate(`/project/${event.project_id}`);
+        return;
+      }
+      // v1.9: any session_updated for this session triggers a full refetch so
+      // SettingsPane (mounted in a workspace pane) picks up system_prompt /
+      // web_search_enabled / model edits made from another tab.
+      if (event.type === 'session_updated' && event.session_id === sessionId) {
+        void api.sessions.get(sessionId).then((s) => {
+          setSession(s);
+          setName((prev) => (editingName ? prev : s.name));
+        }).catch(() => {});
+        return;
+      }
+      // v1.9: project_updated → refetch project so the Project section in
+      // SettingsPane reflects the new defaults.
+      if (event.type === 'project_updated' && project && event.project_id === project.id) {
+        void api.projects.get(project.id).then(setProject).catch(() => {});
+        return;
+      }
+      // v1.9: sidebar Settings button broadcasts this when a session is
+      // mounted; we own the workspace pane state, so we open/focus the
+      // singleton settings pane here.
+      if (event.type === 'open_settings_pane') {
+        panesHook.openOrFocusSettingsPane();
       }
     });
-  }, [sessionId, editingName, navigate]);
+  }, [sessionId, editingName, navigate, project, panesHook]);
 
   // v1.8: URL ?pane= sync (mobile only). Lifted from Workspace.tsx so
   // MobileTabSwitcher's onSwitchPane can push the same URL state and the
@@ -211,15 +234,13 @@ function SessionInner({ sessionId }: { sessionId: string }) {
               </div>
 
               {session && (
-                <div className="inline-flex items-center rounded-full bg-muted/40 hover:bg-muted/70 px-1 shrink-0">
-                  <ModelPicker
-                    value={session.model}
-                    onChange={async (model) => {
-                      const updated = await api.sessions.update(session.id, { model });
-                      setSession(updated);
-                    }}
-                  />
-                </div>
+                <ModelPicker
+                  value={session.model}
+                  onChange={async (model) => {
+                    const updated = await api.sessions.update(session.id, { model });
+                    setSession(updated);
+                  }}
+                />
               )}
 
               <button
@@ -337,6 +358,8 @@ function SessionInner({ sessionId }: { sessionId: string }) {
           }}
           panesHook={panesHook}
           chatsHook={chatsHook}
+          session={session}
+          project={project}
         />
       )}
     </div>

apps/web/src/pages/Settings.tsx

@@ -1,124 +1,46 @@
-import { useState } from 'react';
-import { Check } from 'lucide-react';
-import { toast } from 'sonner';
-import { Card } from '@/components/ui/card';
-import { Label } from '@/components/ui/label';
-import { RadioGroup, RadioGroupItem } from '@/components/ui/radio-group';
-import { THEMES, setTheme, useTheme, type ThemeId, type ThemeMode } from '@/lib/theme';
-import { cn } from '@/lib/utils';
-
-const MODES: { value: ThemeMode; label: string; hint: string }[] = [
-  { value: 'dark', label: 'Dark', hint: 'Use the dark variant.' },
-  { value: 'light', label: 'Light', hint: 'Use the light variant.' },
-  { value: 'system', label: 'System', hint: 'Follow OS preference.' },
-];
+import { ArrowLeft } from 'lucide-react';
+import { useNavigate } from 'react-router-dom';
+import { ThemePicker } from '@/components/ThemePicker';
 
+// v1.9: thin wrapper around <ThemePicker />. The picker itself moved to a
+// reusable component (also rendered in the workspace SettingsPane Theme tab).
+// This page-level shell adds the back affordance + heading chrome that's
+// appropriate when the picker is the entire route.
 export function Settings() {
-  const { id: currentId, mode: currentMode } = useTheme();
-  // Track the most recent in-flight pick so the picker can show a subtle
-  // "applying…" state on the targeted card while the PATCH is in flight.
-  const [pending, setPending] = useState<{ kind: 'theme'; id: ThemeId } | { kind: 'mode'; mode: ThemeMode } | null>(null);
+  const navigate = useNavigate();
 
-  async function pickTheme(id: ThemeId) {
-    if (id === currentId || pending) return;
-    setPending({ kind: 'theme', id });
-    try {
-      await setTheme(id, currentMode);
-    } catch (err) {
-      toast.error(err instanceof Error ? err.message : 'failed to apply theme');
-    } finally {
-      setPending(null);
-    }
-  }
-
-  async function pickMode(mode: ThemeMode) {
-    if (mode === currentMode || pending) return;
-    setPending({ kind: 'mode', mode });
-    try {
-      await setTheme(currentId, mode);
-    } catch (err) {
-      toast.error(err instanceof Error ? err.message : 'failed to apply mode');
-    } finally {
-      setPending(null);
+  function handleBack() {
+    // History-aware: jump back to where the user came from when possible.
+    // Direct loads of /settings (no history) land on Home so the button
+    // always does *something* useful.
+    if (window.history.length > 1) {
+      navigate(-1);
+    } else {
+      navigate('/');
     }
   }
 
   return (
     <div className="flex-1 overflow-y-auto">
       <div className="max-w-[1000px] mx-auto w-full px-6 py-6 space-y-8">
-        <header>
-          <h1 className="text-xl font-semibold">Settings</h1>
-          <p className="text-sm text-muted-foreground mt-1">
-            Theme appearance. Saved on change, applies immediately.
-          </p>
-        </header>
-
-        <section className="space-y-3">
-          <h2 className="text-sm font-medium">Mode</h2>
-          <RadioGroup
-            value={currentMode}
-            onValueChange={(v) => void pickMode(v as ThemeMode)}
-            className="flex flex-wrap gap-4"
+        <header className="space-y-2">
+          <button
+            type="button"
+            onClick={handleBack}
+            className="inline-flex items-center gap-1 text-sm text-muted-foreground hover:text-foreground -ml-1 px-1 py-0.5 rounded"
+            aria-label="Back"
           >
-            {MODES.map((m) => (
-              <div key={m.value} className="flex items-center gap-2">
-                <RadioGroupItem id={`mode-${m.value}`} value={m.value} />
-                <Label htmlFor={`mode-${m.value}`} className="cursor-pointer">
-                  <span className="font-medium">{m.label}</span>
-                  <span className="ml-2 text-xs text-muted-foreground">{m.hint}</span>
-                </Label>
-              </div>
-            ))}
-          </RadioGroup>
-        </section>
-
-        <section className="space-y-3">
-          <h2 className="text-sm font-medium">Theme</h2>
-          <div className="grid grid-cols-2 md:grid-cols-3 gap-3">
-            {THEMES.map((t) => {
-              const isActive = t.id === currentId;
-              const isPending = pending?.kind === 'theme' && pending.id === t.id;
-              const isLightOnly = !t.supportsDark;
-              return (
-                <Card
-                  key={t.id}
-                  onClick={() => void pickTheme(t.id)}
-                  className={cn(
-                    'p-3 cursor-pointer transition-colors',
-                    'hover:bg-accent/10',
-                    isActive && 'ring-2 ring-ring',
-                    isPending && 'opacity-60',
-                  )}
-                >
-                  <div className="flex items-center justify-between gap-2">
-                    <div className="min-w-0">
-                      <div className="font-mono text-sm truncate">{t.name}</div>
-                      <div className="text-xs text-muted-foreground">{t.family}</div>
-                    </div>
-                    {isActive && (
-                      <span className="inline-flex items-center gap-1 text-xs text-primary shrink-0">
-                        <Check className="size-3" /> Selected
-                      </span>
-                    )}
-                  </div>
-                  <div className="flex mt-2 rounded overflow-hidden border border-border/40">
-                    {t.anchors.map((hex, i) => (
-                      <div
-                        key={i}
-                        className="flex-1 h-6"
-                        style={{ backgroundColor: hex }}
-                        aria-hidden="true"
-                      />
-                    ))}
-                  </div>
-                  {isLightOnly && (
-                    <div className="mt-2 text-xs text-muted-foreground italic">Light only</div>
-                  )}
-                </Card>
-              );
-            })}
+            <ArrowLeft className="size-4" />
+            <span>Back</span>
+          </button>
+          <div>
+            <h1 className="text-xl font-semibold">Settings</h1>
+            <p className="text-sm text-muted-foreground mt-1">
+              Theme appearance. Saved on change, applies immediately.
+            </p>
           </div>
-        </section>
+        </header>
+        <ThemePicker />
       </div>
     </div>
   );