add_lesson · Lingua MCP: Risk & Policy

WHAT IT DOES

What add_lesson does on LinguaMCP

AI agents use add_lesson to create or update resources in LinguaMCP — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your LinguaMCP environment.

WHY IT NEEDS A POLICY

Why add_lesson needs a policy

This tool creates new lesson content within the structured curriculum, constituting a Write operation. It reversibly adds data (lessons can presumably be removed via the sibling tool 'remove_lesson'). The severity is low because adding educational content has minimal blast radius—worst case, unwanted lessons are created but can be deleted. No destructive, financial, or code execution capability is involved.

From the tool's definition Tool description states 'Add a new lesson to a chapter', which is a create operation that modifies the curriculum data by inserting a new lesson resource.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

add_lesson Rate-limited

add_lesson stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "add_lesson": {
      "limits": [
        {
          "counter": "add_lesson_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches LinguaMCP, so you can run agents against it safely.

FAQ

Questions about add_lesson

What does the add_lesson tool do? +

Add a new lesson to a chapter. Returns the new lesson ID. It is categorised as a Write tool in the LinguaMCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on add_lesson? +

Register the Lingua MCP server in PolicyLayer and add a rule for add_lesson: 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 LinguaMCP. Nothing to install.

What risk level is add_lesson? +

add_lesson is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit add_lesson? +

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

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

add_lesson is provided by the Lingua MCP server (marsmanleo/linguamcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.