# Cron Job Management

> Patterns for creating, testing, debugging, and maintaining cron-driven automation in workspace-hub, including log strategy, failure analysis, and safe git-aware job design.

- Skill: `vamseeachanta/cron-job-management-2` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add vamseeachanta/cron-job-management-2`
- Raw SKILL.md: https://api.skillmd.com/api/skills/vamseeachanta/cron-job-management-2/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: vamseeachanta (https://skillmd.com/u/vamseeachanta)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/vamseeachanta/cron-job-management-2

---


# Cron Job Management

## When to Use

Use this skill when working on:
- `config/scheduled-tasks/schedule-tasks.yaml`
- `scripts/cron/*`
- machine cron drift / missing jobs
- cron debugging and log inspection
- migrating scheduled jobs to git-safe patterns

## Core Workspace-Hub Pattern

Canonical schedule source:
- `config/scheduled-tasks/schedule-tasks.yaml`

Typical workflow:
1. declare or update the task in YAML
2. implement a dedicated script in `scripts/cron/` when logic is non-trivial
3. ensure logs land in a predictable location
4. test script directly before installing to cron
5. use setup tooling to render/install the crontab
6. verify machine state after install

## Creating a Cron Job

### 0. Check whether the job already exists in weak/stale form

Before creating a new scheduled workflow or a GitHub issue to add one, inspect the existing control-plane surfaces first:
- `config/scheduled-tasks/schedule-tasks.yaml`
- `scripts/cron/<task>.sh`
- `docs/ops/scheduled-tasks.md`
- related cron tests under `tests/cron/`

Common real-world pattern:
- the repo already has a scheduled task entry
- the wrapper script exists but is only a thin AI prompt shell
- tests already exist and may be failing
- the correct move is to **upgrade/replace the existing task path**, not create a second overlapping cron job

Planning rule learned from weekly skills-maintenance work:
- if a weekly job already exists canonically in `schedule-tasks.yaml`, treat that as the upgrade target
- do **not** introduce a second parallel cron for the same concern just because the current implementation is weak
- use failing wrapper tests as resource-intelligence evidence that the workflow is drifted and needs deterministic replacement

### 1. Define the task in YAML

Include:
- id
- label
- schedule or schedule_by_machine
- machines
- requires
- command
- log
- description

### 2. Prefer wrapper scripts over inline complexity

Good:
```bash
bash scripts/cron/my-job.sh
```

Avoid long inline command chains in YAML when the job:
- performs multiple steps
- uses git
- has branching/error handling
- writes multiple artifacts

### 3. Use git-safe patterns for repo-mutating jobs

If a cron task pulls/commits/pushes, use:
- `scripts/cron/lib/git-safe.sh`

Prefer wrappers that call:
- `git_safe_init`
- `git_safe_pull`
- `git_safe_commit`
- `git_safe_push`
- `git_safe_sync`

## Testing a Cron Job

Before cron installation:

```bash
bash scripts/cron/my-job.sh
bash -n scripts/cron/my-job.sh
```

For schedule rendering:

```bash
bash scripts/cron/setup-cron.sh --dry-run
```

For live installation on the current machine:

```bash
bash scripts/cron/setup-cron.sh --replace
crontab -l
```

## Debugging Cron Failures

Check in this order:

1. YAML declaration exists
2. rendered cron entry looks correct
3. script runs manually
4. log path exists and is writable
5. PATH assumptions are explicit inside the cron command/script
6. any required env vars are resolved in cron context
7. machine assignment matches the host actually being configured

Useful checks:

```bash
crontab -l
rg -n "my-job" config/scheduled-tasks/schedule-tasks.yaml scripts/cron/
tail -n 100 logs/path/to/job.log
```

## Common Failure Modes

- works manually but fails in cron due to PATH/env differences
- command too complex inline in YAML
- missing log file path prevents health monitoring
- git operations race or fail under cron
- task declared in YAML but not installed on machine
- cron entry exists but script path changed

## MANDATORY: Cron Script Prologue

Every cron wrapper script MUST start with PATH injection. Cron's environment is minimal and does not include `$HOME/.local/bin` where `uv`, `node`, etc. live. A script that runs fine in your shell but breaks silently in cron is almost always a PATH issue.

```bash
#!/usr/bin/env bash
set -uo pipefail

# ── Ensure PATH for cron environment ────────────────────────────────────────
export PATH="$HOME/.local/bin:$HOME/.npm-global/bin:$PATH"
```

The cron-health-check script had `uv: command not found` for 5 consecutive days because of this exact issue. The schedule-tasks.yaml command lines include PATH overrides, but wrapper scripts called from those commands do not inherit them in subshells.

## Health Monitoring Realities

### False-Positive Awareness
The cron-health-check reports STALE for weekly jobs (Sunday/Monday) when viewed on Tuesday. Day-of-week schedules (`0 3 * * 0`, `0 4 * * 1`) naturally exceed the 25h default staleness threshold. When doing a health review:
- Weekly jobs scheduled for yesterday or today = EXPECTED, not stale
- Weekly jobs scheduled for 3+ days ago = ACTUALLY stale and needs attention
- Daily jobs > 25h old = genuinely stale

Error scans must be bounded to recent log output, not the full append-only log. Use `tail -n 100` (or another explicit recent window) before matching `ERROR`/`Traceback`, otherwise an old transient failure in `logs/daily/cron.log` can keep a healthy job red indefinitely.

Do not let `cron-health` self-poison: its own log legitimately contains `[ERROR]` rows when reporting other broken jobs. Either skip error-pattern scanning for the `cron-health` task itself or restrict self-checking to the current run's process exit/result artifact.

Make `ERROR:` matching case-sensitive and anchored, e.g. `(^|[[:space:]])ERROR:`, so warning prose such as `403 Client Error: Forbidden` is not counted as an operational failure.

### Log Path Gotchas
- `log: null` in YAML means the health checker cannot monitor the task -- this produces a MISS on glob matching. Every task should have a `log:` field with a valid glob pattern.
- The glob pattern is expanded relative to `$WORKSPACE_HUB`, so `logs/quality/thing-*.log` resolves to `/mnt/local-analysis/workspace-hub/logs/quality/thing-*.log`.

### Pre-Create GitHub Labels
Any script that creates issues with `gh issue create --label "X"` must pre-create the label:
```bash
gh label create "X" --description "..." --color "..." 2>/dev/null || true
```
Without this, `gh issue create` fails with `could not add label: 'X' not found` and the issue is silently not created.

### Legal Scan vs Learning Pipeline
The comprehensive-learning pipeline can be blocked by legal-sanity-scan when session JSONL logs contain client names that match deny-list patterns. Session logs are append-only operational data, not source code. Watch for this pattern:
- `RESULT: FAIL — N block violation(s) found` in learning logs
- `WARNING: learning artifact commit failed — changes remain local`
- Changes accumulate uncommitted across multiple runs

Either exclude the log directory from the legal scan, or use `--diff-only` for the learning pipeline's commit path.

## Health Review Workflow

To perform a comprehensive cron health review:
1. Run `cron-health-check.sh` manually -- this is your first pass
2. Check the cron log directory: `tail -10 logs/research/2026-04-*.log` for research, etc.
3. Cross-reference `crontab -l` vs `config/scheduled-tasks/schedule-tasks.yaml`
4. Also compare against `bash scripts/cron/setup-cron.sh --dry-run` -- this is the most reliable rendered view for the current host
5. Verify the `/today` daily report at `logs/daily/YYYY-MM-DD.md` is fresh
6. If reports exist but health-check is broken, fix the script first, then rerun

For full closeout of a "fix all cron jobs / daily report is current" request, collect the evidence bundle in `references/cron-daily-report-closeout.md` before reporting success.

### Canonical vs Drift-Prone Sources
When auditing cron drift in workspace-hub, treat these as canonical:
- `config/scheduled-tasks/schedule-tasks.yaml`
- `scripts/cron/setup-cron.sh`
- `scripts/cron/validate-schedule.py`
- `config/workstations/registry.yaml`

Treat these as legacy or drift-prone unless they are explicitly refreshed to match YAML:
- `scripts/coordination/context/setup_cron.sh`
- `scripts/coordination/productivity/crontab.example`
- `docs/ops/scheduled-tasks.md`
- `docs/WORKSPACE_HUB_CAPABILITIES_SUMMARY.md`
- `scripts/cron/crontab-template.sh`

If live crontab and one of the legacy sources disagree, prefer YAML + `setup-cron.sh --dry-run`, not the legacy file.

Important operational lesson:
- `cron-health-check` can report a low or even zero issue count while the installed crontab is still drifted from YAML.
- Never use the health report alone as proof that cron reconciliation succeeded.
- Primary proof of success is:
  1. fresh crontab header from `setup-cron.sh --replace`
  2. exact parity between `crontab -l` and `bash scripts/cron/setup-cron.sh --dry-run`
  3. at least one near-term canary job (for example `cron-health` at 05:45 or `daily-today` at 06:00) producing a fresh log after reconciliation.

## Troubleshooting Guidance

### Missing job on machine
- compare `crontab -l` with `setup-cron.sh --dry-run`
- if YAML is canonical, reconcile with `bash scripts/cron/setup-cron.sh --replace`
- do NOT use the default additive install mode for drift repair

### Converting an LLM-driven cron wrapper to a deterministic script
When a weekly/daily task used to shell out to Claude/Codex/Gemini and you replace it with a deterministic script, update the scheduler metadata and test contract at the same time — not just the script body.

Required checks:
- update `requires:` in `config/scheduled-tasks/schedule-tasks.yaml` so it matches the new runtime (`python3`/`uv`/`bash` instead of `claude`, etc.)
- update `is_claude_task:` (or equivalent task metadata) so the scheduler no longer advertises the job as provider-driven when it is now deterministic
- update the task `description:` to remove mutating/agent-only behavior that is no longer true
- preserve the canonical task `id` when the cadence/path should stay stable; replace the implementation behind it instead of creating a second overlapping task
- add/refresh wrapper tests so `--dry-run` / print-mode output reflects the new deterministic command line
- support redirectable output roots (CLI flag or env var) so tests and manual runs can write to temp directories instead of dirtying the repo

Common failure mode:
- the script becomes deterministic, but YAML still says `requires: [claude, ...]` and `is_claude_task: true`, while tests/log paths still assume the old wrapper behavior. This creates governance drift and confusing operator docs even if the new script itself works.

Recommended safe sequence:
```bash
cd /mnt/local-analysis/workspace-hub
export WORKSPACE_HUB=/mnt/local-analysis/workspace-hub
bash scripts/cron/setup-cron.sh --dry-run
mkdir -p "$WORKSPACE_HUB/.ops/cron-backups"
crontab -l > "$WORKSPACE_HUB/.ops/cron-backups/crontab.$(hostname -s).$(date +%Y%m%d-%H%M%S).bak"
bash scripts/cron/setup-cron.sh --replace
crontab -l
bash scripts/monitoring/cron-health-check.sh --workspace "$WORKSPACE_HUB"
```

Why `--replace` matters:
- additive/default mode can leave stale commands installed
- additive/default mode can preserve duplicate inline jobs
- one real example was a duplicated `notification-purge` cron line because append-mode dedupe did not recognize a non-script inline `find ... -delete` command
- drift reviews should compare live crontab against dry-run output both before and after replacement

### Silent failure
- add or inspect log redirection
- run the exact cron command manually
- check for non-interactive shell assumptions

### Git contention
- replace raw git pipelines with `git-safe` wrappers

### Health monitoring blind spots
- make sure the task has a stable `log:` glob in YAML
- verify monitoring scripts can parse YAML and locate latest log files

## Key Workspace-Hub References

- `config/scheduled-tasks/schedule-tasks.yaml`
- `scripts/cron/setup-cron.sh`
- `scripts/cron/lib/git-safe.sh`
- `scripts/cron/comprehensive-learning-nightly.sh`
- `scripts/monitoring/cron-health-check.sh`

## YAML Date Escaping Gotcha

The `%` character in crontab date format strings must be escaped as `\%`. In `schedule-tasks.yaml`, the YAML `>-` block scalar strips trailing newlines but also adds an extra layer of backslash handling through the `setup-cron.sh` Python rendering pipeline. This creates a quadruple-escape trap:

- Correct in schedule-tasks.yaml: `$(date +\\\\%Y\\\\%m\\\\%d)` (4 backslashes in YAML → `\%Y\%m\%d` in crontab → `%Y%m%d` for date)
- Broken: `$(date +\\\\\\\\%Y\\\\\\\\%m\\\\\\\\%d)` (too many escapes)
- Also broken: `$(date +\\\\%Y\\\\%m\\\\%d)` with only 2 (becomes `%Y%m%d` with single backslash which also fails)

If a cron log shows date format errors or the log file has literal backslash names, check the YAML escaping level. Use `sed -n '/id: my-job/,/^[^ ]/p' config/scheduled-tasks/schedule-tasks.yaml` to inspect.

## Mandatory: schedule Field

Every task in schedule-tasks.yaml MUST have either a `schedule:` field or a `schedule_by_machine:` field. The `cron-health` entry (#1512) was declared in YAML without either, so `setup-cron.sh` silently skipped it -- the Python parser got an empty schedule string and `continue`d. The cron-health-check.py could not find the crontab entry because it was never installed.

After adding or editing a task, always verify:
```bash
bash scripts/cron/setup-cron.sh --dry-run | grep task_id
bash scripts/cron/setup-cron.sh --replace
crontab -l | grep task_id
```

## requires: Capability Validation Gotcha

The `requires:` list in schedule-tasks.yaml is validated against the flattened capabilities in `config/workstations/registry.yaml`. The validator (`scripts/cron/validate-schedule.py`) merges all values from `agent_clis`, `languages`, and `tools` lists for the host machine.

**Rule**: Any tool name in `requires:` must appear in the machine's capabilities. Adding `requires: [gh]` or `requires: [npm]` will FAIL validation unless `gh` / `npm` are also added to the `tools:` list in registry.yaml for the target machine.

```yaml
# WRONG — validation fails with "unknown capability 'gh'":
- id: my-new-job
  requires: [python3, uv, gh]

# CORRECT — first add gh to registry.yaml:
#   dev-primary capabilities:
#     tools: [uv, git, gh]  # ← add here
# Then in schedule-tasks.yaml:
- id: my-new-job
  requires: [python3, uv, gh]
```

After adding new capabilities to registry.yaml, verify:
```bash
uv run --no-project python scripts/cron/validate-schedule.py
```

## Hermes Gateway Cron Scheduler

Hermes has its OWN cron scheduler inside the Gateway process (separate from system crontab). Jobs managed via the `hermes cron` CLI (gmail-daily-digest, memory-bridge-daily, etc.) require the Gateway to be running.

**Starting the Gateway:**
```bash
# Use the systemd service directly — the hermes CLI wrapper
# requires sudo which may not resolve hermes in root PATH
systemctl --hermes-gateway
# Equivalent: sudo systemctl start hermes-gateway
```

**Diagnosing a dead Hermes cron job:**
```bash
sudo systemctl status hermes-gateway   # if not active, no Hermes cron fires
hermes cron list                        # check job next_run_at dates — stale dates mean gateway has been dead
```

**Warning "No messaging platforms enabled"** is non-fatal — the cron ticker still runs. 'local' delivery works fine. Only 'origin'/platform deliveries may be affected.

## uv PEP 723 Inline Metadata in Cron

Scripts with `# /// script\n# dependencies = ["pyyaml"]\n# ///` blocks are PEP 723 inline-metadata scripts. uv treats them as self-contained scripts and auto-installs dependencies.

**CRITICAL**: Do NOT use `python` between `uv run` and the script path:
```bash
# WRONG — bypasses PEP 723 metadata, dependencies NOT installed:
uv run --no-project python scripts/ai/my-script.py
# RIGHT — uv recognizes the script's inline metadata block:
uv run --no-project scripts/ai/my-script.py
```
This bug caused agent-radar to fail for days with "Install PyYAML: uv add pyyaml" even though the script's metadata block declares pyyaml as a dependency.

## False-Positive Counting in Daily Reports

When investigating alerts like "13 CVE references", "42 ERROR/FAIL", etc., always verify the raw count against unique root causes. Common traps:
- `grep -ci "CVE"` counts "0 blocking CVEs" in daily summary lines — false alarm
- Error counts across rolling windows of multi-day logs inflate perceived severity
- Benchmark regressions on sub-millisecond tests are often run-to-run noise, not code issues

## Absolute Paths in Cron Shell Context

Cron's minimal environment may not have `$HOME` set when PATH is expanded at parse time. Use hardcoded absolute paths rather than `$HOME` expansions in shell scripts:
```bash
# UNRELIABLE in cron:
export PATH="$HOME/.local/bin:$PATH"
# RELIABLE:
export PATH="/home/vamsee/.local/bin:$PATH"
# BEST: use absolute path for specific commands:
/home/vamsee/.local/bin/uv run --no-project ...
```

## Weekly Today Reports Pattern

The daily productivity report is only healthy if you verify both the daily artifact and whether a weekly variant is actually scheduled.

Current canonical daily task pattern:
- YAML task uses `scripts/productivity/daily_today.sh`
- daily artifact path: `logs/daily/YYYY-MM-DD.md`
- daily wrapper log: `logs/daily/cron.log`

Important findings:
- `scripts/productivity/daily_today.sh` already supports `--week` and writes `logs/weekly/YYYY-Www.md`
- if weekly reports are absent, first check whether a `weekly-today` task exists in `config/scheduled-tasks/schedule-tasks.yaml`
- do not assume weekly reporting is broken just because `scripts/coordination/productivity/crontab.example` mentions it; that file may be stale or intentionally deprecated
- preferred scheduling is 5 minutes after the daily run to avoid same-minute overlap with `daily-today`

Preferred restoration pattern for weekly today:
```yaml
- id: weekly-today
  schedule: "5 6 * * 1"
  machines: [dev-primary, ace-linux-1]
  requires: [python3, bash, git]
  command: >-
    PATH=$HOME/.local/bin:$PATH;
    cd $WORKSPACE_HUB &&
    bash scripts/productivity/daily_today.sh --week
    >> $WORKSPACE_HUB/logs/weekly/cron.log 2>&1
  log: logs/weekly/cron.log
```

No script changes are needed for this pattern; only the YAML task and cron reinstall.

Documentation cleanup rule:
- if `scripts/coordination/productivity/crontab.example` still contains installable cron lines, consider converting it to deprecation-only guidance that points operators back to `config/scheduled-tasks/schedule-tasks.yaml` and `scripts/cron/setup-cron.sh`.

## Rule of Thumb

If a cron task is important enough to debug twice, it is important enough to have:
- a dedicated wrapper script
- a clear log path
- a dry-run/install verification path
- a git-safe strategy if it mutates the repo