This lesson covers connecting Claude Code to external tools using MCP servers (Model Context Protocol) and adding automation hooks. It shows how to set up Perplexity for web search, Firecrawl for web scraping, and Notion for reading a content calendar, plus command hooks that auto-format files, block dangerous commands, and check content quality.
What you will be able to do
- Connect Claude Code to Perplexity, Firecrawl, and Notion through MCP servers so it can search the web, scrape pages, and read a content calendar.
- Configure an MCP server with the claude mcp add command, including API keys and environment variables.
- Write command hooks that run shell scripts automatically at PreToolUse, PostToolUse, and Stop events.
- Block dangerous bash commands such as rm -rf and git push --force before they run, using exit code 2.
- Auto-format edited files with Prettier and flag forbidden brand-voice phrases in draft markdown files.
Before you start
- jq installed, for parsing the JSON input hook scripts receive (brew install jq on macOS, sudo apt-get install jq on Linux).
- Node.js and npm installed, for the npx commands used in MCP server setup.
- prettier installed globally or in the project, for the format-on-save hook.
- API keys for Perplexity, Firecrawl, and Notion, plus a Notion integration shared with your content calendar database.
Reference
| Component | Command / Config | What it does |
|---|---|---|
| Perplexity MCP | claude mcp add perplexity --env PERPLEXITY_API_KEY=your-key-here -- npx -y @perplexity-ai/mcp-server |
Adds search and reason tools for live web data |
| Firecrawl MCP | claude mcp add firecrawl --url https://mcp.firecrawl.dev/your-api-key/v2/mcp |
Adds firecrawl_scrape, firecrawl_search, firecrawl_map tools |
| Notion MCP | claude mcp add --transport http notion https://mcp.notion.com/mcp |
Lets Claude Code read and check status of content calendar entries |
| Verify servers | /mcp |
Lists connected MCP servers and their available tools |
| PreToolUse hook | Fires before any tool runs; exit code 2 blocks the action | Used to stop dangerous bash commands before they execute |
| PostToolUse hook | Fires after any tool completes | Used to run Prettier automatically after Edit or Write |
| Stop hook | Fires when Claude finishes responding | Used for cleanup or reporting tasks |
| Exit codes | 0 = proceed, 2 = block, any other code = warning only | How a hook script communicates its result back to Claude Code |
Common errors and fixes
| What goes wrong | The fix |
|---|---|
| "command not found: jq" when a hook fires | Install jq: brew install jq (macOS) or sudo apt-get install jq (Linux) |
| A CLAUDE.md rule like "always format with Prettier" gets skipped sometimes (in testing, followed 7 of 10 sessions) | Use a PostToolUse hook instead; hooks run every time, CLAUDE.md rules are only suggestions |
| The format-on-save hook runs but the file is not formatted | Install prettier in the project or globally (npm install --save-dev prettier or npm install -g prettier); without it the hook skips formatting silently |
| Claude Code attempts a destructive command such as git push --force or rm -rf | The block-dangerous.sh PreToolUse hook matches the pattern and exits with code 2, blocking the command and telling Claude Code why |
| Claude Code cannot see the Notion content calendar after adding the MCP server | Share the Notion database with the integration you created at notion.so/my-integrations; creating the API key alone is not enough |
Read the full walkthrough
The complete lesson, with screenshots and any downloads, is published on Substack as part of Claude Code Masterclass: Build AI Systems Without Writing Code.
More in this section
- Lesson 1: From 3x to 10x: The Content Multiplication Engine
- Lesson 2: The Claude Code Extension Stack: Commands, Skills, Hooks, and Agents Explained
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