---
name: webhook-subscriptions
description: "Webhook subscriptions: event-driven agent runs."
version: 1.3.0
metadata:
  hermes:
    tags: [webhook, events, automation, integrations, notifications, push]
---

# Webhook Subscriptions

Create dynamic webhook subscriptions so external services (GitHub, GitLab, Stripe, CI/CD, IoT sensors, monitoring tools) can trigger Hermes agent runs by POSTing events to a URL.

## Setup (Required First)

The webhook platform must be enabled before subscriptions can be created. Check with:
```bash
hermes webhook list
```

If it says "Webhook platform is not enabled", set it up:

### Option 1: Setup wizard
```bash
hermes gateway setup
```
Follow the prompts to enable webhooks, set the port, and set a global HMAC secret.

### Option 2: Manual config
Add to `~/.hermes/config.yaml`:
```yaml
platforms:
  webhook:
    enabled: true
    extra:
      host: "0.0.0.0"
      port: 8644
      secret: "generate-a-strong-secret-here"
```

### Option 3: Environment variables
Add to `~/.hermes/.env`:
```bash
WEBHOOK_ENABLED=true
WEBHOOK_PORT=8644
WEBHOOK_SECRET=generate-a-strong-secret-here
```

After configuration, start (or restart) the gateway:
```bash
hermes gateway run
# Or if using systemd:
systemctl --user restart hermes-gateway
```

Verify it's running:
```bash
curl http://localhost:8644/health
```

## Commands

All management is via the `hermes webhook` CLI command:

### Create a subscription
```bash
hermes webhook subscribe <name> \
  --prompt "Prompt template with {payload.fields}" \
  --events "event1,event2" \
  --description "What this does" \
  --skills "skill1,skill2" \
  --deliver telegram \
  --deliver-chat-id "12345" \
  --secret "optional-custom-secret"
```

Returns the webhook URL and HMAC secret. The user configures their service to POST to that URL.

### List subscriptions
```bash
hermes webhook list
```

### Remove a subscription
```bash
hermes webhook remove <name>
```

### Test a subscription
```bash
hermes webhook test <name>
hermes webhook test <name> --payload '{"key": "value"}'
```

## Prompt Templates

Prompts support `{dot.notation}` for accessing nested payload fields:

- `{issue.title}` — GitHub issue title
- `{pull_request.user.login}` — PR author
- `{data.object.amount}` — Stripe payment amount
- `{sensor.temperature}` — IoT sensor reading

If no prompt is specified, the full JSON payload is dumped into the agent prompt.

## Common Patterns

### GitHub: new issues
```bash
hermes webhook subscribe github-issues \
  --events "issues" \
  --prompt "New GitHub issue #{issue.number}: {issue.title}\n\nAction: {action}\nAuthor: {issue.user.login}\nBody:\n{issue.body}\n\nPlease triage this issue." \
  --deliver telegram \
  --deliver-chat-id "-100123456789"
```

Then in GitHub repo Settings → Webhooks → Add webhook:
- Payload URL: the returned webhook_url
- Content type: application/json
- Secret: the returned secret
- Events: "Issues"

### GitHub: PR reviews
```bash
hermes webhook subscribe github-prs \
  --events "pull_request" \
  --prompt "PR #{pull_request.number} {action}: {pull_request.title}\nBy: {pull_request.user.login}\nBranch: {pull_request.head.ref}\n\n{pull_request.body}" \
  --skills "github-code-review" \
  --deliver github_comment
```

### Stripe: payment events
```bash
hermes webhook subscribe stripe-payments \
  --events "payment_intent.succeeded,payment_intent.payment_failed" \
  --prompt "Payment {data.object.status}: {data.object.amount} cents from {data.object.receipt_email}" \
  --deliver telegram \
  --deliver-chat-id "-100123456789"
```

### CI/CD: build notifications
```bash
hermes webhook subscribe ci-builds \
  --events "pipeline" \
  --prompt "Build {object_attributes.status} on {project.name} branch {object_attributes.ref}\nCommit: {commit.message}" \
  --deliver discord \
  --deliver-chat-id "1234567890"
```

### Generic monitoring alert
```bash
hermes webhook subscribe alerts \
  --prompt "Alert: {alert.name}\nSeverity: {alert.severity}\nMessage: {alert.message}\n\nPlease investigate and suggest remediation." \
  --deliver origin
```

### Alertmanager: monitoring alerts with automatic RCA

Alertmanager sends a grouped payload with `status`, `commonLabels`, `commonAnnotations`, and an `alerts` array. Use the top-level common fields in the template — individual alerts inside the `alerts` array are NOT accessible via dot notation.

```bash
hermes webhook subscribe alertmanager-rca \
  --prompt 'Alertmanager Event - Status: {status}
Severity: {commonLabels.severity}
Alert: {commonLabels.alertname}
Instance: {commonLabels.instance}
Summary: {commonAnnotations.summary}
Description: {commonAnnotations.description}

Perform a root cause analysis. Investigate the affected system using available
tools (Prometheus queries, SSH to hosts, API calls). Report findings concisely.' \
  --description "Alertmanager alerts → automatic RCA" \
  --deliver telegram \
  --deliver-chat-id "<your-chat-id>"
```

Alertmanager config (receiver side):
```yaml
route:
  receiver: hermes-rca
  group_by: ['alertname', 'instance']
  group_wait: 30s
  group_interval: 5m
  repeat_interval: 4h

receivers:
  - name: hermes-rca
    webhook_configs:
      - url: http://<hermes-ip>:8644/webhooks/alertmanager-rca
        send_resolved: true
        max_alerts: 0
```

**Pitfall**: After changing Prometheus alerting rules, stale alerts can remain in Alertmanager's cache. Restart Alertmanager (`docker restart alertmanager`) to flush them.

**Pitfall — Alertmanager auth gap**: Alertmanager 0.27.0 supports `http_config.authorization` (Bearer/Basic) but does NOT support custom headers like `X-Gitlab-Token` or `X-Hub-Signature-256`. Hermes historically validated only GitHub/GitLab/Svix/generic HMAC headers — NOT `Authorization: Bearer`. This means an Alertmanager → Hermes webhook will get HTTP 401 "Invalid signature" even with the correct secret configured. Fix: either (a) patch `gateway/platforms/webhook.py` `_validate_signature()` to accept `Authorization: Bearer <secret>` as a plain-token match, or (b) set the route secret to `INSECURE_NO_AUTH` (loopback only). See `references/alertmanager-auth-integration.md` for the full patch and config.

See `proxmox-ve-administration` skill → `references/alertmanager-webhook-setup.md` for the full setup guide including PVE-specific alerting rule pitfalls.

### Direct delivery (no agent, zero LLM cost)

For use cases where you just want to push a notification through to a user's chat — no reasoning, no agent loop — add `--deliver-only`. The rendered `--prompt` template becomes the literal message body and is dispatched directly to the target adapter.

Use this for:
- External service push notifications (Supabase/Firebase webhooks → Telegram)
- Monitoring alerts that should forward verbatim
- Inter-agent pings where one agent is telling another agent's user something
- Any webhook where an LLM round trip would be wasted effort

```bash
hermes webhook subscribe antenna-matches \
  --deliver telegram \
  --deliver-chat-id "123456789" \
  --deliver-only \
  --prompt "🎉 New match: {match.user_name} matched with you!" \
  --description "Antenna match notifications"
```

The POST returns `200 OK` on successful delivery, `502` on target failure — so upstream services can retry intelligently. HMAC auth, rate limits, and idempotency still apply.

Requires `--deliver` to be a real target (telegram, discord, slack, github_comment, etc.) — `--deliver log` is rejected because log-only direct delivery is pointless.

## Security

- Each subscription gets an auto-generated HMAC-SHA256 secret (or provide your own with `--secret`)
- The webhook adapter validates signatures on every incoming POST
- Static routes from config.yaml cannot be overwritten by dynamic subscriptions
- Subscriptions persist to `~/.hermes/webhook_subscriptions.json`

## How It Works

1. `hermes webhook subscribe` writes to `~/.hermes/webhook_subscriptions.json`
2. The webhook adapter hot-reloads this file on each incoming request (mtime-gated, negligible overhead)
3. When a POST arrives matching a route, the adapter formats the prompt and triggers an agent run
4. The agent's response is delivered to the configured target (Telegram, Discord, GitHub comment, etc.)

## CRITICAL: Webhook Agent Toolset Is Restricted by Default

The default `hermes-webhook` toolset (`_HERMES_WEBHOOK_SAFE_TOOLS` in `toolsets.py`) only includes `web_search`, `web_extract`, `vision_analyze`, and `clarify` — **no terminal, no file, no SSH, no code execution**. This is intentional for security (webhook payloads are untrusted), but it means a webhook-triggered agent **cannot investigate anything locally**.

If the webhook use case requires local investigation (RCA, SSH to hosts, file reads, Prometheus queries), you MUST add a `webhook` entry to `platform_toolsets` in `~/.hermes/config.yaml`:

```yaml
platform_toolsets:
  cli:
    - browser
    - terminal
    - file
    - web
    # ... (full list)
  webhook:
    - browser
    - code_execution
    - delegation
    - file
    - memory
    - session_search
    - skills
    - terminal
    - todo
    - vision
    - web
```

After adding this, restart the gateway (`hermes gateway restart` from a separate shell — cannot restart from inside the gateway process). The webhook-triggered agent will then have the same investigative tools as a CLI session.

**Without this config change, webhook-triggered agents can only search the web and analyze images — they cannot run commands, read files, or SSH anywhere.**

## Troubleshooting

If webhooks aren't working:

1. **Is the gateway running?** Check with `systemctl --user status hermes-gateway` or `ps aux | grep gateway`
2. **Is the webhook server listening?** `curl http://localhost:8644/health` should return `{"status": "ok"}`
3. **Check gateway logs:** `grep webhook ~/.hermes/logs/gateway.log | tail -20`
4. **Signature mismatch?** Verify the secret in your service matches the one from `hermes webhook list`. GitHub sends `X-Hub-Signature-256`, GitLab sends `X-Gitlab-Token`. Alertmanager sends `Authorization: Bearer <credentials>` via `http_config.authorization` — Hermes supports this only if the `Authorization: Bearer` patch is applied (see `references/alertmanager-auth-integration.md`); otherwise it returns 401 "Invalid signature".
5. **Cannot restart gateway from inside the gateway?** If you're running inside the Hermes process (e.g., a CLI session served by the gateway), `systemctl --user restart hermes-gateway` is blocked by a safety guard (SIGTERM would kill the running command). Workaround: create a one-shot cronjob with `schedule: '1m'` that runs the restart command — it executes in a fresh session outside the gateway process. Clean up the cronjob afterwards.
6. **Firewall/NAT?** The webhook URL must be reachable from the service. For local development, use a tunnel (ngrok, cloudflared).
7. **Wrong event type?** Check `--events` filter matches what the service sends. Use `hermes webhook test <name>` to verify the route works.
8. **Agent can't investigate?** The default webhook toolset is restricted (see "CRITICAL" section above). Add `webhook` to `platform_toolsets` in config.yaml to grant terminal/file/web access.
