Loading...
Visually build, validate, test, and convert JSON Schema function calling and tool definitions for OpenAI, Anthropic Claude, LangChain, DeepSeek R1, and Meta Llama 3.3. Test argument payloads in real time and export TypeScript or Python SDK code with 100% browser-local privacy.
Your function names, descriptions, parameters, and test arguments stay 100% inside your local browser memory.
Select a pre-configured template to populate function parameters immediately.
Configure function arguments and JSON data types.
{
"type": "function",
"function": {
"name": "web_search",
"description": "Execute a web search query to fetch up-to-date information and source URLs.",
"strict": true,
"parameters": {
"type": "object",
"properties": {
"query": {
"type": "string",
"description": "The search query keywords or question"
},
"max_results": {
"type": "integer",
"description": "Maximum number of search results to retrieve (1-10)"
},
"safe_search": {
"type": "boolean",
"description": "Whether to enable strict adult content filtering"
}
},
"required": [
"query"
],
"additionalProperties": false
}
}
}Select a production preset (Web Search, DB Query, Weather API, Send Email) or enter custom function metadata and detailed instructions for LLM guidance.
Visually configure argument property names, JSON types (string, integer, boolean, array), descriptions, enum constraints, and required fields.
Test sample argument JSON output against schema validation guards, convert between OpenAI and Claude formats, and copy ready-to-run TypeScript or Python SDK code.
Zero server network requests. Your custom AI function signatures, database schema parameters, API endpoints, and test payloads stay 100% inside your browser memory.
Convert function definitions between OpenAI `tools` array (`type: 'function'`) and Anthropic Claude `tools` format (`name`, `description`, `input_schema`) with one click.
Visually configure function name, description, required fields, parameter types (string, number, boolean, array, object), enums, and nested property schemas without writing manual JSON.
Test sample JSON argument payloads against generated tool schemas in real time with line-by-line validation diagnostics to ensure your LLM receives valid tool calls.
Instantly generate ready-to-use integration code for Node.js/TypeScript OpenAI & Anthropic SDKs, Python OpenAI & Anthropic SDKs, and LangChain `@tool` decorators.
Load pre-configured production tool schemas (Web Search, Database Query, Weather API, Send Email, Code Execution) and download formatted `.json` files.
Our AI Function Calling & Tool Schema Generator is open source under HiMat Technology. Inspect schema formatting logic, contribute tool templates, or star the repository on GitHub.
Unlike third-party schema utilities that submit API keys or database schema signatures to cloud backends, HiMat's AI Function Calling Schema Generator runs 100% locally in your web browser. Neither your custom tool names, internal data models, API arguments, nor test payloads touch an external server.
Function calling (or tool use) enables Large Language Models (such as GPT-4o, Claude 3.5/3.7, or DeepSeek R1) to produce structured JSON outputs matching a pre-defined JSON Schema. The host application executes the tool (e.g. database query or API call) and feeds the result back to the LLM.
OpenAI uses a `{ type: 'function', function: { name, description, parameters } }` wrapper where `parameters` is a JSON Schema object. Anthropic Claude uses `{ name, description, input_schema }` directly. Our tool bidirectionally converts between both formats instantly.
No. The HiMat AI Function Calling & Tool Schema Generator operates 100% locally in your web browser. Neither your function parameters, schema structures, nor test payloads ever leave your device.
Yes! The built-in Argument Tester lets you paste candidate argument JSON (e.g., `{"city": "Tokyo", "units": "celsius"}`) to verify that required fields exist and property types match the schema before sending prompts to production.
Yes, 100% free with no account registration required, no usage limits, and zero advertisements.
HiMat Technology designs production-grade multi-agent orchestrations, function-calling tool chains, RAG pipelines, and 21-day fixed-scope AI pilots with full source code transfer.
Continue with related utilities, services, and guides from HiMat.