AI agents call get_buf_diagnostics to retrieve information from Nvim without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves diagnostic data from a buffer without modifying anything. Diagnostics are typically read-only outputs from language servers (LSP) or linters. No side effects or state changes occur from querying diagnostics. The semantic pattern matches classic Read operations like 'get', 'fetch', or 'query'.
From the tool's definition Tool name 'get_buf_diagnostics' indicates retrieval of diagnostic information from a buffer. The 'get_' prefix universally indicates a query/read operation.
Documented attack patterns abuse exactly the kind of access get_buf_diagnostics gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Nvim, and nothing reaches the server without passing your rules. This is the rule we recommend for get_buf_diagnostics:
{
"version": "1",
"default": "deny",
"tools": {
"get_buf_diagnostics": {}
}
}get_buf_diagnostics is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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get_buf_diagnostics. It is categorised as a Read tool in the Nvim MCP Server, which means it retrieves data without modifying state.
Register the Nvim MCP server in PolicyLayer and add a rule for get_buf_diagnostics: 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 Nvim. Nothing to install.
get_buf_diagnostics is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the get_buf_diagnostics 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.
Set action: deny in the PolicyLayer policy for get_buf_diagnostics. 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.
get_buf_diagnostics is provided by the Nvim MCP server (paulburgess1357/nvim-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 17 Nvim tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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17 Nvim tools catalogued and risk-classified — across an index of 42,500+ MCP servers.