feat: agent-to-agent communication, dynamic agent creation, self-modification tools

Agent-to-agent: host routes messages with channel_type='agent' to target
agent's inbound.db, enriches with sender info, wakes target container.
Bidirectional routing works via inherited routing context.

Dynamic agents: create_agent MCP tool + system action handler creates
agent groups, folders, and optional CLAUDE.md on the fly.

Self-modification: install_packages (apt/npm, requires admin approval),
add_mcp_server (no approval), request_rebuild (builds per-agent-group
Docker image with approved packages). Approval flow reuses interactive
card infrastructure with pending_approvals table.

Also includes fixes from prior session: attachment download, reply context
extraction, message editing (platform message ID tracking), delivery retry
limits, and card update on button click.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

container/agent-runner/src/mcp-tools/self-mod.ts

@@ -0,0 +1,155 @@
+/**
+ * Self-modification MCP tools: install_packages, add_mcp_server, request_rebuild.
+ *
+ * These tools request changes to the agent's container configuration.
+ * install_packages and request_rebuild require admin approval.
+ * add_mcp_server takes effect on next container restart without approval.
+ */
+import { findQuestionResponse, markCompleted } from '../db/messages-in.js';
+import { writeMessageOut } from '../db/messages-out.js';
+import type { McpToolDefinition } from './types.js';
+
+function log(msg: string): void {
+  console.error(`[mcp-tools] ${msg}`);
+}
+
+function generateId(): string {
+  return `msg-${Date.now()}-${Math.random().toString(36).slice(2, 8)}`;
+}
+
+function ok(text: string) {
+  return { content: [{ type: 'text' as const, text }] };
+}
+
+function err(text: string) {
+  return { content: [{ type: 'text' as const, text: `Error: ${text}` }], isError: true };
+}
+
+function sleep(ms: number): Promise<void> {
+  return new Promise((resolve) => setTimeout(resolve, ms));
+}
+
+async function pollForResponse(requestId: string, timeoutMs: number) {
+  const deadline = Date.now() + timeoutMs;
+  while (Date.now() < deadline) {
+    const response = findQuestionResponse(requestId);
+    if (response) {
+      const parsed = JSON.parse(response.content);
+      markCompleted([response.id]);
+      if (parsed.status === 'success') {
+        return ok(JSON.stringify(parsed.result || 'Success'));
+      }
+      return err(parsed.result?.error || parsed.selectedOption || 'Request denied');
+    }
+    await sleep(2000);
+  }
+  return err(`Request timed out after ${timeoutMs / 1000}s`);
+}
+
+export const installPackages: McpToolDefinition = {
+  tool: {
+    name: 'install_packages',
+    description:
+      'Request installation of system (apt) or Node.js (npm) packages in the container. Requires admin approval. Takes effect after container rebuild.',
+    inputSchema: {
+      type: 'object' as const,
+      properties: {
+        apt: { type: 'array', items: { type: 'string' }, description: 'apt packages to install' },
+        npm: { type: 'array', items: { type: 'string' }, description: 'npm packages to install globally' },
+        reason: { type: 'string', description: 'Why these packages are needed' },
+      },
+    },
+  },
+  async handler(args) {
+    const apt = (args.apt as string[]) || [];
+    const npm = (args.npm as string[]) || [];
+    if (apt.length === 0 && npm.length === 0) return err('At least one apt or npm package is required');
+
+    const requestId = generateId();
+    writeMessageOut({
+      id: requestId,
+      kind: 'system',
+      content: JSON.stringify({
+        action: 'install_packages',
+        requestId,
+        apt,
+        npm,
+        reason: (args.reason as string) || '',
+      }),
+    });
+
+    log(`install_packages: ${requestId} → apt=[${apt.join(',')}] npm=[${npm.join(',')}]`);
+    return await pollForResponse(requestId, 300_000);
+  },
+};
+
+export const addMcpServer: McpToolDefinition = {
+  tool: {
+    name: 'add_mcp_server',
+    description:
+      "Add an MCP server to this agent's configuration. Takes effect on next container restart (no rebuild needed, no approval required).",
+    inputSchema: {
+      type: 'object' as const,
+      properties: {
+        name: { type: 'string', description: 'MCP server name (unique identifier)' },
+        command: { type: 'string', description: 'Command to run the MCP server' },
+        args: { type: 'array', items: { type: 'string' }, description: 'Command arguments' },
+        env: { type: 'object', description: 'Environment variables for the server' },
+      },
+      required: ['name', 'command'],
+    },
+  },
+  async handler(args) {
+    const name = args.name as string;
+    const command = args.command as string;
+    if (!name || !command) return err('name and command are required');
+
+    const requestId = generateId();
+    writeMessageOut({
+      id: requestId,
+      kind: 'system',
+      content: JSON.stringify({
+        action: 'add_mcp_server',
+        requestId,
+        name,
+        command,
+        args: (args.args as string[]) || [],
+        env: (args.env as Record<string, string>) || {},
+      }),
+    });
+
+    log(`add_mcp_server: ${requestId} → "${name}" (${command})`);
+    return await pollForResponse(requestId, 30_000);
+  },
+};
+
+export const requestRebuild: McpToolDefinition = {
+  tool: {
+    name: 'request_rebuild',
+    description:
+      'Request a container rebuild to apply pending package installations. Requires admin approval. The current container will be stopped and restarted with the new image.',
+    inputSchema: {
+      type: 'object' as const,
+      properties: {
+        reason: { type: 'string', description: 'Why the rebuild is needed' },
+      },
+    },
+  },
+  async handler(args) {
+    const requestId = generateId();
+    writeMessageOut({
+      id: requestId,
+      kind: 'system',
+      content: JSON.stringify({
+        action: 'request_rebuild',
+        requestId,
+        reason: (args.reason as string) || '',
+      }),
+    });
+
+    log(`request_rebuild: ${requestId}`);
+    return await pollForResponse(requestId, 300_000);
+  },
+};
+
+export const selfModTools: McpToolDefinition[] = [installPackages, addMcpServer, requestRebuild];