# Slack Channel Monitor

> This skill should be used when the user asks to "monitor a Slack channel", "watch Slack for messages", "create a Slack bot that responds to mentions", "set up an OpenHands Slack integration", "trigger OpenHands from Slack", "respond to @openhands in Slack", or "poll Slack channels for a trigger phrase". Guides the user through creating a cron automation that watches up to 10 Slack channels and starts an OpenHands conversation whenever a configurable trigger phrase is detected.

- Skill: `openhands/slack-channel-monitor` (Agent Skill, multi-file: 10 files)
- Install (CLI): `npx skillmds add openhands/slack-channel-monitor`
- Raw SKILL.md: https://api.skillmd.com/api/skills/openhands/slack-channel-monitor/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Integrations & APIs
- Author: openhands (https://skillmd.com/u/openhands)
- Updated: 2026-09-09
- Page: https://skillmd.com/skills/openhands/slack-channel-monitor

---


# Slack Channel Monitor

Create a cron automation that polls up to 10 Slack channels every minute.
Windows PowerShell equivalents for the setup, packaging, upload, and API-check shell snippets are in `references/windows.md`.
When a message containing the **trigger phrase** (default: `@openhands`) is
detected it:

1. Adds a 👀 reaction to the triggering message.
2. Opens an OpenHands conversation with the message and recent channel context.
3. Posts a reply in the Slack thread with a link to the conversation.

On every subsequent run:
- New Slack thread replies are forwarded only when they contain the trigger
  phrase, so unrelated conversation in the thread is ignored.
- When the conversation finishes (or errors), the agent's final response is
  posted back to the Slack thread.
- Completed conversations stay in a short follow-up watch window, allowing
  triggered Slack replies to continue the same OpenHands conversation.

> **Local mode only.** This automation targets the local OpenHands setup
> (`dev:automation` stack). A cloud/webhook-based variant is out of scope here.

---

## Prerequisites

### Required secrets

Verify that at least one of the following secrets is set in
**OpenHands Settings → Secrets** before proceeding:

| Secret name | Token type | Minimum scopes |
|---|---|---|
| `SLACK_BOT_TOKEN` | Bot (`xoxb-…`) | `channels:history`, `channels:read`, `reactions:write`, `chat:write` |
| `SLACK_USER_TOKEN` | User (`xoxp-…`) | Same as bot, plus `search:read` for multi-channel efficiency |

Check with:
```bash
# For bot token:
curl -s https://slack.com/api/auth.test -H "Authorization: Bearer $SLACK_BOT_TOKEN" \
  | python3 -c "import json,sys; d=json.load(sys.stdin); print('ok' if d.get('ok') else d.get('error'))"

# For user token:
curl -s https://slack.com/api/auth.test -H "Authorization: Bearer $SLACK_USER_TOKEN" \
  | python3 -c "import json,sys; d=json.load(sys.stdin); print('ok' if d.get('ok') else d.get('error'))"
```

If neither token is present, inform the user and stop  -  the automation cannot
function without Slack credentials.

### Optional secret

| Secret name | Default | Purpose |
|---|---|---|
| `OPENHANDS_URL` | `http://localhost:8000` | Base URL used to build conversation links posted in Slack |

---

## Setup Workflow

Follow these steps in order.

### Step 1  -  Collect channels

Ask the user: *"Which Slack channels should be monitored? You can provide
channel names (e.g. `#general`) or IDs (e.g. `C0123456789`)."*

**If the user provides channel names**, resolve them to IDs:

```bash
SLACK_TOKEN="${SLACK_BOT_TOKEN:-$SLACK_USER_TOKEN}"
curl -s "https://slack.com/api/conversations.list?types=public_channel,private_channel&limit=200&exclude_archived=true" \
  -H "Authorization: Bearer $SLACK_TOKEN" \
  | python3 -c "
import json, sys
data = json.load(sys.stdin)
if not data.get('ok'):
    print('ERROR:', data.get('error'))
    exit(1)
names = set(n.lstrip('#') for n in ['CHANNEL_NAMES_HERE'.split(',')])
for ch in data.get('channels', []):
    if ch['name'] in names:
        print(f\"{ch['name']} → {ch['id']}\")
"
```

Replace `CHANNEL_NAMES_HERE` with the comma-separated names the user provided.

**If `conversations.list` returns `missing_scope` or `not_authed`:**
Inform the user: *"The token doesn't have permission to list channels. Please
provide the channel IDs directly (right-click a channel in Slack → Copy link  - 
the last path segment starting with `C` is the ID)."*

**If the bot token lacks `channels:read`** for private channels, the user can
either invite the bot first (`/invite @botname`) or switch to a user token.

Collect up to 10 channel IDs. Record them as a Python list literal, e.g.:
```python
["C0123456789", "C9876543210"]
```

### Step 2  -  Collect trigger phrase

Ask the user: *"What trigger phrase should OpenHands respond to?
(Press Enter to use the default: `@openhands`)"*

Accepted values: any non-empty string unlikely to appear accidentally, e.g.
`@openhands`, `jazz hands`, `take-me-to-funky-town`.

### Step 3  -  Generate the automation script

Read `scripts/main.py` from this skill's directory and **copy it verbatim**.
Apply exactly three constant substitutions near the top of the file:

> **Do not reimplement, simplify, or hand-write a replacement script.**
> The template already contains the correct secret-loading, state-path,
> conversation-creation, and context-forwarding logic. Only the three
> configuration constants below should change unless syntax validation fails.

| Placeholder | Replace with |
|---|---|
| `TRIGGER_PHRASE = "@openhands"` | `TRIGGER_PHRASE = "{user_phrase}"` |
| `CHANNEL_IDS: list[str] = []` | `CHANNEL_IDS: list[str] = {channel_id_list}` |
| `DEFAULT_OPENHANDS_URL = "http://localhost:8000"` | `DEFAULT_OPENHANDS_URL = "{url}"` (keep default if user has no preference) |

Write the customised script to a temporary directory:
```bash
mkdir -p /tmp/slack-monitor-build
# copy scripts/main.py to /tmp/slack-monitor-build/main.py
# then replace only the three constants above
```

Validate syntax before packaging:
```bash
python3 -m py_compile /tmp/slack-monitor-build/main.py && echo "Syntax OK"
```

Then run a quick integrity check to confirm the template structure is still
present and only the configuration block was customised:
```bash
grep -n 'TRIGGER_PHRASE = "' /tmp/slack-monitor-build/main.py
grep -n 'CHANNEL_IDS: list\[str\] =' /tmp/slack-monitor-build/main.py
grep -n 'DEFAULT_OPENHANDS_URL = "' /tmp/slack-monitor-build/main.py
grep -n 'def get_secret' /tmp/slack-monitor-build/main.py
grep -n 'def _state_file_path' /tmp/slack-monitor-build/main.py
grep -n 'def create_conversation' /tmp/slack-monitor-build/main.py
```

If any of those checks fail, stop and re-copy the template instead of trying to
repair a hand-written variant.

### Step 4  -  Package and upload

Determine the Automation backend URL and auth from the `<RUNTIME_SERVICES>`
block in your system context:
- Use the **Automation backend** `url_from_agent` as `OPENHANDS_HOST`
- Auth: `X-Session-API-Key: $OPENHANDS_AUTOMATION_API_KEY`

If no Automation backend is listed in `<RUNTIME_SERVICES>`, stop and tell
the user to start the full automation stack.

```bash
tar -czf /tmp/slack-monitor.tar.gz -C /tmp/slack-monitor-build .

# OPENHANDS_HOST: read from <RUNTIME_SERVICES> Automation backend url_from_agent
OPENHANDS_HOST="<automation-url-from-runtime-services>"

TARBALL_PATH=$(curl -s -X POST \
  "${OPENHANDS_HOST}/api/automation/v1/uploads?name=slack-channel-monitor" \
  -H "X-Session-API-Key: $OPENHANDS_AUTOMATION_API_KEY" \
  -H "Content-Type: application/gzip" \
  --data-binary @/tmp/slack-monitor.tar.gz \
  | python3 -c "import json,sys; print(json.load(sys.stdin)['tarball_path'])")

echo "Uploaded: $TARBALL_PATH"
```

If the upload fails with a size error, the tarball must be under 1 MB.
`main.py` is under 15 KB so this should never trigger.

### Step 5  -  Create the automation

```bash
curl -s -X POST "${OPENHANDS_HOST}/api/automation/v1" \
  -H "X-Session-API-Key: $OPENHANDS_AUTOMATION_API_KEY" \
  -H "Content-Type: application/json" \
  -d "{
    \"name\": \"Slack Channel Monitor\",
    \"trigger\": {\"type\": \"cron\", \"schedule\": \"* * * * *\"},
    \"tarball_path\": \"$TARBALL_PATH\",
    \"entrypoint\": \"python3 main.py\",
    \"timeout\": 55
  }" | python3 -m json.tool
```

A 55-second timeout keeps runs well within the 60-second cron window.

Record the returned `id`  -  share it with the user as confirmation.

### Step 6  -  Confirm

Tell the user:

> ✅ **Slack Channel Monitor** is running!
>
> - Automation ID: `{id}`
> - Channels: `{channel list}`
> - Trigger phrase: `{phrase}`
> - Polling every minute via cron `* * * * *`
> - State file: `~/.openhands/workspaces/automation-state/slack_poller_{id}.json`
>
> Send a message containing `{phrase}` in any monitored channel to test it.
> The bot will react with 👀 and reply with a link to the new conversation.

---

## Runtime Behaviour (per poll)

Each cron run executes `main.py`, which runs **10 polling iterations** (every
5 seconds) within the 55-second timeout window. Each iteration:

1. **Loads state** from the JSON file (see `references/state-schema.md`).
2. **Resolves the Slack token**  -  checks `SLACK_USER_TOKEN` then `SLACK_BOT_TOKEN`.
3. **Fetches new messages:**
   - User token + `search:read` + > 1 channel → single `search.messages` call
     (searches for the trigger phrase across all channels).
   - Otherwise → one `conversations.history` call per channel.
4. **Fetches due thread replies**  -  polls at most one tracked thread per
   iteration using per-thread exponential backoff to stay within Slack rate
   limits.
5. **Processes messages** in chronological order:
   - Skips messages already in `processed_ts` (dedup across the overlap window).
   - Skips bot messages and any `ts` in `bot_message_ts`.
   - Reply in a tracked thread whose text contains the trigger phrase → forwards
     a follow-up request to the existing conversation and resets the follow-up
     watch window. Replies without the trigger phrase are marked processed and
     ignored.
   - Contains trigger phrase outside a tracked conversation → 👀 reaction, create
     a new conversation, post link.
     - Thread replies: agent receives full thread history for context.
     - Root messages: agent receives the trigger text only.
6. **Checks conversation statuses**  -  for each active conversation where
   `time.time() - last_activity > 15 s`:
   - If status is `idle`, `finished`, `error`, or `stuck` → fetch the agent's
     final response via `/api/conversations/{id}/agent_final_response` and post
     it to the Slack thread using Slack's `markdown_text` field so Markdown
     formatting renders correctly. Mark the record `watching` for five minutes
     so triggered follow-up replies can continue the same conversation.
7. **Advances `last_poll`** to `now - 10 s` (overlap window prevents boundary
   races). If a conversation creation failed, pins `last_poll` further back to
   retry on the next iteration.
8. **Saves state** (including `processed_ts`) and continues to the next iteration.
9. After all iterations, fires the completion callback.

Debug output is written to both stdout and a persistent log at:
```
{WORKSPACE_BASE_ROOT}/automation-state/slack_poller_debug.log
```

---

## Additional Resources

### Reference Files

- **`references/slack-api.md`**  -  Slack token types, required scopes, API
  endpoint reference, rate limits, and common error codes.
- **`references/state-schema.md`**  -  State JSON schema, field definitions,
  example file, and conversation lifecycle diagram.

### Script Template

- **`scripts/main.py`**  -  The complete automation script. Customise the three
  constants at the top (`TRIGGER_PHRASE`, `CHANNEL_IDS`, `DEFAULT_OPENHANDS_URL`)
  before packaging.

---

## Troubleshooting

| Symptom | Likely cause | Fix |
|---|---|---|
| Bot doesn't react to messages | Token missing or bot not in channel | Verify token with `auth.test`; `/invite @botname` |
| `not_in_channel` error in run logs | Bot token used but bot not a member | Invite bot or switch to user token |
| `missing_scope` error | Token lacks required scopes | Re-install Slack app with correct scopes (see `references/slack-api.md`) |
| No messages detected | `last_poll` timestamp is in the future | Delete the state file to reset; it will be recreated on next run |
| Conversation link 404 | `OPENHANDS_URL` points to wrong host | Set the `OPENHANDS_URL` secret to the correct base URL |
| Summary never posted | Conversation stuck in `running` state | Check conversation in the OpenHands UI; the agent may need intervention |
| Duplicate conversations created | `processed_ts` state missing or corrupted | Delete the state file to reset; dedup will rebuild on next run |
| Trigger message processed on each cron run | State file deleted between runs | Ensure `automation-state/` directory is persistent across runs |
| Debug info needed | Need detailed per-message trace | Check `{WORKSPACE_BASE_ROOT}/automation-state/slack_poller_debug.log` |