feat: Complete Unit 3 Module 3 - Slack Notification Integration

- Remove Hugging Face Hub Integration module (will be in separate PR huggingface#69)
- Restructure Unit 3 to 3 modules: Build MCP Server, GitHub Actions, Slack Notification
- Build complete Slack Notification module demonstrating Tools + Prompts integration
- Add comprehensive manual testing with curl commands for easy verification
- Include security guidance for webhook URLs and environment variables
- Fix Slack markdown formatting with proper <url|text> syntax
- Create complete starter/solution project structure

Author: zealoushacker

projects/unit3/slack-notification/solution/README.md

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+# Module 3: Slack Notification - Complete Solution
+
+This is the complete implementation of Module 3, demonstrating how to integrate MCP Tools and Prompts for team communication via Slack.
+
+## What This Implements
+
+This solution extends Modules 1 and 2 with:
+
+1. **`send_slack_notification` tool** - Sends formatted messages to Slack via webhook with proper error handling
+2. **`format_ci_failure_alert` prompt** - Creates rich failure alerts with Slack markdown
+3. **`format_ci_success_summary` prompt** - Creates celebration messages for successful deployments
+
+## Setup and Usage
+
+1. Install dependencies:
+   ```bash
+   uv sync
+   ```
+
+2. Set up Slack webhook:
+   ```bash
+   export SLACK_WEBHOOK_URL="https://hooks.slack.com/services/YOUR/WEBHOOK/URL"
+   ```
+
+3. Start services:
+   ```bash
+   # Terminal 1: Webhook server
+   python webhook_server.py
+   
+   # Terminal 2: MCP server
+   uv run server.py
+   
+   # Terminal 3: Cloudflare tunnel (optional)
+   cloudflared tunnel --url http://localhost:8080
+   ```
+
+## Testing
+
+See `manual_test.md` for comprehensive testing instructions using curl commands to simulate GitHub webhook events.
+
+## Key Learning Outcomes
+
+This solution demonstrates all MCP primitives working together for real-world team automation.

projects/unit3/slack-notification/solution/github_events.json

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+[
+  {
+    "timestamp": "2025-05-30T22:42:00.904997",
+    "event_type": "workflow_run",
+    "action": "completed",
+    "workflow_run": {
+      "name": "CI",
+      "status": "completed",
+      "conclusion": "failure",
+      "run_number": 42,
+      "html_url": "https://github.com/test/repo/actions/runs/123",
+      "head_branch": "test",
+      "head_sha": "abc123"
+    },
+    "check_run": null,
+    "repository": null,
+    "sender": null
+  }
+]

projects/unit3/slack-notification/solution/manual_test.md

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+# Manual Testing Guide - Slack Notification Module
+
+This guide provides curl-based tests so you can verify your implementation without setting up a full GitHub repository and Actions workflow.
+
+## Prerequisites
+
+1. MCP server running: `uv run server.py`
+2. Webhook server running: `python webhook_server.py` 
+3. Slack webhook URL set: `export SLACK_WEBHOOK_URL="https://hooks.slack.com/services/..."`
+
+## Test 1: Direct Slack Tool Test
+
+Test your `send_slack_notification` tool directly via Claude Code:
+
+```bash
+# Start your MCP server and connect with Claude Code, then ask:
+# "Send a test message to Slack: 'Hello from MCP Course Module 3!'"
+```
+
+Expected result: Message appears in your Slack channel.
+
+## Test 2: Simulate GitHub Webhook Events
+
+### 2a. Simulate CI Failure Event
+
+Send a fake GitHub Actions failure event to your webhook server:
+
+```bash
+curl -X POST http://localhost:8080/webhook/github \
+  -H "Content-Type: application/json" \
+  -H "X-GitHub-Event: workflow_run" \
+  -d '{
+    "action": "completed",
+    "workflow_run": {
+      "id": 123456789,
+      "name": "CI",
+      "status": "completed",
+      "conclusion": "failure",
+      "run_number": 42,
+      "created_at": "2024-01-15T10:30:00Z",
+      "updated_at": "2024-01-15T10:35:00Z",
+      "html_url": "https://github.com/user/repo/actions/runs/123456789",
+      "head_branch": "feature/slack-integration",
+      "head_sha": "abc123f456789",
+      "repository": {
+        "name": "mcp-course",
+        "full_name": "user/mcp-course",
+        "html_url": "https://github.com/user/mcp-course"
+      },
+      "pull_requests": [{
+        "number": 42,
+        "url": "https://api.github.com/repos/user/mcp-course/pulls/42",
+        "html_url": "https://github.com/user/mcp-course/pull/42"
+      }]
+    }
+  }'
+```
+
+### 2b. Simulate CI Success Event
+
+```bash
+curl -X POST http://localhost:8080/webhook/github \
+  -H "Content-Type: application/json" \
+  -H "X-GitHub-Event: workflow_run" \
+  -d '{
+    "action": "completed",
+    "workflow_run": {
+      "id": 123456790,
+      "name": "Deploy",
+      "status": "completed",
+      "conclusion": "success",
+      "run_number": 43,
+      "created_at": "2024-01-15T11:30:00Z",
+      "updated_at": "2024-01-15T11:35:00Z",
+      "html_url": "https://github.com/user/repo/actions/runs/123456790",
+      "head_branch": "main",
+      "head_sha": "def456g789012",
+      "repository": {
+        "name": "mcp-course",
+        "full_name": "user/mcp-course",
+        "html_url": "https://github.com/user/mcp-course"
+      },
+      "pull_requests": [{
+        "number": 43,
+        "url": "https://api.github.com/repos/user/mcp-course/pulls/43",
+        "html_url": "https://github.com/user/mcp-course/pull/43"
+      }]
+    }
+  }'
+```
+
+## Test 3: End-to-End Workflow Tests
+
+After sending the webhook events above, test the complete workflow via Claude Code:
+
+### 3a. Test Failure Alert Workflow
+
+Ask Claude Code:
+```
+"Check recent CI events, find any failures, format them as a Slack alert, and send to the team"
+```
+
+Expected workflow:
+1. Claude calls `get_recent_actions_events()` → finds failure event
+2. Claude calls `format_ci_failure_alert()` → generates formatted message
+3. Claude calls `send_slack_notification()` → sends to Slack
+
+Expected Slack message:
+```
+❌ *CI Failed* - mcp-course
+
+> CI workflow failed on feature/slack-integration
+
+*Details:*
+• Workflow: `CI`
+• Branch: `feature/slack-integration`
+• Commit: `abc123f`
+
+*Next Steps:*
+• <https://github.com/user/mcp-course/pull/42|View Pull Request>
+• <https://github.com/user/repo/actions/runs/123456789|Check Action Logs>
+```
+
+### 3b. Test Success Summary Workflow
+
+Ask Claude Code:
+```
+"Check recent CI events, find any successful deployments, format them as a celebration message, and send to the team"
+```
+
+Expected workflow:
+1. Claude calls `get_recent_actions_events()` → finds success event
+2. Claude calls `format_ci_success_summary()` → generates formatted message  
+3. Claude calls `send_slack_notification()` → sends to Slack
+
+Expected Slack message:
+```
+✅ *Deployment Successful* - mcp-course
+
+> Deploy workflow completed successfully on main
+
+*Changes:*
+• Module 3 Slack integration added
+• Team notification system implemented
+
+*Links:*
+• <https://github.com/user/mcp-course/pull/43|View Changes>
+• <https://github.com/user/mcp-course|Visit Repository>
+```
+
+## Test 4: Error Handling Tests
+
+### 4a. Test Missing Webhook URL
+
+```bash
+# Temporarily unset the environment variable
+unset SLACK_WEBHOOK_URL
+
+# Ask Claude Code to send a message
+# Expected: Error message about missing environment variable
+```
+
+### 4b. Test Invalid Webhook URL
+
+```bash
+# Set invalid webhook URL
+export SLACK_WEBHOOK_URL="https://invalid-webhook-url.com/test"
+
+# Ask Claude Code to send a message  
+# Expected: Error message about connection failure
+```
+
+### 4c. Restore Valid Webhook URL
+
+```bash
+export SLACK_WEBHOOK_URL="https://hooks.slack.com/services/YOUR/ACTUAL/URL"
+```
+
+## Test 5: Prompt-Only Tests
+
+Test the formatting prompts without sending to Slack:
+
+### 5a. Test Failure Alert Prompt
+
+Ask Claude Code:
+```
+"Use the format_ci_failure_alert prompt to create a failure message for the recent CI failure, but don't send it to Slack yet"
+```
+
+### 5b. Test Success Summary Prompt
+
+Ask Claude Code:
+```
+"Use the format_ci_success_summary prompt to create a success message for the recent deployment, but don't send it to Slack yet"
+```
+
+## Test 6: Integration with Previous Modules
+
+Test that all previous module functionality still works:
+
+### 6a. Module 1 Integration
+
+Ask Claude Code:
+```
+"Analyze current file changes, suggest a PR template, then create a Slack message about the PR status"
+```
+
+### 6b. Module 2 Integration
+
+Ask Claude Code:
+```
+"Check workflow status, analyze the CI results, and create a comprehensive team update for Slack"
+```
+
+## Verification Checklist
+
+After running these tests, verify:
+
+- [ ] Direct Slack tool works (Test 1)
+- [ ] Webhook server receives and stores events (Test 2)
+- [ ] Failure alert workflow works end-to-end (Test 3a)
+- [ ] Success summary workflow works end-to-end (Test 3b)
+- [ ] Error handling works properly (Test 4)
+- [ ] Prompts work independently (Test 5)
+- [ ] Integration with previous modules works (Test 6)
+- [ ] Slack messages display with proper formatting
+- [ ] All tools and prompts are accessible to Claude Code
+
+## Troubleshooting
+
+### Webhook Server Issues
+```bash
+# Check if webhook server is running
+curl http://localhost:8080/health
+
+# Check stored events
+cat github_events.json
+```
+
+### MCP Server Issues
+```bash
+# Check if MCP server is responding
+# Should see server startup messages when running uv run server.py
+```
+
+### Slack Issues
+```bash
+# Test webhook URL directly
+curl -X POST -H 'Content-type: application/json' \
+  --data '{"text":"Direct webhook test"}' \
+  $SLACK_WEBHOOK_URL
+```
+
+This testing approach lets you validate your implementation without needing to set up a real GitHub repository with Actions workflows!

projects/unit3/slack-notification/solution/pyproject.toml

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+[project]
+name = "pr-agent-slack"
+version = "3.0.0"
+description = "MCP server with Slack notifications integrating Tools and Prompts"
+readme = "README.md"
+requires-python = ">=3.10"
+dependencies = [
+    "mcp[cli]>=1.0.0",
+    "aiohttp>=3.10.0,<4.0.0",
+    "requests>=2.32.0,<3.0.0",
+]
+
+[project.optional-dependencies]
+dev = [
+    "pytest>=8.3.0",
+    "pytest-asyncio>=0.21.0",
+]
+
+[build-system]
+requires = ["hatchling"]
+build-backend = "hatchling.build"
+
+[tool.hatch.build.targets.wheel]
+packages = ["."]
+
+[tool.uv]
+dev-dependencies = [
+    "pytest>=8.3.0",
+    "pytest-asyncio>=0.21.0",
+]