feat: add web search, file edit, MCP management, file refs, and /stop to CLI/TUI (#348)

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

@@ -23,6 +23,7 @@ import { createFileTools } from './tools/file-tools.js';
 import { createGitTools } from './tools/git-tools.js';
 import { createShellTools } from './tools/shell-tools.js';
 import { createWebTools } from './tools/web-tools.js';
+import { createSearchTools } from './tools/search-tools.js';
 import type { SessionInfoDto, SessionMetrics } from './session.dto.js';
 import { SystemOverrideService } from '../preferences/system-override.service.js';
 import { PreferencesService } from '../preferences/preferences.service.js';
@@ -146,6 +147,7 @@ export class AgentService implements OnModuleDestroy {
       ...createGitTools(sandboxDir),
       ...createShellTools(sandboxDir),
       ...createWebTools(),
+      ...createSearchTools(),
     ];
   }
 

apps/gateway/src/agent/tools/file-tools.ts

@@ -190,5 +190,169 @@ export function createFileTools(baseDir: string): ToolDefinition[] {
     },
   };
 
-  return [readFileTool, writeFileTool, listDirectoryTool];
+  const editFileTool: ToolDefinition = {
+    name: 'fs_edit_file',
+    label: 'Edit File',
+    description:
+      'Make targeted text replacements in a file. Each edit replaces an exact match of oldText with newText. ' +
+      'All edits are matched against the original file content (not incrementally). ' +
+      'Each oldText must be unique in the file and edits must not overlap.',
+    parameters: Type.Object({
+      path: Type.String({
+        description: 'File path (relative to sandbox base or absolute within it)',
+      }),
+      edits: Type.Array(
+        Type.Object({
+          oldText: Type.String({
+            description: 'Exact text to find and replace (must be unique in the file)',
+          }),
+          newText: Type.String({ description: 'Replacement text' }),
+        }),
+        { description: 'One or more targeted replacements', minItems: 1 },
+      ),
+    }),
+    async execute(_toolCallId, params) {
+      const { path, edits } = params as {
+        path: string;
+        edits: Array<{ oldText: string; newText: string }>;
+      };
+
+      let safePath: string;
+      try {
+        safePath = guardPath(path, baseDir);
+      } catch (err) {
+        if (err instanceof SandboxEscapeError) {
+          return {
+            content: [{ type: 'text' as const, text: `Error: ${err.message}` }],
+            details: undefined,
+          };
+        }
+        return {
+          content: [{ type: 'text' as const, text: `Error: ${String(err)}` }],
+          details: undefined,
+        };
+      }
+
+      try {
+        const info = await stat(safePath);
+        if (!info.isFile()) {
+          return {
+            content: [{ type: 'text' as const, text: `Error: path is not a file: ${path}` }],
+            details: undefined,
+          };
+        }
+        if (info.size > MAX_READ_BYTES) {
+          return {
+            content: [
+              {
+                type: 'text' as const,
+                text: `Error: file too large for editing (${info.size} bytes, limit ${MAX_READ_BYTES} bytes)`,
+              },
+            ],
+            details: undefined,
+          };
+        }
+      } catch (err) {
+        return {
+          content: [{ type: 'text' as const, text: `Error reading file: ${String(err)}` }],
+          details: undefined,
+        };
+      }
+
+      let content: string;
+      try {
+        content = await readFile(safePath, { encoding: 'utf8' });
+      } catch (err) {
+        return {
+          content: [{ type: 'text' as const, text: `Error reading file: ${String(err)}` }],
+          details: undefined,
+        };
+      }
+
+      // Validate all edits before applying any
+      const errors: string[] = [];
+      for (let i = 0; i < edits.length; i++) {
+        const edit = edits[i]!;
+        const occurrences = content.split(edit.oldText).length - 1;
+        if (occurrences === 0) {
+          errors.push(`Edit ${i + 1}: oldText not found in file`);
+        } else if (occurrences > 1) {
+          errors.push(`Edit ${i + 1}: oldText matches ${occurrences} locations (must be unique)`);
+        }
+      }
+
+      // Check for overlapping edits
+      if (errors.length === 0) {
+        const positions = edits.map((edit, i) => ({
+          index: i,
+          start: content.indexOf(edit.oldText),
+          end: content.indexOf(edit.oldText) + edit.oldText.length,
+        }));
+        positions.sort((a, b) => a.start - b.start);
+        for (let i = 1; i < positions.length; i++) {
+          if (positions[i]!.start < positions[i - 1]!.end) {
+            errors.push(
+              `Edits ${positions[i - 1]!.index + 1} and ${positions[i]!.index + 1} overlap`,
+            );
+          }
+        }
+      }
+
+      if (errors.length > 0) {
+        return {
+          content: [
+            {
+              type: 'text' as const,
+              text: `Edit validation failed:\n${errors.join('\n')}`,
+            },
+          ],
+          details: undefined,
+        };
+      }
+
+      // Apply edits: process from end to start to preserve positions
+      const positions = edits.map((edit) => ({
+        edit,
+        start: content.indexOf(edit.oldText),
+      }));
+      positions.sort((a, b) => b.start - a.start); // reverse order
+
+      let result = content;
+      for (const { edit } of positions) {
+        result = result.replace(edit.oldText, edit.newText);
+      }
+
+      if (Buffer.byteLength(result, 'utf8') > MAX_WRITE_BYTES) {
+        return {
+          content: [
+            {
+              type: 'text' as const,
+              text: `Error: resulting file too large (limit ${MAX_WRITE_BYTES} bytes)`,
+            },
+          ],
+          details: undefined,
+        };
+      }
+
+      try {
+        await writeFile(safePath, result, { encoding: 'utf8' });
+        return {
+          content: [
+            {
+              type: 'text' as const,
+              text: `File edited successfully: ${path} (${edits.length} edit(s) applied)`,
+            },
+          ],
+          details: undefined,
+        };
+      } catch (err) {
+        return {
+          content: [{ type: 'text' as const, text: `Error writing file: ${String(err)}` }],
+          details: undefined,
+        };
+      }
+    },
+  };
+
+  return [readFileTool, writeFileTool, listDirectoryTool, editFileTool];
 }

apps/gateway/src/agent/tools/index.ts

@@ -2,6 +2,7 @@ export { createBrainTools } from './brain-tools.js';
 export { createCoordTools } from './coord-tools.js';
 export { createFileTools } from './file-tools.js';
 export { createGitTools } from './git-tools.js';
+export { createSearchTools } from './search-tools.js';
 export { createShellTools } from './shell-tools.js';
 export { createWebTools } from './web-tools.js';
 export { createSkillTools } from './skill-tools.js';

apps/gateway/src/agent/tools/search-tools.ts

@@ -0,0 +1,496 @@
+import { Type } from '@sinclair/typebox';
+import type { ToolDefinition } from '@mariozechner/pi-coding-agent';
+
+const DEFAULT_TIMEOUT_MS = 15_000;
+const MAX_RESULTS = 10;
+const MAX_RESPONSE_BYTES = 256 * 1024; // 256 KB
+
+// ─── Provider helpers ────────────────────────────────────────────────────────
+
+interface SearchResult {
+  title: string;
+  url: string;
+  snippet: string;
+}
+
+interface SearchResponse {
+  provider: string;
+  query: string;
+  results: SearchResult[];
+  error?: string;
+}
+
+async function fetchWithTimeout(
+  url: string,
+  init: RequestInit,
+  timeoutMs: number,
+): Promise<Response> {
+  const controller = new AbortController();
+  const timer = setTimeout(() => controller.abort(), timeoutMs);
+  try {
+    return await fetch(url, { ...init, signal: controller.signal });
+  } finally {
+    clearTimeout(timer);
+  }
+}
+
+async function readLimited(response: Response): Promise<string> {
+  const reader = response.body?.getReader();
+  if (!reader) return '';
+  const chunks: Uint8Array[] = [];
+  let total = 0;
+  while (true) {
+    const { done, value } = await reader.read();
+    if (done) break;
+    total += value.length;
+    if (total > MAX_RESPONSE_BYTES) {
+      chunks.push(value.subarray(0, MAX_RESPONSE_BYTES - (total - value.length)));
+      reader.cancel();
+      break;
+    }
+    chunks.push(value);
+  }
+  const combined = new Uint8Array(chunks.reduce((a, c) => a + c.length, 0));
+  let offset = 0;
+  for (const chunk of chunks) {
+    combined.set(chunk, offset);
+    offset += chunk.length;
+  }
+  return new TextDecoder().decode(combined);
+}
+
+// ─── Brave Search ────────────────────────────────────────────────────────────
+
+async function searchBrave(query: string, limit: number): Promise<SearchResponse> {
+  const apiKey = process.env['BRAVE_API_KEY'];
+  if (!apiKey) return { provider: 'brave', query, results: [], error: 'BRAVE_API_KEY not set' };
+
+  try {
+    const params = new URLSearchParams({
+      q: query,
+      count: String(Math.min(limit, 20)),
+    });
+    const res = await fetchWithTimeout(
+      `https://api.search.brave.com/res/v1/web/search?${params}`,
+      { headers: { 'X-Subscription-Token': apiKey, Accept: 'application/json' } },
+      DEFAULT_TIMEOUT_MS,
+    );
+    if (!res.ok) {
+      const body = await res.text().catch(() => '');
+      return { provider: 'brave', query, results: [], error: `HTTP ${res.status}: ${body}` };
+    }
+    const data = (await res.json()) as {
+      web?: { results?: Array<{ title: string; url: string; description: string }> };
+    };
+    const results: SearchResult[] = (data.web?.results ?? []).slice(0, limit).map((r) => ({
+      title: r.title,
+      url: r.url,
+      snippet: r.description,
+    }));
+    return { provider: 'brave', query, results };
+  } catch (err) {
+    return {
+      provider: 'brave',
+      query,
+      results: [],
+      error: err instanceof Error ? err.message : String(err),
+    };
+  }
+}
+
+// ─── Tavily Search ───────────────────────────────────────────────────────────
+
+async function searchTavily(query: string, limit: number): Promise<SearchResponse> {
+  const apiKey = process.env['TAVILY_API_KEY'];
+  if (!apiKey) return { provider: 'tavily', query, results: [], error: 'TAVILY_API_KEY not set' };
+
+  try {
+    const res = await fetchWithTimeout(
+      'https://api.tavily.com/search',
+      {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({
+          api_key: apiKey,
+          query,
+          max_results: Math.min(limit, 10),
+          include_answer: false,
+        }),
+      },
+      DEFAULT_TIMEOUT_MS,
+    );
+    if (!res.ok) {
+      const body = await res.text().catch(() => '');
+      return { provider: 'tavily', query, results: [], error: `HTTP ${res.status}: ${body}` };
+    }
+    const data = (await res.json()) as {
+      results?: Array<{ title: string; url: string; content: string }>;
+    };
+    const results: SearchResult[] = (data.results ?? []).slice(0, limit).map((r) => ({
+      title: r.title,
+      url: r.url,
+      snippet: r.content,
+    }));
+    return { provider: 'tavily', query, results };
+  } catch (err) {
+    return {
+      provider: 'tavily',
+      query,
+      results: [],
+      error: err instanceof Error ? err.message : String(err),
+    };
+  }
+}
+
+// ─── SearXNG (self-hosted) ───────────────────────────────────────────────────
+
+async function searchSearxng(query: string, limit: number): Promise<SearchResponse> {
+  const baseUrl = process.env['SEARXNG_URL'];
+  if (!baseUrl) return { provider: 'searxng', query, results: [], error: 'SEARXNG_URL not set' };
+
+  try {
+    const params = new URLSearchParams({
+      q: query,
+      format: 'json',
+      pageno: '1',
+    });
+    const res = await fetchWithTimeout(
+      `${baseUrl.replace(/\/$/, '')}/search?${params}`,
+      { headers: { Accept: 'application/json' } },
+      DEFAULT_TIMEOUT_MS,
+    );
+    if (!res.ok) {
+      const body = await res.text().catch(() => '');
+      return { provider: 'searxng', query, results: [], error: `HTTP ${res.status}: ${body}` };
+    }
+    const data = (await res.json()) as {
+      results?: Array<{ title: string; url: string; content: string }>;
+    };
+    const results: SearchResult[] = (data.results ?? []).slice(0, limit).map((r) => ({
+      title: r.title,
+      url: r.url,
+      snippet: r.content,
+    }));
+    return { provider: 'searxng', query, results };
+  } catch (err) {
+    return {
+      provider: 'searxng',
+      query,
+      results: [],
+      error: err instanceof Error ? err.message : String(err),
+    };
+  }
+}
+
+// ─── DuckDuckGo (lite HTML endpoint) ─────────────────────────────────────────
+
+async function searchDuckDuckGo(query: string, limit: number): Promise<SearchResponse> {
+  try {
+    // Use the DuckDuckGo Instant Answer API (JSON, free, no key)
+    const params = new URLSearchParams({
+      q: query,
+      format: 'json',
+      no_html: '1',
+      skip_disambig: '1',
+    });
+    const res = await fetchWithTimeout(
+      `https://api.duckduckgo.com/?${params}`,
+      { headers: { Accept: 'application/json' } },
+      DEFAULT_TIMEOUT_MS,
+    );
+    if (!res.ok) {
+      return {
+        provider: 'duckduckgo',
+        query,
+        results: [],
+        error: `HTTP ${res.status}`,
+      };
+    }
+    const text = await readLimited(res);
+    const data = JSON.parse(text) as {
+      AbstractText?: string;
+      AbstractURL?: string;
+      AbstractSource?: string;
+      RelatedTopics?: Array<{
+        Text?: string;
+        FirstURL?: string;
+        Result?: string;
+        Topics?: Array<{ Text?: string; FirstURL?: string }>;
+      }>;
+    };
+
+    const results: SearchResult[] = [];
+
+    // Main abstract result
+    if (data.AbstractText && data.AbstractURL) {
+      results.push({
+        title: data.AbstractSource ?? 'DuckDuckGo Abstract',
+        url: data.AbstractURL,
+        snippet: data.AbstractText,
+      });
+    }
+
+    // Related topics
+    for (const topic of data.RelatedTopics ?? []) {
+      if (results.length >= limit) break;
+      if (topic.Text && topic.FirstURL) {
+        results.push({
+          title: topic.Text.slice(0, 120),
+          url: topic.FirstURL,
+          snippet: topic.Text,
+        });
+      }
+      // Sub-topics
+      for (const sub of topic.Topics ?? []) {
+        if (results.length >= limit) break;
+        if (sub.Text && sub.FirstURL) {
+          results.push({
+            title: sub.Text.slice(0, 120),
+            url: sub.FirstURL,
+            snippet: sub.Text,
+          });
+        }
+      }
+    }
+
+    return { provider: 'duckduckgo', query, results: results.slice(0, limit) };
+  } catch (err) {
+    return {
+      provider: 'duckduckgo',
+      query,
+      results: [],
+      error: err instanceof Error ? err.message : String(err),
+    };
+  }
+}
+
+// ─── Provider resolution ─────────────────────────────────────────────────────
+
+type SearchProvider = 'brave' | 'tavily' | 'searxng' | 'duckduckgo' | 'auto';
+
+function getAvailableProviders(): SearchProvider[] {
+  const available: SearchProvider[] = [];
+  if (process.env['BRAVE_API_KEY']) available.push('brave');
+  if (process.env['TAVILY_API_KEY']) available.push('tavily');
+  if (process.env['SEARXNG_URL']) available.push('searxng');
+  // DuckDuckGo is always available (no API key needed)
+  available.push('duckduckgo');
+  return available;
+}
+
+async function executeSearch(
+  provider: SearchProvider,
+  query: string,
+  limit: number,
+): Promise<SearchResponse> {
+  switch (provider) {
+    case 'brave':
+      return searchBrave(query, limit);
+    case 'tavily':
+      return searchTavily(query, limit);
+    case 'searxng':
+      return searchSearxng(query, limit);
+    case 'duckduckgo':
+      return searchDuckDuckGo(query, limit);
+    case 'auto': {
+      // Try providers in priority order: Brave > Tavily > SearXNG > DuckDuckGo
+      const available = getAvailableProviders();
+      for (const p of available) {
+        const result = await executeSearch(p, query, limit);
+        if (!result.error && result.results.length > 0) return result;
+      }
+      // Fall back to DuckDuckGo if everything failed
+      return searchDuckDuckGo(query, limit);
+    }
+  }
+}
+
+function formatSearchResults(response: SearchResponse): string {
+  const lines: string[] = [];
+  lines.push(`Search provider: ${response.provider}`);
+  lines.push(`Query: "${response.query}"`);
+
+  if (response.error) {
+    lines.push(`Error: ${response.error}`);
+  }
+
+  if (response.results.length === 0) {
+    lines.push('No results found.');
+  } else {
+    lines.push(`Results (${response.results.length}):\n`);
+    for (let i = 0; i < response.results.length; i++) {
+      const r = response.results[i]!;
+      lines.push(`${i + 1}. ${r.title}`);
+      lines.push(`   URL: ${r.url}`);
+      lines.push(`   ${r.snippet}`);
+      lines.push('');
+    }
+  }
+  return lines.join('\n');
+}
+
+// ─── Tool exports ────────────────────────────────────────────────────────────
+
+export function createSearchTools(): ToolDefinition[] {
+  const webSearch: ToolDefinition = {
+    name: 'web_search',
+    label: 'Web Search',
+    description:
+      'Search the web using configured search providers. ' +
+      'Supports Brave, Tavily, SearXNG, and DuckDuckGo. ' +
+      'Use "auto" provider to pick the best available. ' +
+      'DuckDuckGo is always available as a fallback (no API key needed).',
+    parameters: Type.Object({
+      query: Type.String({ description: 'Search query' }),
+      provider: Type.Optional(
+        Type.String({
+          description:
+            'Search provider: "auto" (default), "brave", "tavily", "searxng", or "duckduckgo"',
+        }),
+      ),
+      limit: Type.Optional(
+        Type.Number({ description: `Max results to return (default 5, max ${MAX_RESULTS})` }),
+      ),
+    }),
+    async execute(_toolCallId, params) {
+      const { query, provider, limit } = params as {
+        query: string;
+        provider?: string;
+        limit?: number;
+      };
+
+      const effectiveProvider = (provider ?? 'auto') as SearchProvider;
+      const validProviders = ['auto', 'brave', 'tavily', 'searxng', 'duckduckgo'];
+      if (!validProviders.includes(effectiveProvider)) {
+        return {
+          content: [
+            {
+              type: 'text' as const,
+              text: `Invalid provider "${provider}". Valid: ${validProviders.join(', ')}`,
+            },
+          ],
+          details: undefined,
+        };
+      }
+
+      const effectiveLimit = Math.min(Math.max(limit ?? 5, 1), MAX_RESULTS);
+
+      try {
+        const response = await executeSearch(effectiveProvider, query, effectiveLimit);
+        return {
+          content: [{ type: 'text' as const, text: formatSearchResults(response) }],
+          details: undefined,
+        };
+      } catch (err) {
+        return {
+          content: [
+            {
+              type: 'text' as const,
+              text: `Search failed: ${err instanceof Error ? err.message : String(err)}`,
+            },
+          ],
+          details: undefined,
+        };
+      }
+    },
+  };
+
+  const webSearchNews: ToolDefinition = {
+    name: 'web_search_news',
+    label: 'Web Search (News)',
+    description:
+      'Search for recent news articles. Uses Brave News API if available, falls back to standard search with news keywords.',
+    parameters: Type.Object({
+      query: Type.String({ description: 'News search query' }),
+      limit: Type.Optional(
+        Type.Number({ description: `Max results (default 5, max ${MAX_RESULTS})` }),
+      ),
+    }),
+    async execute(_toolCallId, params) {
+      const { query, limit } = params as { query: string; limit?: number };
+      const effectiveLimit = Math.min(Math.max(limit ?? 5, 1), MAX_RESULTS);
+
+      // Try Brave News API first (dedicated news endpoint)
+      const braveKey = process.env['BRAVE_API_KEY'];
+      if (braveKey) {
+        try {
+          const newsParams = new URLSearchParams({
+            q: query,
+            count: String(effectiveLimit),
+          });
+          const res = await fetchWithTimeout(
+            `https://api.search.brave.com/res/v1/news/search?${newsParams}`,
+            {
+              headers: {
+                'X-Subscription-Token': braveKey,
+                Accept: 'application/json',
+              },
+            },
+            DEFAULT_TIMEOUT_MS,
+          );
+          if (res.ok) {
+            const data = (await res.json()) as {
+              results?: Array<{
+                title: string;
+                url: string;
+                description: string;
+                age?: string;
+              }>;
+            };
+            const results: SearchResult[] = (data.results ?? [])
+              .slice(0, effectiveLimit)
+              .map((r) => ({
+                title: r.title + (r.age ? ` (${r.age})` : ''),
+                url: r.url,
+                snippet: r.description,
+              }));
+            const response: SearchResponse = { provider: 'brave-news', query, results };
+            return {
+              content: [{ type: 'text' as const, text: formatSearchResults(response) }],
+              details: undefined,
+            };
+          }
+        } catch {
+          // Fall through to generic search
+        }
+      }
+
+      // Fallback: standard search with "news" appended
+      const newsQuery = `${query} news latest`;
+      const response = await executeSearch('auto', newsQuery, effectiveLimit);
+      return {
+        content: [{ type: 'text' as const, text: formatSearchResults(response) }],
+        details: undefined,
+      };
+    },
+  };
+
+  const searchProviders: ToolDefinition = {
+    name: 'web_search_providers',
+    label: 'List Search Providers',
+    description: 'List the currently available and configured web search providers.',
+    parameters: Type.Object({}),
+    async execute() {
+      const available = getAvailableProviders();
+      const allProviders = [
+        { name: 'brave', configured: !!process.env['BRAVE_API_KEY'], envVar: 'BRAVE_API_KEY' },
+        { name: 'tavily', configured: !!process.env['TAVILY_API_KEY'], envVar: 'TAVILY_API_KEY' },
+        { name: 'searxng', configured: !!process.env['SEARXNG_URL'], envVar: 'SEARXNG_URL' },
+        { name: 'duckduckgo', configured: true, envVar: '(none — always available)' },
+      ];
+
+      const lines = ['Search providers:\n'];
+      for (const p of allProviders) {
+        const status = p.configured ? '✓ configured' : '✗ not configured';
+        lines.push(`  ${p.name}: ${status} (${p.envVar})`);
+      }
+      lines.push(`\nActive providers for "auto" mode: ${available.join(', ')}`);
+      return {
+        content: [{ type: 'text' as const, text: lines.join('\n') }],
+        details: undefined,
+      };
+    },
+  };
+
+  return [webSearch, webSearchNews, searchProviders];
+}

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

@@ -18,6 +18,7 @@ import type {
   SlashCommandPayload,
   SystemReloadPayload,
   RoutingDecisionInfo,
+  AbortPayload,
 } from '@mosaic/types';
 import { AgentService, type ConversationHistoryMessage } from '../agent/agent.service.js';
 import { AUTH } from '../auth/auth.tokens.js';
@@ -325,6 +326,38 @@ export class ChatGateway implements OnGatewayInit, OnGatewayConnection, OnGatewa
     });
   }
 
+  @SubscribeMessage('abort')
+  async handleAbort(
+    @ConnectedSocket() client: Socket,
+    @MessageBody() data: AbortPayload,
+  ): Promise<void> {
+    const conversationId = data.conversationId;
+    this.logger.log(`Abort requested by ${client.id} for conversation ${conversationId}`);
+
+    const session = this.agentService.getSession(conversationId);
+    if (!session) {
+      client.emit('error', {
+        conversationId,
+        error: 'No active session to abort.',
+      });
+      return;
+    }
+
+    try {
+      await session.piSession.abort();
+      this.logger.log(`Agent session ${conversationId} aborted successfully`);
+    } catch (err) {
+      this.logger.error(
+        `Failed to abort session ${conversationId}`,
+        err instanceof Error ? err.stack : String(err),
+      );
+      client.emit('error', {
+        conversationId,
+        error: 'Failed to abort the agent operation.',
+      });
+    }
+  }
+
   @SubscribeMessage('command:execute')
   async handleCommandExecute(
     @ConnectedSocket() client: Socket,

apps/gateway/src/commands/command-executor-p8012.spec.ts

@@ -82,6 +82,7 @@ function buildService(): CommandExecutorService {
     mockBrain as never,
     null,
     mockChatGateway as never,
+    null,
   );
 }
 

apps/gateway/src/commands/command-executor.service.ts

@@ -7,6 +7,7 @@ import { ChatGateway } from '../chat/chat.gateway.js';
 import { SessionGCService } from '../gc/session-gc.service.js';
 import { SystemOverrideService } from '../preferences/system-override.service.js';
 import { ReloadService } from '../reload/reload.service.js';
+import { McpClientService } from '../mcp-client/mcp-client.service.js';
 import { BRAIN } from '../brain/brain.tokens.js';
 import { COMMANDS_REDIS } from './commands.tokens.js';
 import { CommandRegistryService } from './command-registry.service.js';
@@ -28,6 +29,9 @@ export class CommandExecutorService {
     @Optional()
     @Inject(forwardRef(() => ChatGateway))
     private readonly chatGateway: ChatGateway | null,
+    @Optional()
+    @Inject(McpClientService)
+    private readonly mcpClient: McpClientService | null,
   ) {}
 
   async execute(payload: SlashCommandPayload, userId: string): Promise<SlashCommandResultPayload> {
@@ -105,6 +109,8 @@ export class CommandExecutorService {
           };
         case 'tools':
           return await this.handleTools(conversationId, userId);
+        case 'mcp':
+          return await this.handleMcp(args ?? null, conversationId);
         case 'reload': {
           if (!this.reloadService) {
             return {
@@ -489,4 +495,92 @@ export class CommandExecutorService {
       conversationId,
     };
   }
+
+  private async handleMcp(
+    args: string | null,
+    conversationId: string,
+  ): Promise<SlashCommandResultPayload> {
+    if (!this.mcpClient) {
+      return {
+        command: 'mcp',
+        conversationId,
+        success: false,
+        message: 'MCP client service is not available.',
+      };
+    }
+
+    const action = args?.trim().split(/\s+/)[0] ?? 'status';
+
+    switch (action) {
+      case 'status':
+      case 'servers': {
+        const statuses = this.mcpClient.getServerStatuses();
+        if (statuses.length === 0) {
+          return {
+            command: 'mcp',
+            conversationId,
+            success: true,
+            message:
+              'No MCP servers configured. Set MCP_SERVERS env var to connect external tool servers.',
+          };
+        }
+        const lines = ['MCP Server Status:\n'];
+        for (const s of statuses) {
+          const status = s.connected ? '✓ connected' : '✗ disconnected';
+          lines.push(`  ${s.name}: ${status}`);
+          lines.push(`    URL: ${s.url}`);
+          lines.push(`    Tools: ${s.toolCount}`);
+          if (s.error) lines.push(`    Error: ${s.error}`);
+          lines.push('');
+        }
+        const tools = this.mcpClient.getToolDefinitions();
+        if (tools.length > 0) {
+          lines.push(`Total bridged tools: ${tools.length}`);
+          lines.push(`Tool names: ${tools.map((t) => t.name).join(', ')}`);
+        }
+        return {
+          command: 'mcp',
+          conversationId,
+          success: true,
+          message: lines.join('\n'),
+        };
+      }
+
+      case 'reconnect': {
+        const serverName = args?.trim().split(/\s+/).slice(1).join(' ');
+        if (!serverName) {
+          return {
+            command: 'mcp',
+            conversationId,
+            success: false,
+            message: 'Usage: /mcp reconnect <server-name>',
+          };
+        }
+        try {
+          await this.mcpClient.reconnectServer(serverName);
+          return {
+            command: 'mcp',
+            conversationId,
+            success: true,
+            message: `MCP server "${serverName}" reconnected successfully.`,
+          };
+        } catch (err) {
+          return {
+            command: 'mcp',
+            conversationId,
+            success: false,
+            message: `Failed to reconnect MCP server "${serverName}": ${err instanceof Error ? err.message : String(err)}`,
+          };
+        }
+      }
+
+      default:
+        return {
+          command: 'mcp',
+          conversationId,
+          success: false,
+          message: `Unknown MCP action: "${action}". Use: /mcp status, /mcp servers, /mcp reconnect <name>`,
+        };
+    }
+  }
 }

apps/gateway/src/commands/command-registry.service.ts

@@ -260,6 +260,23 @@ export class CommandRegistryService implements OnModuleInit {
         execution: 'socket',
         available: true,
       },
+      {
+        name: 'mcp',
+        description: 'Manage MCP server connections (status/reconnect/servers)',
+        aliases: [],
+        args: [
+          {
+            name: 'action',
+            type: 'enum',
+            optional: true,
+            values: ['status', 'reconnect', 'servers'],
+            description: 'Action: status (default), reconnect <name>, servers',
+          },
+        ],
+        scope: 'agent',
+        execution: 'socket',
+        available: true,
+      },
       {
         name: 'reload',
         description: 'Soft-reload gateway plugins and command manifest (admin)',

apps/gateway/src/commands/commands.integration.spec.ts

@@ -65,6 +65,7 @@ function buildExecutor(registry: CommandRegistryService): CommandExecutorService
     mockBrain as never,
     null, // reloadService (optional)
     null, // chatGateway (optional)
+    null, // mcpClient (optional)
   );
 }
 

packages/cli/src/tui/app.tsx

@@ -15,6 +15,7 @@ import { useConversations } from './hooks/use-conversations.js';
 import { useSearch } from './hooks/use-search.js';
 import { executeHelp, executeStatus, executeHistory, commandRegistry } from './commands/index.js';
 import { fetchConversationMessages } from './gateway-api.js';
+import { expandFileRefs, hasFileRefs, handleAttachCommand } from './file-ref.js';
 
 export interface TuiAppProps {
   gatewayUrl: string;
@@ -85,6 +86,36 @@ export function TuiApp({
   // combo is handled by the top-level useInput handler (e.g. Ctrl+T → 't').
   const ctrlJustFired = useRef(false);
 
+  // Wrap sendMessage to expand @file references before sending
+  const sendMessageWithFileRefs = useCallback(
+    (content: string) => {
+      if (!hasFileRefs(content)) {
+        socket.sendMessage(content);
+        return;
+      }
+      void expandFileRefs(content)
+        .then(({ expandedMessage, filesAttached, errors }) => {
+          for (const err of errors) {
+            socket.addSystemMessage(err);
+          }
+          if (filesAttached.length > 0) {
+            socket.addSystemMessage(
+              `📎 Attached ${filesAttached.length} file(s): ${filesAttached.join(', ')}`,
+            );
+          }
+          socket.sendMessage(expandedMessage);
+        })
+        .catch((err: unknown) => {
+          socket.addSystemMessage(
+            `File expansion failed: ${err instanceof Error ? err.message : String(err)}`,
+          );
+          // Send original message without expansion
+          socket.sendMessage(content);
+        });
+    },
+    [socket],
+  );
+
   const handleLocalCommand = useCallback(
     (parsed: ParsedCommand) => {
       switch (parsed.command) {
@@ -123,9 +154,36 @@ export function TuiApp({
               socket.addSystemMessage('Failed to create new conversation.');
             });
           break;
+        case 'attach': {
+          if (!parsed.args) {
+            socket.addSystemMessage('Usage: /attach <file-path>');
+            break;
+          }
+          void handleAttachCommand(parsed.args)
+            .then(({ content, error }) => {
+              if (error) {
+                socket.addSystemMessage(`Attach error: ${error}`);
+              } else if (content) {
+                // Send the file content as a user message
+                socket.sendMessage(content);
+              }
+            })
+            .catch((err: unknown) => {
+              socket.addSystemMessage(
+                `Attach failed: ${err instanceof Error ? err.message : String(err)}`,
+              );
+            });
+          break;
+        }
         case 'stop':
-          // Currently no stop mechanism exposed — show feedback
+          if (socket.isStreaming && socket.socketRef.current?.connected && socket.conversationId) {
-          socket.addSystemMessage('Stop is not available for the current session.');
+            socket.socketRef.current.emit('abort', {
+              conversationId: socket.conversationId,
+            });
+            socket.addSystemMessage('Abort signal sent.');
+          } else {
+            socket.addSystemMessage('No active stream to stop.');
+          }
           break;
         case 'cost': {
           const u = socket.tokenUsage;
@@ -348,7 +406,7 @@ export function TuiApp({
           }
           setTuiInput(val);
         }}
-        onSubmit={socket.sendMessage}
+        onSubmit={sendMessageWithFileRefs}
         onSystemMessage={socket.addSystemMessage}
         onLocalCommand={handleLocalCommand}
         onGatewayCommand={handleGatewayCommand}

packages/cli/src/tui/commands/registry.ts

@@ -56,6 +56,22 @@ const LOCAL_COMMANDS: CommandDef[] = [
     available: true,
     scope: 'core',
   },
+  {
+    name: 'attach',
+    description: 'Attach a file to the next message (@file syntax also works inline)',
+    aliases: [],
+    args: [
+      {
+        name: 'path',
+        type: 'string' as const,
+        optional: false,
+        description: 'File path to attach',
+      },
+    ],
+    execution: 'local',
+    available: true,
+    scope: 'core',
+  },
   {
     name: 'new',
     description: 'Start a new conversation',

packages/cli/src/tui/file-ref.ts

@@ -0,0 +1,202 @@
+/**
+ * File reference expansion for TUI chat input.
+ *
+ * Detects @path/to/file patterns in user messages, reads the file contents,
+ * and inlines them as fenced code blocks in the message.
+ *
+ * Supports:
+ *   - @relative/path.ts
+ *   - @./relative/path.ts
+ *   - @/absolute/path.ts
+ *   - @~/home-relative/path.ts
+ *
+ * Also provides an /attach <path> command handler.
+ */
+
+import { readFile, stat } from 'node:fs/promises';
+import { resolve, extname, basename } from 'node:path';
+import { homedir } from 'node:os';
+
+const MAX_FILE_SIZE = 256 * 1024; // 256 KB
+const MAX_FILES_PER_MESSAGE = 10;
+
+/**
+ * Regex to detect @file references in user input.
+ * Matches @<path> where path starts with /, ./, ~/, or a word char,
+ * and continues until whitespace or end of string.
+ * Excludes @mentions that look like usernames (no dots/slashes).
+ */
+const FILE_REF_PATTERN = /(?:^|\s)@((?:\.{0,2}\/|~\/|[a-zA-Z0-9_])[^\s]+)/g;
+
+interface FileRefResult {
+  /** The expanded message text with file contents inlined */
+  expandedMessage: string;
+  /** Files that were successfully read */
+  filesAttached: string[];
+  /** Errors encountered while reading files */
+  errors: string[];
+}
+
+function resolveFilePath(ref: string): string {
+  if (ref.startsWith('~/')) {
+    return resolve(homedir(), ref.slice(2));
+  }
+  return resolve(process.cwd(), ref);
+}
+
+function getLanguageHint(filePath: string): string {
+  const ext = extname(filePath).toLowerCase();
+  const map: Record<string, string> = {
+    '.ts': 'typescript',
+    '.tsx': 'typescript',
+    '.js': 'javascript',
+    '.jsx': 'javascript',
+    '.py': 'python',
+    '.rb': 'ruby',
+    '.rs': 'rust',
+    '.go': 'go',
+    '.java': 'java',
+    '.c': 'c',
+    '.cpp': 'cpp',
+    '.h': 'c',
+    '.hpp': 'cpp',
+    '.cs': 'csharp',
+    '.sh': 'bash',
+    '.bash': 'bash',
+    '.zsh': 'zsh',
+    '.fish': 'fish',
+    '.json': 'json',
+    '.yaml': 'yaml',
+    '.yml': 'yaml',
+    '.toml': 'toml',
+    '.xml': 'xml',
+    '.html': 'html',
+    '.css': 'css',
+    '.scss': 'scss',
+    '.md': 'markdown',
+    '.sql': 'sql',
+    '.graphql': 'graphql',
+    '.dockerfile': 'dockerfile',
+    '.tf': 'terraform',
+    '.vue': 'vue',
+    '.svelte': 'svelte',
+  };
+  return map[ext] ?? '';
+}
+
+/**
+ * Check if the input contains any @file references.
+ */
+export function hasFileRefs(input: string): boolean {
+  FILE_REF_PATTERN.lastIndex = 0;
+  return FILE_REF_PATTERN.test(input);
+}
+
+/**
+ * Expand @file references in a message by reading file contents
+ * and appending them as fenced code blocks.
+ */
+export async function expandFileRefs(input: string): Promise<FileRefResult> {
+  const refs: string[] = [];
+  FILE_REF_PATTERN.lastIndex = 0;
+  let match;
+  while ((match = FILE_REF_PATTERN.exec(input)) !== null) {
+    const ref = match[1]!;
+    if (!refs.includes(ref)) {
+      refs.push(ref);
+    }
+  }
+
+  if (refs.length === 0) {
+    return { expandedMessage: input, filesAttached: [], errors: [] };
+  }
+
+  if (refs.length > MAX_FILES_PER_MESSAGE) {
+    return {
+      expandedMessage: input,
+      filesAttached: [],
+      errors: [`Too many file references (${refs.length}). Maximum is ${MAX_FILES_PER_MESSAGE}.`],
+    };
+  }
+
+  const filesAttached: string[] = [];
+  const errors: string[] = [];
+  const attachments: string[] = [];
+
+  for (const ref of refs) {
+    const filePath = resolveFilePath(ref);
+    try {
+      const info = await stat(filePath);
+      if (!info.isFile()) {
+        errors.push(`@${ref}: not a file`);
+        continue;
+      }
+      if (info.size > MAX_FILE_SIZE) {
+        errors.push(
+          `@${ref}: file too large (${(info.size / 1024).toFixed(0)} KB, limit ${MAX_FILE_SIZE / 1024} KB)`,
+        );
+        continue;
+      }
+      const content = await readFile(filePath, 'utf8');
+      const lang = getLanguageHint(filePath);
+      const name = basename(filePath);
+      attachments.push(`\n📎 ${ref} (${name}):\n\`\`\`${lang}\n${content}\n\`\`\``);
+      filesAttached.push(ref);
+    } catch (err) {
+      const msg = err instanceof Error ? err.message : String(err);
+      // Only report meaningful errors — ENOENT is common for false @mention matches
+      if (msg.includes('ENOENT')) {
+        // Check if this looks like a file path (has extension or slash)
+        if (ref.includes('/') || ref.includes('.')) {
+          errors.push(`@${ref}: file not found`);
+        }
+        // Otherwise silently skip — likely an @mention, not a file ref
+      } else {
+        errors.push(`@${ref}: ${msg}`);
+      }
+    }
+  }
+
+  if (attachments.length === 0) {
+    return { expandedMessage: input, filesAttached, errors };
+  }
+
+  const expandedMessage = input + '\n' + attachments.join('\n');
+  return { expandedMessage, filesAttached, errors };
+}
+
+/**
+ * Handle the /attach <path> command.
+ * Reads a file and returns the content formatted for inclusion in the chat.
+ */
+export async function handleAttachCommand(
+  args: string,
+): Promise<{ content: string; error?: string }> {
+  const filePath = args.trim();
+  if (!filePath) {
+    return { content: '', error: 'Usage: /attach <file-path>' };
+  }
+
+  const resolved = resolveFilePath(filePath);
+  try {
+    const info = await stat(resolved);
+    if (!info.isFile()) {
+      return { content: '', error: `Not a file: ${filePath}` };
+    }
+    if (info.size > MAX_FILE_SIZE) {
+      return {
+        content: '',
+        error: `File too large (${(info.size / 1024).toFixed(0)} KB, limit ${MAX_FILE_SIZE / 1024} KB)`,
+      };
+    }
+    const content = await readFile(resolved, 'utf8');
+    const lang = getLanguageHint(resolved);
+    const name = basename(resolved);
+    return {
+      content: `📎 Attached file: ${name} (${filePath})\n\`\`\`${lang}\n${content}\n\`\`\``,
+    };
+  } catch (err) {
+    const msg = err instanceof Error ? err.message : String(err);
+    return { content: '', error: `Failed to read file: ${msg}` };
+  }
+}

packages/types/src/chat/events.ts

@@ -99,6 +99,11 @@ export interface SetThinkingPayload {
   level: string;
 }
 
+/** Client request to abort the current agent operation */
+export interface AbortPayload {
+  conversationId: string;
+}
+
 /** Socket.IO typed event map: server → client */
 export interface ServerToClientEvents {
   'message:ack': (payload: MessageAckPayload) => void;
@@ -120,4 +125,5 @@ export interface ClientToServerEvents {
   message: (data: ChatMessagePayload) => void;
   'set:thinking': (data: SetThinkingPayload) => void;
   'command:execute': (data: SlashCommandPayload) => void;
+  abort: (data: AbortPayload) => void;
 }

packages/types/src/chat/index.ts

@@ -11,6 +11,7 @@ export type {
   SessionInfoPayload,
   RoutingDecisionInfo,
   SetThinkingPayload,
+  AbortPayload,
   ErrorPayload,
   ChatMessagePayload,
   ServerToClientEvents,

scratchpads/cli-tui-tools-enhancement.md

@@ -0,0 +1,66 @@
+# CLI/TUI Tools Enhancement Scratchpad
+
+## Objective
+
+Add 5 capability areas to the Mosaic CLI/TUI + gateway agent:
+
+1. Web search tools (multi-provider: Brave, DuckDuckGo, Tavily, SearXNG)
+2. File edit tool (`fs_edit_file` with targeted text replacement)
+3. MCP management TUI commands (`/mcp status`, `/mcp reconnect`, `/mcp servers`)
+4. File reference in chat (`@file` syntax + `/attach` command)
+5. Implement `/stop` to cancel streaming
+
+## Plan
+
+### 1. Web Search Tools (gateway agent tools)
+
+- Create `apps/gateway/src/agent/tools/search-tools.ts`
+- Providers: Brave Search API, DuckDuckGo (HTML scraping), Tavily API, SearXNG (self-hosted)
+- Each provider activated by env var (BRAVE_API_KEY, TAVILY_API_KEY, SEARXNG_URL)
+- Tools: `web_search` (unified), `web_search_news` (news-specific)
+- Export from `apps/gateway/src/agent/tools/index.ts`
+- Wire into `agent.service.ts` buildToolsForSandbox
+
+### 2. File Edit Tool (gateway agent tool)
+
+- Add `fs_edit_file` to `apps/gateway/src/agent/tools/file-tools.ts`
+- Parameters: path, edits[{oldText, newText}] — same semantics as pi's Edit tool
+- Validates uniqueness of each oldText, applies all edits atomically
+
+### 3. MCP Management Commands (TUI + gateway)
+
+- Add gateway endpoints: GET /api/mcp/status, POST /api/mcp/:name/reconnect
+- Add TUI gateway-api.ts functions for MCP
+- Add gateway slash commands: /mcp (with subcommands status, reconnect, servers)
+- Register in command manifest from gateway
+- Handle in TUI via gateway command forwarding (already works)
+
+### 4. File Reference in Chat (@file syntax)
+
+- TUI-side: detect @path/to/file in input, read file contents, inline into message
+- Add `/attach <path>` local command as alternative
+- gateway-api.ts helper not needed — this is purely client-side pre-processing
+- Modify InputBar or sendMessage to expand @file references before sending
+
+### 5. Implement /stop
+
+- Add `abort` event to ClientToServerEvents in @mosaic/types
+- TUI sends abort event on /stop command
+- Gateway chat handler aborts the Pi session prompt
+- Update use-socket to support abort
+- Wire /stop in app.tsx
+
+## Progress
+
+- [x] 1. Web search tools
+- [x] 2. File edit tool
+- [x] 3. MCP management commands
+- [x] 4. File reference in chat
+- [x] 5. Implement /stop
+
+## Risks
+
+- DuckDuckGo has no official API — need HTML scraping or use lite endpoint
+- SearXNG needs self-hosted instance
+- @file expansion could be large — need size limits
+- /stop requires Pi SDK abort support — need to check API