publish_to_topic · ROS 2 MCP Server MCP: Risk & Policy

WHAT IT DOES

What publish_to_topic does on ROS 2 MCP Server

AI agents invoke publish_to_topic to trigger actions in ROS 2 MCP Server. 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 publish_to_topic needs a policy

Publishing to a ROS 2 topic is an active operation that triggers real-world side effects (e.g., moving robot joints, activating hardware, controlling drones). It is not a simple write to a database — it dispatches commands to live systems. The blast radius is high because misuse could cause physical harm or equipment damage.

From the tool's definition "Publish a message to a topic" — actively sends/triggers messages on a ROS 2 topic, which can command physical actuators, robots, or external systems depending on the topic.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

publish_to_topic Rate-limited

publish_to_topic 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": {
    "publish_to_topic": {
      "limits": [
        {
          "counter": "publish_to_topic_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 ROS 2 MCP Server, so you can run agents against it safely.

FAQ

Questions about publish_to_topic

What does the publish_to_topic tool do? +

Publish a message to a topic. It is categorised as a Execute tool in the ROS 2 MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on publish_to_topic? +

Register the ROS 2 MCP Server MCP server in PolicyLayer and add a rule for publish_to_topic: 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 ROS 2 MCP Server. Nothing to install.

What risk level is publish_to_topic? +

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

Can I rate-limit publish_to_topic? +

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

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

publish_to_topic is provided by the ROS 2 MCP Server MCP server (ranch-hand-robotics/rde-mcp-ros-2). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.