JSON Formatter & Validator MCP Server

JSON Formatter & Validator

Work with JSON text locally: pretty-print with options, validate with human-readable error locations, or minify to the smallest valid form. All operations use strict parsing — invalid JSON is rejected with clear diagnostics (except the dedicated validate tool, which returns structured error details instead of failing the call).

Capabilities

• Pretty-print and normalize: Parse a JSON string and emit stable, formatted output. Control indent width (including compact single-line output with spaces after separators), optionally sort object keys for deterministic diffs, and optionally force ASCII escaping for non-Unicode-safe channels.
• Validate with diagnostics: Confirm whether input is valid JSON. On success, walk the entire value recursively and report structure statistics: total object keys (all nesting levels), maximum nesting depth of arrays and objects, counts of arrays, objects, and leaf values, plus the top-level JSON type. On failure, return the decoder message, line and column, and a three-line excerpt of the source with a caret marking the error position.
• Minify: Parse and re-serialize with no redundant whitespace, using compact separators. Returns minified text, input and output byte lengths, and a percentage size reduction vs. the original string.

Gotchas

• Numbers and types: Parsed numbers follow JSON rules (e.g. no trailing commas). After parsing, Python may represent integers and floats; output reflects standard json serialization.
• Key sorting: Sorting applies to object keys at every depth when enabled on the format tool.
• Compression ratio: Minify compares string lengths before and after; heavily compact input may show little or no reduction.