Cron

Overview

Use this skill to manage Codex automations through the native Zig

cron

CLI. Runtime paths are Zig-only (no Python fallback, no shell launchd wrappers).

Zig CLI Iteration Repos

When iterating on

cron

, use these two repos:

```
skills-zig
```
(
```
/Users/tk/workspace/tk/skills-zig
```
): source for the
```
cron
```
binary, build/test wiring, release tags.
```
homebrew-tap
```
(
```
/Users/tk/workspace/tk/homebrew-tap
```
): formula/checksum updates for released binaries.

Quick Start

bash

run_cron_tool() {
  install_cron_direct() {
    local repo="${SKILLS_ZIG_REPO:-$HOME/workspace/tk/skills-zig}"
    if ! command -v zig >/dev/null 2>&1; then
      echo "zig not found. Install Zig from https://ziglang.org/download/ and retry." >&2
      return 1
    fi
    if [ ! -d "$repo" ]; then
      echo "skills-zig repo not found at $repo." >&2
      echo "clone it with: git clone https://github.com/tkersey/skills-zig \"$repo\"" >&2
      return 1
    fi
    if ! (cd "$repo" && zig build build-cron -Doptimize=ReleaseFast); then
      echo "direct Zig build failed in $repo." >&2
      return 1
    fi
    if [ ! -x "$repo/zig-out/bin/cron" ]; then
      echo "direct Zig build did not produce $repo/zig-out/bin/cron." >&2
      return 1
    fi
    mkdir -p "$HOME/.local/bin"
    install -m 0755 "$repo/zig-out/bin/cron" "$HOME/.local/bin/cron"
  }

  local os="$(uname -s)"
  if command -v cron >/dev/null 2>&1 && cron --help 2>&1 | grep -q "cron.zig"; then
    cron "$@"
    return
  fi

  if [ "$os" = "Darwin" ]; then
    if ! command -v brew >/dev/null 2>&1; then
      echo "homebrew is required on macOS: https://brew.sh/" >&2
      return 1
    fi
    if ! brew install tkersey/tap/cron; then
      echo "brew install tkersey/tap/cron failed." >&2
      return 1
    fi
  elif ! (command -v cron >/dev/null 2>&1 && cron --help 2>&1 | grep -q "cron.zig"); then
    if ! install_cron_direct; then
      return 1
    fi
  fi

  if command -v cron >/dev/null 2>&1 && cron --help 2>&1 | grep -q "cron.zig"; then
    cron "$@"
    return
  fi
  echo "cron binary missing or incompatible after install attempt." >&2
  if [ "$os" = "Darwin" ]; then
    echo "expected install path: brew install tkersey/tap/cron" >&2
  else
    echo "expected direct path: SKILLS_ZIG_REPO=<skills-zig-path> zig build build-cron -Doptimize=ReleaseFast" >&2
  fi
  return 1
}

List automations:
```
run_cron_tool list
```
Show one automation:
```
run_cron_tool show --id <id>
```

Create an automation:

run_cron_tool create --name "Weekly release notes" --prompt-file /path/to/prompt.md --rrule "RRULE:FREQ=WEEKLY;BYDAY=FR;BYHOUR=9;BYMINUTE=0"

Update an automation:

run_cron_tool update --id <id> --rrule "RRULE:FREQ=DAILY;BYHOUR=9;BYMINUTE=0"

Enable or disable:

run_cron_tool enable --id <id>

run_cron_tool disable --id <id>

Run immediately:
```
run_cron_tool run-now --id <id>
```
Delete:
```
run_cron_tool delete --id <id>
```
Run due automations once:
```
run_cron_tool run-due
```
Run due automations dry-run:
```
run_cron_tool run-due --dry-run
```
Install/start launchd scheduler (macOS):
```
run_cron_tool scheduler install
```
Stop/remove launchd scheduler (macOS):
```
run_cron_tool scheduler uninstall
```
Show scheduler status (macOS):
```
run_cron_tool scheduler status
```

Runtime bootstrap policy mirrors

seq

cas

lift

: require the Zig binary, default to Homebrew install on macOS, and fallback to direct Zig install from

skills-zig

on non-macOS.

Subcommand

--help

prints top-level usage. For detailed options, use the matrix below.

Workflow

Choose working directories (
```
cwds
```
). Default is current repo if omitted on
```
create
```
.
Write the automation prompt (use
```
--prompt-file
```
for multi-line prompts).
Provide an RFC5545 RRULE string.
Create or update with
```
cron
```
.
For unattended execution, install scheduler via
```
cron scheduler install
```
.

Headless Runner

cron run-due

executes due automations by calling

codex exec

and updates:

```
automations.last_run_at
```
```
automations.next_run_at
```
```
automation_runs
```
rows

cron run-due --dry-run

is read-only:

no
```
automation_runs
```
rows are inserted/updated
no
```
automations.last_run_at
```
/
```
next_run_at
```
updates
no automation files or
```
memory.md
```
writes

```
--codex-bin
```
accepts executable name or absolute path (default resolves
```
$CODEX_BIN
```
or
```
codex
```
in
```
PATH
```
).
Locking is label-scoped and fail-closed (
```
--lock-label
```
, or env
```
CRON_LAUNCHD_LABEL
```
).
```
--lock-label
```
uses strict label validation: only
```
[A-Za-z0-9._-]
```
(no slashes/spaces).
```
run-due
```
default batch limit is
```
10
```
automations per invocation (
```
--limit
```
overrides).
Scheduler commands are macOS-only and manage
```
~/Library/LaunchAgents/<label>.plist
```
directly from Zig.
Launchd scheduler runs
```
run-due
```
with default DB path and default limit unless you invoke
```
cron
```
manually with overrides.

Logs:

~/Library/Logs/codex-automation-runner/out.log

and

~/Library/Logs/codex-automation-runner/err.log

Command Options (High Signal)

```
list
```
:
```
--status <ACTIVE|PAUSED>
```
,
```
--json
```
```
show
```
:
```
--id <id>
```
or
```
--name <name>
```
, optional
```
--json
```

create

--name

--prompt|--prompt-file

--rrule

, optional

--status

--cwd

(repeatable),

--cwds-json

--clear-cwds

--next-run-at

update

--id|--name

, optional

--new-name

--prompt|--prompt-file

--rrule

--status

--cwd

(repeatable),

--cwds-json

--clear-cwds

--next-run-at

--clear-next-run-at

```
enable|disable|run-now|delete
```
:
```
--id
```
or
```
--name
```

run-due

: optional

--id

--limit

--dry-run

--codex-bin

--lock-label

(

[A-Za-z0-9._-]

only)

scheduler install

: optional

--label

--interval-seconds

--path

--codex-bin

```
scheduler uninstall|status
```
: optional
```
--label
```
Scheduler
```
--label
```
is strict: only
```
[A-Za-z0-9._-]
```
(no slashes/spaces).

Clarify When Ambiguous

Ask questions only when the request is ambiguous or when the user explicitly asks for guidance. Do not block otherwise.

Essential elements to confirm or infer:

Automation name.
Prompt content (single line or file path).
Schedule as an RFC5545 RRULE string (include
```
RRULE:
```
prefix).
Working directories (
```
cwds
```
), default to current repo if not specified.
Status if explicitly requested; otherwise default to
```
ACTIVE
```
.

When ambiguous, ask for missing details. Examples:

If user says “daily”/“weekly” without time, ask for required time/day fields.
If user says “run it for this repo” without paths, confirm repo root as
```
cwd
```
.

Schedule (RRULE)

Accept only RFC5545 RRULE strings. Cron expressions are unsupported.
Rules are canonicalized to
```
RRULE:
```
-prefixed form.
Legacy non-prefixed stored values (
```
FREQ=...
```
) are still accepted at run time for compatibility.
Validation is fail-closed.
```
BYHOUR
```
/
```
BYMINUTE
```
are interpreted in UTC.

Supported frequencies:

```
HOURLY
```
requires
```
BYMINUTE
```
```
DAILY
```
requires
```
BYHOUR
```
and
```
BYMINUTE
```
```
WEEKLY
```
requires
```
BYDAY
```
,
```
BYHOUR
```
, and
```
BYMINUTE
```

Example rules:

Daily at 09:00:
```
RRULE:FREQ=DAILY;BYHOUR=9;BYMINUTE=0
```

Weekly on Friday at 09:00:

RRULE:FREQ=WEEKLY;BYDAY=FR;BYHOUR=9;BYMINUTE=0

Every 24 hours:

RRULE:FREQ=HOURLY;INTERVAL=24;BYMINUTE=0

Task Examples

Daily standup summary

Name:

Summarize yesterday's git activity

Prompt: Summarize yesterday's git activity for standup. Include notable commits, files touched, and any risks or follow-ups. Schedule:

RRULE:FREQ=DAILY;BYHOUR=9;BYMINUTE=0

Weekly release notes

Name:

Draft weekly release notes

Prompt: Draft weekly release notes from merged PRs. Include links when available and group by area. Schedule:

RRULE:FREQ=WEEKLY;BYDAY=FR;BYHOUR=9;BYMINUTE=0

CI failure triage

Name:

Summarize CI failures

Prompt: Summarize CI failures and flaky tests from the last CI window, group by root cause, and suggest minimal fixes. Schedule:

RRULE:FREQ=DAILY;BYHOUR=8;BYMINUTE=30

Data Model Reference

See

references/db.md

for schema and field notes.

cron

NPX Install

Tags

SKILL.md Content

Cron

Overview

Zig CLI Iteration Repos

Quick Start

Workflow

Headless Runner

Command Options (High Signal)

Clarify When Ambiguous

Schedule (RRULE)

Task Examples

Daily standup summary

Weekly release notes

CI failure triage

Data Model Reference