brain_link · Claude Team MCP: Risk & Policy

WHAT IT DOES

What brain_link does on Claude Team MCP

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

WHY IT NEEDS A POLICY

Why brain_link needs a policy

This tool creates a relationship/link between two existing notes in the knowledge graph. It modifies data by adding connections, but does not delete or irreversibly destroy anything. This is a reversible write operation — links can presumably be removed. Severity is low because the blast radius of incorrectly linking notes is minimal.

From the tool's definition Connect two second-brain notes (builds the knowledge graph)

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

brain_link Rate-limited

brain_link 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": {
    "brain_link": {
      "limits": [
        {
          "counter": "brain_link_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 Claude Team MCP, so you can run agents against it safely.

FAQ

Questions about brain_link

What does the brain_link tool do? +

Connect two second-brain notes (builds the knowledge graph). It is categorised as a Write tool in the Claude Team MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on brain_link? +

Register the Claude Team MCP server in PolicyLayer and add a rule for brain_link: 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 Claude Team MCP. Nothing to install.

What risk level is brain_link? +

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

Can I rate-limit brain_link? +

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

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

brain_link is provided by the Claude Team MCP server (lakshan12367/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.