feat: add in-chat skill discovery and local registry install command

README.md

@@ -474,6 +474,7 @@ Notes:
 | `/approvals` | List pending approval gates for current session |
 | `/approve [id]` | Approve latest (or specific) pending gate |
 | `/deny [id] [reason]` | Deny latest (or specific) pending gate |
+| `/skill <list|search|install>` | In-chat skill discovery/install (`list`, `search <term>`, `install <registry-id>`) |
 
 ## Web UI Dashboard
 
@@ -524,6 +525,7 @@ pnpm tui:fs
 | `/approvals` | List pending approval gates for current session |
 | `/approve [id]` | Approve latest (or specific) pending gate |
 | `/deny [id] [reason]` | Deny latest (or specific) pending gate |
+| `/skill <list|search|install>` | In-chat skill discovery/install (`list`, `search <term>`, `install <registry-id>`) |
 | `/quit` | Exit |
 
 #### Runtime Model Switching

docs/plans/state.json

@@ -5305,6 +5305,24 @@
         "docs/plans/state.json"
       ],
       "test_status": "pnpm test:run src/hooks/engine.test.ts src/commands/builtin/index.test.ts src/daemon/routing.test.ts src/tools/executor.test.ts + pnpm typecheck passing"
+    },
+    "skill-discovery-in-chat-tier-b4": {
+      "status": "completed",
+      "date": "2026-02-18",
+      "updated": "2026-02-18",
+      "summary": "Completed Tier B4 in-chat discovery/install surface by adding `/skill` command (`list|search|install`) through command fast-path. Reused existing registry source/catalog infrastructure and managed-skill installer, with local registry-source install support and explicit remote-source fallback guidance to CLI.",
+      "files_modified": [
+        "src/commands/types.ts",
+        "src/commands/builtin/index.ts",
+        "src/commands/builtin/index.test.ts",
+        "src/commands/index.ts",
+        "src/daemon/routing.ts",
+        "src/daemon/routing.test.ts",
+        "src/daemon/index.ts",
+        "README.md",
+        "docs/plans/state.json"
+      ],
+      "test_status": "pnpm test:run src/commands/builtin/index.test.ts src/daemon/routing.test.ts + pnpm typecheck passing"
     }
   },
   "overall_progress": {
@@ -5328,7 +5346,7 @@
     "gmail_auth_cli": "flynn gmail-auth command implemented with OAuth2 flow, doctor check, config routed to Telegram",
     "native_audio_support": "completed — smart routing for native audio (Gemini/OpenAI/GitHub) vs Whisper transcription fallback",
     "remaining_phases_completion": "Phase 1: 3/3 (100%) — context levels, command registry, memory structure. Phase 2: 3/3 (100%) — component registry, confidence routing, history index. Phase 3: 2/2 (100%) — adaptive memory/compaction, truthfulness/autonomy hardening",
-    "next_up": "Implement Tier B4 skill discovery index (registry-backed search/install flow)"
+    "next_up": "Implement Tier B3 progressive web app push notifications for WebChat"
   },
   "soul_md_and_cron_create": {
     "date": "2026-02-11",

src/commands/builtin/index.test.ts

@@ -1,6 +1,6 @@
 import { describe, it, expect, vi } from 'vitest';
 
-import { createApproveCommand, createApprovalsCommand, createContextCommand, createDenyCommand, createElevateCommand, createModelCommand, createQueueCommand, createResearchCommand, createTransferCommand } from './index.js';
+import { createApproveCommand, createApprovalsCommand, createContextCommand, createDenyCommand, createElevateCommand, createModelCommand, createQueueCommand, createResearchCommand, createSkillCommand, createTransferCommand } from './index.js';
 
 describe('builtin /model command', () => {
   it('passes through the full argument string', async () => {
@@ -241,3 +241,19 @@ describe('builtin approval commands', () => {
     expect(result).toEqual({ handled: true, text: 'denied' });
   });
 });
+
+describe('builtin /skill command', () => {
+  it('passes subcommand text to skillCommand service', async () => {
+    const cmd = createSkillCommand();
+    const skillCommand = vi.fn(() => 'ok');
+    const result = await cmd.execute(['search', 'calendar'], {
+      channel: 'test',
+      senderId: 'user',
+      sessionId: 's1',
+      rawInput: '/skill search calendar',
+      services: { skillCommand },
+    });
+    expect(skillCommand).toHaveBeenCalledWith('search calendar');
+    expect(result).toEqual({ handled: true, text: 'ok' });
+  });
+});

src/commands/builtin/index.ts

@@ -284,6 +284,22 @@ export function createDenyCommand(): CommandDefinition {
   };
 }
 
+export function createSkillCommand(): CommandDefinition {
+  return {
+    name: 'skill',
+    description: 'In-chat skill discovery and install (list/search/install)',
+    execute: async (args, ctx) => {
+      if (!ctx.services?.skillCommand) {
+        return notAvailable('Skill command');
+      }
+      return {
+        handled: true,
+        text: await ctx.services.skillCommand(args.join(' ').trim()),
+      };
+    },
+  };
+}
+
 export function registerBuiltinCommands(registry: CommandRegistry): void {
   registry.register(createHelpCommand(registry));
   registry.register(createStatusCommand());
@@ -299,4 +315,5 @@ export function registerBuiltinCommands(registry: CommandRegistry): void {
   registry.register(createApprovalsCommand());
   registry.register(createApproveCommand());
   registry.register(createDenyCommand());
+  registry.register(createSkillCommand());
 }

src/commands/index.ts

@@ -13,5 +13,6 @@ export {
   createApprovalsCommand,
   createApproveCommand,
   createDenyCommand,
+  createSkillCommand,
   registerBuiltinCommands,
 } from './builtin/index.js';

src/commands/types.ts

@@ -38,4 +38,5 @@ export interface CommandServices {
   getApprovals?: () => Promise<string> | string;
   approvePending?: (input: string) => Promise<string> | string;
   denyPending?: (input: string) => Promise<string> | string;
+  skillCommand?: (input: string) => Promise<string> | string;
 }

src/daemon/index.ts

@@ -213,7 +213,7 @@ export async function startDaemon(config: Config, options?: StartDaemonOptions):
 
   const messageRouter = createMessageRouter({
     sessionManager, modelRouter, systemPrompt, toolRegistry, toolExecutor,
-    config, memoryStore, agentConfigRegistry, agentRouter, sandboxManager, commandRegistry, hookEngine, intentRegistry, routingPolicy, skillRegistry,
+    config, memoryStore, agentConfigRegistry, agentRouter, sandboxManager, commandRegistry, hookEngine, intentRegistry, routingPolicy, skillRegistry, skillInstaller,
     ...createConfiguredExternalBackends(config),
   });
   channelRegistry.setMessageHandler(messageRouter.handler);

src/daemon/routing.test.ts

@@ -911,6 +911,79 @@ describe('daemon command fast-path integration', () => {
     await expect(pendingPromise).resolves.toEqual({ approved: true });
     expect(processSpy).not.toHaveBeenCalled();
   });
+
+  it('handles /skill list via command fast-path', async () => {
+    const processSpy = vi.spyOn(AgentOrchestrator.prototype, 'process');
+    const session = {
+      id: 'telegram:skill-user',
+      addMessage: vi.fn(),
+      getHistory: vi.fn(() => []),
+      clear: vi.fn(),
+      replaceHistory: vi.fn(),
+      getConfig: vi.fn(() => undefined),
+      setConfig: vi.fn(),
+      deleteConfig: vi.fn(),
+    };
+
+    const commandRegistry = new CommandRegistry();
+    registerBuiltinCommands(commandRegistry);
+
+    const router = createMessageRouter({
+      sessionManager: {
+        getSession: vi.fn(() => session),
+      } as unknown as MessageRouterDeps['sessionManager'],
+      modelRouter: {
+        getAvailableTiers: () => ['fast', 'default', 'complex', 'local'],
+        getAllLabels: () => ({ fast: 'fast', default: 'default', complex: 'complex', local: 'local' }),
+        getLabel: (tier: string) => tier,
+      } as unknown as MessageRouterDeps['modelRouter'],
+      systemPrompt: 'test prompt',
+      toolRegistry: {
+        clone() { return this; },
+        register: vi.fn(),
+      } as unknown as MessageRouterDeps['toolRegistry'],
+      toolExecutor: {} as unknown as MessageRouterDeps['toolExecutor'],
+      config: {
+        agents: {
+          primary_tier: 'default',
+          delegation: {
+            compaction: 'fast',
+            memory_extraction: 'fast',
+            classification: 'fast',
+            tool_summarisation: 'fast',
+            complex_reasoning: 'complex',
+          },
+          max_delegation_depth: 3,
+          max_iterations: 10,
+        },
+        compaction: { enabled: false },
+        models: { default: { provider: 'anthropic', model: 'claude' } },
+      } as unknown as MessageRouterDeps['config'],
+      commandRegistry,
+      skillRegistry: {
+        listAvailable: () => ([
+          { manifest: { name: 'calendar', tier: 'managed', version: '1.2.0' } },
+          { manifest: { name: 'todoist', tier: 'workspace', version: '0.4.1' } },
+        ]),
+      } as unknown as MessageRouterDeps['skillRegistry'],
+    });
+
+    const reply = vi.fn(async (_message: OutboundMessage) => {});
+    await router.handler({
+      id: 'skill-1',
+      channel: 'telegram',
+      senderId: 'skill-user',
+      text: '/skill list',
+      timestamp: Date.now(),
+      metadata: { isCommand: true, command: 'skill', commandArgs: 'list' },
+    } as MessageRouterInput, reply);
+
+    expect(processSpy).not.toHaveBeenCalled();
+    const outbound = reply.mock.calls[0]?.[0] as OutboundMessage | undefined;
+    expect(String(outbound?.text)).toContain('Available skills (2):');
+    expect(String(outbound?.text)).toContain('calendar');
+    expect(String(outbound?.text)).toContain('todoist');
+  });
 });
 
 describe('daemon external backend integration', () => {

src/daemon/routing.ts

@@ -23,9 +23,11 @@ import type { RoutingPolicy } from '../routing/index.js';
 import type { HookEngine } from '../hooks/index.js';
 import { createClientFromConfig } from './models.js';
 import { matchReactionPrompt } from '../automation/reactions.js';
-import type { SkillRegistry } from '../skills/index.js';
+import { loadSkillRegistryCatalog } from '../skills/index.js';
+import type { SkillInstaller, SkillRegistry, SkillRegistryEntry, SkillRegistrySource } from '../skills/index.js';
 import { auditLogger } from '../audit/index.js';
 import { randomUUID } from 'crypto';
+import { dirname, resolve } from 'path';
 
 function buildProviderConfigMap(config: Config): Partial<Record<ModelProvider, ModelConfig>> {
   const providerConfigs: Partial<Record<ModelProvider, ModelConfig>> = {};
@@ -98,6 +100,47 @@ function isTtsEnabledForChannel(config: Config, channel: string): boolean {
   }
   return enabledChannels.includes(channel);
 }
+
+function resolveRegistrySource(config: Config): { source?: SkillRegistrySource; error?: string } {
+  const raw = config.skills.registry_source?.trim() || process.env.FLYNN_SKILLS_REGISTRY_SOURCE?.trim();
+  if (!raw) {
+    return {
+      error: 'Skills registry is not configured. Set `skills.registry_source` (or FLYNN_SKILLS_REGISTRY_SOURCE).',
+    };
+  }
+  if (raw.startsWith('http://')) {
+    return { error: `Registry URL must use https:// (${raw})` };
+  }
+  if (raw.startsWith('https://')) {
+    return { source: { type: 'url', url: raw } };
+  }
+  return { source: { type: 'file', path: raw } };
+}
+
+function resolveRegistryEntryLocalPath(entry: SkillRegistryEntry, registrySource: SkillRegistrySource): string | null {
+  const source = entry.source.trim();
+  if (!source) {
+    return null;
+  }
+
+  if (source.startsWith('http://') || source.startsWith('https://') || source.startsWith('git+https://')) {
+    return null;
+  }
+
+  if (source.startsWith('file://')) {
+    try {
+      return decodeURIComponent(new URL(source).pathname);
+    } catch {
+      return null;
+    }
+  }
+
+  if (registrySource.type === 'file' && (source.startsWith('./') || source.startsWith('../'))) {
+    return resolve(dirname(resolve(registrySource.path)), source);
+  }
+
+  return resolve(source);
+}
 /**
  * Create the unified message handler for the channel registry.
  * Each channel+sender pair gets its own AgentOrchestrator backed by a persistent session.
@@ -121,6 +164,7 @@ export function createMessageRouter(deps: {
   intentRegistry?: ComponentRegistry;
   routingPolicy?: RoutingPolicy;
   skillRegistry?: SkillRegistry;
+  skillInstaller?: SkillInstaller;
   externalBackends?: Partial<Record<ExternalBackendName, ExternalBackend>>;
   defaultName?: ExternalBackendName;
 }): {
@@ -1018,6 +1062,97 @@ export function createMessageRouter(deps: {
               ? `Denied: ${selected.tool} (${selected.id}) — ${reason}`
               : `Approval request is no longer pending: ${selected.id}`;
           },
+
+          skillCommand: async (inputRaw: string) => {
+            const input = inputRaw.trim();
+            const [actionRaw, ...rest] = input.split(/\s+/).filter(Boolean);
+            const action = actionRaw?.toLowerCase();
+
+            if (!action || action === 'help') {
+              return [
+                'Usage: /skill <list|search|install>',
+                '/skill list',
+                '/skill search <term>',
+                '/skill install <registry-id>',
+              ].join('\n');
+            }
+
+            if (action === 'list') {
+              const skills = deps.skillRegistry?.listAvailable() ?? [];
+              if (skills.length === 0) {
+                return 'No available skills are currently loaded.';
+              }
+              return [
+                `Available skills (${skills.length}):`,
+                ...skills.map((skill) => `- ${skill.manifest.name} (${skill.manifest.tier}, v${skill.manifest.version})`),
+              ].join('\n');
+            }
+
+            if (action === 'search') {
+              const term = rest.join(' ').trim().toLowerCase();
+              if (!term) {
+                return 'Usage: /skill search <term>';
+              }
+              const sourceResolved = resolveRegistrySource(deps.config);
+              if (!sourceResolved.source) {
+                return sourceResolved.error ?? 'Failed to resolve registry source.';
+              }
+              try {
+                const catalog = await loadSkillRegistryCatalog(sourceResolved.source);
+                const matches = catalog.skills.filter((entry) => {
+                  const haystack = `${entry.id} ${entry.name} ${entry.summary} ${entry.publisher ?? ''}`.toLowerCase();
+                  return haystack.includes(term);
+                }).slice(0, 12);
+                if (matches.length === 0) {
+                  return `No registry skills found for "${term}".`;
+                }
+                return [
+                  `Registry matches (${matches.length}):`,
+                  ...matches.map((entry) => `- ${entry.id} (${entry.version}) — ${entry.summary}`),
+                ].join('\n');
+              } catch (error) {
+                return `Registry lookup failed: ${error instanceof Error ? error.message : String(error)}`;
+              }
+            }
+
+            if (action === 'install') {
+              const registryId = rest.join(' ').trim().toLowerCase();
+              if (!registryId) {
+                return 'Usage: /skill install <registry-id>';
+              }
+              if (!deps.skillInstaller || !deps.skillRegistry) {
+                return 'Skill installation is unavailable in this runtime.';
+              }
+
+              const sourceResolved = resolveRegistrySource(deps.config);
+              if (!sourceResolved.source) {
+                return sourceResolved.error ?? 'Failed to resolve registry source.';
+              }
+
+              try {
+                const catalog = await loadSkillRegistryCatalog(sourceResolved.source);
+                const entry = catalog.skills.find((item) => item.id.toLowerCase() === registryId);
+                if (!entry) {
+                  return `Registry skill not found: ${registryId}`;
+                }
+                const localPath = resolveRegistryEntryLocalPath(entry, sourceResolved.source);
+                if (!localPath) {
+                  return `Registry entry '${entry.id}' points to a remote source. Use CLI install for remote sources.`;
+                }
+
+                const installed = deps.skillInstaller.install(localPath);
+                if (!installed) {
+                  return `Failed to install skill from ${entry.source}`;
+                }
+                deps.skillRegistry.register(installed);
+                return `Installed skill '${installed.manifest.name}' (${installed.manifest.version}) from registry id '${entry.id}'.`;
+              } catch (error) {
+                return `Skill install failed: ${error instanceof Error ? error.message : String(error)}`;
+              }
+            }
+
+            return 'Unknown skill action. Use: list, search, install';
+          },
         },
       });