save_buffer · Vigentic MCP: Risk & Policy

WHAT IT DOES

What save_buffer does on Vigentic MCP

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

WHY IT NEEDS A POLICY

Why save_buffer needs a policy

This tool modifies files on disk by persisting buffer contents. While reversible (files can be edited or restored), it is a Write operation with high severity because an AI agent could overwrite important source files, configuration files, or other critical data without user intent. The tool operates on 'explicit open buffer target', meaning the agent has discretion over which files to modify, increasing risk.

From the tool's definition Tool name 'save_buffer' and description 'Save the current Neovim buffer or an explicit open buffer target to disk' directly indicate writing data to persistent storage.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

save_buffer Rate-limited

save_buffer 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": {
    "save_buffer": {
      "limits": [
        {
          "counter": "save_buffer_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 Vigentic MCP, so you can run agents against it safely.

FAQ

Questions about save_buffer

What does the save_buffer tool do? +

Save the current Neovim buffer or an explicit open buffer target to disk. It is categorised as a Write tool in the Vigentic 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 save_buffer? +

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

What risk level is save_buffer? +

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

Can I rate-limit save_buffer? +

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

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

save_buffer is provided by the Vigentic MCP server (munozu/vigentic-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.