Each of these fills a different gap in a stock Claude Code setup. All five are open source. Context7 and 21st MCP work better with a free key, and Strix needs Docker plus an API key from your AI provider. Every install command below comes from the tool's own README.
Agent Skills
24 engineering skills from Addy Osmani, a former Director at Google. They cover the whole job: writing the spec, planning, tests, code review, security and shipping. Claude picks up the skill that fits the step you're on.
Get it: github.com/addyosmani/agent-skills
/plugin marketplace add addyosmani/agent-skills /plugin install agent-skills@addy-agent-skills
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Context7
Claude often writes code for an older version of a library than the one you have. Context7 feeds it the current, version-specific docs for the tools in your project.
Get it: github.com/upstash/context7
npx ctx7 setup
A free API key from context7.com/dashboard gives you higher limits.
Graphify
Graphify turns your project, including docs, configs and PDFs, into a knowledge graph Claude can search. Claude looks things up in the graph so it doesn't have to re-read every file each time.
Get it: github.com/Graphify-Labs/graphify
uv tool install graphifyy graphify install
No uv? Use pipx install graphifyy instead. Then open Claude Code in your project and type /graphify . to build the graph.
21st MCP
A library of more than 12,000 React components and templates you can search and drop into your project from Claude Code. It can also generate new UI pieces for you.
Get it: github.com/21st-dev/magic-mcp
claude plugin marketplace add 21st-dev/magic-mcp
Then type /plugin install 21st inside Claude Code. Get a free key at 21st.dev/mcp and set it as API_KEY_21ST.
Strix
Open-source AI agents that test your app the way an attacker would, then help you fix what they find. It's a good check before you put a vibe-coded app in front of customers.
Get it: github.com/usestrix/strix
You need Docker running and an API key from an AI provider (OpenAI, Anthropic, Google and others work).
curl -sSL https://strix.ai/install | bash strix --target ./app-directory
Only point Strix at apps you own or have permission to test.
