Build Cron Skill

Convert user requirements into the

openclaw cron add

command and execute it.

Installation Method

bash

npx skills add https://github.com/Rinsonlaw/law-skills.git

Workflow

Step 1: Collect Information

Ask the user for the following information (do not skip steps; proceed only after the user replies):

Task Name — The name given by the user for this cron job, e.g.,
```
daily-report
```
Task Description — The user's exact words, directly fill into
```
--message
```
(do not summarize or rewrite)
Execution Time — The user's desired execution time, supporting four modes:
- Fixed Time: Ask for hour (0-23) and minute (0-59), e.g., "20 30" means 8:30 PM
- Interval Loop: Ask for the interval value and unit, e.g., "every 5 minutes", "every 2 hours"
- Periodic Time: Specify a day of the week or day of the month, e.g., "9 AM every Monday", "12 AM on the 1st of every month"
- Hourly Range: Specify which hours to execute, e.g., "every 1 hour between 10 AM and 12 PM"

Automatic Session Key Retrieval: Automatically obtained from the current session's metadata; no manual input required from the user.

Step 2: Parse sessionKey (Automatic Retrieval)

Automatically retrieve the sessionKey from the current session metadata without user cooperation. Then split it with a colon

to extract the following fields:

session_key = "agent:research:feishu:direct:ou_xxx"
agent_id    = session_key_parts[1]   # → "research"
channel_name = session_key_parts[2]   # → "feishu"
target_id   = session_key_parts[4]   # → "ou_xxx"

Step 3: Parse Execution Time

Cron expression format explanation (left to right):

Position	Meaning	Value Range
1st	Minute	0-59, `*/N` means every N minutes
2nd	Hour	0-23, `*/N` means every N hours
3rd	Day of Month	1-31
4th	Month	1-12
5th	Day of Week	0-6 (0=Sunday)

Range Syntax:

```
*
```
— Any value
```
A
```
— Specified value
```
A-B
```
— Range, applicable to any position, e.g.,
```
10-12
```
(hours),
```
5-31
```
(days),
```
2-5
```
(weekdays)
```
*/N
```
— Interval, e.g.,
```
*/5
```
means every 5 units
```
A-B/N
```
— Range with interval, e.g.,
```
10-12/1
```
means every 1 unit from 10 to 12
Example: Every 5 minutes →
```
"*/5 * * * *"
```
(1st position is
```
*/5
```
)
Example: Every 2 hours →
```
"0 */2 * * *"
```
(2nd position is
```
*/2
```
)
Example: Every hour →
```
"0 * * * *"
```
Example: 9 AM every Monday →
```
"0 9 * * 1"
```
Example: 12 AM on the 1st of every month →
```
"0 0 1 * *"
```
Example: Every 1 hour between 10 AM and 12 PM →
```
"0 10-12/1 * * *"
```
Example: Every 2 hours between 9 AM and 6 PM on workdays →
```
"0 9-18/2 * * 1-5"
```

Execution time supports four modes:

Mode A: Fixed Time

User says "8 AM every day", "8:30 PM", etc.
Need to parse hour (0-23) and minute (0-59)
Generate cron expression:
```
{minute} {hour} * * *
```
Example: hour=8, minute=0 →
```
"0 8 * * *"
```

Mode B: Interval Loop

User says "every 5 minutes", "every 30 minutes", "every hour", etc.
Need to parse interval value and unit (minute/hour)
Cron expression format for interval loop:
```
*/{interval} * * * *
```
(every N minutes) or
```
0 */{interval} * * *
```
(every N hours)

Mode C: Periodic Time

User says "9 AM every Monday", "12 AM on the 1st of every month", etc.
Need to parse: period type (week/month), specific date (Monday/1st), hour and minute

Generate cron expression:

{minute} {hour} {day_of_month} {month} {day_of_week}

Day of week: 0=Sunday, 1=Monday, ..., 6=Saturday
Example: 9 AM every Monday →
```
"0 9 * * 1"
```
Example: 12 AM on the 1st of every month →
```
"0 0 1 * *"
```

Mode D: Scheduled Range

User says "every 1 hour between 10 AM and 12 PM", "every 2 hours between 9 AM and 6 PM on workdays", etc.
Need to parse: start time, end time, execution interval

Cron expression format:

{minute} {start_hour}-{end_hour}/{interval} * * *

Example: Every 1 hour between 10 AM and 12 PM, execute at 0 minutes →
```
"0 10-12/1 * * *"
```
Example: Every 2 hours between 9 AM and 6 PM →
```
"0 9-18/2 * * *"
```
Note: The range usually refers to hourly range, and the interval unit is hours

Judgment Rules:

If the user mentions "every", "every * minutes", "every * hours", it is considered Interval Loop mode
If the user mentions "every week", "every month", "day of week", it is considered Periodic Time mode
If the user mentions "every X hours between A and B", it is considered Scheduled Range mode
If the user only mentions a time point (e.g., "8 AM", "20:30"), it is considered Fixed Time mode

Step 4: Get Time Zone and Construct CLI Command

Construct the

openclaw cron add

command using the following parameters:

bash

TZ=$(readlink /etc/localtime | sed 's|.*zoneinfo/||')
openclaw cron add \
  --name "{task_name}" \
  --agent "{agent_id}" \
  --session-key "{session_key}" \
  --cron "{cron_expr}" \
  --tz "$TZ" \
  --session "isolated" \
  --wake "now" \
  --message "{task_message}" \
  --timeout-seconds 600 \
  --announce \
  --channel "{channel_name}" \
  --to "{target_id}"

Parameter Explanation:

CLI Parameter	Description	Default Value
`--name`	Task name	Required
`--agent`	Parsed from sessionKey	Required
`--session-key`	Complete session key	Required
`--cron`	Cron expression	Required
`--tz`	Time zone	Automatically detected via `readlink /etc/localtime`
`--session`	Session mode	`"isolated"`
`--wake`	Wake-up mode	`"now"`
`--message`	Task description (user's exact words, no modifications)	Required
`--timeout-seconds`	Timeout in seconds	`600`
`--announce`	Enable result announcement to channel	Disabled by default
`--channel`	Announcement channel	Parsed from sessionKey
`--to`	Announcement target	Parsed from sessionKey

Note: The time zone is fixed to
"Asia/Shanghai"
; users can replace it if other time zones are needed.

Step 5: Execute the Creation Command

Show the constructed command to the user for confirmation, and execute it after the user inputs

yes

Complete Conversation Examples

Fixed Time Example:

User: I want to create a scheduled task that runs every day at 8 PM
Assistant: What is the name of this task?
User: nightly-digest
Assistant: What does this task specifically do? (Please provide the exact words to fill into message)
User: Compile and summarize the day's competitor dynamics every night
Assistant: What is the execution time in hour and minute? (e.g., 20 30 means 8:30 PM)
User: 20 30
Assistant: (Automatically retrieves current session key)
     Identified as Fixed Time mode, constructed the following command. Please confirm creation:
TZ=$(readlink /etc/localtime | sed 's|.*zoneinfo/||')
openclaw cron add \
  --name "nightly-digest" \
  --agent "research" \
  --session-key "agent:research:feishu:direct:ou_xxx" \
  --cron "30 20 * * *" \
  --tz "$TZ" \
  --session "isolated" \
  --wake "now" \
  --message "Compile and summarize the day's competitor dynamics every night" \
  --timeout-seconds 600 \
  --announce \
  --channel "feishu" \
  --to "ou_xxx"
Confirm creation? (Enter yes to confirm)
User: yes
Assistant: Executing command...

Interval Loop Example:

User: I want to check server status every 5 minutes
Assistant: What is the name of this task?
User: server-health-check
Assistant: What does this task specifically do? (Please provide the exact words to fill into message)
User: Check if the server status is normal
Assistant: What is the execution time pattern? (e.g., "every 5 minutes" or "every 2 hours")
User: every 5 minutes
Assistant: (Automatically retrieves current session key)
     Identified as Interval Loop mode (every 5 minutes), constructed the following command. Please confirm creation:
TZ=$(readlink /etc/localtime | sed 's|.*zoneinfo/||')
openclaw cron add \
  --name "server-health-check" \
  --agent "research" \
  --session-key "agent:research:feishu:direct:ou_xxx" \
  --cron "*/5 * * * *" \
  --tz "$TZ" \
  --session "isolated" \
  --wake "now" \
  --message "Check if the server status is normal" \
  --timeout-seconds 600 \
  --announce \
  --channel "feishu" \
  --to "ou_xxx"
Confirm creation? (Enter yes to confirm)
User: yes
Assistant: Executing command...

Notes

Must wait for user replies before proceeding to the next step; do not assume information provided by the user
If automatic session key retrieval fails, record the error and inform the user
All fixed-value parameters are pre-written in the command template; no user input required
The generated command must be confirmed by the user before execution

build-cron

NPX Install

Tags

SKILL.md Content (Chinese)