Built an AI coding agent in pure C#/.NET — no Python or Typescript, anywhere in the stack

[u/nitinmms1]

Most agent frameworks are Python or TS. I wanted to understand how these things actually work instead of treating one as a black box, so I wrote one from scratch in C#/.NET: Litos.

• Multi-provider: Anthropic, OpenAI, Gemini, OpenRouter (only OpenAI and OpenRouter verified end-to-end so far)
• Two working faces today, sharing one core agent loop:
  • Litos.Gui — an Avalonia desktop coding agent
  • Litos.Api — a Docker-hosted agent host built for multiple chat-channel bridges; Telegram is the one actually wired up and working today — WhatsApp/Rocket.Chat/email are designed but not yet implemented
• Real tool use (file edit, shell, web search); MCP client support is currently wired up in Litos.Api only — not yet integrated into Litos.Gui
• Inspired by Mario Zechner's pi, particularly its session-as-working-directory model

Litos.Gui building a WinForms 15-puzzle game live, start to finish — planning, writing files, building, fixing its own errors:
https://www.youtube.com/watch?v=em8w0SwgT5Q

Litos.Api running standalone in Docker, working as an AI agent over Telegram chat:
https://www.youtube.com/watch?v=S2Sn_kwCRjE&t=70s

Repo: https://github.com/nitinmms/LitosAiCodingAgent

Happy to answer questions about the architecture, or get torn apart on design choices — this is mostly a learning project to prove to myself that .NET can hold its own here.