MCP Tool Generator
Generate a spec-compliant Model Context Protocol tool definition from a plain-English description, or validate one you already wrote — so agents call your tool correctly on the first try.
Try an example:
Why MCP tool descriptions matter
The Model Context Protocol (MCP) is the standard AI agents use to discover and call external tools — over 17,000 public MCP servers exist as of 2026. But an agent only knows what a tool does from its description and schema. A vague or incomplete description means agents call the wrong tool, pass the wrong parameters, or silently fail — even when the underlying function works perfectly.
Writing a good tool description is a prompt engineering problem, not a documentation afterthought: it needs to lead with purpose, state clearly when to call it, and document every parameter well enough that an agent never has to guess.
What the validator checks
Description quality
Long enough, and states when the tool should be called — not just what it does.
Naming conventions
Tool name uses only letters, numbers, underscores, or hyphens.
Schema structure
"inputSchema" is present and typed as an object with defined properties.
Required vs optional
Every parameter has a type and description; optional ones document their default behavior.
Frequently asked questions
What is MCP?
The Model Context Protocol is a vendor-neutral standard (originally from Anthropic, now under the Linux Foundation) that lets AI agents discover and call external tools — search, databases, APIs, internal systems — in a consistent way across ChatGPT, Claude, Gemini, and other clients.
Does the generator write working code?
No — it writes the tool definition (name, description, inputSchema) that goes in your MCP server's tool registration. You still implement the function logic itself.
Why does the description matter more than the code?
Agents decide which tool to call and what parameters to pass based entirely on the description and schema, not the implementation. A well-implemented tool with a vague description still gets called incorrectly or ignored.
Is my tool description stored?
No. Validation happens entirely in your browser. Generation sends your description to an AI model to produce the definition, but nothing is saved.