🧿 One MCP for developers - No tool tax, no context rot.
240+ tools including Brave, Google, Context7, Excalidraw, Version Checker, Excel, File Ops, Database, Image Vision, Playwright & Chrome DevTools Utils and many more.

Works with Claude Code or any MCP client

Each MCP server consumes 3K-30K tokens per request. Connect 5 servers and you've burned 55K tokens before the conversation starts. Connect 10+ and you're at 100K tokens.

The math is brutal: Claude Opus 4.5 at $5/M input tokens, 20 days × 10 conversations × 10 messages × 3K tokens = $30/month per MCP server - even if you never use the tools.

And then there's context rot - your AI literally gets dumber as you add more tools (Chroma Research, 2025).

OneTool is one MCP server that exposes tools as a Python API. Instead of reading tool definitions, your agent writes code:

__onetool brave.search(query="react docs 2026")

Configure one MCP server. Use unlimited tools.

"Agents scale better by writing code to call tools instead. This reduces the token usage from 150,000 tokens to 2,000 tokens...a cost saving of 98.7%"

— Anthropic Engineering

96% fewer tokens. 30× lower cost. No context rot.

📖 Read the full story

Framework feature vs. installed product. FastMCP is a toolkit for building MCP servers; Code Mode, ProxyProvider, and the Monty sandbox are ingredients a developer must adopt and expose when authoring their own MCP server. None of them reach an end user (a Claude Code / Cursor / Codex user) unless someone builds and ships a server around them. OneTool is that shipped server: it turns those framework capabilities into something a user installs and uses immediately, wrapped with 200+ curated tools, the param/alias/snippet forgiveness layer, ctx handles, the prompt + skill that teach an LLM to drive it, rich config, and a security model. A framework capability you'd have to build vs. a product you install.

Corollary: adopting a FastMCP internal (Code Mode, ProxyProvider, Monty) is an implementation choice OneTool makes internally — never a positioning risk, because the story is the product, not the plumbing.

Bootstrap (installs uv if missing, installs OneTool, initialises config, prints MCP config):

curl -LsSf https://onetool.beycom.online/install.sh | sh          # macOS / Linux
irm https://onetool.beycom.online/install.ps1 | iex               # Windows (PowerShell)

Or install manually with uv:

uv tool install 'onetool-mcp[all]'   # everything
onetool init --config ~/.onetool

Then print ready-to-paste MCP client config with resolved absolute paths and add it to your client (claude-code, claude-desktop, cursor, or vscode):

onetool init mcp-config --client claude-code   # or omit --client for all four

That's it. All 240+ tools work out of the box.

Verify: onetool init validate --config ~/.onetool/onetool.yaml

Install the ot-ref skill into your agent with vercel-labs/skills:

npx skills add https://github.com/beycom/onetool-mcp --skill ot-ref --agent claude

📖 Full installation guide

Works as an MCP server and as a direct CLI bridge into a running MCP process. Useful for agent harnesses, scripts, and automation:

# Recommended local MCP root mode: stdio
onetool serve --config .onetool/onetool.yaml

# URL-based MCP root mode for containerized clients
onetool serve --transport http --config .onetool/onetool.yaml --host 127.0.0.1 --port 8767 --path /mcp

# Enable the MCP-owned direct API in onetool.yaml:
# direct.host.enabled: true

# Start OneTool as MCP, then use the port printed in startup logs.
onetool direct run --port 8765 "ot.packs()" --format json | jq '.[0].name'
onetool direct run --port 8765 "brave.search(query='latest AI news')" --format raw

📖 Direct usage guide

27+ packs, 240+ tools ready to use:

📖 Complete tools reference — full summary table with all 240+ tools

Wrap any existing MCP server and call it explicitly - simple yaml config without the tool tax:

# .onetool/onetool.yaml
servers:
  local_tools:
    type: stdio
    command: npx
    args: ["-y", "some-mcp-server@latest"]
  private_api:
    type: http
    url: ${PRIVATE_MCP_URL}
    auth:
      type: bearer
      token: ${PRIVATE_MCP_TOKEN}

__onetool private_api.read_resource(path="README.md")

📖 Configuration guide

Drop a Python file, get a pack. No registration, no config:

# .onetool/tools/wiki.py
pack = "wiki"

def summary(*, title: str) -> str:
    """Get Wikipedia article summary."""
    import httpx
    url = f"https://en.wikipedia.org/api/rest_v1/page/summary/{title}"
    return httpx.get(url).json().get("extract", "Not found")

__onetool wiki.summary(title="Python_(programming_language)")

📖 Creating tools guide

• Quickstart - 30 seconds to first tool call
• Installation - All platforms
• Configuration - YAML schema
• Tools Reference - All 240+ tools
• Security - Security layers
• Extending - Build your own
• Dev Docs - Internal developer documentation
• Specifications - OpenSpec specifications index

• Code Execution with MCP - Anthropic Engineering
• Context Rot - Chroma Research

OneTool sends anonymous startup pings (event type, version, OS). No personal data. Opt out: export DO_NOT_TRACK=1 or set telemetry.enabled: false in onetool.yaml. Details

Check for existing issues first:

• Browse the tracker: github.com/beycom/onetool-mcp/issues
• Search with GitHub syntax: is:issue repo:beycom/onetool-mcp <keyword>

Raise a new issue: github.com/beycom/onetool-mcp/issues/new

If you find OneTool useful:

GPLv3