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LLM Tool Schema Validator

Validate LLM tool-call schemas against JSON Schema.

Output will appear here…

How to Use This Tool

  1. Fill in JSON Schema, and Data (JSON). Each control is labeled; you do not need to paste a JSON blob.
  2. Click "Run" to run the tool in your browser.
  3. Read the result below the form and copy it if you need it in another app.

Learn More About LLM Tool Schema Validator

About LLM Tool Schema Validator

Validate LLM tool-call arguments against JSON Schema. Uses Ajv for strict validation.

About

Validate LLM tool-call arguments against JSON Schema. Uses Ajv for strict validation.
Validate LLM tool-call arguments against JSON Schema. Uses Ajv for strict validation.
Runs in browser
Yes
No signup required
Yes

Examples

Valid

Valid
Input
{
  "schema": "{\"type\":\"object\",\"required\":[\"name\"],\"properties\":{\"name\":{\"type\":\"string\"}}}",
  "data": "{\"name\":\"Alice\"}"
}
Output
✓ Valid: data matches the schema.

Data mismatch

Data mismatch
Input
{
  "schema": "{\"type\":\"object\",\"required\":[\"name\"],\"properties\":{\"name\":{\"type\":\"string\"}}}",
  "data": "{\"name\":123}"
}
Output
✗ Invalid:
  - /name: must be string

Integer count

Integer count
Input
{
  "schema": "{\"type\":\"object\",\"required\":[\"count\"],\"properties\":{\"count\":{\"type\":\"integer\",\"minimum\":0}}}",
  "data": "{\"count\":3}"
}
Output
✓ Valid: data matches the schema.

Use Cases

  • Check llm tool schema validator values while you draft a page, spreadsheet, or config.
  • Fill JSON Schema, Data (JSON) and compare the result to a second source.
  • Keep sensitive inputs on-device — this page runs the calculation in the browser.

Frequently Asked Questions

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