Collect real-time market probability changes via WebSocket for a specified duration. Returns all accumulated changes (market ID, probability patches, spread/midpoint updates). Useful for seeing which markets are active right now.
AI agents call stream_live_markets to retrieve information from Alpha Arcade without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool streams and returns market data (probabilities, spreads, midpoints) without modifying any state, executing code, or committing financial transactions. It is analogous to a market data feed subscription. While the server as a whole enables trading (a Financial operation), this specific tool only reads live market information. No side effects or irreversible actions occur.
From the tool's definition Tool description states it 'Collect[s] real-time market probability changes' and 'Returns all accumulated changes' — these are retrieval and observation operations with no modification, creation, deletion, or financial commitment.
Documented attack patterns abuse exactly the kind of access stream_live_markets gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Alpha Arcade, and nothing reaches the server without passing your rules. This is the rule we recommend for stream_live_markets:
{
"version": "1",
"default": "deny",
"tools": {
"stream_live_markets": {}
}
}stream_live_markets is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
Free to start. No card required.
Collect real-time market probability changes via WebSocket for a specified duration. Returns all accumulated changes (market ID, probability patches, spread/midpoint updates). Useful for seeing which markets are active right now. It is categorised as a Read tool in the Alpha Arcade MCP Server, which means it retrieves data without modifying state.
Register the Alpha Arcade MCP server in PolicyLayer and add a rule for stream_live_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 Alpha Arcade. Nothing to install.
stream_live_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 stream_live_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 stream_live_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.
stream_live_markets is provided by the Alpha Arcade MCP server (phara23/alpha-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Alpha Arcade, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
20 Alpha Arcade tools catalogued and risk-classified — across an index of 43,000+ MCP servers.