add_text · MCP Bear MCP: Risk & Policy

WHAT IT DOES

What add_text does on MCP Bear

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

WHY IT NEEDS A POLICY

Why add_text needs a policy

This tool creates or modifies data reversibly by appending/inserting text into an existing note. It does not delete, execute code, or cause irreversible changes. The modification is reversible (text can be edited or removed).

From the tool's definition Tool description states 'Add text to an existing note', which modifies content reversibly. The server uses 'x-callback-url for modifications', confirming write capability.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

add_text Rate-limited

add_text 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_text": {
      "limits": [
        {
          "counter": "add_text_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 MCP Bear, so you can run agents against it safely.

FAQ

Questions about add_text

What does the add_text tool do? +

Add text to an existing note. It is categorised as a Write tool in the MCP Bear 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_text? +

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

What risk level is add_text? +

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

Can I rate-limit add_text? +

Yes. Add a rate_limit block to the add_text 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_text completely? +

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

add_text is provided by the MCP Bear MCP server (maxim-ist/mcp-bear). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.