schema-check

name	schema-check
description	Validate a JSON file against the schema referenced in its $schema property. Use when the user asks to check JSON against its own schema, validate self-describing JSON, auto-validate JSON files, or verify JSON with embedded schema reference.

Validate JSON Against Embedded $schema

Validate a JSON file against the schema referenced in its $schema property. This is useful for self-describing JSON documents that declare their own schema.

Usage

npx tsx scripts/check.ts <json-file> [options]

Arguments

Argument	Required	Description
json-file	Yes	Path to the JSON file with $schema property

Options

Option	Description
--all-errors	Report all errors, not just the first
--no-cache	Bypass cache when fetching remote schemas
--strict	Enable strict mode validation
--verbose	Show detailed validation output
--format	Output format: text (default), json

Output

Valid JSON:

Valid
  Schema: https://json-schema.org/draft/2020-12/schema
  File: my-schema.json

Invalid JSON:

Invalid (2 errors)
  Schema: ./schemas/config.schema.json
  1. /settings/timeout: must be number
  2. /settings/retries: must be >= 0

No schema reference:

Error: No $schema property found in config.json
  Hint: Use schema-validate to validate against a specific schema

Script Execution

npx tsx scripts/check.ts config.json
npx tsx scripts/check.ts config.json --all-errors
npx tsx scripts/check.ts config.json --no-cache --verbose

Run from the json-schema plugin directory: ~/.claude/plugins/cache/json-schema/

Schema Resolution

The $schema property can reference:

1. Remote URLs - Fetched and cached (24h TTL)

   { "$schema": "https://json-schema.org/draft/2020-12/schema" }
   

2. Local file paths - Resolved relative to the JSON file

   { "$schema": "./schemas/config.schema.json" }
   

3. Absolute paths

   { "$schema": "/Users/joe/schemas/config.schema.json" }
   

Common $schema Values

Schema URI	Description
https://json-schema.org/draft/2020-12/schema	JSON Schema Draft 2020-12
https://json-schema.org/draft/2019-09/schema	JSON Schema Draft 2019-09
http://json-schema.org/draft-07/schema#	JSON Schema Draft 7
http://json-schema.org/draft-06/schema#	JSON Schema Draft 6
http://json-schema.org/draft-04/schema#	JSON Schema Draft 4

Caching

Remote schemas are cached for 24 hours using the OS temporary directory. Use --no-cache to bypass caching and fetch fresh schemas.

Related Skills

• Use schema-meta to validate that a schema is well-formed
• Use schema-validate to validate JSON against an arbitrary schema file