replace_buffer · Vigentic MCP: Risk & Policy

WHAT IT DOES

What replace_buffer does on Vigentic MCP

AI agents use replace_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 replace_buffer needs a policy

This tool modifies file contents by rewriting an entire buffer, which is a reversible write operation. It does not delete files (which would be Destructive) but rather overwrites their contents. The high severity reflects the risk that an AI agent could accidentally overwrite significant code or data by targeting the wrong buffer.

From the tool's definition Tool description states it can 'Replace the entire current Neovim buffer or explicit target buffer as a fallback full-buffer rewrite', which modifies file contents. The name 'replace_buffer' and description confirm this is a write/modification operation.

Risk signalsBulk/mass operation — affects multiple targets

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

replace_buffer Rate-limited

replace_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": {
    "replace_buffer": {
      "limits": [
        {
          "counter": "replace_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 replace_buffer

What does the replace_buffer tool do? +

Replace the entire current Neovim buffer or explicit target buffer as a fallback full-buffer rewrite. useLatestChangedTick is current-buffer-only; useLatestSessionChangedTick works for explicit path targets or already-open explicit bufferId targets in the editor session. 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 replace_buffer? +

Register the Vigentic MCP server in PolicyLayer and add a rule for replace_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 replace_buffer? +

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

Can I rate-limit replace_buffer? +

Yes. Add a rate_limit block to the replace_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 replace_buffer completely? +

Set action: deny in the PolicyLayer policy for replace_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 replace_buffer? +

replace_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.