Open a file in the LSP server for analysis. Use this tool before performing operations like getting diagnostics, hover information, or completions for a file. The file remains open for continued analysis until explicitly closed. The language_id parameter tells the server which language service to...
AI agents call open_document to retrieve information from LSP MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The tool opens a file for read-only analysis purposes (diagnostics, hover info, completions). It does not modify or create any file content; it merely registers the file with the LSP server so it can be queried. This is fundamentally a read/query operation, though it does maintain server-side state (file remains open).
From the tool's definition Open a file in the LSP server for analysis. Use this tool before performing operations like getting diagnostics, hover information, or completions for a file.
Documented attack patterns abuse exactly the kind of access open_document gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and LSP MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for open_document:
{
"version": "1",
"default": "deny",
"tools": {
"open_document": {}
}
}open_document is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Open a file in the LSP server for analysis. Use this tool before performing operations like getting diagnostics, hover information, or completions for a file. The file remains open for continued analysis until explicitly closed. The language_id parameter tells the server which language service to use (e.g.,. It is categorised as a Read tool in the LSP MCP Server MCP Server, which means it retrieves data without modifying state.
Register the LSP MCP Server MCP server in PolicyLayer and add a rule for open_document: 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 LSP MCP Server. Nothing to install.
open_document 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 open_document 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 open_document. 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.
open_document is provided by the LSP MCP Server MCP server (tritlo/lsp-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 9 LSP MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
9 LSP MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.