semgrep · Python MCP: Risk & Policy

WHAT IT DOES

What semgrep does on Python

AI agents invoke semgrep to trigger actions in Python. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why semgrep needs a policy

The tool executes an external static analysis tool (Semgrep) against code. While primarily a read/analysis operation, it actively runs a tool on code with potential to scan arbitrary paths. The blast radius is medium since it doesn't modify or delete data, but could be used to scan sensitive codebases or be directed at unintended targets.

From the tool's definition Runs Semgrep static analysis with structured rules and findings

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

semgrep Rate-limited

semgrep stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "semgrep": {
      "limits": [
        {
          "counter": "semgrep_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Python, so you can run agents against it safely.

FAQ

Questions about semgrep

What does the semgrep tool do? +

Runs Semgrep static analysis with structured rules and findings. Returns structured finding data with severity summary. It is categorised as a Execute tool in the Python MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on semgrep? +

Register the Python MCP server in PolicyLayer and add a rule for semgrep: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Python. Nothing to install.

What risk level is semgrep? +

semgrep is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit semgrep? +

Yes. Add a rate_limit block to the semgrep rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block semgrep completely? +

Set action: deny in the PolicyLayer policy for semgrep. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides semgrep? +

semgrep is provided by the Python MCP server (Dave-London/Pare). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

// THE FULL RECORD

semgrep is one line of Python's registry record.

The record carries the whole server: verified identity, auth posture, risk grade, every tool classified, recommended policy — re-checked continuously.

Teams ship this data inside their own products. See what a licence covers →