CronLint -- Scheduled Task & Cron Job Anti-Pattern Analyzer

CronLint scans codebases for scheduled task and cron job anti-patterns: overlapping execution risks, timezone scheduling errors, missing error recovery, resource contention, lifecycle management issues, and observability gaps. It uses regex-based pattern matching against 90 scheduling-specific patterns across 6 categories, lefthook for git hook integration, and produces markdown reports with actionable remediation guidance. 100% local. Zero telemetry.

Note: CronLint focuses on cron jobs, schedulers (node-cron, APScheduler, Quartz, Celery beat, Bull/BullMQ), setInterval/setTimeout scheduling, Kubernetes CronJobs, and periodic task code. It detects anti-patterns in scheduling logic, not HTTP cron endpoints.

Commands

Free Tier (No license required)

cronlint scan [file|directory]

One-shot scheduling quality scan of files or directories.

How to execute:

bash "<SKILL_DIR>/scripts/dispatcher.sh" --path [target]

What it does:

1. Accepts a file path or directory (defaults to current directory)
2. Discovers all source files (skips .git, node_modules, binaries, images, .min.js)
3. Runs 30 scheduling patterns against each file (free tier limit)
4. Calculates a scheduling quality score (0-100) per file and overall
5. Grades: A (90-100), B (80-89), C (70-79), D (60-69), F (<60)
6. Outputs findings with: file, line number, check ID, severity, description, recommendation
7. Exit code 0 if score >= 70, exit code 1 if scheduling quality is poor
8. Free tier limited to first 30 patterns (OE + TZ categories)

Example usage scenarios:

• "Scan my code for cron job issues" -> runs cronlint scan .
• "Check this file for scheduling anti-patterns" -> runs cronlint scan src/scheduler.ts
• "Find overlapping cron execution risks" -> runs cronlint scan src/
• "Audit timezone handling in scheduled tasks" -> runs cronlint scan .
• "Check for missing error handling in cron jobs" -> runs cronlint scan .

Pro Tier ($19/user/month -- requires CRONLINT_LICENSE_KEY)

cronlint scan --tier pro [file|directory]

Extended scan with 60 patterns covering overlap, timezone, error recovery, and resource contention.

How to execute:

bash "<SKILL_DIR>/scripts/dispatcher.sh" --path [target] --tier pro

What it does:

1. Validates Pro+ license
2. Runs 60 scheduling patterns (OE, TZ, ER, RC categories)
3. Detects missing error recovery and retry logic in scheduled jobs
4. Identifies resource contention: every-minute crons, unbounded queries, no rate limiting
5. Full category breakdown reporting

cronlint scan --format json [directory]

Generate JSON output for CI/CD integration.

bash "<SKILL_DIR>/scripts/dispatcher.sh" --path [directory] --format json

cronlint scan --format html [directory]

Generate HTML report for browser viewing.

bash "<SKILL_DIR>/scripts/dispatcher.sh" --path [directory] --format html

cronlint scan --category OE [directory]

Filter scan to a specific check category (OE, TZ, ER, RC, LM, OB).

bash "<SKILL_DIR>/scripts/dispatcher.sh" --path [directory] --category OE

Team Tier ($39/user/month -- requires CRONLINT_LICENSE_KEY with team tier)

cronlint scan --tier team [directory]

Full scan with all 90 patterns across all 6 categories including lifecycle and observability.

How to execute:

bash "<SKILL_DIR>/scripts/dispatcher.sh" --path [directory] --tier team

What it does:

1. Validates Team+ license
2. Runs all 90 patterns across 6 categories
3. Includes lifecycle management checks (graceful shutdown, orphaned tasks, stale entries)
4. Includes observability checks (missing metrics, no duration logging, no alerting)
5. Full category breakdown with per-file results

cronlint scan --verbose [directory]

Verbose output showing every matched line and pattern details.

bash "<SKILL_DIR>/scripts/dispatcher.sh" --path [directory] --verbose

cronlint status

Show license and configuration information.

bash "<SKILL_DIR>/scripts/dispatcher.sh" status

cronlint patterns

List all detection patterns with their IDs, severities, and descriptions.

bash "<SKILL_DIR>/scripts/dispatcher.sh" patterns

Check Categories

CronLint detects 90 scheduled task anti-patterns across 6 categories:

| Category | Code | Patterns | Description | Severity Range |

|----------|------|----------|-------------|----------------|

| Overlapping Execution | OE | 15 | Missing locks, concurrent runs, no mutex, no pid file check | low -- critical |

| Timezone & Scheduling | TZ | 15 | Hardcoded TZ, DST risks, UTC confusion, midnight pitfalls | low -- high |

| Error & Recovery | ER | 15 | No try/catch, missing retry, silent failure, no dead letter queue | low -- critical |

| Resource Contention | RC | 15 | Every-minute cron, no rate limit, unbounded queries, memory risk | low -- critical |

| Lifecycle Management | LM | 15 | No graceful shutdown, orphaned tasks, stale entries, no health check | low -- high |

| Observability | OB | 15 | No duration logging, no metrics, no alerting, no execution history | low -- high |

Tier-Based Pattern Access

| Tier | Patterns | Categories |

|------|----------|------------|

| Free | 30 | OE, TZ |

| Pro | 60 | OE, TZ, ER, RC |

| Team | 90 | OE, TZ, ER, RC, LM, OB |

| Enterprise | 90 | OE, TZ, ER, RC, LM, OB + priority support |

Scoring

CronLint uses a deductive scoring system starting at 100 (perfect):

| Severity | Point Deduction | Description |

|----------|-----------------|-------------|

| Critical | -25 per finding | Severe risk (overlapping execution, silent failure, resource abuse) |

| High | -15 per finding | Significant problem (missing locks, DST scheduling, no error handling) |

| Medium | -8 per finding | Moderate concern (hardcoded TZ, missing retry, no rate limiting) |

| Low | -3 per finding | Informational / best practice suggestion |

Grading Scale

| Grade | Score Range | Meaning |

|-------|-------------|---------|

| A | 90-100 | Excellent scheduling quality |

| B | 80-89 | Good scheduling with minor issues |

| C | 70-79 | Acceptable but needs improvement |

| D | 60-69 | Poor scheduling quality |

| F | Below 60 | Critical scheduling problems |

• Pass threshold: 70 (Grade C or better)
• Exit code 0 = pass (score >= 70)
• Exit code 1 = fail (score < 70)

Configuration

Users can configure CronLint in ~/.openclaw/openclaw.json:

{
  "skills": {
    "entries": {
      "cronlint": {
        "enabled": true,
        "apiKey": "YOUR_LICENSE_KEY_HERE",
        "config": {
          "severityThreshold": "medium",
          "ignorePatterns": ["**/test/**", "**/fixtures/**", "**/*.test.*"],
          "ignoreChecks": [],
          "reportFormat": "text"
        }
      }
    }
  }
}

Important Notes

• Free tier works immediately with no configuration
• All scanning happens locally -- no code is sent to external servers
• License validation is offline -- no phone-home or network calls
• Pattern matching only -- no AST parsing, no external dependencies beyond bash
• Supports scanning all file types in a single pass
• Git hooks use lefthook which must be installed (see install metadata above)
• Exit codes: 0 = pass (score >= 70), 1 = fail (for CI/CD integration)
• Output formats: text (default), json, html

Error Handling

• If lefthook is not installed and user tries hooks, prompt to install it
• If license key is invalid or expired, show clear message with link to https://cronlint.pages.dev/renew
• If a file is binary, skip it automatically with no warning
• If no scannable files found in target, report clean scan with info message
• If an invalid category is specified with --category, show available categories

When to Use CronLint

The user might say things like:

• "Scan my code for cron job issues"
• "Check my scheduled task logic"
• "Find overlapping execution risks"
• "Detect timezone problems in schedulers"
• "Are there any cron anti-patterns?"
• "Check for missing error handling in cron jobs"
• "Audit my scheduling architecture"
• "Find resource contention in batch jobs"
• "Check for missing job observability"
• "Scan for graceful shutdown issues"
• "Run a scheduling quality audit"
• "Generate a cron health report"
• "Check if my jobs have overlap protection"
• "Find silent failure patterns in scheduled tasks"
• "Check my code for DST scheduling vulnerabilities"