Find usage of a symbol. Args: project: Project name symbol: Symbol name to find file_path: Optional file to look in (for local symbols) language: Language to search in Returns: List of usage locations
AI agents call find_usage to retrieve information from Tree Sitter without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool performs code analysis queries to locate where a symbol is used within a codebase. It accepts parameters (project, symbol, file_path, language) and returns location data. There are no side effects, no code execution, no data modification, and no destructive operations.
From the tool's definition Tool name 'find_usage' and description 'Find usage of a symbol' with returns 'List of usage locations' indicate a search/query operation that retrieves data about code symbol references without modifying, executing, or deleting anything.
Documented attack patterns abuse exactly the kind of access find_usage gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Tree Sitter, and nothing reaches the server without passing your rules. This is the rule we recommend for find_usage:
{
"version": "1",
"default": "deny",
"tools": {
"find_usage": {}
}
}find_usage is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Find usage of a symbol. Args: project: Project name symbol: Symbol name to find file_path: Optional file to look in (for local symbols) language: Language to search in Returns: List of usage locations. It is categorised as a Read tool in the Tree Sitter MCP Server, which means it retrieves data without modifying state.
Register the Tree Sitter MCP server in PolicyLayer and add a rule for find_usage: 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 Tree Sitter. Nothing to install.
find_usage 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 find_usage 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 find_usage. 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.
find_usage is provided by the Tree Sitter MCP server (wrale/mcp-server-tree-sitter). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 26 Tree Sitter tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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26 Tree Sitter tools catalogued and risk-classified — across an index of 42,500+ MCP servers.