AI agents call schwab_quote to retrieve information from Open Stocks MCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool performs a read-only retrieval of public market data (current stock quotes). It has no side effects, does not execute commands, does not create or modify data, does not delete anything, and does not involve financial transactions. The worst misuse would be information gathering, which poses minimal risk. Confidence is high because the description is explicit about its read-only nature.
From the tool's definition Tool name 'schwab_quote' and description 'Get current quote for a stock symbol from Schwab' indicate a retrieval operation that queries live stock price data without modifying, executing code, deleting, or moving money.
Documented attack patterns abuse exactly the kind of access schwab_quote gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Open Stocks MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for schwab_quote:
{
"version": "1",
"default": "deny",
"tools": {
"schwab_quote": {}
}
}schwab_quote is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Get current quote for a stock symbol from Schwab. It is categorised as a Read tool in the Open Stocks MCP MCP Server, which means it retrieves data without modifying state.
Register the Open Stocks MCP server in PolicyLayer and add a rule for schwab_quote: 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 Open Stocks MCP. Nothing to install.
schwab_quote 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 schwab_quote 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 schwab_quote. 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.
schwab_quote is provided by the Open Stocks MCP server (open-agent-tools/open-stocks-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Open Stocks MCP, 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.
152 Open Stocks MCP tools catalogued and risk-classified — across an index of 43,000+ MCP servers.