String
String
Section titled “String”String is an operating system for AI.
It sits on top of existing operating systems and the web, giving AI agents a single, consistent interface to the outside world — apps, documents, websites, APIs, and files.
AI reads everything as Markdown. AI acts through a handful of commands. That’s the entire interface.
How it works
Section titled “How it works”Context is text. String presents all content as text, preferring Markdown — the format AI understands best. SFMD (String Flavored Markdown) adds lightweight extensions for navigation, block addressing, and actions while remaining 100% CommonMark compatible.
Actions are commands. Two primitives cover nearly everything:
/open— see something (a document, a page, a block, a shortcut)/act— do something (call an API, run a workflow, submit data)
New capabilities come from new documents, not new commands.
What’s in this documentation
Section titled “What’s in this documentation”| # | Document | What it covers |
|---|---|---|
| 1 | Why String | The problem, the vision, and why AI needs its own OS |
| 2 | The Model | Context hierarchy, SFMD principles, command surface |
| 3 | The AI Loop | How an AI agent discovers, navigates, and acts |
| 4 | Topics | Sessions, typed topics (file, web, app, bash) |
| 5 | Actions | Action definition, invocation, response templates |
| 6 | State | Variables, secrets, session state, configuration |
| 7 | Navigation | /open, /nav, menus, shortcuts, history |
| 8 | Authoring | How to write SFMD documents |
| 9 | Editing | Creating and modifying documents through String |
| 10 | Errors | Error codes, format, and handling |
| 11 | Transport | ChanFlow channel tags, AI ↔ String communication |
| 12 | Response Format | Response structure and formatting |
| 13 | Tools | /tool invocation, cmd blocks, tool vs app |
Cookbook
Section titled “Cookbook”Practical, scenario-based guides showing AI using String end-to-end.
Each guide is a real AI↔String conversation using channel tags. The
cookbook lives in its own repository: string-os/cookbook.
| # | Guide | Scenario |
|---|---|---|
| 0 | CLI Quick Start | Install string and run your first command |
| 1 | Document Editing | Create, edit, undo, commit, and version a document |
| 2 | Web Browsing | Research multiple sites, manage tabs, compile findings |
| 3 | Single-Page App | One-file weather app — all /act, no navigation |
| 4 | Multi-Page App | Multi-file weather app — /open to move, /act to do |
| 5 | Multi-Topic Workflows | API docs→code, email→report, build+changelog |
| 6 | CLI App | Wrap a shell CLI as an SFMD action surface |
| 7 | Cross-Agent Portability | One file, three AI agents, same behavior |