feat: add Claude Code as a supported MCP client

[GilbertLS]

Changes

Adds Claude Code (the Anthropic CLI) as a sixth supported MCP client for the init command, alongside Claude Desktop, Cursor, Windsurf, VS Code, and Gemini.

• New class ClaudeCodeClientManager (src/clients/claude-code.ts) extending BaseClientManager. It overrides configure() to prompt for a configuration scope, then delegates to the base merge logic since both scopes use the standard mcpServers key:
  • User scope → ~/.claude.json (available across all projects). Default when prompted.
  • Project scope → .mcp.json at a user-specified project folder (shared via version control).
• Registry (src/clients/index.ts): registered under the key 'claude-code' — the key must equal the ClientType string exactly, since init resolves managers via clients[clientType].
• Type (src/clients/types.ts): added 'claude-code' to the ClientType union.
• CLI (src/index.ts, src/commands/init.ts): added claude-code to the --client help text, an example invocation, and JSDoc.
• Docs (README.md): new "Claude Code" section documenting init --client claude-code and the user-vs-project scope prompt.

Config format written matches what Claude Code expects for a stdio server (verified against the Claude Code MCP docs):

{
  "mcpServers": {
    "auth0": {
      "command": "npx",
      "args": ["-y", "@auth0/auth0-mcp-server", "run", "--tools", "*"],
      "env": { "DEBUG": "auth0-mcp" }
    }
  }
}

Usage

npx @auth0/auth0-mcp-server init --client claude-code

References

• Jira: https://auth0team.atlassian.net/browse/DXAA-619

Testing

Verified with both automated tests and a manual end-to-end run against a real Auth0 tenant and a live Claude Code install.

Automated: npm run build, npm run typecheck, npm run lint, and npm test all pass (388 tests, 35 files). New suite test/clients/claude-code.test.ts covers: default user-scope path resolution; project-scope path resolution; throw when the project folder does not exist; getConfigPath fallback when no folder is set; the scope prompt (default user); the project-folder prompt; and that the mcpServers merge preserves pre-existing top-level keys in ~/.claude.json. Existing init/registry suites were extended to include the new client.

Manual end-to-end (real CLI, real tenant):

1. Project scope — ran node dist/index.js init --client claude-code --scopes 'read:clients', completed the device-auth browser login, chose Project, and entered a project folder. Confirmed <folder>/.mcp.json was written with the auth0 entry under mcpServers.
2. User scope — re-ran the same command, chose User. Confirmed the auth0 entry was merged into ~/.claude.json under mcpServers, and that all pre-existing servers (asana, atlassian, github, lucid, playwright, slack, zoom) and ~40 other top-level keys (projects, userID, etc.) were preserved untouched.
3. Live connection — ran claude mcp list from the project directory and confirmed auth0: npx -y @auth0/auth0-mcp-server run --tools * - ✓ Connected, proving Claude Code actually loads and connects to the configured server. (Project-scope .mcp.json takes precedence over the user-scope entry in that directory, per Claude Code's documented scope hierarchy.)

• This change adds unit test coverage
• This change adds integration test coverage

Checklist

• I have read the Auth0 general contribution guidelines
• I have read the Auth0 Code of Conduct
• All existing and new tests complete without errors