Run custom rules analysis on a directory. Returns violations found.
AI agents call check_custom_rules to retrieve information from Project Graph without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool performs static analysis and returns violations—a retrieval and reporting function with no side effects. It does not create, modify, delete, or execute arbitrary code; it only reads the directory structure and reports findings. The verb 'check' and 'returns violations' clearly indicate a read-only query operation.
From the tool's definition Tool name 'check_custom_rules' and description 'Run custom rules analysis on a directory. Returns violations found.' indicates a read-only analysis operation that scans and reports violations without modifying any data.
Attacks that exploit this kind of access
Run custom rules analysis on a directory. Returns violations found. It is categorised as a Read tool in the Project Graph MCP Server, which means it retrieves data without modifying state.
Register the Project Graph MCP server in PolicyLayer and add a rule for check_custom_rules: 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 Project Graph. Nothing to install.
check_custom_rules 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_custom_rules 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_custom_rules. 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_custom_rules is provided by the Project Graph MCP server (rnd-pro/project-graph-mcp). 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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