Available Tools¶

The jpx MCP server provides 29 tools organized into seven categories.

Server Info¶

engine_info¶

Get information about the jpx engine including version, mode, function count, and session state.

{
  "include_schema": false,
  "include_index_stats": false
}

Returns:

{
  "name": "jpx-mcp",
  "version": "0.4.0",
  "strict_mode": false,
  "function_count": 395,
  "category_count": 31,
  "categories": ["Array", "Color", "Computing", ...]
}

Set include_schema to get the discovery registration JSON schema, or include_index_stats for discovery index statistics.

Function Discovery¶

Tools for exploring the 400+ JMESPath extension functions.

search¶

Fuzzy search for functions by name, description, category, or signature.

{
  "query": "string manipulation",
  "limit": 10
}

similar¶

Find functions related to a specified function.

{
  "function": "upper"
}

Returns functions with similar purpose (e.g., lower, capitalize, title_case).

functions¶

List available functions, optionally filtered by category.

{
  "category": "string"
}

describe¶

Get detailed documentation for a specific function including signature, parameters, return type, and examples.

{
  "name": "pad_left"
}

categories¶

List all function categories with function counts.

{}

Query Execution¶

Tools for running JMESPath expressions.

evaluate¶

Run a JMESPath expression against JSON input.

{
  "expression": "users[?age > `30`].name",
  "input": "{\"users\": [{\"name\": \"Alice\", \"age\": 35}, {\"name\": \"Bob\", \"age\": 25}]}"
}

Returns: ["Alice"]

evaluate_file¶

Query a JSON file directly from disk. More efficient than passing large JSON content through the protocol.

{
  "expression": "length(items)",
  "file_path": "/path/to/data.json"
}

batch_evaluate¶

Run multiple expressions against the same input. Parses the input once and runs all expressions.

{
  "expressions": ["length(@)", "keys(@)", "@.name"],
  "input": "{\"name\": \"test\", \"value\": 42}"
}

validate¶

Check expression syntax without executing.

{
  "expression": "users[?active].name"
}

Returns validation status and any syntax errors.

explain¶

Break down a JMESPath expression into steps. Returns node types, descriptions, functions used, and a complexity rating. Also works for invalid expressions (returns the parse error).

{
  "expression": "users[?age > `30`].name | sort(@)"
}

Data Analysis¶

Tools for understanding JSON structure before writing queries.

stats¶

Analyze JSON structure and statistics.

{
  "input": "{\"users\": [{\"name\": \"Alice\"}, {\"name\": \"Bob\"}]}"
}

Returns type, size, depth, and field analysis.

paths¶

Extract all paths in a JSON document using dot notation.

{
  "input": "{\"user\": {\"profile\": {\"name\": \"Alice\"}}}",
  "include_types": true,
  "include_values": false
}

keys¶

Extract object keys, optionally recursive with dot notation.

{
  "input": "{\"a\": {\"b\": 1}}",
  "recursive": true
}

JSON Utilities¶

Tools for JSON manipulation following RFC standards (RFC 6902 for JSON Patch, RFC 7396 for Merge Patch).

format¶

Pretty-print JSON with configurable indentation. Use indent: 0 for compact output.

{
  "input": "{\"compact\":true}",
  "indent": 2
}

diff¶

Generate RFC 6902 JSON Patch between two documents.

{
  "source": "{\"a\": 1}",
  "target": "{\"a\": 2, \"b\": 3}"
}

Returns patch operations: [{"op": "replace", "path": "/a", "value": 2}, {"op": "add", "path": "/b", "value": 3}]

patch¶

Apply RFC 6902 JSON Patch operations.

{
  "input": "{\"a\": 1}",
  "patch": "[{\"op\": \"add\", \"path\": \"/b\", \"value\": 2}]"
}

merge¶

Apply RFC 7396 JSON Merge Patch.

{
  "input": "{\"a\": 1, \"b\": 2}",
  "patch": "{\"b\": null, \"c\": 3}"
}

Returns: {"a": 1, "c": 3} (null removes keys)

Query Store¶

Session-scoped named queries for iterative development. Queries persist for the duration of the MCP session.

define_query¶

Store a named JMESPath query for reuse. The query is validated before storing.

{
  "name": "active_users",
  "expression": "users[?status == 'active'].name",
  "description": "Get names of active users"
}

get_query¶

Retrieve a stored query by name.

{
  "name": "active_users"
}

run_query¶

Execute a stored query by name against JSON input.

{
  "name": "active_users",
  "input": "{\"users\": [{\"name\": \"Alice\", \"status\": \"active\"}, {\"name\": \"Bob\", \"status\": \"inactive\"}]}"
}

list_queries¶

List all named queries stored in this session.

{}

delete_query¶

Delete a stored query by name.

{
  "name": "active_users"
}

Multi-Server Discovery¶

Tools for semantic search across multiple MCP servers. See Multi-Server Discovery for full documentation.

register_tools¶

Register an MCP server's tools for BM25 indexing. Accepts either a full discovery spec (via spec) or a simplified format (via server_name + tools).

Full spec:

{
  "spec": {
    "server": {"name": "myserver", "version": "1.0.0"},
    "tools": [
      {"name": "tool_one", "description": "Does something useful", "category": "utils"}
    ]
  }
}

Simplified:

{
  "server_name": "myserver",
  "tools": [
    {"name": "backup_db", "description": "Backup the database", "tags": ["database", "backup"]},
    {"name": "restore_db", "description": "Restore from backup", "tags": ["database", "restore"]}
  ]
}

query_tools¶

Semantic search across all registered tools using BM25.

{
  "query": "backup database",
  "top_k": 5
}

Returns ranked results with BM25 scores.

similar_tools¶

Find tools related to a specific tool.

{
  "tool_id": "myserver:tool_one",
  "top_k": 5
}

unregister_discovery¶

Remove a server from the registry.

{
  "server_name": "myserver"
}

list_discovery_servers¶

List all registered servers with tool counts.

{}

list_discovery_categories¶

List tool categories across all registered servers.

{}