Return metadata for all 24 stock screeners on the platform, including each screener's slug, name, description, category, and tier. Use this to discover which screeners are available before calling get_screener_data. Call this once per session — the list changes very rarely. Returns { tier, total,...
Part of the StockMarketScan server.
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AI agents call list_screeners to retrieve information from StockMarketScan 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 list_screeners 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": {
"list_screeners": {}
}
}See the full StockMarketScan policy for all 19 tools.
These attack patterns abuse exactly the kind of access list_screeners 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.
Return metadata for all 24 stock screeners on the platform, including each screener's slug, name, description, category, and tier. Use this to discover which screeners are available before calling get_screener_data. Call this once per session — the list changes very rarely. Returns { tier, total, accessible, screeners: [...] }.. It is categorised as a Read tool in the StockMarketScan MCP Server, which means it retrieves data without modifying state.
Register the StockMarketScan MCP server in PolicyLayer and add a rule for list_screeners: 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 StockMarketScan. Nothing to install.
list_screeners 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_screeners 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_screeners. 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_screeners is provided by the StockMarketScan MCP server (https://mcp.stockmarketscan.com/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 19 StockMarketScan tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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