fleet_cancel_query
AI agents invoke fleet_cancel_query to trigger actions in Fleet. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.
The name 'fleet_cancel_query' suggests it cancels a running query on Fleet-managed hosts. Cancelling an in-progress operation is an action that affects external state (stopping an active execution), most closely aligned with Execute. However, with no description available, confidence is low. Severity is medium as cancelling queries could disrupt ongoing operations or data collection.
From the tool's definition Tool name: fleet_cancel_query — no description provided
Documented attack patterns abuse exactly the kind of access fleet_cancel_query gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Fleet, and nothing reaches the server without passing your rules. This is the rule we recommend for fleet_cancel_query:
{
"version": "1",
"default": "deny",
"tools": {
"fleet_cancel_query": {
"limits": [
{
"counter": "fleet_cancel_query_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}fleet_cancel_query stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
Free to start. No card required.
fleet_cancel_query. It is categorised as a Execute tool in the Fleet MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Fleet MCP server in PolicyLayer and add a rule for fleet_cancel_query: 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 Fleet. Nothing to install.
fleet_cancel_query is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the fleet_cancel_query 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 fleet_cancel_query. 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.
fleet_cancel_query is provided by the Fleet MCP server (fleet-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Fleet, 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.
85 Fleet tools catalogued and risk-classified — across an index of 43,000+ MCP servers.