AI agents call lsp_selection_range to retrieve information from Lsp without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves structural metadata about code (semantic ranges at a given position) to inform subsequent operations. It has no side effects, performs no modifications, and executes no external code. It is a read-only introspection tool, similar to lsp_document_symbols and other sibling query tools on this LSP bridge server.
From the tool's definition Tool description states 'Get the chain of semantic ranges enclosing a position' — a pure query operation that retrieves syntactic/semantic information without modifying or executing anything.
Attacks that exploit this kind of access
Get the chain of semantic ranges enclosing a position — the expression, then its statement, then its block, up to the file. Use to pick the right range for lsp_code_actions (e.g.,. It is categorised as a Read tool in the Lsp MCP Server, which means it retrieves data without modifying state.
Register the Lsp MCP server in PolicyLayer and add a rule for lsp_selection_range: 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. Nothing to install.
lsp_selection_range 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 lsp_selection_range 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 lsp_selection_range. 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.
lsp_selection_range is provided by the Lsp MCP server (lsp-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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