Summary
Plugs JSON, YAML, and CSV manipulation directly into Claude through stdio. You get seven tools: schema validation with detailed error paths, structural diffs showing what changed where, transformations like pick/rename/flatten, and bidirectional conversion between all three formats with configurable delimiters and type casting. Useful when you're building workflows that need to validate API payloads against schemas, compare configuration files, reshape data structures without writing throwaway scripts, or convert between formats during data pipeline work. Install via npm, point Claude Desktop or Claude Code at the built index.js, and the tools appear in your agent's toolkit.
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Public tool metadata for what this MCP can expose to an agent.
6 tools
json_formatPretty-print or minify JSON. Specify indent level (default 2) or set minify=true to compact JSON into a single line.3 params
Pretty-print or minify JSON. Specify indent level (default 2) or set minify=true to compact JSON into a single line.
Parameters* required
indentintegerIndentation spaces (1-8, default 2)default: 2
jsonstringThe JSON string to format
minifybooleanIf true, output compact single-line JSON (overrides indent)default: false
json_validateValidate a JSON string. Returns valid=true with type info on success, or valid=false with line, column, error message, and a suggestion for fixing common mistakes.1 params
Validate a JSON string. Returns valid=true with type info on success, or valid=false with line, column, error message, and a suggestion for fixing common mistakes.
Parameters* required
jsonstringThe JSON string to validate
json_diffCompare two JSON values and return a structured diff showing added paths, removed paths, and changed values. Supports nested objects and arrays.2 params
Compare two JSON values and return a structured diff showing added paths, removed paths, and changed values. Supports nested objects and arrays.
Parameters* required
json_astringThe original JSON (before state)
json_bstringThe new JSON (after state)
json_queryQuery JSON data using JSONPath-like syntax. Supports: root ($), dot notation ($.a.b), bracket notation ($["key"]), array index ($[0]), wildcard (*), deep scan (..), slice ([1:3]), filter ([?(@.age>18)]), and union ([0,1]).2 params
Query JSON data using JSONPath-like syntax. Supports: root ($), dot notation ($.a.b), bracket notation ($["key"]), array index ($[0]), wildcard (*), deep scan (..), slice ([1:3]), filter ([?(@.age>18)]), and union ([0,1]).
Parameters* required
jsonstringThe JSON string to query
querystringJSONPath expression (e.g. "$.users[0].name", "$.items[*].price", "$..[?(@.active==true)]")
json_transformTransform JSON data. Operations: "flatten" (nested→flat with dot keys), "unflatten" (flat→nested), "pick" (keep only specified keys), "omit" (remove specified keys), "rename" (rename keys via a map). Use options.deep=true for recursive key operations.3 params
Transform JSON data. Operations: "flatten" (nested→flat with dot keys), "unflatten" (flat→nested), "pick" (keep only specified keys), "omit" (remove specified keys), "rename" (rename keys via a map). Use options.deep=true for recursive key operations.
Parameters* required
jsonstringThe JSON string to transform
operationstringThe transformation operationone of
flatten · unflatten · pick · omit · renameoptionsobjectOperation-specific options
json_schema_generateGenerate a JSON Schema (draft-07 compatible) from a sample JSON object. Infers types, required fields, formats (date-time, email, uri, uuid), and nested structure. Ideal for API documentation or validation setup.2 params
Generate a JSON Schema (draft-07 compatible) from a sample JSON object. Infers types, required fields, formats (date-time, email, uri, uuid), and nested structure. Ideal for API documentation or validation setup.
Parameters* required
jsonstringSample JSON to generate schema from
titlestringSchema title (default "GeneratedSchema")default: GeneratedSchema
mcp-json-tools
An MCP (Model Context Protocol) server that provides JSON and data manipulation tools for AI agents. Designed for use with Claude Code, Claude Desktop, and any MCP-compatible client.
Tools
| Tool | Description |
|---|---|
json_validate | Validate JSON data against a JSON Schema, returning detailed errors with paths |
json_diff | Compare two JSON objects, showing additions, removals, and changes with paths |
json_transform | Transform JSON with pick, rename, flatten, and unflatten operations |
csv_to_json | Convert CSV text to a JSON array with configurable headers, delimiters, and type casting |
json_to_csv | Convert a JSON array of objects to CSV text |
yaml_to_json | Convert YAML text to JSON |
json_to_yaml | Convert JSON text to YAML |
Installation
npm install
npm run build
Usage with Claude Code
claude mcp add json-tools -- node D:/products/mcp-servers/mcp-json-tools/dist/index.js
Usage with Claude Desktop
Add the following to your Claude Desktop configuration file:
Windows: %APPDATA%\Claude\claude_desktop_config.json
macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
{
"mcpServers": {
"json-tools": {
"command": "node",
"args": ["D:/products/mcp-servers/mcp-json-tools/dist/index.js"]
}
}
}
Tool Details
json_validate
Validate JSON data against a JSON Schema. Returns a valid boolean and an array of errors, each with the field path, message, and schema keyword that failed.
Parameters:
data(string) — JSON data to validateschema(string) — JSON Schema to validate against
json_diff
Compare two JSON objects and produce a structured diff. Each difference includes the dot-notation path, the type of change (added, removed, or changed), and the old/new values.
Parameters:
original(string) — Original JSON objectmodified(string) — Modified JSON object
json_transform
Apply transformations to JSON data. Supports four operations:
- pick — Extract specific fields by dot-notation paths
- rename — Rename top-level keys using a mapping object
- flatten — Flatten nested objects into dot-separated keys
- unflatten — Restore dot-separated keys into nested objects
Parameters:
data(string) — JSON data to transformoperation(string) — One of: pick, rename, flatten, unflattenfields(string[]) — For pick: field paths to extractmapping(object) — For rename: old-to-new key mappingseparator(string) — For flatten/unflatten: separator character (default: ".")
csv_to_json
Parse CSV text into a JSON array of objects.
Parameters:
csv(string) — CSV text to converthasHeaders(boolean) — Whether the first row is headers (default: true)delimiter(string) — Column delimiter (default: ",")castTypes(boolean) — Auto-cast numbers and booleans (default: false)
json_to_csv
Convert a JSON array of objects to CSV text. Headers are derived from the union of all object keys.
Parameters:
data(string) — JSON array to convertdelimiter(string) — Column delimiter (default: ",")includeHeaders(boolean) — Include header row (default: true)
yaml_to_json / json_to_yaml
Convert between YAML and JSON formats.
Parameters:
yamlText/jsonText(string) — Text to convertindent(number) — Indentation spaces (default: 2)
License
MIT
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Plug Mailtrap into your AI workflow and let it handle the email.
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Install now →Make coding agent sessions - Searchable, Shareable, Vendor-neutral & Scored.
Try For Free →Your agent targets a perfect 10 Code Health score. Deterministic. Every commit.
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Registryactive
Package@rog0x/mcp-json-tools
TransportSTDIO
UpdatedMar 22, 2026
