run_tests_json

THE RISK

High Risk

Why run_tests_json needs a policy

Running tests is a form of code execution that triggers external operations (test runners) whose effects depend on test suite contents and environment. This constitutes Execute rather than Read or Write. Severity is high because test execution can modify system state (create temp files, call external services, modify databases), and an AI agent could run malicious or unvetted tests.

From the tool's definition Tool name 'run_tests_json' indicates execution of test suites. Server description states the MCP server enables 'AI agents to run tests' and uses debugpy/Debug Adapter Protocol.

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

POLICY

How to control run_tests_json

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

policy.json

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

run_tests_json 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.

Create a free account and register Mcp Debugpy — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

RATE-LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More Mcp Debugpy tools

Execute dap_continue Continue execution on the specified (or last stopped) thread. Execute dap_launch dap_launch Execute dap_shutdown Terminate the current DAP adapter session. Execute dap_step_in Step into the next function call on the active thread. Execute dap_step_out Step out of the current function on the active thread. Execute dap_step_over Step over the next line on the active thread. Execute dap_wait_for_event Wait for a specific DAP event (e.g., 'stopped'). Execute run_tests_focus Run a focused subset: pytest -k <keyword> with JSON report.

All 16 Mcp Debugpy tools →

Execute tools on other servers

Android Forensics ADB MCP Server adb_shell_command EMBA-MCP run_emba_scan Frida Game Hacking MCP remove_breakpoint Procmon request_elevation

Go deeper

High-risk tools in Mcp Debugpy → Every high-risk tool this server exposes, in one view.
All high-risk MCP tools → Every high-risk tool across the catalogue, and the policy pattern that contains them.
The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Agent sandbox → Bounding what an agent can execute and where the boundary should sit.
Least privilege for MCP → Granting agents the minimum tool surface the task needs.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about run_tests_json

What does the run_tests_json tool do? +

run_tests_json. It is categorised as a Execute tool in the Mcp Debugpy 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_json? +

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

What risk level is run_tests_json? +

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

Can I rate-limit run_tests_json? +

Yes. Add a rate_limit block to the run_tests_json 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_json completely? +

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

run_tests_json is provided by the Mcp Debugpy MCP server (markomanninen/mcp-debugpy). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Mcp Debugpy tool call.

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

CHECK YOUR STACK →