vim_register · Mcp Neovim Server MCP: Risk & Policy

WHAT IT DOES

What vim_register does on Mcp Neovim Server

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

WHY IT NEEDS A POLICY

Why vim_register needs a policy

Registers are reversibly modifiable in-memory structures. The tool does not delete data permanently (Destructive), execute arbitrary code (Execute), or create/delete files. It modifies editor state that can be undone or overwritten, placing it in the Write category.

From the tool's definition Tool name 'vim_register' and description 'Manage Neovim register contents' indicate the tool can modify register state. Registers in Neovim are mutable storage for clipboard, macro, and command history data.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

vim_register Rate-limited

vim_register 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": {
    "vim_register": {
      "limits": [
        {
          "counter": "vim_register_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 Neovim Server, so you can run agents against it safely.

FAQ

Questions about vim_register

What does the vim_register tool do? +

Manage Neovim register contents. It is categorised as a Write tool in the Mcp Neovim Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on vim_register? +

Register the Mcp Neovim Server MCP server in PolicyLayer and add a rule for vim_register: 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 Neovim Server. Nothing to install.

What risk level is vim_register? +

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

Can I rate-limit vim_register? +

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

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

vim_register is provided by the Mcp Neovim Server MCP server (mcp-neovim-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.