Cron Composer

🧩 STARTER_CHARACTER = 🧩

Composable block system for OpenClaw cron job prompts. Define reusable blocks once; assemble prompts from them via a YAML manifest.

Why: When you have many cron jobs sharing common behaviours (git identity, error handling, backup patterns), editing each prompt individually is error-prone. Cron Composer centralises shared logic in block files and assembles final prompts on demand.

Quick Start

# Set this to the actual installed package directory; do not assume the workspace.
SKILL_DIR="/path/to/skills/cron-composer"
python3 -m pip install -r "$SKILL_DIR/requirements.txt"

# List all crons in manifest
python3 "$SKILL_DIR/scripts/cron-compose.py" "$SKILL_DIR/example-manifest.yaml" list

# Preview assembled prompt (dry-run)
python3 "$SKILL_DIR/scripts/cron-compose.py" /path/to/my-manifest.yaml apply my-cron --dry-run

# Apply one cron
python3 "$SKILL_DIR/scripts/cron-compose.py" /path/to/my-manifest.yaml apply my-cron

# Apply all crons
python3 "$SKILL_DIR/scripts/cron-compose.py" /path/to/my-manifest.yaml apply --all

# Validate manifest
python3 "$SKILL_DIR/scripts/cron-compose.py" /path/to/my-manifest.yaml lint

Key Concepts

• Blocks — Markdown files in blocks/<category>/. Prepended to every cron that references them.
• Manifest — YAML file mapping cron names → block lists + task prompt + variables.
• Variables — {{VAR}} placeholders in blocks/tasks, resolved from the vars: section per cron.

Manifest Format

blocks_dir: /path/to/your/blocks   # absolute or relative to manifest file

crons:
  my-cron-name:
    id: "uuid-from-openclaw-cron-list"
    blocks:
      - env/error-handling        # prepended first
      - env/workspace-context
      - ops/git-commit
      - ops/file-backup
    vars:
      PROJECT: /home/user/myproject   # replaces {{PROJECT}} in blocks + task
      SITE: my-site
    task: |
      Task-specific instructions only. Don't repeat what blocks already cover.
      Check {{PROJECT}}/status.txt and report findings.

Commands

Block Categories (convention)

Writing Blocks

1. Create blocks/<category>/<name>.md
2. Write reusable instructions. Use {{VAR}} for anything job-specific.
3. Reference as <category>/<name> in manifests (no .md extension).

Good blocks cover one concern (commit, backup, error handling). Keep them short and composable.

blocks_dir Resolution

The assembler resolves blocks relative to blocks_dir in the manifest. You can:

• Set blocks_dir: to an absolute path
• Set blocks_dir: relative to the manifest file location
• Omit blocks_dir: — defaults to a blocks/ directory next to the manifest

Example

See the example manifest, the assembler, and the blocks directory for working examples.