Check whether a C++ header file has correct include guards or #pragma once directives. Detects missing guards, malformed macro names, mismatched #endif comments, and suggests correctly formatted guard macros based on the file path.
Risk signalsAccepts freeform code/query input (code) · Accepts file system path (file_path)
Part of the C++ Core Guidelines server.
Free to start. No card required.
AI agents call check_include_guard to retrieve information from C++ Core Guidelines without modifying any data. This is common in research, monitoring, and reporting workflows where the agent needs context before taking action. Because read operations don't change state, they are generally safe to allow without restrictions -- but you may still want rate limits to control API costs.
Even though check_include_guard only reads data, uncontrolled read access can leak sensitive information or rack up API costs. An agent caught in a retry loop could make thousands of calls per minute. A rate limit gives you a safety net without blocking legitimate use.
Read-only tools are safe to allow by default. No rate limit needed unless you want to control costs.
{
"version": "1",
"default": "deny",
"tools": {
"check_include_guard": {}
}
}See the full C++ Core Guidelines policy for all 5 tools.
These attack patterns abuse exactly the kind of access check_include_guard gives an agent. Each links to the full case and the policy that stops it:
Other read tools across the catalogue. The same approach applies to each: allow, with a rate cap to control cost.
Check whether a C++ header file has correct include guards or #pragma once directives. Detects missing guards, malformed macro names, mismatched #endif comments, and suggests correctly formatted guard macros based on the file path.. It is categorised as a Read tool in the C++ Core Guidelines MCP Server, which means it retrieves data without modifying state.
Register the C++ Core Guidelines MCP server in PolicyLayer and add a rule for check_include_guard: 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++ Core Guidelines. Nothing to install.
check_include_guard 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 check_include_guard 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 check_include_guard. 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.
check_include_guard is provided by the C++ Core Guidelines MCP server (SongJiangzhou/cpp_guidelines). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 5 C++ Core Guidelines tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
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