Most of the time we spend "working with AI" isn't spent on the AI at all. It's spent around it: estimating what a workload will cost, getting a prompt into the right shape, writing a CLAUDE.md, wiring up an MCP server, or doing the small jobs (formatting JSON, testing a regex, decoding a token) that pile up in between.
So we built a toolbox for exactly that work. Today we're opening it up for free at buonnet.com/tools.
No sign-up. No paywall. And almost everything runs entirely in your browser, so nothing you type is sent to our servers.
The highlights
A free MCP server for Claude
Language models are great at reasoning and surprisingly unreliable at things a calculator never gets wrong: exact arithmetic, time zones, date differences, cron schedules, hashes.
Our Free MCP Server gives Claude (or any MCP client) 23 tools for exactly those jobs. Connecting it from Claude Code is one line:
claude mcp add --transport http buonnet https://www.buonnet.com/api/mcp
It also works as a custom connector in Claude Desktop and claude.ai, and through the MCP connector in the Claude API.
MCP Tool Studio: build your own MCP server without code
The MCP Tool Studio lets you turn your own knowledge into tools any AI can use:
- Knowledge-base lookups: FAQs, team directories, product catalogs
- Templates: consistent replies, reports and updates
- Random pickers: standup order, writing prompts, test data
- Pipelines: chain built-in tools into a multi-step workflow
- Prompts: reusable instructions that show up as slash commands in Claude Code
The interesting part: your whole server is encoded in its URL. There's no database and nothing to host. Share the link and you've shared the server.
AI Playground and Prompt Lab
Bring your own Anthropic API key and chat with any Claude model in the AI Playground. It shows token usage and cost for every message, and can call MCP tools live. Your key goes straight from your browser to Anthropic.
When one prompt isn't enough, Prompt Lab runs a prompt template over a whole CSV, compares two models side by side, and checks every answer automatically.
Everything in the toolbox
| Area | Tools |
|---|---|
| AI Tools (MCP) | Free MCP Server, MCP Tool Studio |
| Connect your AI | AI Playground, Prompt Lab |
| Prompting | Prompt Builder, Prompt Library, Tool Definition Builder |
| Claude Code | CLAUDE.md Generator, Settings & Permissions Builder, MCP Config Builder, Skill & Subagent Builder |
| Cost & Context | Token & Cost Calculator, Context Packer, Model Picker |
| Developer Utilities | JSON Toolkit, Text Diff, Regex Tester, Encode/Decode & Hash, Generators, Cron Helper, Timestamp Converter, Color Tools |
| Text & Writing | Markdown Editor, Text Toolkit |
A few small touches make the toolbox quicker to use:
- Press Ctrl + K on any tool page to jump to another tool.
- Most tools save your draft locally, and many can create a share link.
- "Run with AI" buttons send a prompt from any tool straight to the Playground or claude.ai.
- There's a dark mode for late-night sessions.
Why we built it
At Buonnet we build AI and software products for our clients every day, and these are the utilities we kept wishing we had in one place. Making them free is our way of giving back to the community we learn so much from.
Tell us what to build next
Try the tools at buonnet.com/tools and tell us what's missing. If you'd like help building an AI product of your own, we'd love to hear from you at hello@buonnet.com.