AI agents call find_usages to retrieve information from MCP Code Analysis Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The tool performs semantic code search to locate references to functions or classes within a codebase. This is a read-only operation with no side effects, no code execution, and no data modification. It retrieves information about where symbols are used, making it a classic Read category tool with low severity since misuse would only expose information about code structure.
From the tool's definition Tool name: 'find_usages'. Description: 'Find where a function or class is used'. This is a query/search operation that retrieves usage locations without modifying, executing, or deleting anything.
Documented attack patterns abuse exactly the kind of access find_usages gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and MCP Code Analysis Server, and nothing reaches the server without passing your rules. This is the rule we recommend for find_usages:
{
"version": "1",
"default": "deny",
"tools": {
"find_usages": {}
}
}find_usages is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Find where a function or class is used. It is categorised as a Read tool in the MCP Code Analysis Server MCP Server, which means it retrieves data without modifying state.
Register the MCP Code Analysis Server MCP server in PolicyLayer and add a rule for find_usages: 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 MCP Code Analysis Server. Nothing to install.
find_usages 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_usages 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_usages. 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_usages is provided by the MCP Code Analysis Server MCP server (johannhartmann/mcpcodeanalysis). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from MCP Code Analysis Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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44 MCP Code Analysis Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.