What is documented here#
TERSL is a text format for state that people and language models read and write directly, with a matching syntax for querying it and for declaring changes to it. It is an open specification with open-source implementations. TERSL/DB is the hosted service from Tourbillon.ai that stores TERSL documents, keeps a verifiable history of every change, and controls who may read and write each part of a document.
This site has four parts. The language section explains TERSL itself and applies whether you use the open-source tools or TERSL/DB. The system section explains what TERSL/DB adds: namespaces, keys and grants, the record, plans. The portal guide describes each page of the TERSL/DB portal. The API section is the reference for calling TERSL/DB over HTTP.
TERSL, the language
The shape of state, reading with queries, writing with declarations, and the open-source tooling.
TERSL/DB, the system
Namespaces, keys and grants, the record of every change, moments and copies, plans and limits.
Portal guide
One page for each page of the portal: what it shows, what each action does, who can use it.
HTTP API
The wire format, every header, every status code, and the diagnostic codes a caller can see.
Where to start#
If you are new to TERSL, read What TERSL is and then The shape of state; the two pages take about fifteen minutes and cover everything the rest of the site assumes. If you already know the language and have a TERSL/DB account, start with How it works and then the portal guide. If you are integrating from code, the HTTP API section is self-contained.
The glossary defines the terms used across the site.
Other resources#
The open-source repository, terse-lang/terse, holds the specification, the Python and TypeScript implementations, the MCP server and the integrations. The main site, tourbillon.ai, has a getting-started guide, a syntax cheatsheet, a cookbook and an interactive explorer.
This documentation describes the system as it exists. Where a page and the behaviour of the software disagree, the software is right and the page has a defect; please report it.