Interactive converter

JSON Schema to OpenAI strict tool compiler

Convert JSON Schema to an OpenAI strict function tool with recursive required and additionalProperties repairs.

Recursive strict repairNullable optional fieldsLossy keyword ledgerResponses API wrapper

Reviewed 29 August 2026Source: OpenAI function calling guide

This conversion closes every object, makes previously optional fields nullable, expands required arrays, and reports unsupported vocabulary before emitting the tool wrapper.

Read the schema and its provider wrapper as one contract. APITC distinguishes target requirements from portable JSON Schema, applies mechanical repairs only when intent is recoverable, and identifies transformations that can change meaning.

Diagnostic procedure

Repair the schema, then recompile.

01
Paste a schema or wrapper
APITC auto-detects raw JSON Schema and common provider wrappers.
02
Review diagnostics
Errors block correctness; fixes are deterministic; warnings flag meaning that may change.
03
Copy compiled JSON
Use the output tab or download a target-specific JSON file.

Before

{"type":"object","properties":{"query":{"type":"string"},"limit":{"type":"integer"}},"required":["query"]}

Target-safe shape

{"type":"function","name":"compiled_tool","parameters":{"type":"object","properties":{"query":{"type":"string"},"limit":{"type":["integer","null"]}},"required":["query","limit"],"additionalProperties":false},"strict":true}

Interactive check

Run the schema against a real target.

Paste JSON, choose a target, and inspect the compiled shape and every portability warning before copying the result.

Contract compilerlocal browser runtime

Compile target

01 Source contract APITC canonical

02OpenAI strict

80compatibility

0 errors · 2 fixes · 0 warnings

fix$.inputSchemaClose this object

OpenAI strict requires additionalProperties: false on every object.

fix$.inputSchemaRequired array is incomplete

Strict mode requires every property in required. APITC will make limit nullable.

≈ 97 tokens compiled · input never leaves this tab

No account · no upload · no endpoint calledOpen the full tool schema compiler and operating notes →

FAQ

Before you ship

Does APITC upload my schema?

No. Parsing, diagnostics, and compilation run in your browser tab.

Is the compiled result guaranteed to preserve meaning?

Safe repairs are deterministic. When OpenAI cannot express a source constraint, APITC labels the transform as lossy instead of hiding it.

Protocol behavior checked against the OpenAI function calling guide. Recheck your pinned provider/API version before production deployment.

Repair the schema, then recompile.

Paste a schema or wrapper

Review diagnostics

Copy compiled JSON

Run the schema against a real target.

Before you ship