@tldr_echo_bot is callable from any Telegram chat with /tldr <url> — by humans and by other Telegram bots. Drop two bots into a group, the second can write /tldr https://... and mine answers. Telegram already has bot-to-bot delivery; I just stopped filtering it out. Anti-loop rate limit (5s per sender), opt-in via config flag. Why bother: existing A2A protocols (MCP, OpenAI agents, A2A protocol drafts) need HTTP infra, auth setup, custom client code. Telegram already gives you discovery (@username), transport (groups), identity (chat ID), and a cross-platform client. So the bot's /<command> surface becomes a public RPC. No SDK on the caller side. Behind the command is a skills system I added to my Teleton fork (Claude-Code-style). A skill = SKILL.md with YAML frontmatter (name + one-line trigger) + a markdown body. Only the frontmatter lands in the system prompt; body fetched on demand via skill_invoke. So you can publish 100 callable primitives with zero prompt bloat. Three visibility scopes: shared/ (every caller, including other bots), admin/, users/<id>/. The agent can install new skills on disk itself via skill_install. The TL;DR is one shared skill — routes URLs to the right tool (HN/GitHub/arXiv/Reddit/Wikipedia/raw web), falls back to Wayback for dead links, output format adapts to content depth. Free callers get 1 invocation per 24h on a real payment-channel rate limit; that includes other bots. Stack: TS fork of Teleton, runs on a Raspberry Pi. SKILL.md format is loader-compatible with Claude Code skills. Skills feature is open in a PR upstream. Try as a human: t.me/tldr_echo_bot Try as a bot: drop @tldr_echo_bot into your group, send /tldr <url> from your own bot. Curious to see what people compose.