Tool / function schema review ·

Does your tool schema actually hold together?

Paste a tool/function-calling JSON schema — the shape used by LLM function-calling and MCP tool definitions — and see which of 7 structural checks it passes: a valid name, a real description, typed and described parameters, and a required list that actually matches your properties. A common, entirely mechanical bug that silently breaks validation. Free.

7structural checks
3score bands
0bytes transmitted

Paste your tool schema

Standard function-calling shape: { name, description, parameters: { type, properties, required } }.

Pricing

Unlimited reviewing is free and stays free. The Design Kit adds what a structural check can't: how to actually write a description that gets picked correctly, and the scope mistakes that don't show up as a schema error.

Free
$0
  • The full 7-item structural checklist, scored
  • A fix tip for every check that fails
  • Works on any standard function-calling / MCP tool schema
  • 100% client-side, nothing transmitted
Design Kit
$29 one-time
  • Before/after description examples that actually help a model pick the right tool
  • Scope design guidance — the single-responsibility mistakes a schema check can't catch
  • A pre-ship checklist beyond pure schema validity
Get the Design Kit

Team licence for a platform/agents org? Email for a group rate.

Straight answers

Enter your licence code

Unlocks the Design Kit on this device and survives reloads. No account, nothing transmitted.