High Risk →

pytest

Runs pytest and returns structured test results (passed, failed, errors, skipped, failures).

How to control pytest ↓

What pytest does on Http

AI agents invoke pytest to trigger actions in Http. 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.

High Risk

Why pytest needs a policy

pytest executes arbitrary Python test code on the host system. An AI agent could misuse this to trigger execution of malicious test files or side-effecting fixtures. The blast radius is high because pytest can run arbitrary Python code with the permissions of the server process.

From the tool's definition 'Runs pytest' — explicitly executes a test framework process on the system

Documented attack patterns abuse exactly the kind of access pytest gives an agent:

How to control pytest

PolicyLayer is an MCP gateway — it sits between your AI agents and Http, and nothing reaches the server without passing your rules. This is the rule we recommend for pytest:

policy.json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "pytest": {
      "limits": [
        {
          "counter": "pytest_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

pytest 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.

  1. Create a free account and register Http — nothing to install.
  2. Add this policy — paste it, or build it visually.
  3. Point your MCP client (Claude, Cursor, anything) at your gateway URL.
RATE-LIMIT THIS TOOL →

Free to start. No card required.

Related tools and policies

Go deeper

Questions about pytest

What does the pytest tool do? +

Runs pytest and returns structured test results (passed, failed, errors, skipped, failures). It is categorised as a Execute tool in the Http MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on pytest? +

Register the Http MCP server in PolicyLayer and add a rule for pytest: 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 Http. Nothing to install.

What risk level is pytest? +

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

Can I rate-limit pytest? +

Yes. Add a rate_limit block to the pytest 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 pytest completely? +

Set action: deny in the PolicyLayer policy for pytest. 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 pytest? +

pytest is provided by the Http MCP server (@paretools/http). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Http tool call.

Start from Http, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

Free to start. No card required.

202 Http tools catalogued and risk-classified — across an index of 43,000+ MCP servers.

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