AI agents use calculate_sum to create or update resources in MCP-Guide — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your MCP-Guide environment.
An AI agent can call calculate_sum faster than any human can review — one bad instruction and it creates or modifies resources in MCP-Guide by the hundred, each call as confident as the last.
Documented attack patterns abuse exactly the kind of access calculate_sum gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and MCP-Guide, and nothing reaches the server without passing your rules. This is the rule we recommend for calculate_sum:
{
"version": "1",
"default": "deny",
"tools": {
"calculate_sum": {
"limits": [
{
"counter": "calculate_sum_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}calculate_sum stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
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Add two numbers together. It is categorised as a Write tool in the MCP-Guide MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the MCP-Guide MCP server in PolicyLayer and add a rule for calculate_sum: 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 MCP-Guide. Nothing to install.
calculate_sum is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the calculate_sum 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 calculate_sum. 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.
calculate_sum is provided by the MCP-Guide MCP server (qpd-v/mcp-guide). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 5 MCP-Guide tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
5 MCP-Guide tools catalogued and risk-classified — across an index of 42,500+ MCP servers.