apps/gateway/package.json

@@ -5,7 +5,7 @@
   "main": "dist/main.js",
   "scripts": {
     "build": "tsc",
-    "dev": "tsc --watch",
+    "dev": "tsx watch src/main.ts",
     "lint": "eslint src",
     "typecheck": "tsc --noEmit",
     "test": "vitest run"
@@ -14,12 +14,19 @@
     "@nestjs/common": "^11.0.0",
     "@nestjs/core": "^11.0.0",
     "@nestjs/platform-fastify": "^11.0.0",
+    "@nestjs/platform-socket.io": "^11.0.0",
+    "@nestjs/websockets": "^11.0.0",
+    "@mariozechner/pi-coding-agent": "~0.57.1",
     "fastify": "^5.0.0",
     "reflect-metadata": "^0.2.0",
-    "rxjs": "^7.8.0"
+    "rxjs": "^7.8.0",
+    "socket.io": "^4.8.0",
+    "uuid": "^11.0.0"
   },
   "devDependencies": {
     "@types/node": "^22.0.0",
+    "@types/uuid": "^10.0.0",
+    "tsx": "^4.0.0",
     "typescript": "^5.8.0",
     "vitest": "^2.0.0"
   }

apps/gateway/src/agent/agent.module.ts

@@ -0,0 +1,9 @@
+import { Global, Module } from '@nestjs/common';
+import { AgentService } from './agent.service.js';
+
+@Global()
+@Module({
+  providers: [AgentService],
+  exports: [AgentService],
+})
+export class AgentModule {}

apps/gateway/src/agent/agent.service.ts

@@ -0,0 +1,94 @@
+import { Injectable, Logger, type OnModuleDestroy } from '@nestjs/common';
+import {
+  createAgentSession,
+  SessionManager,
+  type AgentSession as PiAgentSession,
+  type AgentSessionEvent,
+} from '@mariozechner/pi-coding-agent';
+
+export interface AgentSession {
+  id: string;
+  piSession: PiAgentSession;
+  listeners: Set<(event: AgentSessionEvent) => void>;
+  unsubscribe: () => void;
+}
+
+@Injectable()
+export class AgentService implements OnModuleDestroy {
+  private readonly logger = new Logger(AgentService.name);
+  private readonly sessions = new Map<string, AgentSession>();
+
+  async createSession(sessionId: string): Promise<AgentSession> {
+    if (this.sessions.has(sessionId)) {
+      return this.sessions.get(sessionId)!;
+    }
+
+    this.logger.log(`Creating agent session: ${sessionId}`);
+
+    const { session: piSession } = await createAgentSession({
+      sessionManager: SessionManager.inMemory(),
+      tools: [],
+    });
+
+    const listeners = new Set<(event: AgentSessionEvent) => void>();
+
+    const unsubscribe = piSession.subscribe((event) => {
+      for (const listener of listeners) {
+        try {
+          listener(event);
+        } catch (err) {
+          this.logger.error(`Event listener error in session ${sessionId}`, err);
+        }
+      }
+    });
+
+    const session: AgentSession = {
+      id: sessionId,
+      piSession,
+      listeners,
+      unsubscribe,
+    };
+
+    this.sessions.set(sessionId, session);
+    this.logger.log(`Agent session ${sessionId} ready`);
+
+    return session;
+  }
+
+  getSession(sessionId: string): AgentSession | undefined {
+    return this.sessions.get(sessionId);
+  }
+
+  async prompt(sessionId: string, message: string): Promise<void> {
+    const session = this.sessions.get(sessionId);
+    if (!session) {
+      throw new Error(`No agent session found: ${sessionId}`);
+    }
+    await session.piSession.prompt(message);
+  }
+
+  onEvent(sessionId: string, listener: (event: AgentSessionEvent) => void): () => void {
+    const session = this.sessions.get(sessionId);
+    if (!session) {
+      throw new Error(`No agent session found: ${sessionId}`);
+    }
+    session.listeners.add(listener);
+    return () => session.listeners.delete(listener);
+  }
+
+  async destroySession(sessionId: string): Promise<void> {
+    const session = this.sessions.get(sessionId);
+    if (session) {
+      this.logger.log(`Destroying agent session ${sessionId}`);
+      session.unsubscribe();
+      session.listeners.clear();
+      this.sessions.delete(sessionId);
+    }
+  }
+
+  async onModuleDestroy(): Promise<void> {
+    this.logger.log('Shutting down all agent sessions');
+    const stops = Array.from(this.sessions.keys()).map((id) => this.destroySession(id));
+    await Promise.allSettled(stops);
+  }
+}

apps/gateway/src/app.module.ts

@@ -1,7 +1,10 @@
 import { Module } from '@nestjs/common';
 import { HealthController } from './health/health.controller.js';
+import { AgentModule } from './agent/agent.module.js';
+import { ChatModule } from './chat/chat.module.js';
 
 @Module({
+  imports: [AgentModule, ChatModule],
   controllers: [HealthController],
 })
 export class AppModule {}

apps/gateway/src/chat/chat.controller.ts

@@ -0,0 +1,55 @@
+import { Controller, Post, Body, Logger } from '@nestjs/common';
+import type { AgentSessionEvent } from '@mariozechner/pi-coding-agent';
+import { AgentService } from '../agent/agent.service.js';
+import { v4 as uuid } from 'uuid';
+
+interface ChatRequest {
+  conversationId?: string;
+  content: string;
+}
+
+interface ChatResponse {
+  conversationId: string;
+  text: string;
+}
+
+@Controller('api/chat')
+export class ChatController {
+  private readonly logger = new Logger(ChatController.name);
+
+  constructor(private readonly agentService: AgentService) {}
+
+  @Post()
+  async chat(@Body() body: ChatRequest): Promise<ChatResponse> {
+    const conversationId = body.conversationId ?? uuid();
+
+    let agentSession = this.agentService.getSession(conversationId);
+    if (!agentSession) {
+      agentSession = await this.agentService.createSession(conversationId);
+    }
+
+    let responseText = '';
+
+    const done = new Promise<void>((resolve) => {
+      const cleanup = this.agentService.onEvent(conversationId, (event: AgentSessionEvent) => {
+        if (event.type === 'message_update' && event.assistantMessageEvent.type === 'text_delta') {
+          responseText += event.assistantMessageEvent.delta;
+        }
+        if (event.type === 'agent_end') {
+          cleanup();
+          resolve();
+        }
+      });
+
+      setTimeout(() => {
+        cleanup();
+        resolve();
+      }, 120_000);
+    });
+
+    await this.agentService.prompt(conversationId, body.content);
+    await done;
+
+    return { conversationId, text: responseText };
+  }
+}

apps/gateway/src/chat/chat.gateway.ts

@@ -0,0 +1,139 @@
+import { Logger } from '@nestjs/common';
+import {
+  WebSocketGateway,
+  WebSocketServer,
+  SubscribeMessage,
+  OnGatewayConnection,
+  OnGatewayDisconnect,
+  type OnGatewayInit,
+  ConnectedSocket,
+  MessageBody,
+} from '@nestjs/websockets';
+import { Server, Socket } from 'socket.io';
+import type { AgentSessionEvent } from '@mariozechner/pi-coding-agent';
+import { AgentService } from '../agent/agent.service.js';
+import { v4 as uuid } from 'uuid';
+
+interface ChatMessage {
+  conversationId?: string;
+  content: string;
+}
+
+@WebSocketGateway({
+  cors: { origin: '*' },
+  namespace: '/chat',
+})
+export class ChatGateway implements OnGatewayInit, OnGatewayConnection, OnGatewayDisconnect {
+  @WebSocketServer()
+  server!: Server;
+
+  private readonly logger = new Logger(ChatGateway.name);
+  private readonly clientSessions = new Map<
+    string,
+    { conversationId: string; cleanup: () => void }
+  >();
+
+  constructor(private readonly agentService: AgentService) {}
+
+  afterInit(): void {
+    this.logger.log('Chat WebSocket gateway initialized');
+  }
+
+  handleConnection(client: Socket): void {
+    this.logger.log(`Client connected: ${client.id}`);
+  }
+
+  handleDisconnect(client: Socket): void {
+    this.logger.log(`Client disconnected: ${client.id}`);
+    const session = this.clientSessions.get(client.id);
+    if (session) {
+      session.cleanup();
+      this.clientSessions.delete(client.id);
+    }
+  }
+
+  @SubscribeMessage('message')
+  async handleMessage(
+    @ConnectedSocket() client: Socket,
+    @MessageBody() data: ChatMessage,
+  ): Promise<void> {
+    const conversationId = data.conversationId ?? uuid();
+
+    this.logger.log(`Message from ${client.id} in conversation ${conversationId}`);
+
+    // Ensure agent session exists for this conversation
+    let agentSession = this.agentService.getSession(conversationId);
+    if (!agentSession) {
+      agentSession = await this.agentService.createSession(conversationId);
+    }
+
+    // Clean up any previous event subscription for this client
+    const existing = this.clientSessions.get(client.id);
+    if (existing && existing.conversationId !== conversationId) {
+      existing.cleanup();
+    }
+
+    // Subscribe to agent events and relay to client
+    const cleanup = this.agentService.onEvent(conversationId, (event: AgentSessionEvent) => {
+      this.relayEvent(client, conversationId, event);
+    });
+
+    this.clientSessions.set(client.id, { conversationId, cleanup });
+
+    // Send acknowledgment
+    client.emit('message:ack', { conversationId, messageId: uuid() });
+
+    // Dispatch to agent
+    try {
+      await this.agentService.prompt(conversationId, data.content);
+    } catch (err) {
+      this.logger.error(`Agent prompt failed: ${err}`);
+      client.emit('error', { conversationId, error: String(err) });
+    }
+  }
+
+  private relayEvent(client: Socket, conversationId: string, event: AgentSessionEvent): void {
+    switch (event.type) {
+      case 'agent_start':
+        client.emit('agent:start', { conversationId });
+        break;
+
+      case 'agent_end':
+        client.emit('agent:end', { conversationId });
+        break;
+
+      case 'message_update': {
+        const assistantEvent = event.assistantMessageEvent;
+        if (assistantEvent.type === 'text_delta') {
+          client.emit('agent:text', {
+            conversationId,
+            text: assistantEvent.delta,
+          });
+        } else if (assistantEvent.type === 'thinking_delta') {
+          client.emit('agent:thinking', {
+            conversationId,
+            text: assistantEvent.delta,
+          });
+        }
+        break;
+      }
+
+      case 'tool_execution_start':
+        client.emit('agent:tool:start', {
+          conversationId,
+          toolCallId: event.toolCallId,
+          toolName: event.toolName,
+        });
+        break;
+
+      case 'tool_execution_end':
+        client.emit('agent:tool:end', {
+          conversationId,
+          toolCallId: event.toolCallId,
+          toolName: event.toolName,
+          isError: event.isError,
+        });
+        break;
+    }
+  }
+}

apps/gateway/src/chat/chat.module.ts

@@ -0,0 +1,9 @@
+import { Module } from '@nestjs/common';
+import { ChatGateway } from './chat.gateway.js';
+import { ChatController } from './chat.controller.js';
+
+@Module({
+  controllers: [ChatController],
+  providers: [ChatGateway],
+})
+export class ChatModule {}

packages/cli/package.json

@@ -1,10 +1,11 @@
 {
   "name": "@mosaic/cli",
   "version": "0.0.0",
+  "type": "module",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",
   "bin": {
-    "mosaic": "dist/index.js"
+    "mosaic": "dist/cli.js"
   },
   "exports": {
     ".": {
@@ -14,11 +15,22 @@
   },
   "scripts": {
     "build": "tsc",
+    "dev": "tsx src/cli.ts",
     "lint": "eslint src",
     "typecheck": "tsc --noEmit",
     "test": "vitest run"
   },
+  "dependencies": {
+    "ink": "^5.0.0",
+    "ink-text-input": "^6.0.0",
+    "ink-spinner": "^5.0.0",
+    "react": "^18.3.0",
+    "socket.io-client": "^4.8.0",
+    "commander": "^13.0.0"
+  },
   "devDependencies": {
+    "@types/react": "^18.3.0",
+    "tsx": "^4.0.0",
     "typescript": "^5.8.0",
     "vitest": "^2.0.0"
   }

packages/cli/src/cli.ts

@@ -0,0 +1,28 @@
+#!/usr/bin/env node
+
+import { Command } from 'commander';
+
+const program = new Command();
+
+program.name('mosaic').description('Mosaic Stack CLI').version('0.0.0');
+
+program
+  .command('tui')
+  .description('Launch interactive TUI connected to the gateway')
+  .option('-g, --gateway <url>', 'Gateway URL', 'http://localhost:4000')
+  .option('-c, --conversation <id>', 'Resume a conversation by ID')
+  .action(async (opts: { gateway: string; conversation?: string }) => {
+    // Dynamic import to avoid loading React/Ink for other commands
+    const { render } = await import('ink');
+    const React = await import('react');
+    const { TuiApp } = await import('./tui/app.js');
+
+    render(
+      React.createElement(TuiApp, {
+        gatewayUrl: opts.gateway,
+        conversationId: opts.conversation,
+      }),
+    );
+  });
+
+program.parse();

packages/cli/src/tui/app.tsx

@@ -0,0 +1,144 @@
+import React, { useState, useCallback, useEffect, useRef } from 'react';
+import { Box, Text, useInput, useApp } from 'ink';
+import TextInput from 'ink-text-input';
+import Spinner from 'ink-spinner';
+import { io, type Socket } from 'socket.io-client';
+
+interface Message {
+  role: 'user' | 'assistant';
+  content: string;
+}
+
+interface TuiAppProps {
+  gatewayUrl: string;
+  conversationId?: string;
+}
+
+export function TuiApp({ gatewayUrl, conversationId: initialConversationId }: TuiAppProps) {
+  const { exit } = useApp();
+  const [messages, setMessages] = useState<Message[]>([]);
+  const [input, setInput] = useState('');
+  const [isStreaming, setIsStreaming] = useState(false);
+  const [connected, setConnected] = useState(false);
+  const [conversationId, setConversationId] = useState(initialConversationId);
+  const [currentStreamText, setCurrentStreamText] = useState('');
+  const socketRef = useRef<Socket | null>(null);
+
+  useEffect(() => {
+    const socket = io(`${gatewayUrl}/chat`, {
+      transports: ['websocket'],
+    });
+
+    socketRef.current = socket;
+
+    socket.on('connect', () => setConnected(true));
+    socket.on('disconnect', () => setConnected(false));
+
+    socket.on('message:ack', (data: { conversationId: string }) => {
+      setConversationId(data.conversationId);
+    });
+
+    socket.on('agent:start', () => {
+      setIsStreaming(true);
+      setCurrentStreamText('');
+    });
+
+    socket.on('agent:text', (data: { text: string }) => {
+      setCurrentStreamText((prev) => prev + data.text);
+    });
+
+    socket.on('agent:end', () => {
+      setCurrentStreamText((prev) => {
+        if (prev) {
+          setMessages((msgs) => [...msgs, { role: 'assistant', content: prev }]);
+        }
+        return '';
+      });
+      setIsStreaming(false);
+    });
+
+    socket.on('error', (data: { error: string }) => {
+      setMessages((msgs) => [...msgs, { role: 'assistant', content: `Error: ${data.error}` }]);
+      setIsStreaming(false);
+    });
+
+    return () => {
+      socket.disconnect();
+    };
+  }, [gatewayUrl]);
+
+  const handleSubmit = useCallback(
+    (value: string) => {
+      if (!value.trim() || isStreaming || !socketRef.current) return;
+
+      setMessages((msgs) => [...msgs, { role: 'user', content: value }]);
+      setInput('');
+
+      socketRef.current.emit('message', {
+        conversationId,
+        content: value,
+      });
+    },
+    [conversationId, isStreaming],
+  );
+
+  useInput((ch, key) => {
+    if (key.ctrl && ch === 'c') {
+      exit();
+    }
+  });
+
+  return (
+    <Box flexDirection="column" padding={1}>
+      <Box marginBottom={1}>
+        <Text bold color="blue">
+          Mosaic
+        </Text>
+        <Text> </Text>
+        <Text dimColor>{connected ? `connected` : 'connecting...'}</Text>
+        {conversationId && <Text dimColor> | {conversationId.slice(0, 8)}</Text>}
+      </Box>
+
+      <Box flexDirection="column" marginBottom={1}>
+        {messages.map((msg, i) => (
+          <Box key={i} marginBottom={1}>
+            <Text bold color={msg.role === 'user' ? 'green' : 'cyan'}>
+              {msg.role === 'user' ? '> ' : '  '}
+            </Text>
+            <Text wrap="wrap">{msg.content}</Text>
+          </Box>
+        ))}
+
+        {isStreaming && currentStreamText && (
+          <Box marginBottom={1}>
+            <Text bold color="cyan">
+              {'  '}
+            </Text>
+            <Text wrap="wrap">{currentStreamText}</Text>
+          </Box>
+        )}
+
+        {isStreaming && !currentStreamText && (
+          <Box>
+            <Text color="cyan">
+              <Spinner type="dots" />
+            </Text>
+            <Text dimColor> thinking...</Text>
+          </Box>
+        )}
+      </Box>
+
+      <Box>
+        <Text bold color="green">
+          {'> '}
+        </Text>
+        <TextInput
+          value={input}
+          onChange={setInput}
+          onSubmit={handleSubmit}
+          placeholder={isStreaming ? 'waiting...' : 'type a message'}
+        />
+      </Box>
+    </Box>
+  );
+}

packages/cli/tsconfig.json

@@ -2,7 +2,8 @@
   "extends": "../../tsconfig.base.json",
   "compilerOptions": {
     "outDir": "dist",
-    "rootDir": "src"
+    "rootDir": "src",
+    "jsx": "react-jsx"
   },
   "include": ["src/**/*"],
   "exclude": ["node_modules", "dist"]

plugins/discord/package.json

@@ -11,11 +11,17 @@
   },
   "scripts": {
     "build": "tsc",
+    "dev": "tsx watch src/index.ts",
     "lint": "eslint src",
     "typecheck": "tsc --noEmit",
     "test": "vitest run"
   },
+  "dependencies": {
+    "discord.js": "^14.16.0",
+    "socket.io-client": "^4.8.0"
+  },
   "devDependencies": {
+    "tsx": "^4.0.0",
     "typescript": "^5.8.0",
     "vitest": "^2.0.0"
   }

plugins/discord/src/index.ts

@@ -1 +1,153 @@
-export const VERSION = '0.0.0';
+import { Client, GatewayIntentBits, type Message as DiscordMessage } from 'discord.js';
+import { io, type Socket } from 'socket.io-client';
+
+export interface DiscordPluginConfig {
+  token: string;
+  gatewayUrl: string;
+  /** Which guild to bind to (single-guild only for v0.1.0) */
+  guildId?: string;
+}
+
+export class DiscordPlugin {
+  private client: Client;
+  private socket: Socket | null = null;
+  private config: DiscordPluginConfig;
+  /** Map Discord channel ID → Mosaic conversation ID */
+  private channelConversations = new Map<string, string>();
+  /** Track in-flight responses to avoid duplicate streaming */
+  private pendingResponses = new Map<string, string>();
+
+  constructor(config: DiscordPluginConfig) {
+    this.config = config;
+    this.client = new Client({
+      intents: [
+        GatewayIntentBits.Guilds,
+        GatewayIntentBits.GuildMessages,
+        GatewayIntentBits.MessageContent,
+        GatewayIntentBits.DirectMessages,
+      ],
+    });
+  }
+
+  async start(): Promise<void> {
+    // Connect to gateway WebSocket
+    this.socket = io(`${this.config.gatewayUrl}/chat`, {
+      transports: ['websocket'],
+    });
+
+    this.socket.on('connect', () => {
+      console.log('[discord] Connected to gateway');
+    });
+
+    // Handle streaming text from gateway
+    this.socket.on('agent:text', (data: { conversationId: string; text: string }) => {
+      const pending = this.pendingResponses.get(data.conversationId);
+      if (pending !== undefined) {
+        this.pendingResponses.set(data.conversationId, pending + data.text);
+      }
+    });
+
+    // When agent finishes, send the accumulated response
+    this.socket.on('agent:end', (data: { conversationId: string }) => {
+      const text = this.pendingResponses.get(data.conversationId);
+      if (text) {
+        this.sendToDiscord(data.conversationId, text);
+        this.pendingResponses.delete(data.conversationId);
+      }
+    });
+
+    this.socket.on('agent:start', (data: { conversationId: string }) => {
+      this.pendingResponses.set(data.conversationId, '');
+    });
+
+    // Set up Discord message handler
+    this.client.on('messageCreate', (message) => this.handleDiscordMessage(message));
+
+    this.client.on('ready', () => {
+      console.log(`[discord] Bot logged in as ${this.client.user?.tag}`);
+    });
+
+    await this.client.login(this.config.token);
+  }
+
+  async stop(): Promise<void> {
+    this.socket?.disconnect();
+    await this.client.destroy();
+  }
+
+  private handleDiscordMessage(message: DiscordMessage): void {
+    // Ignore bot messages
+    if (message.author.bot) return;
+
+    // Check guild binding
+    if (this.config.guildId && message.guildId !== this.config.guildId) return;
+
+    // Respond to DMs always, or mentions in channels
+    const isDM = !message.guildId;
+    const isMention = message.mentions.has(this.client.user!);
+
+    if (!isDM && !isMention) return;
+
+    // Strip bot mention from message content
+    const content = message.content
+      .replace(new RegExp(`<@!?${this.client.user!.id}>`, 'g'), '')
+      .trim();
+
+    if (!content) return;
+
+    // Get or create conversation for this Discord channel
+    const channelId = message.channelId;
+    let conversationId = this.channelConversations.get(channelId);
+    if (!conversationId) {
+      conversationId = `discord-${channelId}`;
+      this.channelConversations.set(channelId, conversationId);
+    }
+
+    // Send to gateway
+    this.socket?.emit('message', {
+      conversationId,
+      content,
+    });
+  }
+
+  private sendToDiscord(conversationId: string, text: string): void {
+    // Find the Discord channel for this conversation
+    const channelId = Array.from(this.channelConversations.entries()).find(
+      ([, convId]) => convId === conversationId,
+    )?.[0];
+
+    if (!channelId) return;
+
+    const channel = this.client.channels.cache.get(channelId);
+    if (!channel || !('send' in channel)) return;
+
+    // Chunk responses for Discord's 2000-char limit
+    const chunks = this.chunkText(text, 1900);
+    for (const chunk of chunks) {
+      (channel as { send: (content: string) => Promise<unknown> }).send(chunk);
+    }
+  }
+
+  private chunkText(text: string, maxLength: number): string[] {
+    if (text.length <= maxLength) return [text];
+
+    const chunks: string[] = [];
+    let remaining = text;
+
+    while (remaining.length > 0) {
+      if (remaining.length <= maxLength) {
+        chunks.push(remaining);
+        break;
+      }
+
+      // Try to break at a newline
+      let breakPoint = remaining.lastIndexOf('\n', maxLength);
+      if (breakPoint <= 0) breakPoint = maxLength;
+
+      chunks.push(remaining.slice(0, breakPoint));
+      remaining = remaining.slice(breakPoint).trimStart();
+    }
+
+    return chunks;
+  }
+}