Your first MCP server, claude mcp add
Install your first MCP server in Claude Code or Codex in under two minutes. We pick context7 (library docs), small, useful, no API key.
Your first MCP server
MCP (Model Context Protocol) is how Claude Code, Codex, and Cursor talk to external tools. An MCP server runs as a subprocess (stdio) or remote HTTP endpoint and exposes a list of "tools" the AI can call. Installing one is two commands.
We start with context7 because it's the lowest-friction win, it gives Claude up-to-date library docs (React, Next.js, Prisma, you name it) without any API keys. Once you've done this once, every other MCP server installs the same way.
Schritt 1: Pick the client (Claude Code or Codex)
Claude Code uses claude mcp add ... which writes ~/.claude.json.
Codex uses ~/.codex/config.toml directly (or codex mcp add ... if you have CLI 0.x+).
If you have both, do both, they share most servers but the config file differs.
Schritt 2: Install context7 in Claude Code
claude mcp add context7 -s user -- npx -y @upstash/context7-mcp
Breakdown:
claude mcp add, register a new servercontext7, the local name (whatever you want)-s user, user-scope (vs project-scope.mcp.json)-- npx -y @upstash/context7-mcp, the command that starts the server (npx auto-installs from npm)
npx -y is the magic, first call downloads the package, subsequent calls run from npm cache. No global install pollution.
Schritt 3: Same in Codex (optional)
Edit ~/.codex/config.toml:
[mcp_servers.context7]
command = "npx"
args = ["-y", "@upstash/context7-mcp"]
Restart Codex (Cmd+Q on macOS, then reopen. VS Code Extension also needs a window reload).
Schritt 4: Verify
Run academy_validate_step. The validator runs claude mcp list and checks that at least one server is registered. To verify context7 specifically:
claude mcp list | grep context7
Or open a fresh Claude Code session and ask "what does the latest Next.js docs say about server actions?". Claude will call context7's query-docs tool and you'll see the citation.
Schritt 5: The next servers worth installing
These three are all zero-config (no API keys) and pay off fast. Add them now or save them for later phases:
- sequential-thinking, multi-step reasoning. Tiny, helps on hard problems.
claude mcp add sequential-thinking -s user -- npx -y @modelcontextprotocol/server-sequential-thinking - filesystem, local file operations from a sandboxed root.
claude mcp add filesystem -s user -- npx -y @modelcontextprotocol/server-filesystem /path/you/want/sandboxed - fetch, fetch web pages and parse them as text.
claude mcp add fetch -s user -- npx -y @modelcontextprotocol/server-fetch
After this recipe you have a working MCP setup. The next four recipes layer in memory, web research, code intelligence, and GitHub, the four servers that turn Claude Code from "smart autocomplete" into "second engineer".
claude mcp list 2>&1 | head -20