1WRITE
Put your project in plain words.
A README that says what you are doing, a decisions file, notes. Markdown, in folders. Write it yourself or let the first AI you connect do it with you.
README.mddecisions.mdcustomers/research/notes/
Sharing AI context should be simple.
The easiest way for you and your AI agents to share context. Organize markdown files for your AIs to reference.
Free. No credit card. Connect as many AI tools as you like.
ChatGPT
Claude
Cursor
Agents
CarbonSHARED DOCS
ChatGPT
Claude
Cursor
Agents
WHAT EACH TOOL WRITES →
→ WHAT EVERY TOOL READS
WORKS WITHClaudeChatGPTClaude CodeCursorYour own agentsvia MCP + REST API
Folders. Markdown. Nothing to learn.
It looks like the docs folder in a code repository, because that is what works for AI tools. You get a clean editor and history; they get ten simple actions.
Example workspace: a sidebar with README.md, decisions.md and folders for customers, research and notes; the decisions document open; a list of recent changes by Claude, Cursor, Sarah and ChatGPT.
How it works
Write it down once. Every tool reads it.
2CONNECT
Connect your AI tools in a minute.
Claude and ChatGPT sign in from their own settings. Claude Code and Cursor take one command. No servers, no config files to understand.
Claudewants to connect to NorthwindAllow
3SHARE
Every tool starts from the same page.
Each connected tool can read, search, write, edit and append. Every change is saved as a version, signed by the tool or person who made it.
carbon_overview
carbon_list
carbon_read
carbon_search
carbon_write
carbon_edit
+ 4 moreMCP + REST
What you get
Simple enough for anyone. Built for agents first.
Folders and Markdown. That is the whole model.
No databases to design, no page types, no properties. A tree of plain text files is what every AI tool already understands, and what people can read without training.
Agents write directly. You can always see who, and undo it.
There is no approval queue to babysit. Every save is a version, signed by the tool or person who made it. See exactly what changed, line by line, and restore any version in one click; nothing is ever lost.
Ten actions, the same in every tool.
Read, search, write, edit, append, move, delete, history, list and an overview that starts with your README. Delivered over MCP for AI tools and a plain REST API for scripts.
Private by default. Yours to take.
Encrypted in transit and at rest, isolated per workspace, with a revocable key per connected tool. Your docs are plain Markdown and the API gives them back any time.
Compare
Why pay per seat for a wiki your agents can't write to?
Most knowledge tools were designed for people to browse, then had AI bolted on. Carbon was designed for AI tools to read and write, with a simple enough face that people use it too. That is also why it can be free: Markdown in a database costs almost nothing to keep.
| Criterion | Carbon | Team wiki (Notion, Confluence…) | A GitHub repo | Notes app (Obsidian, Apple Notes…) |
|---|---|---|---|---|
| Price | Free | Per person per month, usually more for AI features | Free for public, per seat for private teams | Free to cheap, per device |
| Built for AI agents | Yes. MCP and REST are the product, not an add-on | Partial. Connectors exist, but read-only or bolted on | Yes for coding tools, if you know git | Rarely. Local files, one person, plugins |
| Non-technical people | Log in, click a folder, edit | Good editors, lots of concepts to learn | Commits, branches, pull requests | Easy, but hard to share |
| Who wrote what | Every version signed by a person or a named AI tool | People, yes. Agents, usually as one shared account | Yes, with a commit history | No history, or sync conflicts |
| Your data | Plain Markdown, exportable in one API call | Proprietary blocks, lossy export | Plain files | Plain files, on one device |
Other products change often; this is how they compare in spirit, not a price list. Check their sites for current plans.
Pricing
Free. Because Markdown is cheap and your docs are yours.
No seats, no per-agent fees, no token meters. Plans with more room will come later for heavy use, and nothing you store on the free plan will ever be locked behind one.
$0for the free plan
- Unlimited people and unlimited connected AI tools
- 2,000 documents, 100 MB of Markdown
- Version history (50 versions per document)
- MCP server and REST API
- Full-text search
- Encrypted in transit and at rest
Fair-use limits apply to API requests (120 a minute per connected tool). That is plenty for a busy agent; if you hit it, tell us.
Stop teaching every AI the same things.
Write it down once, in Carbon. Every tool you use reads it, and keeps it current.
Start freeFree · no credit card · connect your first AI tool in a minute