Cron Expression Skill
The tool
Cron Expression Generator simplifies cron expression creation by converting plain English schedule descriptions into standard 5-field cron format using AI.
Once your client is connected to the VerveKit MCP server, this appears in its tool list as CronExpressionSkill. It is read-only and open-world: it fetches, it never mutates anything on your side, so most clients will call it without asking you to confirm.
{
"name": "CronExpressionSkill",
"arguments": {
"schedule": "every weekday at 9am"
}
}What that looks like in a conversation
You don't name the tool — the model picks it. Asking about every weekday at 9am in the terms this source covers is enough for it to reach for CronExpressionSkill on its own.
Connecting
One server URL covers every skill in the catalog, including this one. Authorization is OAuth — the client opens a browser once and there is no key to paste into a config file.
{
"mcpServers": {
"vervekit": {
"url": "https://api.vervekit.com/v1/mcp"
}
}
}https://api.vervekit.com/v1/mcpPer-client setup — Claude Desktop, Cursor, VS Code, ChatGPT — is on the MCP setup page.
Arguments
These are the properties on the tool's inputSchema, so a well-behaved client validates them before the call is made.
| Argument | Type | Example | Description |
|---|---|---|---|
scheduleRequired | string | every weekday at 9am | Natural language description of the schedule (max 200 characters) |
What the model gets back
The result carries a structuredContent object matching the tool's declared outputSchema, so a client can read fields without parsing prose. status is "ok" on success and error is null; a null field means the value wasn't available for that input, not that the call failed.
{
"status": "ok",
"error": null,
"data": {
"schedule": "every weekday at 9am",
"expression": "0 9 * * 1-5",
"description": "Runs every weekday at 9:00 AM."
}
}Fields
| Field | Type | Example | Description |
|---|---|---|---|
schedule | string | every weekday at 9am | Original natural language schedule description provided |
expression | string | 0 9 * * 1-5 | Generated cron expression in standard 5-field format |
descriptionPremium | string | Runs every weekday at 9:00 AM. | Human-readable explanation of the cron expression behavior |
Failure modes
Errors come back as tool errors with a sentence the model can act on, not a bare status code.
| Status | What it means |
|---|---|
400 / 422 | The arguments didn't validate. The message names the offending one. |
401 | The OAuth session is invalid or expired — reconnect the server. |
403 | Out of credits. Not a bad key — the month's allowance is spent. |
404 | This skill isn't part of VerveKit. Check the catalog. |
429 | Brief rate limit. Retrying after a moment succeeds. |
Other ways to use Cron Expression Skill
Set up Cron Expression Skill on VerveKit, or reach the same source a different way. Your VerveKit account and credits work on all of them — one key, one balance.
Frequently asked questions
Do I have to tell the agent to use CronExpressionSkill?
No. The tool's name and description are in the model's context once the server is connected, so it selects the tool when the question calls for it. Naming it explicitly works too and is useful when you want to force the call.
Does connecting the server expose every tool at once?
Yes — one connection lists the whole VerveKit catalog. Clients with a tool budget can usually filter the list; the credit cost is per call, so an unused tool costs nothing.
What does a call cost?
5 credits each time the tool actually runs. A model that reasons about the tool without calling it costs nothing.
Is there a REST version of this?
Yes — the same source is available as a plain HTTPS endpoint on APIVerve, linked above. Same data, same credits, same account.