AI agents call get_major_holders to retrieve information from IsoFinancial-MCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries and returns financial information about major stockholders. It is a read-only operation that retrieves existing public or semi-public information about shareholding patterns. There are no side effects, no data modification, no execution of code, no deletion of data, and no financial transactions. The tool fits squarely within the Read category as a data retrieval endpoint.
From the tool's definition get_major_holders retrieves major shareholders data; the description explicitly states 'Get major shareholders,' indicating data retrieval without modification or side effects.
Documented attack patterns abuse exactly the kind of access get_major_holders gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and IsoFinancial-MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for get_major_holders:
{
"version": "1",
"default": "deny",
"tools": {
"get_major_holders": {}
}
}get_major_holders is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Get major shareholders. It is categorised as a Read tool in the IsoFinancial-MCP MCP Server, which means it retrieves data without modifying state.
Register the IsoFinancial- MCP server in PolicyLayer and add a rule for get_major_holders: 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 IsoFinancial-MCP. Nothing to install.
get_major_holders 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 get_major_holders 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 get_major_holders. 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.
get_major_holders is provided by the IsoFinancial- MCP server (niels-8/isofinancial-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from IsoFinancial-MCP, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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26 IsoFinancial-MCP tools catalogued and risk-classified — across an index of 43,000+ MCP servers.