Single-tool server with a focused, read-only operation. The 'query' tool has a complete input schema with proper types and descriptions for all parameters. Tool description is adequate (97 chars) but could be more explicit about when to use it and what it returns. Parameter descriptions are present and reasonably clear. However, output schema is not documented, the tool returns a JSON object with a 'matches' field, but this structure is not declared in the tool definition. Error handling returns actionable messages but lacks recovery guidance. No tool annotations (readOnlyHint) despite being read-only.

• Add output schema documentation to the tool definition: 'Returns: {matches: any[], type: "array"}' or similar, describing the structure of results.
• Expand tool description to 100-150 chars: 'Query JSON structures using JSONPath expressions ($.foo.bar[*], $..price). Returns matching values, paths, or both. Useful for extracting nested data from complex JSON.'
• Add readOnlyHint: true to the tool definition to signal that this tool does not modify state.
• Improve error messages with recovery hints: 'Invalid JSONPath: <error>. Ensure path starts with $ and uses valid syntax (e.g., $.items[*].price, $..name).'
• Add type constraint to 'json' parameter: change {description: 'Any JSON value.'} to {type: ['object', 'array', 'string', 'number', 'boolean', 'null'], description: 'Any JSON value (object, array, string, number, boolean, or null).'}