Show HN: Ocarina – Automate and test MCP servers from YAML, no LLM
Ocarina is a new tool that lets users automate and test MCP (Model Context Protocol) servers using YAML-based scripts called "Rondos," without requiring an LLM. It allows inspecting server capabilities, chaining tool calls, and validating outputs step-by-step, similar to Ansible playbooks. The creator built it to test MCP servers in their job and sees broader potential in the MCP ecosystem.
Background
MCP (Model Context Protocol) is an open standard created by Anthropic that lets AI models discover and call tools on remote servers through a typed interface — think of it as a universal "API for AI." As MCP servers have proliferated (GitHub, databases, file systems, etc.), the ecosystem has been almost entirely LLM-driven: you need an AI to call the tools.
Ocarina is a command-line tool that flips that model — it lets you write YAML "Rondos" (like Ansible playbooks) that call MCP server tools directly, without an LLM. This makes MCP servers testable, scriptable, and automatable by traditional CI/CD pipelines, not just by chatbots. The author comes from the Ansible/automation world and is applying that paradigm to the new MCP ecosystem.