expand_rrule
utilpeek: Expand an iCalendar RRULE into dates. For cron use cron_next_runs; to build an event use build_ics_event. Returns an RFC 5545 RRULE and a start expanded into its occurrence list with python-dateutil in an IANA time zone: wall-clock times keep across DST changes. Up to 1,000 occurrences,...
This record as markdown: /tools/dev-tanod-tanod/expand-rrule.md
What expand_rrule does on Tanod
AI agents invoke expand_rrule to trigger actions in Tanod. 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 |
|---|---|---|---|
limit | integer | — | Most occurrences to return (1-1000). |
rrule | string | Yes | RFC 5545 RRULE, with or without the RRULE: prefix. |
until | object | — | Extra upper bound (ISO 8601). |
between | object | — | [from, to] ISO 8601 window (inclusive). |
dtstart | string | Yes | ISO 8601 first occurrence (date or datetime). |
exdates | object | — | ISO 8601 occurrences to leave out. |
timezone | object | — | IANA zone the rule runs in (wall-clock times keep across DST). Default UTC. |
Parameters from the server's own tool schema.
Why expand_rrule is rated High
expand_rrule 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.
Attacks that exploit this kind of access
The rule that runs expand_rrule safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Tanod, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For expand_rrule, this is the rule to start with:
expand_rrule 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 Tanod, apply this rule, and every expand_rrule call is checked against it from then on.
Questions about expand_rrule
utilpeek: Expand an iCalendar RRULE into dates. For cron use cron_next_runs; to build an event use build_ics_event. Returns an RFC 5545 RRULE and a start expanded into its occurrence list with python-dateutil in an IANA time zone: wall-clock times keep across DST changes. Up to 1,000 occurrences, an optional [from, to] window, extra until and exdates. Returns ISO 8601 times with offset and whether more exist. Pure computation: no network access, nothing stored. The search stops at search_horizon (1 hour for SECONDLY up to 100 years for YEARLY) and after 1.5 s. A bad rule, a rule that never matches (Feb 31) or a bad date or zone is a 422 (not charged). Typically under 0.1 s. Price: USD 0.001. Free: 10 utilpeek calls per IP per UTC day. Docs: https://tanod.dev/learn/ics-calendar-api.html. It is categorised as a Execute tool in the Tanod MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
expand_rrule accepts 7 parameters: limit, rrule, until, between, dtstart, exdates, timezone. Required: rrule, dtstart. The full parameter table on this page comes from the server's own tool schema.
Register the Tanod MCP server in PolicyLayer and add a rule for expand_rrule: 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 Tanod. Nothing to install.
expand_rrule 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 expand_rrule 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 expand_rrule. 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.
expand_rrule is provided by the Tanod MCP server (https://tanod.dev/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
More on Tanod, and thousands of servers like it.
Across the catalogue