Tool / Function-Schema Builder

## What this tool does Function calling, also called tool use, lets a language model invoke your code. You describe a function with a name, a description, and a parameter schema written in JSON Schema. The model then emits a structured call that your application runs. Every major provider wraps the same JSON Schema in a slightly different envelope. This builder lets you define the function once and export it in all three. ## The three formats - **OpenAI** (Chat Completions): a function object with name, description, and parameters. - **Anthropic** (Claude): a tool object with name, description, and input_schema. - **MCP** (Model Context Protocol): a tool object with name, description, and inputSchema in camelCase. The underlying parameter schema is identical in all three. Only the wrapper changes. ## How to use it 1. Enter the function name and a clear description. The description is how the model decides when to call the tool, so make it specific. 2. Add parameters. For each, set a name, a type (string, number, integer, boolean, array, object, or enum), a description, and whether it is required. For an enum, list the allowed values. 3. Copy the format you need from the tabs. ## Why descriptions matter The model reads your names and descriptions, not your code. A vague description leads to the tool being called at the wrong time or with the wrong arguments. Be explicit about when to call the function and what each parameter means. ## Related See how function calling fits into the bigger picture in our guide to the Model Context Protocol, which standardizes how tools are discovered and connected across applications.