cron
Explain/validate/next-run cron expressions (150 sats/call; free tier 100 calls/mo)
This record as markdown: /tools/com-thetempleofdoom-hyperion-hyperion/cron.md
What cron does on Hyperion
AI agents invoke cron to trigger actions in Hyperion. 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.
| Parameter | Type | Required | Description |
|---|---|---|---|
count | number | — | Number of upcoming execution times to calculate (default 5). |
expression | string | Yes | 5-part cron string e.g. "*/15 * * * *". |
Parameters from the server's own tool schema.
Why cron is rated High
cron triggers real processes with real consequences. An agent gone sideways doesn't fire it once. It starts dozens of builds, sends mass notifications, or burns through compute before anyone looks up.
Risk signalsAccepts freeform code/query input (expression)
Attacks that exploit this kind of access
The rule that runs cron safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Hyperion, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For cron, this is the rule to start with:
cron 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.
The button opens the PolicyLayer dashboard: create your workspace, connect Hyperion, apply this rule, and every cron call is checked against it from then on.
Questions about cron
Explain/validate/next-run cron expressions (150 sats/call; free tier 100 calls/mo). It is categorised as a Execute tool in the Hyperion MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
cron accepts 2 parameters: count, expression. Required: expression. The full parameter table on this page comes from the server's own tool schema.
Register the Hyperion MCP server in PolicyLayer and add a rule for cron: 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 Hyperion. Nothing to install.
cron 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 cron 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 cron. 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.
cron is provided by the Hyperion MCP server (https://hyperion.thetempleofdoom.com/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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