List visible challenges. Optional filter by category and unsolved only.
AI agents call list_challenges to retrieve information from CTFd MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and queries challenge data from a CTFd platform. It performs no writes, deletions, code execution, or financial operations. The blast radius of misuse is minimal—an attacker could enumerate challenges but cannot modify competition state, execute code, or cause harm beyond information disclosure. Low severity is appropriate for read-only enumeration in a competition context.
From the tool's definition Tool name 'list_challenges' and description 'List visible challenges' indicates data retrieval with no modification or side effects. The optional filtering parameters (category, unsolved only) are read-only query parameters.
Documented attack patterns abuse exactly the kind of access list_challenges gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and CTFd MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for list_challenges:
{
"version": "1",
"default": "deny",
"tools": {
"list_challenges": {}
}
}list_challenges is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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List visible challenges. Optional filter by category and unsolved only. It is categorised as a Read tool in the CTFd MCP Server MCP Server, which means it retrieves data without modifying state.
Register the CTFd MCP Server MCP server in PolicyLayer and add a rule for list_challenges: 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 CTFd MCP Server. Nothing to install.
list_challenges 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 list_challenges 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 list_challenges. 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.
list_challenges is provided by the CTFd MCP Server MCP server (umbra2728/ctfd-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from CTFd 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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5 CTFd MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.