Tool Definition Converter
🔒 In your browserConvert a tool/function schema between MCP, Anthropic (Claude) & OpenAI formats.
How it works
Paste an existing tool or function definition in any format — OpenAI function-calling, Anthropic (Claude), an MCP tools/list entry, or a bare JSON Schema — and convert it to the other two. Great for migrating an agent between providers. The full schema is preserved and everything runs in your browser.
Building a tool from scratch instead? Use the Tool Definition Generator. Conversion keeps your schema exactly as-is — including nested and advanced keywords — and never uploads it.
About the Tool Definition Converter
Every LLM platform describes tools with the same JSON Schema underneath, but wraps it differently — OpenAI nests it under function.parameters, Anthropic uses input_schema, and an MCP server returns inputSchema. This free tool definition converter detects the format you paste and rewrites it as the other two, preserving your schema exactly.
It's the fastest way to migrate an agent's tools between providers, and it runs entirely in your browser — nothing you paste is uploaded.
How to use it
- Paste a tool definition in any format: an OpenAI function, an Anthropic tool, an MCP tools/list entry, or a bare JSON Schema.
- The tool auto-detects the format and shows the converted result in all three.
- Switch tabs and copy the format you need. Paste an array or a full tools/list to convert a whole set at once.
What's preserved
Conversion only changes the wrapper around your schema — the JSON Schema itself is kept exactly as-is, including nested objects, arrays, enums, and validation keywords like minimum, maximum and pattern. Only the outer shape (function.parameters vs input_schema vs inputSchema) and the top-level name and description move.
Frequently asked questions
Which formats are supported?
OpenAI function-calling, Anthropic (Claude) tools, MCP tools/list entries, and bare JSON Schema. It detects the input automatically and outputs Anthropic, OpenAI and MCP.
Can I convert several tools at once?
Yes. Paste a JSON array of definitions, or a full tools/list response, and each tool is converted. The output is an array (or a tools/list) in each format.
Does it change my schema?
No. Only the wrapper and the name/description placement change; the parameter schema — including nested and advanced keywords — is preserved byte-for-byte.
How is this different from the Tool Definition Generator?
The generator builds a definition from scratch using a form. This converter takes an existing definition you already have and translates it between formats — ideal for migrating between providers.
Is my definition uploaded?
No. Detection and conversion happen entirely in your browser.
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🔗 Embed this tool on your website — free
Copy this and paste it into your page's HTML. The tool runs in the visitor's browser, just like here. Change height to fit, or add the optional auto-resize snippet below. Add ?theme=dark to the URL for dark mode.
<iframe src="https://toolhq.dev/embed/tool-definition-converter/" title="Tool Definition Converter — ToolsHub" width="100%" height="520" style="border:1px solid #e5e7eb;border-radius:12px;max-width:680px" loading="lazy"></iframe>Optional: auto-resize the iframe height
Add this once on the same page so the iframe grows to fit the tool:
<script>
addEventListener("message", function (e) {
if (e.data && e.data.type === "toolshub:resize") {
document.querySelectorAll('iframe[src*="/embed/"]').forEach(function (f) {
if (f.contentWindow === e.source) f.style.height = e.data.height + "px";
});
}
});
</script>