// SCAN REPORT

Joern MCP Server

21 tools. 0 can modify or destroy data without limits.

Read-only server. Low risk, but rate limits prevent runaway API costs.

Last updated:

0 can modify or destroy data
21 read-only
21 tools total

Community server · catalogue entry verified 11/06/2026

How to control Joern MCP Server ↓

TOOL MAP

Read (21) Write / Execute (0) Destructive / Financial (0)

WHAT CAN GO WRONG

✕

Even read-only tools carry cost. An agent in a retry loop can make thousands of API calls per minute, exhausting rate limits and running up bills.

HOW TO CONTROL JOERN MCP SERVER

PolicyLayer is an MCP gateway — it sits between your AI agents and Joern MCP Server, and nothing reaches the server without passing your rules. These are the rules we recommend:

Cap read operations
{
  "check_connection": {
    "limits": [
      {
        "counter": "check_connection_per_minute",
        "window": "minute",
        "max": 60,
        "scope": "grant"
      }
    ]
  }
}

Controls API costs and prevents retry loops from exhausting upstream rate limits.

  1. Create a free account and register Joern MCP Server — nothing to install.
  2. Add these rules — paste them, or build them visually. Tune the limits to your setup.
  3. Point your MCP client (Claude, Cursor, anything) at your gateway URL.
ENFORCE POLICY ON JOERN →

Free to start. No card required.

ALL 21 JOERN MCP SERVER TOOLS

READ 21 tools
Read check_connection Check if the Joern MCP plugin is running Read find_flows_from_method_params_to_sink_method find_flows_from_method_params_to_sink_method Read find_flows_from_param_index_to_sink_call find_flows_from_param_index_to_sink_call Read find_flows_from_source_call_to_sink_call find_flows_from_source_call_to_sink_call Read get_call_code_by_id Get the source code of a specific call node from the loaded CPG by the call id Read get_calls_in_method_by_method_full_name Get the calls info by the method full name which the call is in the method Read get_class_full_name_by_id Retrieves the fully name of a class by its ID Read get_class_methods_by_class_full_name Get the methods of a class by its fully qualified name Read get_derived_classes_by_class_full_name Get the derived classes of a class Read get_help Get help information from joern server Read get_method_by_call_id Get the method info by the call id which the call is in the method Read get_method_callees get_method_callees Read get_method_callers get_method_callers Read get_method_code_by_class_full_name_and_method_name get_method_code_by_class_full_name_and_method_name Read get_method_code_by_full_name get_method_code_by_full_name Read get_method_code_by_id Get the code of a method by its class full name and method name Read get_method_full_name_by_id get_method_full_name_by_id Read get_parent_classes_by_class_full_name Get the parent classes of a class Read get_referenced_method_full_name_by_call_id Get the method info by the call id which the call is referenced the method Read load_cpg Loads a CPG from a file if the cpg is not loaded or the cpg is not the same as the filepath. Read ping Checks if the Joern server is running and responsive by querying its version

FAQ

Is the Joern MCP Server MCP server safe to use without restrictions? +

The Joern MCP Server server is primarily read-only with 21 read tools. While it cannot modify data, an agent in a retry loop can make thousands of API calls per minute, exhausting rate limits and running up costs. Rate limiting is still recommended.

How many tools does the Joern MCP Server MCP server expose? +

21 tools across 1 categories: Read. 21 are read-only. 0 can modify, create, or delete data.

How do I enforce a policy on Joern MCP Server? +

Register the Joern MCP Server MCP server in PolicyLayer, apply the suggested rules above (adjust the limits to your use case), and point your AI client at the PolicyLayer proxy URL instead of the server directly. Your agents keep the same tools; PolicyLayer evaluates every call against policy before it executes. Nothing to install, live in minutes.

Enforce policy on every Joern MCP Server tool call.

Deterministic rules across all 21 Joern MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.

ENFORCE POLICY ON JOERN →

Free to start. No card required.

21 Joern MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.

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