Merge v1.9-skills: skills + /skill slash command

Trigger /<name>, dropdown lists all skills filtered by name prefix,
arg passthrough sends the rest as the user message. Synthetic
skill_use tool_use renders identically to model-invoked skills.

AGENTS.md

@@ -3,7 +3,6 @@
 ## Code Reviewer
 ---
 temperature: 0.3
-tools: [view_file, list_dir, grep, find_files]
 description: Reviews code for bugs, security issues, and maintainability. Read-only.
 ---
 You review code. Find real problems, not style nits.
@@ -33,7 +32,6 @@ If nothing critical or major, say so in one line. Do not pad.
 ## Debugger
 ---
 temperature: 0.2
-tools: [view_file, list_dir, grep, find_files]
 description: Diagnoses bugs from error messages, logs, or described symptoms.
 ---
 You diagnose bugs. Form a hypothesis, prove it with evidence from the code.
@@ -62,7 +60,6 @@ Output:
 ## Refactorer
 ---
 temperature: 0.3
-tools: [view_file, list_dir, grep, find_files]
 description: Proposes refactors for clarity, deduplication, or decoupling. Read-only — outputs plans, not edits.
 ---
 You propose refactors. You do not apply them. The user applies via OpenCode or Claude Code.
@@ -95,7 +92,6 @@ Output:
 ## Architect
 ---
 temperature: 0.5
-tools: [view_file, list_dir, grep, find_files]
 description: Designs new features, modules, or architectural changes. Outputs a build plan.
 ---
 You design. You produce build plans, not code.
@@ -128,7 +124,6 @@ Output:
 ## Security Auditor
 ---
 temperature: 0.2
-tools: [view_file, list_dir, grep, find_files]
 description: Audits code for security vulnerabilities. Read-only.
 ---
 You audit for security issues. Concrete findings only, no generic warnings.
@@ -165,7 +160,6 @@ If the code is clean, say so. Do not invent findings.
 ## Prompt Builder
 ---
 temperature: 0.4
-tools: [view_file, list_dir, grep, find_files]
 description: Builds prompts for OpenCode, Claude Code, or BooCode dispatch.
 ---
 You write prompts that another coding agent will execute. Your output is the prompt, not the work.

apps/server/src/index.ts

@@ -15,8 +15,10 @@ import { registerSidebarRoutes } from './routes/sidebar.js';
 import { registerWebSocket } from './routes/ws.js';
 import { registerModelRoutes } from './routes/models.js';
 import { registerAgentRoutes } from './routes/agents.js';
+import { registerSkillsRoutes } from './routes/skills.js';
 import { createInferenceRunner } from './services/inference.js';
 import { createBroker } from './services/broker.js';
+import { listSkills } from './services/skills.js';
 
 async function main() {
   const config = loadConfig();
@@ -62,6 +64,15 @@ async function main() {
   registerSidebarRoutes(app, sql);
   registerChatRoutes(app, sql, broker);
 
+  // Batch 9.6: warm the skills cache at boot and surface the count. Empty or
+  // missing /data/skills is non-fatal — the skill tools just return empty.
+  try {
+    const skills = await listSkills();
+    app.log.info(`skills loaded: ${skills.length}`);
+  } catch (err) {
+    app.log.warn({ err }, 'skills boot walk failed');
+  }
+
   const inference = createInferenceRunner(
     {
       sql,
@@ -113,6 +124,33 @@ async function main() {
       });
     },
   });
+  registerSkillsRoutes(app, sql, {
+    enqueueInference: (sessionId, chatId, assistantId, user) => {
+      inference.enqueue(sessionId, chatId, assistantId, user);
+    },
+    publishUserMessage: (sessionId, chatId, userMessageId, content) => {
+      broker.publish(sessionId, {
+        type: 'message_started',
+        message_id: userMessageId,
+        chat_id: chatId,
+        role: 'user',
+      });
+      broker.publish(sessionId, {
+        type: 'delta',
+        message_id: userMessageId,
+        chat_id: chatId,
+        content,
+      });
+      broker.publish(sessionId, {
+        type: 'message_complete',
+        message_id: userMessageId,
+        chat_id: chatId,
+      });
+    },
+    publishSessionFrame: (sessionId, frame) => {
+      broker.publish(sessionId, frame);
+    },
+  });
   registerWebSocket(app, sql, broker);
 
   const webDist = process.env.WEB_DIST_PATH ?? resolve(process.cwd(), '../web/dist');

apps/server/src/routes/skills.ts

@@ -0,0 +1,156 @@
+import { randomUUID } from 'node:crypto';
+import type { FastifyInstance } from 'fastify';
+import { z } from 'zod';
+import type { Sql } from '../db.js';
+import type { Chat } from '../types/api.js';
+import { getSkillBody, listSkills } from '../services/skills.js';
+
+// Batch 9.6 slash-invoke handlers. Mirrors the MessageHandlers shape in
+// routes/messages.ts so index.ts can pass thin adapters around broker +
+// inference runner without skills.ts importing them directly.
+export interface SkillInvokeHandlers {
+  enqueueInference: (
+    sessionId: string,
+    chatId: string,
+    assistantMessageId: string,
+    user: string,
+  ) => void;
+  publishUserMessage: (
+    sessionId: string,
+    chatId: string,
+    userMessageId: string,
+    content: string,
+  ) => void;
+  publishSessionFrame: (
+    sessionId: string,
+    frame: Record<string, unknown> & { type: string },
+  ) => void;
+}
+
+const SkillInvokeBody = z.object({
+  skill_name: z.string().min(1),
+  // Optional — server fills in a default if absent or whitespace-only so the
+  // model always has something to act on (matches the spec's "Apply this
+  // skill." filler).
+  user_message: z.string().max(64_000).nullable().optional(),
+});
+
+const DEFAULT_USER_MESSAGE = 'Apply this skill.';
+
+export function registerSkillsRoutes(
+  app: FastifyInstance,
+  sql: Sql,
+  handlers: SkillInvokeHandlers,
+): void {
+  // Debug/admin surface — the model interacts with skills via the three
+  // skill_* tools, not through this endpoint.
+  app.get('/api/skills', async () => {
+    return { skills: await listSkills() };
+  });
+
+  // POST /api/chats/:id/skill_invoke — slash-command entry point. Loads the
+  // skill body server-side (clients never get to forge file content),
+  // persists 4 messages in one transaction (synthetic assistant tool_use,
+  // synthetic tool result, real user message, streaming assistant), and
+  // enqueues inference against the updated history.
+  app.post<{ Params: { id: string } }>(
+    '/api/chats/:id/skill_invoke',
+    async (req, reply) => {
+      const parsed = SkillInvokeBody.safeParse(req.body);
+      if (!parsed.success) {
+        reply.code(400);
+        return { error: 'invalid body', details: parsed.error.flatten() };
+      }
+      const { skill_name } = parsed.data;
+      const userText = parsed.data.user_message?.trim() ? parsed.data.user_message : DEFAULT_USER_MESSAGE;
+
+      const chatRows = await sql<Chat[]>`
+        SELECT id, session_id FROM chats WHERE id = ${req.params.id} AND status = 'open'
+      `;
+      if (chatRows.length === 0) {
+        reply.code(404);
+        return { error: 'chat not found' };
+      }
+      const chat = chatRows[0]!;
+      const sessionId = chat.session_id;
+
+      const body = await getSkillBody(skill_name);
+      if (body === null) {
+        reply.code(404);
+        return { error: 'unknown_skill', message: `unknown skill: ${skill_name}` };
+      }
+
+      const toolCallId = randomUUID();
+      const toolCalls = [{ id: toolCallId, name: 'skill_use', args: { name: skill_name } }];
+      const toolResults = { tool_call_id: toolCallId, output: body, truncated: false };
+
+      const result = await sql.begin(async (tx) => {
+        const [synthAssistant] = await tx<{ id: string }[]>`
+          INSERT INTO messages (session_id, chat_id, role, content, tool_calls, status, created_at)
+          VALUES (${sessionId}, ${chat.id}, 'assistant', '', ${sql.json(toolCalls as never)}, 'complete', clock_timestamp())
+          RETURNING id
+        `;
+        const [toolMsg] = await tx<{ id: string }[]>`
+          INSERT INTO messages (session_id, chat_id, role, content, tool_results, status, created_at)
+          VALUES (${sessionId}, ${chat.id}, 'tool', '', ${sql.json(toolResults as never)}, 'complete', clock_timestamp())
+          RETURNING id
+        `;
+        const [userMsg] = await tx<{ id: string }[]>`
+          INSERT INTO messages (session_id, chat_id, role, content, status, created_at)
+          VALUES (${sessionId}, ${chat.id}, 'user', ${userText}, 'complete', clock_timestamp())
+          RETURNING id
+        `;
+        const [assistantMsg] = await tx<{ id: string }[]>`
+          INSERT INTO messages (session_id, chat_id, role, content, status, created_at)
+          VALUES (${sessionId}, ${chat.id}, 'assistant', '', 'streaming', clock_timestamp())
+          RETURNING id
+        `;
+        await tx`UPDATE sessions SET updated_at = clock_timestamp() WHERE id = ${sessionId}`;
+        await tx`UPDATE chats SET updated_at = clock_timestamp() WHERE id = ${chat.id}`;
+        return {
+          synth_assistant_id: synthAssistant!.id,
+          tool_message_id: toolMsg!.id,
+          user_message_id: userMsg!.id,
+          assistant_message_id: assistantMsg!.id,
+        };
+      });
+
+      // Synthetic frames so useSessionStream's reducer reflects the new
+      // history without a refetch. Frame shapes match the streaming-inference
+      // protocol (see services/inference.ts InferenceFrame).
+      handlers.publishSessionFrame(sessionId, {
+        type: 'message_started',
+        message_id: result.synth_assistant_id,
+        chat_id: chat.id,
+        role: 'assistant',
+      });
+      handlers.publishSessionFrame(sessionId, {
+        type: 'tool_call',
+        message_id: result.synth_assistant_id,
+        chat_id: chat.id,
+        tool_call: toolCalls[0]!,
+      });
+      handlers.publishSessionFrame(sessionId, {
+        type: 'message_complete',
+        message_id: result.synth_assistant_id,
+        chat_id: chat.id,
+      });
+      // The tool_result frame's reducer branch creates the tool-role message
+      // in-place when it doesn't already exist — no separate message_started
+      // is needed for the tool side.
+      handlers.publishSessionFrame(sessionId, {
+        type: 'tool_result',
+        tool_message_id: result.tool_message_id,
+        tool_call_id: toolCallId,
+        chat_id: chat.id,
+        output: body,
+        truncated: false,
+      });
+      handlers.publishUserMessage(sessionId, chat.id, result.user_message_id, userText);
+      handlers.enqueueInference(sessionId, chat.id, result.assistant_message_id, 'default');
+
+      reply.code(202);
+      return result;
+    },
+  );
+}

apps/server/src/services/agents.ts

@@ -11,7 +11,14 @@ const GLOBAL_AGENTS_PATH = '/data/AGENTS.md';
 const CACHE_TTL_MS = 60_000;
 
 // Tools whitelist universe matches services/tools.ts ALL_TOOLS. Keep in sync.
-const ALL_TOOL_NAMES = ['view_file', 'list_dir', 'grep', 'find_files', 'git_status'] as const;
+// Batch 9.6: skill_find / skill_use / skill_resource added. Agents without an
+// explicit `tools:` field inherit the full default set (which now includes
+// the skill tools); agents with an explicit `tools:` array must list any
+// skill tool they want to use — strict opt-in.
+const ALL_TOOL_NAMES = [
+  'view_file', 'list_dir', 'grep', 'find_files', 'git_status',
+  'skill_find', 'skill_use', 'skill_resource',
+] as const;
 const DEFAULT_TOOLS: string[] = [...ALL_TOOL_NAMES];
 const DEFAULT_TEMPERATURE = 0.7;
 

apps/server/src/services/skills.ts

@@ -0,0 +1,321 @@
+import { promises as fs } from 'node:fs';
+import { join, isAbsolute, basename } from 'node:path';
+import { pathGuard, PathScopeError } from './path_guard.js';
+
+// Batch 9.6: read-only skill library. Folders under /data/skills/<group>/<skill>/
+// contain a SKILL.md with YAML frontmatter (name + description) and a markdown
+// body. Three tools expose the library: skill_find (search), skill_use (load
+// body), skill_resource (read a support file inside the folder).
+//
+// Layout is intentionally uniform — scan /data/skills/*/*/SKILL.md at fixed
+// depth 3. Group folders (depth 1) hold LICENSE + ATTRIBUTION.md + skill
+// subfolders and are NOT themselves skills. Support files inside skill
+// folders are reachable via skill_resource, never auto-parsed.
+//
+// Cache model mirrors agents.ts: walk on first access, TTL re-walk to pick up
+// new skills, per-entry mtime check on body access so a hot-edited SKILL.md
+// is re-read without a restart. No watcher.
+
+const SKILLS_ROOT = '/data/skills';
+const MAX_RESOURCE_BYTES = 5 * 1024 * 1024;
+const LIST_CACHE_TTL_MS = 60_000;
+
+export interface Skill {
+  name: string;
+  description: string;
+  path: string;
+  mtime: number;
+}
+
+interface CachedSkill extends Skill {
+  body: string;
+}
+
+const cache = new Map<string, CachedSkill>();
+let lastWalkedAt = 0;
+
+// ---- Frontmatter parser ----------------------------------------------------
+// Minimal `---\n...\n---` extractor. Only `name` and `description` keys are
+// honored; other frontmatter keys are silently ignored for forward-compat
+// with the anthropics/skills upstream spec.
+
+interface Frontmatter {
+  name?: string;
+  description?: string;
+}
+
+function stripQuotes(s: string): string {
+  if (s.length >= 2 && (s[0] === '"' || s[0] === "'") && s[0] === s[s.length - 1]) {
+    return s.slice(1, -1);
+  }
+  return s;
+}
+
+function parseFrontmatter(yaml: string): Frontmatter {
+  const fm: Frontmatter = {};
+  for (const raw of yaml.split('\n')) {
+    const line = raw.trim();
+    if (line.length === 0) continue;
+    const colon = line.indexOf(':');
+    if (colon < 0) continue;
+    const key = line.slice(0, colon).trim();
+    const val = stripQuotes(line.slice(colon + 1).trim());
+    if (key === 'name') fm.name = val;
+    else if (key === 'description') fm.description = val;
+  }
+  return fm;
+}
+
+interface ParsedSkillFile {
+  name: string;
+  description: string;
+  body: string;
+}
+
+function parseSkillFile(content: string): ParsedSkillFile {
+  const lines = content.split('\n');
+  let openIdx = -1;
+  for (let i = 0; i < lines.length; i++) {
+    const t = lines[i]!.trim();
+    if (t === '') continue;
+    if (t === '---') openIdx = i;
+    break;
+  }
+  if (openIdx < 0) throw new Error('missing opening --- fence');
+  let closeIdx = -1;
+  for (let i = openIdx + 1; i < lines.length; i++) {
+    if (lines[i]!.trim() === '---') { closeIdx = i; break; }
+  }
+  if (closeIdx < 0) throw new Error('missing closing --- fence');
+
+  const yamlText = lines.slice(openIdx + 1, closeIdx).join('\n');
+  const body = lines.slice(closeIdx + 1).join('\n');
+
+  const fm = parseFrontmatter(yamlText);
+  if (!fm.name) throw new Error('frontmatter missing name');
+  if (!fm.description) throw new Error('frontmatter missing description');
+  return { name: fm.name, description: fm.description, body };
+}
+
+// ---- Tree walk -------------------------------------------------------------
+
+// Fixed depth-3 scan: /data/skills/<group>/<skill>/SKILL.md. Two layers of
+// readdir, no recursion. Group folders without SKILL.md are skipped silently;
+// LICENSE / ATTRIBUTION.md / other non-SKILL.md files are ignored entirely.
+// Returns all parseable skills as-found — dedup + collision logging happens
+// in ensureCache where the sort order is established.
+async function walkSkills(root: string): Promise<CachedSkill[]> {
+  const found: CachedSkill[] = [];
+  let groups;
+  try {
+    groups = await fs.readdir(root, { withFileTypes: true });
+  } catch {
+    return found;
+  }
+  for (const group of groups) {
+    if (!group.isDirectory() || group.name.startsWith('.')) continue;
+    const groupPath = join(root, group.name);
+    let entries;
+    try {
+      entries = await fs.readdir(groupPath, { withFileTypes: true });
+    } catch {
+      continue;
+    }
+    for (const entry of entries) {
+      if (!entry.isDirectory() || entry.name.startsWith('.')) continue;
+      const skillFolder = join(groupPath, entry.name);
+      const skillFile = join(skillFolder, 'SKILL.md');
+      let stat;
+      try {
+        stat = await fs.stat(skillFile);
+      } catch {
+        continue; // folder without SKILL.md — silent skip
+      }
+      if (!stat.isFile()) continue;
+      try {
+        const content = await fs.readFile(skillFile, 'utf8');
+        const parsed = parseSkillFile(content);
+        found.push({
+          name: parsed.name,
+          description: parsed.description,
+          path: skillFolder,
+          mtime: stat.mtimeMs,
+          body: parsed.body,
+        });
+      } catch (err) {
+        const reason = err instanceof Error ? err.message : String(err);
+        console.warn(`skills: failed to parse ${skillFile} — ${reason}`);
+      }
+    }
+  }
+  return found;
+}
+
+// ---- Cache ----------------------------------------------------------------
+
+async function ensureCache(): Promise<void> {
+  const now = Date.now();
+  if (cache.size > 0 && now - lastWalkedAt < LIST_CACHE_TTL_MS) return;
+  let stat;
+  try {
+    stat = await fs.stat(SKILLS_ROOT);
+  } catch {
+    cache.clear();
+    lastWalkedAt = now;
+    return;
+  }
+  if (!stat.isDirectory()) {
+    cache.clear();
+    lastWalkedAt = now;
+    return;
+  }
+  const found = await walkSkills(SKILLS_ROOT);
+  // Sort by name asc, then path asc — gives alphabetically-first-wins on
+  // collision and stable, deterministic ordering for /api/skills + skill_find.
+  found.sort((a, b) => {
+    const n = a.name.localeCompare(b.name);
+    return n !== 0 ? n : a.path.localeCompare(b.path);
+  });
+  cache.clear();
+  const winnerPath = new Map<string, string>();
+  for (const skill of found) {
+    const prev = winnerPath.get(skill.name);
+    if (prev) {
+      console.warn(
+        `skills: name collision "${skill.name}" — kept ${prev}, skipped ${skill.path}`,
+      );
+      continue;
+    }
+    winnerPath.set(skill.name, skill.path);
+    cache.set(skill.name, skill);
+  }
+  lastWalkedAt = now;
+}
+
+// ---- Public API -----------------------------------------------------------
+
+export async function listSkills(): Promise<Skill[]> {
+  await ensureCache();
+  return Array.from(cache.values()).map((s) => ({
+    name: s.name,
+    description: s.description,
+    path: s.path,
+    mtime: s.mtime,
+  }));
+}
+
+export interface SkillSummary {
+  name: string;
+  description: string;
+}
+
+export async function findSkills(query: string): Promise<SkillSummary[]> {
+  await ensureCache();
+  const all = Array.from(cache.values());
+  const q = (query ?? '').trim().toLowerCase();
+  if (q === '' || q === '*') {
+    return all.map((s) => ({ name: s.name, description: s.description }));
+  }
+  // name match weighted 2x description match. No fancy ranking — substring
+  // scoring is enough for ≤20 skills.
+  const scored = all
+    .map((s) => {
+      let score = 0;
+      if (s.name.toLowerCase().includes(q)) score += 2;
+      if (s.description.toLowerCase().includes(q)) score += 1;
+      return { s, score };
+    })
+    .filter((x) => x.score > 0)
+    .sort((a, b) => b.score - a.score)
+    .slice(0, 5);
+  return scored.map(({ s }) => ({ name: s.name, description: s.description }));
+}
+
+// Returns the SKILL.md body with frontmatter stripped, or null if the skill
+// is unknown. Single-entry mtime refresh: a hot edit shows up on next call.
+export async function getSkillBody(name: string): Promise<string | null> {
+  await ensureCache();
+  const cached = cache.get(name);
+  if (!cached) return null;
+
+  let stat;
+  try {
+    stat = await fs.stat(join(cached.path, 'SKILL.md'));
+  } catch {
+    cache.delete(name);
+    return null;
+  }
+  if (stat.mtimeMs === cached.mtime) return cached.body;
+  try {
+    const raw = await fs.readFile(join(cached.path, 'SKILL.md'), 'utf8');
+    const parsed = parseSkillFile(raw);
+    if (parsed.name !== name) {
+      // Skill renamed itself; drop the stale entry. Next listSkills() walks.
+      cache.delete(name);
+      return null;
+    }
+    cached.body = parsed.body;
+    cached.description = parsed.description;
+    cached.mtime = stat.mtimeMs;
+    return cached.body;
+  } catch (err) {
+    const reason = err instanceof Error ? err.message : String(err);
+    console.warn(`skills: re-parse failed for ${name} — ${reason}`);
+    cache.delete(name);
+    return null;
+  }
+}
+
+export type SkillResourceErrorCode = 'unknown_skill' | 'unknown_resource' | 'path_escape';
+
+export type SkillResourceResult =
+  | { ok: true; content: string }
+  | { ok: false; code: SkillResourceErrorCode; message: string };
+
+export async function getSkillResource(
+  name: string,
+  relativePath: string,
+): Promise<SkillResourceResult> {
+  await ensureCache();
+  const cached = cache.get(name);
+  if (!cached) {
+    return { ok: false, code: 'unknown_skill', message: `unknown skill: ${name}` };
+  }
+  if (typeof relativePath !== 'string' || relativePath.trim() === '') {
+    return { ok: false, code: 'unknown_resource', message: 'path is required' };
+  }
+  // Syntactic pre-check — catches the common "../../etc/passwd" attempt
+  // before realpath dereferences any symlinks.
+  if (isAbsolute(relativePath) || relativePath.split(/[\\/]/).some((seg) => seg === '..')) {
+    return { ok: false, code: 'path_escape', message: `path escapes skill folder: ${relativePath}` };
+  }
+  // SKILL.md is the manifest — skill_use is the right tool to read it.
+  if (basename(relativePath) === 'SKILL.md') {
+    return { ok: false, code: 'unknown_resource', message: 'use skill_use to read SKILL.md' };
+  }
+  let real: string;
+  try {
+    real = await pathGuard(cached.path, relativePath);
+  } catch (err) {
+    if (err instanceof PathScopeError) {
+      const code: SkillResourceErrorCode = err.message.includes('escapes')
+        ? 'path_escape'
+        : 'unknown_resource';
+      return { ok: false, code, message: err.message };
+    }
+    throw err;
+  }
+  const stat = await fs.stat(real);
+  if (!stat.isFile()) {
+    return { ok: false, code: 'unknown_resource', message: 'not a file' };
+  }
+  if (stat.size > MAX_RESOURCE_BYTES) {
+    return {
+      ok: false,
+      code: 'unknown_resource',
+      message: `file too large (${stat.size} bytes, max ${MAX_RESOURCE_BYTES})`,
+    };
+  }
+  const content = await fs.readFile(real, 'utf8');
+  return { ok: true, content };
+}

apps/server/src/services/tools.ts

@@ -4,6 +4,7 @@ import { z } from 'zod';
 import { pathGuard, PathScopeError } from './path_guard.js';
 import { grep as fileOpsGrep, findFiles as fileOpsFindFiles } from './file_ops.js';
 import { getGitMeta } from './git_meta.js';
+import { findSkills, getSkillBody, getSkillResource } from './skills.js';
 
 const MAX_FILE_BYTES = 5 * 1024 * 1024;
 const DEFAULT_VIEW_LINES = 200;
@@ -300,12 +301,119 @@ export const gitStatus: ToolDef<GitStatusInputT> = {
   },
 };
 
+// Batch 9.6: skill_find, skill_use, skill_resource. Lazy-loaded markdown
+// playbooks at /data/skills/. Three tools rather than one to keep each call
+// cheap — the model lists, then loads, then optionally pulls support files.
+
+const SkillFindInput = z.object({
+  query: z.string().optional(),
+});
+type SkillFindInputT = z.infer<typeof SkillFindInput>;
+
+export const skillFind: ToolDef<SkillFindInputT> = {
+  name: 'skill_find',
+  description:
+    'Find skills (markdown playbooks under /data/skills) by name or description. Returns up to 5 matches. Empty query or "*" returns all available skills. Call this first to discover what skills are available.',
+  inputSchema: SkillFindInput,
+  jsonSchema: {
+    type: 'function',
+    function: {
+      name: 'skill_find',
+      description:
+        'Find skills by name or description. Returns up to 5 matches. Empty or "*" returns all.',
+      parameters: {
+        type: 'object',
+        properties: {
+          query: { type: 'string', description: 'substring matched against skill name and description' },
+        },
+        additionalProperties: false,
+      },
+    },
+  },
+  async execute(input) {
+    return await findSkills(input.query ?? '');
+  },
+};
+
+const SkillUseInput = z.object({
+  name: z.string().min(1),
+});
+type SkillUseInputT = z.infer<typeof SkillUseInput>;
+
+export const skillUse: ToolDef<SkillUseInputT> = {
+  name: 'skill_use',
+  description:
+    "Load the full body of a skill's SKILL.md by name. Returns the markdown playbook to follow. Discover names via skill_find. Errors: unknown_skill.",
+  inputSchema: SkillUseInput,
+  jsonSchema: {
+    type: 'function',
+    function: {
+      name: 'skill_use',
+      description: "Load the full body of a skill's SKILL.md by name.",
+      parameters: {
+        type: 'object',
+        properties: {
+          name: { type: 'string', description: 'skill name from skill_find' },
+        },
+        required: ['name'],
+        additionalProperties: false,
+      },
+    },
+  },
+  async execute(input) {
+    const body = await getSkillBody(input.name);
+    if (body === null) {
+      return { error: 'unknown_skill', message: `unknown skill: ${input.name}` };
+    }
+    return { body };
+  },
+};
+
+const SkillResourceInput = z.object({
+  name: z.string().min(1),
+  path: z.string().min(1),
+});
+type SkillResourceInputT = z.infer<typeof SkillResourceInput>;
+
+export const skillResource: ToolDef<SkillResourceInputT> = {
+  name: 'skill_resource',
+  description:
+    "Read a support file inside a skill's folder (e.g. references/root-cause-tracing.md). Path is relative to the skill folder. Use skill_use to read SKILL.md itself. Errors: unknown_skill, unknown_resource, path_escape.",
+  inputSchema: SkillResourceInput,
+  jsonSchema: {
+    type: 'function',
+    function: {
+      name: 'skill_resource',
+      description: "Read a support file inside a skill's folder. Path is relative to the skill folder.",
+      parameters: {
+        type: 'object',
+        properties: {
+          name: { type: 'string', description: 'skill name' },
+          path: { type: 'string', description: 'relative path under the skill folder' },
+        },
+        required: ['name', 'path'],
+        additionalProperties: false,
+      },
+    },
+  },
+  async execute(input) {
+    const result = await getSkillResource(input.name, input.path);
+    if (!result.ok) {
+      return { error: result.code, message: result.message };
+    }
+    return { content: result.content };
+  },
+};
+
 export const ALL_TOOLS: ReadonlyArray<ToolDef<unknown>> = [
   viewFile as ToolDef<unknown>,
   listDir as ToolDef<unknown>,
   grep as ToolDef<unknown>,
   findFiles as ToolDef<unknown>,
   gitStatus as ToolDef<unknown>,
+  skillFind as ToolDef<unknown>,
+  skillUse as ToolDef<unknown>,
+  skillResource as ToolDef<unknown>,
 ];
 
 // v1.8.2: forward-compatible read-only whitelist. An agent whose `tools` is
@@ -313,12 +421,16 @@ export const ALL_TOOLS: ReadonlyArray<ToolDef<unknown>> = [
 // anything outside means the agent can mutate state and gets a tighter
 // default (10). Every tool in v1.8.2 happens to be read-only, so the
 // non-RO branch only takes effect once BooCoder lands write tools.
+// Batch 9.6: skill_* added; all still read-only.
 export const READ_ONLY_TOOL_NAMES = [
   'view_file',
   'list_dir',
   'grep',
   'find_files',
   'git_status',
+  'skill_find',
+  'skill_use',
+  'skill_resource',
 ] as const;
 
 export const TOOLS_BY_NAME: Record<string, ToolDef<unknown>> = Object.fromEntries(

apps/web/src/api/client.ts

@@ -10,6 +10,7 @@ import type {
   ViewFileResult,
   AgentsResponse,
   GitMeta,
+  Skill,
 } from './types';
 
 export class ApiError extends Error {
@@ -187,6 +188,20 @@ export const api = {
         method: 'POST',
         body: JSON.stringify({ message_id: body.messageId, name: body.name }),
       }),
+    // Batch 9.6: slash-command invocation. Server loads the skill body
+    // authoritatively (client doesn't get to forge file contents), persists
+    // a synthetic skill_use tool_use + tool_result + user message + streaming
+    // assistant, and enqueues inference. Returns all 4 new message IDs.
+    skillInvoke: (chatId: string, skillName: string, userMessage: string | null) =>
+      request<{
+        synth_assistant_id: string;
+        tool_message_id: string;
+        user_message_id: string;
+        assistant_message_id: string;
+      }>(`/api/chats/${chatId}/skill_invoke`, {
+        method: 'POST',
+        body: JSON.stringify({ skill_name: skillName, user_message: userMessage }),
+      }),
   },
 
   messages: {
@@ -218,6 +233,10 @@ export const api = {
       request<AgentsResponse>(`/api/projects/${projectId}/agents`),
   },
 
+  skills: {
+    list: () => request<{ skills: Skill[] }>('/api/skills'),
+  },
+
   settings: {
     get: () => request<Record<string, unknown>>('/api/settings'),
     patch: (body: Record<string, unknown>) =>

apps/web/src/api/types.ts

@@ -231,6 +231,16 @@ export interface GitMeta {
   behind: number;
 }
 
+// Batch 9.6: skill catalog row. Returned by GET /api/skills and consumed by
+// the slash-command dropdown. `path` and `mtime` are exposed for debug surface
+// (/api/skills) but the dropdown only renders name + description.
+export interface Skill {
+  name: string;
+  description: string;
+  path: string;
+  mtime: number;
+}
+
 // 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 toggleSettingsPane().

apps/web/src/components/ChatInput.tsx

@@ -1,4 +1,4 @@
-import { useCallback, useEffect, useRef, useState, type DragEvent, type KeyboardEvent } from 'react';
+import { useCallback, useEffect, useMemo, useRef, useState, type DragEvent, type KeyboardEvent } from 'react';
 import { Check, Plus, Send } from 'lucide-react';
 import { toast } from 'sonner';
 import { Textarea } from '@/components/ui/textarea';
@@ -22,8 +22,10 @@ import { AttachmentPreviewModal } from '@/components/AttachmentPreviewModal';
 import { FileMentionPopover } from '@/components/FileMentionPopover';
 import { DropOverlay } from '@/components/DropOverlay';
 import { AgentPicker } from '@/components/AgentPicker';
+import { SkillSlashCommand } from '@/components/SkillSlashCommand';
 import { api } from '@/api/client';
 import { sessionEvents } from '@/hooks/sessionEvents';
+import { useSkills } from '@/hooks/useSkills';
 import { useViewport } from '@/hooks/useViewport';
 
 const MAX_ATTACHMENTS = 10;
@@ -44,9 +46,14 @@ interface Props {
   webSearchEnabled?: boolean | null;
   onSend: (content: string) => void | Promise<void>;
   onForceSend?: (content: string) => void | Promise<void>;
+  // Batch 9.6: slash-command dispatch. When the input parses to a known skill,
+  // ChatInput calls this with the skill name + the post-name args (possibly
+  // empty). Callers wire this to api.chats.skillInvoke. Omitting the prop
+  // disables slash-command dispatch (input is sent as literal text).
+  onSlashCommand?: (skillName: string, userMessage: string) => void | Promise<void>;
 }
 
-export function ChatInput({ disabled, projectId, agentId, onAgentChange, sessionId, webSearchEnabled, onSend, onForceSend }: Props) {
+export function ChatInput({ disabled, projectId, agentId, onAgentChange, sessionId, webSearchEnabled, onSend, onForceSend, onSlashCommand }: Props) {
   const { isMobile } = useViewport();
   const [value, setValue] = useState('');
   const [busy, setBusy] = useState(false);
@@ -61,6 +68,19 @@ export function ChatInput({ disabled, projectId, agentId, onAgentChange, session
     atIdx: number;
     anchorRect: { top: number; left: number };
   } | null>(null);
+  // Batch 9.6: slash-command dropdown. Opens when `/` is the first char of
+  // the input and stays open while the input is `/<word>` with no whitespace.
+  // Disabled entirely when the caller doesn't pass onSlashCommand.
+  const [slashState, setSlashState] = useState<{
+    query: string;
+    anchorRect: { top: number; left: number };
+  } | null>(null);
+  const { skills } = useSkills();
+  const skillsLookup = useMemo(() => {
+    const m = new Map<string, true>();
+    for (const s of skills) m.set(s.name, true);
+    return m;
+  }, [skills]);
   const [fileIndex, setFileIndex] = useState<string[] | null>(null);
   const textareaRef = useRef<HTMLTextAreaElement | null>(null);
 
@@ -95,6 +115,31 @@ export function ChatInput({ disabled, projectId, agentId, onAgentChange, session
     const text = value.trim();
     if (!text && attachments.length === 0) return;
     if (disabled || busy) return;
+
+    // Batch 9.6: slash-command dispatch. Only when no attachments and the
+    // input parses to a known skill. Falls through to onSend for unknown
+    // slash names (literal text) or when slash dispatch isn't wired.
+    if (onSlashCommand && attachments.length === 0 && text.startsWith('/')) {
+      const match = text.match(/^\/(\S+)\s*([\s\S]*)$/);
+      if (match && skillsLookup.has(match[1]!)) {
+        const skillName = match[1]!;
+        const args = (match[2] ?? '').trim();
+        setBusy(true);
+        try {
+          await onSlashCommand(skillName, args);
+          setValue('');
+          setAttachments([]);
+          setSlashState(null);
+        } catch (err) {
+          toast.error(err instanceof Error ? err.message : 'skill invocation failed');
+        } finally {
+          setBusy(false);
+        }
+        return;
+      }
+      // Unknown skill name — fall through and send as literal text.
+    }
+
     setBusy(true);
     try {
       const body = flattenToMessage(attachments, text);
@@ -108,6 +153,19 @@ export function ChatInput({ disabled, projectId, agentId, onAgentChange, session
     }
   }
 
+  function handleSlashSelect(skillName: string) {
+    const next = `/${skillName} `;
+    setValue(next);
+    setSlashState(null);
+    requestAnimationFrame(() => {
+      const ta = textareaRef.current;
+      if (ta) {
+        ta.selectionStart = ta.selectionEnd = next.length;
+        ta.focus();
+      }
+    });
+  }
+
   function getCaretCoords(textarea: HTMLTextAreaElement): { top: number; left: number } {
     const mirror = document.createElement('div');
     const style = window.getComputedStyle(textarea);
@@ -158,6 +216,23 @@ export function ChatInput({ disabled, projectId, agentId, onAgentChange, session
     const ta = e.target;
     const pos = ta.selectionStart;
 
+    // Batch 9.6: slash-command trigger. Active while the input is a single
+    // slash-prefixed token with no whitespace (i.e. user is still typing the
+    // skill name). Hand off to args mode the moment a space appears or the
+    // slash leaves position 0.
+    if (onSlashCommand && /^\/[^\s]*$/.test(newValue)) {
+      const query = newValue.slice(1);
+      if (!slashState) {
+        const rect = ta.getBoundingClientRect();
+        setSlashState({ query, anchorRect: { top: rect.top, left: rect.left } });
+      } else if (slashState.query !== query) {
+        setSlashState({ ...slashState, query });
+      }
+      if (mentionState?.open) setMentionState(null);
+      return;
+    }
+    if (slashState) setSlashState(null);
+
     // Check for @ trigger
     if (pos > 0 && newValue[pos - 1] === '@') {
       const charBefore = pos >= 2 ? newValue[pos - 2] : null;
@@ -374,6 +449,9 @@ export function ChatInput({ disabled, projectId, agentId, onAgentChange, session
 
   function onKeyDown(e: KeyboardEvent<HTMLTextAreaElement>) {
     if (mentionState?.open) return;
+    // SkillSlashCommand owns Arrow/Enter/Tab/Esc via a document listener; let
+    // it consume them so the textarea doesn't also submit on Enter.
+    if (slashState) return;
     // IME safety: never act on Enter while an IME composition is in flight
     // (CJK input methods commit composition via Enter). Without this, the
     // first Enter of a Japanese/Chinese/Korean composition would submit
@@ -524,6 +602,15 @@ export function ChatInput({ disabled, projectId, agentId, onAgentChange, session
           onClose={closeMention}
         />
       )}
+      {slashState && (
+        <SkillSlashCommand
+          query={slashState.query}
+          skills={skills}
+          anchorRect={slashState.anchorRect}
+          onSelect={handleSlashSelect}
+          onClose={() => setSlashState(null)}
+        />
+      )}
     </div>
   );
 }

apps/web/src/components/SkillSlashCommand.tsx

@@ -0,0 +1,137 @@
+import { useEffect, useMemo, useRef, useState } from 'react';
+import { cn } from '@/lib/utils';
+import type { Skill } from '@/api/types';
+
+interface Props {
+  query: string;
+  skills: Skill[];
+  anchorRect: { top: number; left: number };
+  onSelect: (skillName: string) => void;
+  onClose: () => void;
+}
+
+// Batch 9.6: slash-command dropdown. Models FileMentionPopover's pattern —
+// fixed-positioned popover, keyboard nav, click-outside-to-close. shadcn
+// `Command` (cmdk) isn't installed in this project; per the addendum we use
+// a plain div + Tailwind instead of pulling a new primitive autonomously.
+
+// Case-insensitive prefix match on `name` only. Description is display-only
+// in v1 (substring search across description is deferred to a polish batch).
+function filterByPrefix(skills: Skill[], query: string): Skill[] {
+  const q = query.toLowerCase();
+  const filtered = q
+    ? skills.filter((s) => s.name.toLowerCase().startsWith(q))
+    : skills;
+  // Stable alphabetical ordering matches the server's cache order (skills.ts
+  // sorts on name asc) but we re-sort here so a stale client cache doesn't
+  // surprise the user.
+  return [...filtered].sort((a, b) => a.name.localeCompare(b.name));
+}
+
+export function SkillSlashCommand({ query, skills, anchorRect, onSelect, onClose }: Props) {
+  const [highlightIndex, setHighlightIndex] = useState(0);
+  const popoverRef = useRef<HTMLDivElement>(null);
+  const filtered = useMemo(() => filterByPrefix(skills, query), [skills, query]);
+
+  useEffect(() => { setHighlightIndex(0); }, [query]);
+
+  // Arrow / Enter / Tab / Escape. Bound on document so keystrokes from the
+  // textarea reach the popover even though focus stays in the textarea.
+  useEffect(() => {
+    function handleKeyDown(e: KeyboardEvent) {
+      if (e.key === 'ArrowDown') {
+        e.preventDefault();
+        setHighlightIndex((prev) => (prev < filtered.length - 1 ? prev + 1 : 0));
+      } else if (e.key === 'ArrowUp') {
+        e.preventDefault();
+        setHighlightIndex((prev) => (prev > 0 ? prev - 1 : filtered.length - 1));
+      } else if (e.key === 'Enter' || e.key === 'Tab') {
+        if (filtered.length === 0) return;
+        e.preventDefault();
+        const target = filtered[highlightIndex] ?? filtered[0];
+        if (target) onSelect(target.name);
+      } else if (e.key === 'Escape') {
+        e.preventDefault();
+        onClose();
+      }
+    }
+    document.addEventListener('keydown', handleKeyDown);
+    return () => document.removeEventListener('keydown', handleKeyDown);
+  }, [filtered, highlightIndex, onSelect, onClose]);
+
+  useEffect(() => {
+    function handleMouseDown(e: MouseEvent) {
+      if (popoverRef.current && !popoverRef.current.contains(e.target as Node)) {
+        onClose();
+      }
+    }
+    document.addEventListener('mousedown', handleMouseDown);
+    return () => document.removeEventListener('mousedown', handleMouseDown);
+  }, [onClose]);
+
+  useEffect(() => {
+    const el = popoverRef.current?.querySelector('[data-highlighted="true"]');
+    if (el) el.scrollIntoView({ block: 'nearest' });
+  }, [highlightIndex]);
+
+  // Anchor sits above the input — translate(-100%) on Y so the dropdown
+  // expands upward from the anchor point rather than over the textarea.
+  const style = {
+    top: anchorRect.top,
+    left: anchorRect.left,
+    transform: 'translateY(-100%)',
+  } as const;
+
+  if (filtered.length === 0) {
+    return (
+      <div
+        ref={popoverRef}
+        className="fixed z-50 bg-popover border border-border rounded-md shadow min-w-[320px] p-2"
+        style={style}
+      >
+        <div className="text-xs text-muted-foreground px-2 py-1">
+          {query ? `No skill starts with "/${query}"` : 'No skills available'}
+        </div>
+      </div>
+    );
+  }
+
+  return (
+    <div
+      ref={popoverRef}
+      className="fixed z-50 bg-popover border border-border rounded-md shadow min-w-[320px] max-w-[420px] max-h-[320px] overflow-y-auto"
+      style={style}
+    >
+      {filtered.map((skill, i) => (
+        <button
+          key={skill.name}
+          type="button"
+          data-highlighted={i === highlightIndex}
+          className={cn(
+            'w-full text-left px-2.5 py-2 cursor-pointer block',
+            i === highlightIndex && 'bg-muted',
+          )}
+          onMouseEnter={() => setHighlightIndex(i)}
+          onMouseDown={(e) => {
+            // mousedown not click — click runs after blur/focus shuffles which
+            // can race with the textarea's onBlur close path.
+            e.preventDefault();
+            onSelect(skill.name);
+          }}
+        >
+          <div className="font-mono text-xs font-bold text-foreground">/{skill.name}</div>
+          <div
+            className="text-xs text-muted-foreground overflow-hidden"
+            style={{
+              display: '-webkit-box',
+              WebkitLineClamp: 2,
+              WebkitBoxOrient: 'vertical',
+            }}
+          >
+            {skill.description}
+          </div>
+        </button>
+      ))}
+    </div>
+  );
+}

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

@@ -96,6 +96,18 @@ export function ChatPane({ sessionId, chatId, projectId, agentId, onAgentChange,
     }
   }, [chatId]);
 
+  // Batch 9.6: slash-command dispatch. Sent regardless of streaming state —
+  // matches the existing /compact precedent (which also fires immediately).
+  // Empty args go to the server as null; the server fills in a default user
+  // message ("Apply this skill.") so the model has something to act on.
+  const handleSlashCommand = useCallback(async (skillName: string, userMessage: string) => {
+    try {
+      await api.chats.skillInvoke(chatId, skillName, userMessage.length > 0 ? userMessage : null);
+    } catch (err) {
+      toast.error(err instanceof Error ? err.message : `/${skillName} failed`);
+    }
+  }, [chatId]);
+
   function removeQueued(idx: number) {
     setQueue((prev) => prev.filter((_, i) => i !== idx));
   }
@@ -183,6 +195,7 @@ export function ChatPane({ sessionId, chatId, projectId, agentId, onAgentChange,
           webSearchEnabled={webSearchEnabled}
           onSend={handleSend}
           onForceSend={streaming ? handleForceSend : undefined}
+          onSlashCommand={handleSlashCommand}
         />
       </div>
     </div>

apps/web/src/hooks/useSkills.ts

@@ -0,0 +1,43 @@
+import { useEffect, useState } from 'react';
+import { api } from '@/api/client';
+import type { Skill } from '@/api/types';
+
+// Batch 9.6: shared in-memory cache for the slash-command dropdown. One fetch
+// per process; subsequent mounts of useSkills() return the cached list and
+// don't re-hit /api/skills. Matches the useSidebar / useChatStatus module-
+// singleton pattern so the dropdown stays cheap even with many ChatInputs
+// mounted at once.
+
+let cachedSkills: Skill[] | null = null;
+let inflight: Promise<Skill[]> | null = null;
+const subscribers = new Set<(s: Skill[]) => void>();
+
+async function loadSkills(): Promise<Skill[]> {
+  if (inflight) return inflight;
+  inflight = api.skills
+    .list()
+    .then((r) => {
+      cachedSkills = r.skills;
+      for (const sub of subscribers) {
+        try { sub(cachedSkills); } catch { /* swallow */ }
+      }
+      return cachedSkills;
+    })
+    .finally(() => { inflight = null; });
+  return inflight;
+}
+
+export function useSkills(): { skills: Skill[]; loaded: boolean } {
+  const [skills, setSkills] = useState<Skill[]>(cachedSkills ?? []);
+  const [loaded, setLoaded] = useState<boolean>(cachedSkills !== null);
+
+  useEffect(() => {
+    subscribers.add(setSkills);
+    if (cachedSkills === null) {
+      void loadSkills().then(() => setLoaded(true)).catch(() => setLoaded(true));
+    }
+    return () => { subscribers.delete(setSkills); };
+  }, []);
+
+  return { skills, loaded };
+}

docker-compose.yml

@@ -9,15 +9,11 @@ services:
     environment:
       DATABASE_URL: postgres://boocode:${POSTGRES_PASSWORD}@boocode_db:5432/boocode
     volumes:
-      # Read-only mount for legacy/existing project add-existing flow.
+      - /opt:/opt
-      - /opt:/opt:ro
-      # Writable mount only for the create-new-project bootstrap target.
-      # Host must `mkdir -p /opt/projects` before container start.
       - /opt/projects:/opt/projects:rw
       - ./secrets/boocode_gitea:/root/.ssh/id_ed25519:ro
-      # v1.8.1: global agents file. Host seeds it once before deploy:
+      - ./data:/data
-      # cp /opt/boocode/AGENTS.md /opt/boocode/data/AGENTS.md
+      - /opt/skills:/data/skills
-      - ./data:/data:ro
     depends_on:
       - boocode_db
     networks: