# 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

Agent View of the PolicyLayer registry record for `expand_rrule`. HTML page: https://policylayer.com/tools/dev-tanod-tanod/expand-rrule

## Facts

- Tool: `expand_rrule`
- Server: Tanod (`https://tanod.dev/mcp`) — https://policylayer.com/tools/dev-tanod-tanod.md
- Homepage: https://github.com/https://tanod.dev/mcp
- Risk category: Execute (High risk)
- Registry record: grade F, identity unverified
- Server auth posture: open
- Server CORS policy: *
- Server rate-limited: no
- Parameters: 7 (2 required)
- Recommended policy verdict: Rate-limited

## Parameters

| Parameter | Type | Required | Description |
| --- | --- | --- | --- |
| `limit` | integer | no | Most occurrences to return (1-1000). |
| `rrule` | string | yes | RFC 5545 RRULE, with or without the RRULE: prefix. |
| `until` | object | no | Extra upper bound (ISO 8601). |
| `between` | object | no | [from, to] ISO 8601 window (inclusive). |
| `dtstart` | string | yes | ISO 8601 first occurrence (date or datetime). |
| `exdates` | object | no | ISO 8601 occurrences to leave out. |
| `timezone` | object | no | IANA zone the rule runs in (wall-clock times keep across DST). Default UTC. |

Parameters from the server's own tool schema.

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "expand_rrule",
    "arguments": {
      "rrule": "<rrule>",
      "dtstart": "<dtstart>"
    }
  }
}
```

## 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.

## Use case

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.

## Recommended policy (PolicyLayer)

Verdict: **Rate-limited**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Tanod:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "expand_rrule": {
      "limits": [
        {
          "counter": "expand_rrule_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}
```

## Other tools on Tanod (307)

- `audit_token_approvals` — Destructive — https://policylayer.com/tools/dev-tanod-tanod/audit-token-approvals.md
- `aurora_forecast` — Destructive — https://policylayer.com/tools/dev-tanod-tanod/aurora-forecast.md
- `diff_text` — Destructive — https://policylayer.com/tools/dev-tanod-tanod/diff-text.md
- `image_metadata` — Destructive — https://policylayer.com/tools/dev-tanod-tanod/image-metadata.md
- `pdf_pipeline` — Destructive — https://policylayer.com/tools/dev-tanod-tanod/pdf-pipeline.md
- `pdf_protect` — Destructive — https://policylayer.com/tools/dev-tanod-tanod/pdf-protect.md
- `pdf_remove_pages` — Destructive — https://policylayer.com/tools/dev-tanod-tanod/pdf-remove-pages.md
- `pdf_reorder_pages` — Destructive — https://policylayer.com/tools/dev-tanod-tanod/pdf-reorder-pages.md
- `build_ics_event` — Execute — https://policylayer.com/tools/dev-tanod-tanod/build-ics-event.md
- `build_pptx_deck` — Execute — https://policylayer.com/tools/dev-tanod-tanod/build-pptx-deck.md
- `build_xlsx_workbook` — Execute — https://policylayer.com/tools/dev-tanod-tanod/build-xlsx-workbook.md
- `bulk_agent_index` — Execute — https://policylayer.com/tools/dev-tanod-tanod/bulk-agent-index.md
- `cron_next_runs` — Execute — https://policylayer.com/tools/dev-tanod-tanod/cron-next-runs.md
- `decode_calldata` — Execute — https://policylayer.com/tools/dev-tanod-tanod/decode-calldata.md
- `html_to_pdf` — Execute — https://policylayer.com/tools/dev-tanod-tanod/html-to-pdf.md
- `image_crop` — Execute — https://policylayer.com/tools/dev-tanod-tanod/image-crop.md
- `parse_ics` — Execute — https://policylayer.com/tools/dev-tanod-tanod/parse-ics.md
- `parse_phone_number` — Execute — https://policylayer.com/tools/dev-tanod-tanod/parse-phone-number.md
- `parse_rss_feed` — Execute — https://policylayer.com/tools/dev-tanod-tanod/parse-rss-feed.md
- `parse_sitemap` — Execute — https://policylayer.com/tools/dev-tanod-tanod/parse-sitemap.md
- `parse_url` — Execute — https://policylayer.com/tools/dev-tanod-tanod/parse-url.md
- `parse_user_agent` — Execute — https://policylayer.com/tools/dev-tanod-tanod/parse-user-agent.md
- `render_mermaid` — Execute — https://policylayer.com/tools/dev-tanod-tanod/render-mermaid.md
- `satellite_passes` — Execute — https://policylayer.com/tools/dev-tanod-tanod/satellite-passes.md
- `sec_financials` — Execute — https://policylayer.com/tools/dev-tanod-tanod/sec-financials.md
- `transcribe_audio` — Execute — https://policylayer.com/tools/dev-tanod-tanod/transcribe-audio.md
- `x402_well_known_file` — Execute — https://policylayer.com/tools/dev-tanod-tanod/x402-well-known-file.md
- `compare_stablecoin_transfer_fees` — Financial — https://policylayer.com/tools/dev-tanod-tanod/compare-stablecoin-transfer-fees.md
- `transfer_preflight` — Financial — https://policylayer.com/tools/dev-tanod-tanod/transfer-preflight.md
- `airport_distance` — Read — https://policylayer.com/tools/dev-tanod-tanod/airport-distance.md
- …and 277 more: https://policylayer.com/tools/dev-tanod-tanod.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=dev-tanod-tanod · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/dev-tanod-tanod