AI agents call cancel_order to permanently remove resources in Fyers MCP Server — typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
Order cancellation is an irreversible action that destroys the state of an existing order in the trading system. While not a traditional data deletion, it terminates a financial commitment/instruction whose effects cannot be undone without manual re-entry.
From the tool's definition Tool name 'cancel_order' with description 'Cancel an existing order' indicates irreversible termination of a pending financial order.
Documented attack patterns abuse exactly the kind of access cancel_order gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Fyers MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for cancel_order:
{
"version": "1",
"default": "deny",
"hide": [
"cancel_order"
]
}cancel_order disappears from the agent's tool list entirely, and any attempt to call it is denied. The rest of the server keeps working.
Free to start. No card required.
Cancel an existing order. It is categorised as a Destructive tool in the Fyers MCP Server MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
Register the Fyers MCP Server MCP server in PolicyLayer and add a rule for cancel_order: 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 Fyers MCP Server. Nothing to install.
cancel_order is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.
Yes. Add a rate_limit block to the cancel_order 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 cancel_order. 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.
cancel_order is provided by the Fyers MCP Server MCP server (quantabox/fyers-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Fyers MCP Server, 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.
11 Fyers MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.