Available Tools¶

The jpx MCP server provides 31 tools organized into seven categories.

Server Info¶

engine_info¶

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

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

Returns:

{
  "name": "jpx-mcp",
  "version": "0.5.0",
  "strict_mode": false,
  "function_count": 498,
  "category_count": 33,
  "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 470+ 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).

suggest_function¶

Describe a task in natural language and get ranked function suggestions with relevance notes.

{
  "task": "remove duplicate values from an array",
  "limit": 5
}

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"
}

batch_describe¶

Get details for several functions in one call. Returns one {name, detail} entry per requested name, in order; unknown names yield a null detail rather than failing the whole batch.

{
  "names": ["pad_left", "split", "join"]
}

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. The path must be absolute and at most 50 MiB. The server can read any path permitted to its operating-system user, so only expose this tool to trusted clients.

{
  "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¶

Named queries for iterative development. They live in memory for the server process, are shared by every connected client, and disappear when the process exits.

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 server process.

{}

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.

{}