run_tests

Run Jest tests for a service. Returns pass/fail counts and structured failure details with test names and error messages. Optionally scope to a test name pattern.

SERVERMcp Dev SOURCE2loch-ness6/mempalace-mcp-dev

High RISK CLASS

Category Execute

Parameters 00 required

Recommended Rate-limitedsee the rule below

Registry record Grade D, identity unverified Pull the record →

This record as markdown: /tools/2loch-ness6-mempalace-mcp-dev/run-tests.md

WHAT IT DOES

What run_tests does on Mcp Dev

AI agents invoke run_tests to trigger actions in Mcp Dev. 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.

RISK

Why run_tests is rated High

This tool executes external operations (Jest test runner) whose effects depend on the test suite arguments and implementation. While tests are typically read-only in intent, the execution itself is a code-running action that can trigger side effects, potentially including data modifications, API calls, or resource consumption depending on what the tests are configured to do.

From the tool's definition Tool description states "Run Jest tests for a service" - explicitly runs code execution via a testing framework.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs run_tests safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Mcp Dev, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For run_tests, this is the rule to start with:

run_tests Rate-limited

run_tests 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": {
    "run_tests": {
      "limits": [
        {
          "counter": "run_tests_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Mcp Dev, apply this rule, and every run_tests call is checked against it from then on.

FAQ

Questions about run_tests

What does the run_tests tool do? +

Run Jest tests for a service. Returns pass/fail counts and structured failure details with test names and error messages. Optionally scope to a test name pattern. It is categorised as a Execute tool in the Mcp Dev MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on run_tests? +

Register the Mcp Dev MCP server in PolicyLayer and add a rule for run_tests: 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 Mcp Dev. Nothing to install.

What risk level is run_tests? +

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

Can I rate-limit run_tests? +

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

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

run_tests is provided by the Mcp Dev MCP server (2loch-ness6/mempalace-mcp-dev). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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