start_runtime

Use this to start a Genkit runtime process (This is typically the entry point to the users app). Once started, the runtime will be picked up by the \

SERVERGenkit MCP SOURCEgenkit-ai/genkit

High RISK CLASS

Category Execute

Parameters 00 required

Recommended Rate-limitedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/firebase-genkit/start-runtime.md

WHAT IT DOES

What start_runtime does on Genkit MCP

AI agents invoke start_runtime to trigger actions in Genkit MCP. 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 start_runtime is rated High

Starting a runtime process is an Execute action—it triggers the execution of arbitrary application code whose effects depend entirely on what that runtime does. While not immediately destructive, the blast radius is high because a misconfigured or compromised runtime could execute harmful operations.

From the tool's definition "start a Genkit runtime process" and "entry point to the users app" indicate launching/executing code that triggers external operations with effects dependent on what the runtime does.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs start_runtime safely

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

start_runtime Rate-limited

start_runtime 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": {
    "start_runtime": {
      "limits": [
        {
          "counter": "start_runtime_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 Genkit MCP, apply this rule, and every start_runtime call is checked against it from then on.

FAQ

Questions about start_runtime

What does the start_runtime tool do? +

Use this to start a Genkit runtime process (This is typically the entry point to the users app). Once started, the runtime will be picked up by the \. It is categorised as a Execute tool in the Genkit MCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on start_runtime? +

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

What risk level is start_runtime? +

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

Can I rate-limit start_runtime? +

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

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

start_runtime is provided by the Genkit MCP server (genkit-ai/genkit). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

KEEP EXPLORING

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