vim_mark · Mcp Neovim Server MCP: Risk & Policy

WHAT IT DOES

What vim_mark does on Mcp Neovim Server

AI agents use vim_mark 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_mark needs a policy

Setting marks in a Neovim buffer is a write operation that modifies editor state but is fully reversible. The user can clear or change marks at any time. This is not a Read (no data retrieval), Execute (doesn't run arbitrary code), Destructive (marks can be undone), or Financial operation. The blast radius of misuse is low since marks are navigation aids with no data loss or system impact.

From the tool's definition Tool description states 'Set named marks at specific positions in the buffer' — this modifies buffer state by creating/updating marks, which is a reversible operation (marks can be cleared or moved).

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

vim_mark Rate-limited

vim_mark 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_mark": {
      "limits": [
        {
          "counter": "vim_mark_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_mark

What does the vim_mark tool do? +

Set named marks at specific positions in the buffer. 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_mark? +

Register the Mcp Neovim Server MCP server in PolicyLayer and add a rule for vim_mark: 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_mark? +

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

Can I rate-limit vim_mark? +

Yes. Add a rate_limit block to the vim_mark 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_mark completely? +

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

vim_mark 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.