* feat(skills): watchers skill — poll RSS / HTTP JSON / GitHub via cron no-agent Ships three reusable polling scripts plus a shared watermark helper as an optional skill. Users wire them into the existing cron (no_agent=True) mode rather than learning a new subsystem. Supersedes the closed PR #21497 (parallel watcher subsystem). Same value, zero new core surface. ## What ships - optional-skills/devops/watchers/SKILL.md: pattern + three example cron commands - optional-skills/devops/watchers/scripts/_watermark.py: shared helper (atomic state writes, bounded ID set, first-run baseline) - optional-skills/devops/watchers/scripts/watch_rss.py: RSS 2.0 + Atom - optional-skills/devops/watchers/scripts/watch_http_json.py: any JSON endpoint with configurable id_field / items_path / headers - optional-skills/devops/watchers/scripts/watch_github.py: issues / pulls / releases / commits (uses GITHUB_TOKEN if present) ## Invariants enforced by the shared helper - First run records baseline, emits nothing (never replays existing feed) - Watermark file is <state_dir>/<name>.json, atomic replace on write - Bounded to 500 IDs (configurable) - Empty stdout when no new items — cron treats that as silent delivery ## Validation - watch_rss.py against news.ycombinator.com/rss first run → empty stdout, watermark populated - Removed one seen-id, second run → emitted exactly that item - No DeprecationWarnings (ET element truth-value footgun dodged explicitly) End-user pattern: 'hermes cron create my-feed --schedule "*/15 * * * *" --no-agent --script $HERMES_HOME/skills/devops/watchers/scripts/watch_rss.py --script-args "--name hn --url https://news.ycombinator.com/rss" --deliver telegram' * docs(skills/watchers): tighten description to match peer optional skills * docs(skills/watchers): align frontmatter + structure with peer optional skills * docs(skills/watchers): gate to linux/macos (shell syntax in examples)
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| name | description | version | author | license | platforms | metadata | ||||||||||||||||||||
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| watchers | Poll RSS, JSON APIs, and GitHub with watermark dedup. | 1.0.0 | Hermes Agent | MIT |
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Watchers
Poll external sources on an interval and react only to new items. Three ready-made scripts plus a shared watermark helper; wire them into a cron job (or run them ad-hoc from the terminal).
When to Use
- User wants to watch an RSS/Atom feed and be notified of new entries
- User wants to watch a GitHub repo's issues / pulls / releases / commits
- User wants to poll an arbitrary JSON endpoint and get notified on new items
- User asks for "a watcher for X" or "notify me when X changes"
Mental model
A watcher is just a script that:
- Fetches data from the external source
- Compares against a watermark file of previously-seen IDs
- Writes the new watermark back
- Prints new items to stdout (or nothing on no-change)
The scripts below handle all three. The agent runs them via the terminal tool — from a cron job, a webhook, or an interactive chat — and reports what's new.
Ready-made scripts
All three live in $HERMES_HOME/skills/devops/watchers/scripts/ once the skill is installed. Each reads WATCHER_STATE_DIR (defaults to $HERMES_HOME/watcher-state/) for its state file, keyed by the --name argument.
| Script | What it watches | Dedup key |
|---|---|---|
watch_rss.py |
RSS 2.0 or Atom feed URL | <guid> / <id> |
watch_http_json.py |
Any JSON endpoint returning a list of objects | Configurable id field |
watch_github.py |
GitHub issues / pulls / releases / commits for a repo | id / sha |
All three:
- First run records a baseline — never replays existing feed
- Watermark is a bounded ID set (max 500) to cap memory
- Output format:
## <title>\n<url>\n\n<optional body>per item - Empty stdout on no-new — the caller treats that as silent
- Non-zero exit on fetch errors
Usage
Run a watcher directly from the terminal tool:
python $HERMES_HOME/skills/devops/watchers/scripts/watch_rss.py \
--name hn --url https://news.ycombinator.com/rss --max 5
Watch a GitHub repo (set GITHUB_TOKEN in ~/.hermes/.env to avoid the 60 req/hr anonymous rate limit):
python $HERMES_HOME/skills/devops/watchers/scripts/watch_github.py \
--name hermes-issues --repo NousResearch/hermes-agent --scope issues
Poll an arbitrary JSON API:
python $HERMES_HOME/skills/devops/watchers/scripts/watch_http_json.py \
--name api --url https://api.example.com/events \
--id-field event_id --items-path data.events
Wiring into cron
Ask the agent to schedule a cron job with a prompt like:
Every 15 minutes, run
watch_rss.py --name hn --url https://news.ycombinator.com/rss. If it prints anything, summarize the headlines and deliver them. If it prints nothing, stay silent.
The agent invokes the script via the terminal tool inside the cron job's agent loop; no changes to cron's built-in --script flag are needed.
State files
Every watcher writes $HERMES_HOME/watcher-state/<name>.json. Inspect:
cat $HERMES_HOME/watcher-state/hn.json
Force a replay (next run treated as first poll):
rm $HERMES_HOME/watcher-state/hn.json
Writing your own
All three scripts use the same template: load watermark, fetch, diff, save, emit. scripts/_watermark.py is the shared helper; import it to get atomic writes + bounded ID set + first-run baseline for free. See any of the three reference scripts for how little boilerplate it takes.
Common Pitfalls
- Printing a "no new items" header every tick. Callers rely on empty stdout = silent. If you print anything on an empty delta, you spam the channel. The shipped scripts handle this; custom scripts must too.
- Expecting the first run to emit items. It won't — first run records a baseline. If you need an initial digest, delete the state file after the first run or add a
--prime-with-latest Nflag in your own script. - Unbounded watermark growth. The shared helper caps at 500 IDs. Raise it for high-churn feeds; lower it on constrained filesystems.
- Putting the state dir where the agent's sandbox can't write.
$HERMES_HOME/watcher-state/is always writable. Docker/Modal backends may not see arbitrary host paths.