slack-notifications

This skill provides Slack API operations with progressive disclosure for optimal context usage.

Context Savings: ~90% reduction

• MCP Mode: ~15,000 tokens always loaded (30+ tools)
• Skill Mode: ~500 tokens metadata + on-demand loading

• SLACK_BOT_TOKEN environment variable (required)
• SLACK_SIGNING_SECRET environment variable (optional, for event verification)
• SLACK_APP_TOKEN environment variable (optional, for Socket Mode)

Setting up Slack Bot Token

1. Create a Slack App at https://api.slack.com/apps
2. Navigate to "OAuth & Permissions"
3. Add required bot token scopes:

- chat:write - Send messages

- channels:read - List channels

- channels:history - Read channel history

- users:read - List users

- files:write - Upload files

- reactions:write - Add reactions

1. Install app to workspace
2. Copy "Bot User OAuth Token" to SLACK_BOT_TOKEN environment variable

The skill provides 14 tools across 5 categories:

| Category | Tools | Confirmation Required |

| ------------- | --------------------------------------------------------- | --------------------- |

| Messaging | post-message, post-thread, update-message, delete-message | Yes (all) |

| Channels | list-channels, get-channel, channel-history | No |

| Users | list-users, get-user, user-presence | No |

| Files | upload-file, list-files | Yes (upload only) |

| Reactions | add-reaction, get-reactions | No |

```bash

# Post message to channel

curl -X POST https://slack.com/api/chat.postMessage \

-H "Authorization: Bearer $SLACK_BOT_TOKEN" \

-H "Content-Type: application/json" \

-d '{"channel": "C1234567890", "text": "Hello from Claude!"}'

# List channels

curl -X GET "https://slack.com/api/conversations.list" \

-H "Authorization: Bearer $SLACK_BOT_TOKEN"

# Upload file

curl -X POST https://slack.com/api/files.upload \

-H "Authorization: Bearer $SLACK_BOT_TOKEN" \

-F "channels=C1234567890" \

-F "file=@report.pdf" \

-F "title=Weekly Report"

```

Messaging Tools (Confirmation Required)

#### post-message

Send a message to a Slack channel.

Parameters:

• channel (required): Channel ID or name (e.g., "C1234567890" or "#general")
• text (required): Message text (supports Slack markdown)
• thread_ts (optional): Parent message timestamp for threading
• blocks (optional): Rich message blocks (JSON array)

Example:

```bash

curl -X POST https://slack.com/api/chat.postMessage \

-H "Authorization: Bearer $SLACK_BOT_TOKEN" \

-H "Content-Type: application/json" \

-d '{

"channel": "C1234567890",

"text": "Deployment successful!",

"blocks": [

{

"type": "section",

"text": {

"type": "mrkdwn",

"text": "Deployment Status\n:white_check_mark: Production deployed successfully"

}

}

]

}'

```

#### post-thread

Reply to a message in a thread.

Parameters:

• channel (required): Channel ID
• thread_ts (required): Parent message timestamp
• text (required): Reply text

Example:

```bash

curl -X POST https://slack.com/api/chat.postMessage \

-H "Authorization: Bearer $SLACK_BOT_TOKEN" \

-H "Content-Type: application/json" \

-d '{

"channel": "C1234567890",

"thread_ts": "1234567890.123456",

"text": "Thread reply here"

}'

```

#### update-message

Update an existing message.

Parameters:

• channel (required): Channel ID
• ts (required): Message timestamp
• text (required): New message text

Example:

```bash

curl -X POST https://slack.com/api/chat.update \

-H "Authorization: Bearer $SLACK_BOT_TOKEN" \

-H "Content-Type: application/json" \

-d '{

"channel": "C1234567890",

"ts": "1234567890.123456",

"text": "Updated message"

}'

```

#### delete-message

Delete a message.

Parameters:

• channel (required): Channel ID
• ts (required): Message timestamp

Example:

```bash

curl -X POST https://slack.com/api/chat.delete \

-H "Authorization: Bearer $SLACK_BOT_TOKEN" \

-H "Content-Type: application/json" \

-d '{

"channel": "C1234567890",

"ts": "1234567890.123456"

}'

```

Channel Tools

#### list-channels

List all channels in workspace.

Parameters:

• types (optional): Comma-separated channel types (default: "public_channel")

- Options: "public_channel", "private_channel", "mpim", "im"

• limit (optional): Max channels to return (default: 100)

Example:

```bash

curl -X GET "https://slack.com/api/conversations.list?types=public_channel,private_channel" \

-H "Authorization: Bearer $SLACK_BOT_TOKEN"

```

#### get-channel

Get channel information.

Parameters:

• channel (required): Channel ID

Example:

```bash

curl -X GET "https://slack.com/api/conversations.info?channel=C1234567890" \

-H "Authorization: Bearer $SLACK_BOT_TOKEN"

```

#### channel-history

Get channel message history.

Parameters:

• channel (required): Channel ID
• limit (optional): Max messages to return (default: 100)
• oldest (optional): Start of time range (Unix timestamp)
• latest (optional): End of time range (Unix timestamp)

Example:

```bash

curl -X GET "https://slack.com/api/conversations.history?channel=C1234567890&limit=50" \

-H "Authorization: Bearer $SLACK_BOT_TOKEN"

```

Security Note: Channel history may contain sensitive information. Use with caution.

User Tools

#### list-users

List all users in workspace.

Parameters:

• limit (optional): Max users to return (default: 100)

Example:

```bash

curl -X GET "https://slack.com/api/users.list" \

-H "Authorization: Bearer $SLACK_BOT_TOKEN"

```

#### get-user

Get user profile information.

Parameters:

• user (required): User ID

Example:

```bash

curl -X GET "https://slack.com/api/users.info?user=U1234567890" \

-H "Authorization: Bearer $SLACK_BOT_TOKEN"

```

#### user-presence

Get user online status.

Parameters:

• user (required): User ID

Example:

```bash

curl -X GET "https://slack.com/api/users.getPresence?user=U1234567890" \

-H "Authorization: Bearer $SLACK_BOT_TOKEN"

```

File Tools

#### upload-file (Confirmation Required)

Upload a file to Slack channel.

Parameters:

• channels (required): Comma-separated channel IDs
• file (required): File path to upload
• title (optional): File title
• initial_comment (optional): Message text

Example:

```bash

curl -X POST https://slack.com/api/files.upload \

-H "Authorization: Bearer $SLACK_BOT_TOKEN" \

-F "channels=C1234567890" \

-F "file=@C:\reports\weekly.pdf" \

-F "title=Weekly Report" \

-F "initial_comment=Here is this week's report"

```

#### list-files

List files in channel.

Parameters:

• channel (optional): Channel ID to filter by
• user (optional): User ID to filter by
• count (optional): Max files to return (default: 100)

Example:

```bash

curl -X GET "https://slack.com/api/files.list?channel=C1234567890" \

-H "Authorization: Bearer $SLACK_BOT_TOKEN"

```

Reaction Tools

#### add-reaction

Add emoji reaction to a message.

Parameters:

• channel (required): Channel ID
• timestamp (required): Message timestamp
• name (required): Emoji name (without colons, e.g., "thumbsup")

Example:

```bash

curl -X POST https://slack.com/api/reactions.add \

-H "Authorization: Bearer $SLACK_BOT_TOKEN" \

-H "Content-Type: application/json" \

-d '{

"channel": "C1234567890",

"timestamp": "1234567890.123456",

"name": "thumbsup"

}'

```

#### get-reactions

Get reactions on a message.

Parameters:

• channel (required): Channel ID
• timestamp (required): Message timestamp

Example:

```bash

curl -X GET "https://slack.com/api/reactions.get?channel=C1234567890×tamp=1234567890.123456" \

-H "Authorization: Bearer $SLACK_BOT_TOKEN"

```

Primary Agents

• devops: Infrastructure alerts, deployment notifications, monitoring
• incident-responder: Incident alerts, status updates, escalations

Secondary Agents

• pm: Sprint notifications, milestone updates, team announcements
• developer: Build notifications, PR alerts, test results
• qa: Test failure alerts, quality reports
• security-architect: Security alerts, vulnerability notifications

Deployment Notifications

```bash

# Notify channel of successful deployment

curl -X POST https://slack.com/api/chat.postMessage \

-H "Authorization: Bearer $SLACK_BOT_TOKEN" \

-H "Content-Type: application/json" \

-d '{

"channel": "#deployments",

"text": ":rocket: Production deployment completed",

"blocks": [

{

"type": "section",

"text": {

"type": "mrkdwn",

"text": "Production Deployment\n:white_check_mark: v1.2.3 deployed successfully\nDuration: 5m 23s"

}

}

]

}'

```

Incident Alerts

```bash

# Alert on-call team of incident

curl -X POST https://slack.com/api/chat.postMessage \

-H "Authorization: Bearer $SLACK_BOT_TOKEN" \

-H "Content-Type: application/json" \

-d '{

"channel": "#incidents",

"text": " :rotating_light: High severity incident detected",

"blocks": [

{

"type": "section",

"text": {

"type": "mrkdwn",

"text": "Incident INC-1234\n:rotating_light: Severity: P1\nService: API Gateway\nStatus: 503 errors increasing"

}

}

]

}'

```

Test Results

```bash

# Post test results

curl -X POST https://slack.com/api/chat.postMessage \

-H "Authorization: Bearer $SLACK_BOT_TOKEN" \

-H "Content-Type: application/json" \

-d '{

"channel": "#qa",

"text": "Test suite completed",

"blocks": [

{

"type": "section",

"text": {

"type": "mrkdwn",

"text": "Test Results\n:white_check_mark: 245 passed\n:x: 3 failed\n:warning: 2 skipped"

}

}

]

}'

```

Token Security

• NEVER expose bot token in logs or error messages
• Store token in environment variable, not in code
• Use least-privilege scopes for bot token
• Rotate tokens periodically

Message Security

• All message operations require confirmation
• Channel history may contain sensitive information (PII, credentials, etc.)
• Validate channel permissions before posting
• Use private channels for sensitive communications

Data Privacy

• Comply with workspace data retention policies
• Avoid posting PII or credentials in messages
• Use Slack's data export features for compliance
• Respect user privacy and online status

Common Errors

| Error | Cause | Solution |

| ------------------- | ----------------------------- | ---------------------------------------- |

| not_authed | Missing or invalid token | Check SLACK_BOT_TOKEN is set correctly |

| channel_not_found | Invalid channel ID | Verify channel ID with list-channels |

| missing_scope | Bot lacks required permission | Add scope in Slack App settings |

| rate_limited | Too many requests | Implement exponential backoff |

| message_not_found | Invalid timestamp | Check message timestamp is correct |

Retry Strategy

For rate limiting errors, implement exponential backoff:

1. Wait 1 second, retry
2. Wait 2 seconds, retry
3. Wait 4 seconds, retry
4. Wait 8 seconds, retry
5. Give up after 5 attempts

Slack API rate limits:

• Tier 1: 1 request per second
• Tier 2: 20 requests per minute
• Tier 3: 50 requests per minute
• Tier 4: 100 requests per minute

Methods by tier:

• chat.postMessage: Tier 3 (50/min)
• conversations.list: Tier 2 (20/min)
• users.list: Tier 2 (20/min)
• files.upload: Tier 4 (100/min)

• Slack API Documentation: https://api.slack.com/docs
• Block Kit Builder: https://app.slack.com/block-kit-builder
• Slack App Management: https://api.slack.com/apps

Before starting:

Read .claude/context/memory/learnings.md

After completing:

• New pattern -> .claude/context/memory/learnings.md
• Issue found -> .claude/context/memory/issues.md
• Decision made -> .claude/context/memory/decisions.md

> ASSUME INTERRUPTION: If it's not in memory, it didn't happen.