Compare the same event contract across Polymarket, Kalshi, and Limitless side-by-side: probability, liquidity, settlement rules, and venue type. Use when the user wants to know "what's the spread between Polymarket and Kalshi on X" or "which venue has better liquidity for Y". Returns match confid...
Risk signalsAccepts freeform code/query input (query)
Part of the Parlay server.
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AI agents call compare_markets to retrieve information from Parlay 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 compare_markets 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": {
"compare_markets": {}
}
}See the full Parlay policy for all 6 tools.
These attack patterns abuse exactly the kind of access compare_markets 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.
Compare the same event contract across Polymarket, Kalshi, and Limitless side-by-side: probability, liquidity, settlement rules, and venue type. Use when the user wants to know "what's the spread between Polymarket and Kalshi on X" or "which venue has better liquidity for Y". Returns match confidence buckets (high/medium/low) and explains any mismatches. Real-money venues only — Manifold is excluded because play-money pricing isn't comparable to real-money.. It is categorised as a Read tool in the Parlay MCP Server, which means it retrieves data without modifying state.
Register the Parlay MCP server in PolicyLayer and add a rule for compare_markets: 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 Parlay. Nothing to install.
compare_markets 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 compare_markets 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 compare_markets. 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.
compare_markets is provided by the Parlay MCP server (https://mcp.parlay.run/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 6 Parlay tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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