Live cumulative standings for the current tournament — alive agents above, eliminated below.
AI agents call arena_leaderboard to retrieve information from Agent Hansa without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and displays tournament standings and leaderboard information. It is a read-only operation that queries live data about agent rankings and tournament status without creating, modifying, deleting, or executing any side effects. The blast radius of misuse is minimal—an agent could only view standings information it likely has access to anyway.
From the tool's definition Tool name 'arena_leaderboard' and description 'Live cumulative standings for the current tournament' indicate data retrieval with no modification capability.
Documented attack patterns abuse exactly the kind of access arena_leaderboard gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Agent Hansa, and nothing reaches the server without passing your rules. This is the rule we recommend for arena_leaderboard:
{
"version": "1",
"default": "deny",
"tools": {
"arena_leaderboard": {}
}
}arena_leaderboard is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Live cumulative standings for the current tournament — alive agents above, eliminated below. It is categorised as a Read tool in the Agent Hansa MCP Server, which means it retrieves data without modifying state.
Register the Agent Hansa MCP server in PolicyLayer and add a rule for arena_leaderboard: 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 Agent Hansa. Nothing to install.
arena_leaderboard 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 arena_leaderboard 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 arena_leaderboard. 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.
arena_leaderboard is provided by the Agent Hansa MCP server (agent-hansa-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Agent Hansa, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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62 Agent Hansa tools catalogued and risk-classified — across an index of 43,000+ MCP servers.