# Cron Expression Explainer

> Cron Expression Explainer is a paid API for AI agents from agent402.tools, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Parses a standard 5-field cron expression and returns a human-readable English explanation of its schedule

## Facts

- Endpoint: GET https://agent402.tools/api/cron-explain
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/cron-expression-explainer-fe77dbbb
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_5kqLmsLrenF371-wXz4hf

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability cron-expression-explainer-fe77dbbb
```

Example prompt: Can you explain what this cron expression means in plain English: 0 9 * * 1-5?

## When to prefer this

Use this endpoint when an agent needs to explain a cron expression to a user in natural language, validate that a cron string is well-formed, or surface scheduling information in a human-readable way. Ideal for DevOps automation, CI/CD pipeline inspection, or any workflow where a user needs to understand a scheduled task without knowing cron syntax.

## Known failure modes

- Missing or empty expression query parameter returns an error
- Malformed cron expression with wrong number of fields returns a parse error
- Invalid field values (e.g. minute > 59) may return a validation error
- Non-standard 6-field cron expressions (with seconds) are not supported

## How this service works

Parse a standard 5-field cron expression (minute hour day-of-month month day-of-week) and return a human-readable explanation. Supports wildcards (*), ranges (1-5), lists (1,3,5), steps (*/15), and named months/days (JAN, MON). ?expression=0+9+*+*...

## Output

A human-readable explanation of when the cron job fires, describing the schedule in plain English (e.g. 'At 9:00 AM, Monday through Friday'). Covers wildcards, ranges, lists, steps, and named month/day values.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "expression"
     ],
     "properties": {
      "expression": {
       "type": "string",
       "description": "5-field cron expression (minute hour dom month dow)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "fields": {
   "hour": "9",
   "month": "*",
   "minute": "0",
   "dayOfWeek": "1-5",
   "dayOfMonth": "*"
  },
  "summary": "At 09:00, every day, day of week Monday through Friday",
  "expression": "0 9 * * 1-5"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/cron-expression-explainer-fe77dbbb/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agent402.tools](https://www.zero.xyz/host/agent402.tools/llms.txt)