Search for C++ functions by name pattern (regex supported)
AI agents call search_functions to retrieve information from C++ MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool performs semantic code analysis and retrieval operations on a C++ codebase. It scans for functions matching a regex pattern and returns information about them—a classic Read operation with no side effects. Even though it uses regex patterns, those patterns only constrain the search; they do not execute arbitrary code or modify the codebase.
From the tool's definition Tool searches for C++ functions by name pattern and returns results without modifying code. The description indicates it 'Search[es] for C++ functions' with no mention of writing, executing, or deleting functionality.
Documented attack patterns abuse exactly the kind of access search_functions gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and C++ MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for search_functions:
{
"version": "1",
"default": "deny",
"tools": {
"search_functions": {}
}
}search_functions is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Search for C++ functions by name pattern (regex supported). It is categorised as a Read tool in the C++ MCP Server MCP Server, which means it retrieves data without modifying state.
Register the C++ MCP Server MCP server in PolicyLayer and add a rule for search_functions: 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 C++ MCP Server. Nothing to install.
search_functions 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 search_functions 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 search_functions. 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.
search_functions is provided by the C++ MCP Server MCP server (kandrwmrtn/cplusplus_mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from C++ MCP 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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14 C++ MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.