slack-channel-monitor

name

slack-channel-monitor

description

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.

Slack Channel Monitor

Create a cron automation that polls up to 10 Slack channels every minute. 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:

• Replies in the thread are forwarded to the running conversation.
• When the conversation finishes (or errors), the agent's final response is posted back to the Slack thread.

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

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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:

# 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:

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.:

["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. Apply exactly three constant substitutions near the top of the file:

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:

mkdir -p /tmp/slack-monitor-build
# (write the customised main.py to /tmp/slack-monitor-build/main.py)

Validate syntax before packaging:

python3 -m py_compile /tmp/slack-monitor-build/main.py && echo "Syntax OK"

Fix any syntax errors before proceeding.

Step 4 - Package and upload

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

# Determine the API host (use <HOST> from the system prompt, else localhost:8000)
OPENHANDS_HOST="http://localhost:8000"

TARBALL_PATH=$(curl -s -X POST \
  "${OPENHANDS_HOST}/api/automation/v1/uploads?name=slack-channel-monitor" \
  -H "Authorization: Bearer $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

curl -s -X POST "${OPENHANDS_HOST}/api/automation/v1" \
  -H "Authorization: Bearer $OPENHANDS_AUTOMATION_API_KEY" \
  -H "Content-Type: application/json" \
  -d "{
    \"name\": \"Slack Channel Monitor\",
    \"trigger\": {\"type\": \"cron\", \"schedule\": \"* * * * *\"},
    \"tarball_path\": \"$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:

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 thread replies - one conversations.replies call per active thread.
5. Processes messages in chronological order:
   • Skips bot messages and any ts in bot_message_ts.
   • Reply in a tracked thread → forwards to the existing conversation.
   • Contains trigger phrase → 👀 reaction, create conversation, post link.
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. Mark conversation closed.
7. Saves state and fires the completion callback.

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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.

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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