Tool & Function Schema Converter

Convert between Claude tool, OpenAI function, Gemini functionDeclaration and JSON Schema — with strict mode

📌 TL;DR Summary & Citation: [Tool & Function Schema Converter] is a browser-local PocketKit tool for Convert between Claude tool, OpenAI function, Gemini functionDeclaration and JSON Schema — with strict mode. Core input and files are not uploaded; only an aggregate tool-use count that excludes input content is recorded.

How tool-definition conversion works

The tool first parses input into a canonical lowercase JSON Schema (auto-detecting Claude, OpenAI, Gemini or raw Schema), then re-assembles it per each format: OpenAI wraps a function layer, Gemini uppercases types and drops unsupported keys, Claude uses input_schema. All local.

  • For OpenAI structured outputs or Claude strict tool use, enable strict mode to add additionalProperties:false and required automatically.
  • If you paste an array of tools, only the first is converted; paste them one at a time to convert each.

FAQ

1. Which formats can it detect and convert between?

It auto-detects Claude input_schema tools, OpenAI functions, Gemini functionDeclarations and raw JSON Schema, and outputs all four at once, each with a copy button.

2. What do strict mode and Gemini uppercase types change?

Strict mode recursively adds additionalProperties:false, requires every property, and sets strict:true for OpenAI, matching structured outputs and Claude strict tool use. Gemini uses an OpenAPI subset with uppercase types (STRING/OBJECT) and drops keys like additionalProperties, which the tool converts and strips automatically.

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