crontap-natural-language-schedules

Preview natural-language schedules

Use this skill to resolve timing before another skill creates or updates a schedule. A preview is read-only.

Prerequisites

Before using the required tools, check whether they are available. If any are missing, stop and offer the user exactly two choices:

1. Connect Crontap MCP at https://mcp.crontap.com/mcp. MCP access works on

every Crontap tier.

1. Configure $CRONTAP_CLIENT_ID and $CRONTAP_API_KEY for the raw API. Raw

API access requires Ultra.

Do not silently choose a path or continue until the user selects one.

• Identify the user's intended local timezone.
• Ask whether business-day wording means weekdays or a holiday-aware calendar.
• Capture any boundary requirement, such as start date or final day of month.

Phrase schedules precisely

Prefer phrases with a frequency, local time, and calendar scope:

• every weekday at 09:15
• every 6 hours
• at 02:30 every Sunday
• on the first day of every month at 08:00

Avoid phrases such as in the morning, twice a month, month end, or weekdays without a timezone. Five-field cron cannot represent every holiday-aware or last-business-day rule.

Workflow

1. Resolve an exact IANA timezone with the user.
2. Call preview_schedule with the original cadence and timezone.
3. If the response needs clarification, present its question and options.
4. Preview again with the user's answer.
5. Report the resolved cron, timezone, and every returned next run.
6. Ask for confirmation before any separate create or update operation.

MCP example

{
  "tool": "preview_schedule",
  "arguments": {
    "text": "every weekday at 09:15",
    "timezone": "America/New_York"
  }
}

Do not save a guessed cron if the response has needs_clarification or rejected status. Treat returned options as choices, not as permission to pick for the user.

DST and calendar checks

• Verify next runs on both sides of a nearby daylight-saving transition.
• A named timezone preserves local wall-clock intent. A UTC schedule preserves

a fixed UTC time.

• Confirm whether weekday excludes only Saturday and Sunday.
• For last-business-day logic, schedule a safe candidate cadence and put the

final calendar check inside an idempotent endpoint.

• For one-time work, use a one-time schedule only after confirming its exact

timestamp and cleanup behavior.

REST fallback

The public API fallback requires Ultra API access:

curl --fail-with-body https://api.crontap.com/v1/schedule/preview \
  -X POST \
  -H "ClientId: $CRONTAP_CLIENT_ID" \
  -H "ApiKey: $CRONTAP_API_KEY" \
  -H "Content-Type: application/json" \
  --data '{"text":"every weekday at 09:15","timezone":"America/New_York"}'

MCP remains available without Ultra. Prefer MCP when connected.

Safety and plan limits

• Previewing does not consume resource capacity.
• A valid preview can still produce a cadence below the account's creation

floor. Creation is the authoritative entitlement check.

• If creation later returns a plan-limit response, preserve its four-option

ladder and identify the smallest viable plan.

• Never infer user consent to create from a read-only preview.

Troubleshooting

• If the phrase is rejected, simplify it to one frequency and one local time.
• If the cron looks right but next runs look wrong, check the timezone first.
• If a desired calendar rule cannot be represented, move that condition into

the endpoint and keep the endpoint idempotent.

References

• Crontap Agent Skills catalogue
• Cron from English
• Cron syntax reference
• Cron troubleshooting
• Machine-readable product reference