telegram-ai-bridge: Instructions file for GitHub Copilot

Copilot Coding Agent — Repository Instructions

Project context

This is a Telegram bridge that wraps multiple AI CLI backends (Claude Code, Codex, Kilo, Gemini, Copilot) behind a single bot interface. Node.js, ESM, Grammy (Telegram framework), better-sqlite3 for local state.

Code style

• ESM imports, no CommonJS
• No TypeScript — plain JS with JSDoc where helpful
• node:test + node:assert/strict for tests, no external test frameworks
• Prefer node: prefix for built-in modules
• Trailing newline on all files
• No semicolons except where ASI is ambiguous

Architecture rules

• Each CLI backend is a class in src/backends.js with a sendMessage() method
• Chat bindings (which session is bound to which Telegram chat) live in SQLite via src/db.js
• Commands are registered in src/commands.js, callback queries handled in src/message-handler.js
• Config comes from env vars via src/config.js — never hardcode paths, ports, tokens, or thresholds
• Session scanning (discovering CLI sessions on disk) lives in src/cli-scanner.js

No hardcoding

This is non-negotiable:

• Never hardcode values that could change: URLs, ports, paths, feature flags, thresholds
• Environment variables for anything deployment-specific — define defaults in src/config.js, document in .env.example
• Credentials and secrets: never in source, never in commits, never in logs

Security awareness

AI-generated code has a 40-45% vulnerability rate in studies. Actively counter this:

• SQL: parameterize all queries. This project uses better-sqlite3 with named parameters (@param). Never interpolate user input into SQL strings.
• Input handling: all Telegram message text and callback data is untrusted user input. Validate and sanitize before using in file paths, shell args, or SQL.
• Shell execution: this project uses execFile (not exec) for CLI spawning. Never construct shell command strings from user input. Pass arguments as array elements.
• Secrets in logs: the log module is used throughout. Never log tokens, API keys, session secrets, or user messages in full. Use redactString() from src/log.js for sensitive values.
• Dependencies: prefer stdlib (node:fs, node:path, node:child_process) or deps already in package.json. Do not add new dependencies without explicit justification. When updating or adding versions, follow the existing package.json versioning convention rather than switching to exact pins.
• Path traversal: when resolving directories from user input (e.g., /new command workspace path), always canonicalize and validate against allowed paths before use.