slack-notifications

SKILL.md

Mode: Cognitive/Prompt-Driven — No standalone utility script; use via agent context.

Slack Notifications Skill

Overview

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

Requirements

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

Create a Slack App at https://api.slack.com/apps

Navigate to "OAuth & Permissions"

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

Install app to workspace

Copy "Bot User OAuth Token" to SLACK_BOT_TOKEN environment variable

Tools

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

Quick Reference

# 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"

Tool Details

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:

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:

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:

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:

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:

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:

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:

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:

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:

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:

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:

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:

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:

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:

curl -X GET "https://slack.com/api/reactions.get?channel=C1234567890&timestamp=1234567890.123456" \
  -H "Authorization: Bearer $SLACK_BOT_TOKEN"

Agent Integration

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

Common Use Cases

Deployment Notifications

# 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\n*Duration:* 5m 23s"
        }
      }
    ]
  }'

Incident Alerts

# 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": "<!channel> :rotating_light: High severity incident detected",
    "blocks": [
      {
        "type": "section",
        "text": {
          "type": "mrkdwn",
          "text": "*Incident INC-1234*\n:rotating_light: *Severity:* P1\n*Service:* API Gateway\n*Status:* 503 errors increasing"
        }
      }
    ]
  }'

Test Results

# 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"
        }
      }
    ]
  }'

Security Considerations

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

Error Handling

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:

Wait 1 second, retry

Wait 2 seconds, retry

Wait 4 seconds, retry

Wait 8 seconds, retry

Give up after 5 attempts

Rate Limits

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)

Related

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

Memory Protocol (MANDATORY)

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.