Name: OneTool MCP
Author: beycom

The Problem

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).

The Solution

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

>>> 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

Install

Requires uv:

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

Add to Claude Code:

claude mcp add onetool -- onetool --config ~/.onetool/onetool.yaml --secrets ~/.onetool/secrets.yaml

Or manually add to ~/.claude/mcp.json:

{
  "mcpServers": {
    "onetool": {
      "command": "onetool",
      "args": ["--config", "/Users/yourname/.onetool/onetool.yaml", "--secrets", "/Users/yourname/.onetool/secrets.yaml"]
    }
  }
}

That's it. All 100+ tools work out of the box.

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

📖 Full installation guide

Features

Feature	Description
96% Token Savings	~2K tokens no matter how many tools you add
100+ Built-in Tools	Web search, AWS, databases, file ops, diagrams, conversions
Explicit Execution	See exactly what runs — `>>> brave.search(q="AI")`
Dynamic AWS	Proxy all 57+ AWSlabs MCP servers; SSO and credentials handled
Live Whiteboard	Draw diagrams with a Mermaid-compatible DSL via Excalidraw
MCP Server Proxy	Wrap existing MCP servers without the tool tax
Encrypted Secrets	age-encrypted `secrets.yaml` backed by your OS keychain
Forge Tools	Build new tools as part of the conversation
Image Vision	Routes to a cheaper, better vision model via `ot_image` (`img`). Zero host tokens. Supports local files, URLs, clipboard; PNG, JPEG, GIF, WebP, TIFF, HEIC, AVIF, SVG.
Smart Context	`ot_context` (`ctx`) — SQLite+FTS5 store. Search and navigate large outputs without filling the context window.
Smart Tools	Delegate to cheaper LLMs (10× savings)
Security Layers	AST validation, path boundaries, output sanitisation

Tools

27+ packs, 230+ tools ready to use:

Pack	Tools	Extra	Description
`aws`	`whoami`, `login`, `start_packs`, `roles`	`[dev]`	Dynamic AWS proxy (57+ servers)
`brave`	`search`, `news`	`[util]`	Web and news search
`chrome_util`	`highlight_element`, `guide_user`	`[dev]`	Browser annotations (DevTools)
`context7`	`search`, `doc`	`[dev]`	Library documentation
`convert`	`pdf_to_md`, `docx_to_md`, `pptx_to_md`	`[util]`	Document conversion
`db`	`query`, `schema`, `tables`	`[dev]`	Database operations
`diagram`	`create`, `get_playground_url`	`[dev]`	Mermaid / Kroki diagrams
`excel`	`read`, `write`, `query`	`[util]`	Excel files
`file`	`read`, `write`, `grep`, `slice`, `toc`	`[util]`	File operations
`ground`	`search`	`[util]`	Google Grounding search
`knowledge`	`search`, `ask`, `write`, `read`, `grep`	`[util]`	RAG knowledge base (FTS5+vector)
`mem`	`write`, `read`, `search`, `grep`, `ask`, `inspect`, `query`	`[util]`	Persistent memory
`ot_forge`	`create_ext`, `validate_ext`, `install_skills`		Scaffold new tool packs
`ot_context` (`ctx`)	`write`, `read`, `search`, `grep`, `slice`, `toc`		Smart context store (SQLite+FTS5)
`ot_image` (`img`)	`load`, `load_batch`, `ask`, `summary`, `list`, `delete`, `purge`	`[util]`	Image vision via dedicated model
`ot_llm`	`transform`, `transform_file`		LLM-powered transforms
`ot_secrets`	`init`, `encrypt`, `audit`, `rotate`		Secrets encryption
`ot_timer`	`start`, `elapsed`, `list`		Named timers
`ot`	`help`, `tools`, `stats`, `skills`		Introspection
`package`	`npm`, `pypi`, `cargo`	`[dev]`	Package versions
`play_util`	`highlight_element`, `guide_user`	`[dev]`	Browser annotations (Playwright)
`ripgrep`	`search`, `count`	`[dev]`	Fast code search
`tavily`	`search`, `search_batch`, `research`	`[util]`	AI-native search
`webfetch`	`fetch`, `fetch_batch`	`[dev]`	Web fetching
`whiteboard`	`open`, `draw`, `screenshot`, `save`	`[dev]`	Live Excalidraw canvas

📖 Complete tools reference — full summary table with all 230+ tools

MCP Server Proxy

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

# .onetool/onetool.yaml
servers:
  chrome_devtools:
    type: stdio
    command: npx
    args: ["-y", "@anthropic-ai/chrome-devtools-mcp@latest"]
  github:
    type: stdio
    command: npx
    args: ["-y", "@anthropic-ai/github-mcp-server@latest"]

>>> mcp.call(server="github", tool="get_file_contents", arguments={"path": "README.md"})

📖 Configuration guide

Extending

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")

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

📖 Creating tools guide

Documentation

Quickstart - 30 seconds to first tool call
Installation - All platforms
Configuration - YAML schema
Tools Reference - All 100+ tools
Security - Security layers
Extending - Build your own
Dev Docs - Internal developer documentation
Specifications - OpenSpec specifications index

References

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

Telemetry

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

Issues

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

Support

If you find OneTool useful:

Ko-fi

License

GPLv3

OneTool MCP