SideButton

Claude Code MCP Server — Install SideButton in Claude Code

Claude Code is Anthropic's terminal-native coding agent. SideButton adds a Model Context Protocol server behind it — browser and workflow tools, plus installable knowledge packs for any web app. Setup takes five minutes.

What You Unlock — AI Coding Agent Tools for Claude Code

Browser automation

Claude Code drives a real Chrome instance — not a headless puppeteer shim. DOM queries, clicks, network capture, screenshots, everything.

Installable knowledge packs

One command adds a pack for any site — GitHub, Jira, Linear, LinkedIn. Claude Code picks up selectors and workflows instantly.

YAML Agentic Workflows

Bundle multi-step agent routines as reusable YAML files. Claude Code calls them like functions.

Role playbooks

Load SE, QA, PM, or custom role prompts from a skill pack. Claude Code adopts the role for that session.

1. Install SideButton

Install the server globally from npm.

$ npm install -g sidebutton

2. Start the server (optional, for HTTP transport)

If you plan to use the HTTP MCP URL instead of stdio, start the long-running server. For the stdio config below, Claude Code spawns the process on demand — you can skip this step.

$ sidebutton

Server listens on http://localhost:9876 — see the MCP overview for what each exposed URL is for.

3. Add SideButton to Claude Code

One command registers the SideButton MCP server with Claude Code over HTTP. The server from step 2 must be running on localhost:9876.

$ claude mcp add sidebutton --transport http http://localhost:9876/mcp

Persists to ~/.claude.json. Use --scope project to write to ./.mcp.json instead — useful for committing the MCP config to a repo.

4. Verify the MCP Integration and Run Your First Prompt

Restart Claude Code. Inside a session, run:

> /mcp

You should see the Manage MCP servers panel with sidebutton marked as connected:

Manage MCP servers
5 servers

  Local MCPs (~/.claude.json [project: ~/your-repo])
> sidebutton  ·  ✓ connected
  claude.ai
  ...

Select sidebutton to see the full tool list — browser control, workflow execution, skill-pack installers, and more. Then install a knowledge pack and try an agentic prompt:

$ sidebutton install github.com

Back inside Claude Code, prompt:

"Using sidebutton, open github.com, find every open PR on sidebutton/sidebutton, and group them by reviewer."

Troubleshooting

sidebutton: command not found

Your npm global bin isn't on PATH. Run npm bin -g to find it and add the result to your shell's PATH. On Windows, restart the terminal after install.

"MCP server disconnected" in Claude Code

Run sidebutton status to check the server. If it exits immediately, rerun with sidebutton serve --stdio --verbose in a separate terminal and watch the logs.

Browser tools return "Chrome not connected"

The Chrome extension needs to be installed and pointed at the same SideButton instance. See installation docs for the extension setup. Non-browser tools (workflows, filesystem, shell) work without the extension.

How do I inspect what SideButton is doing?

Run Claude Code with --mcp-debug, or launch SideButton manually with sidebutton serve --stdio --verbose. Tool-call payloads print to stderr.

Frequently asked questions

Do I need Chrome for SideButton to work inside Claude Code?

Only for the browser-automation tools. The workflow engine, filesystem, shell, and skill-pack tools run without a browser. Install the Chrome extension only when you want Claude Code to drive a real browser session.

How is this different from the upcoming native Claude Code integration?

The MCP path in this guide is stable today and works with every version of Claude Code that supports MCP servers. The native integration — currently in development — will reduce configuration to a single command and let SideButton register richer resources. The MCP transport itself does not change; native integration is a thinner client wrapper on top.

Does this work on Windows and Linux, not just macOS?

Yes. SideButton is pure Node.js. Anywhere Claude Code runs (macOS, Windows with WSL or native, Linux), SideButton runs. The config path differs per OS — see the Configure step for locations.

Can I run Claude Code and OpenAI Codex against the same SideButton install?

Yes. One sidebutton process serves every connected MCP client. Point Claude Code and the Codex CLI at the same binary — each gets its own stdio connection.

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