# Changelog

URL: /changelog · Id: `page:changelog`

> The current contract of the startup-builder package and its API, SDK, CLI and MCP, and each change to it, newest first.

The `startup-builder` package and [api.sb](/code/platform/api-sb) are at version 1, the first version. Each later change to the contract is logged here, newest first, with the [Verbs](/business/nouns/verb) it touches.

## The current contract
Each [Interface](/business/nouns/interface) has one source of truth, and the generated reference reads from it.

| Interface | Defined by |
| --- | --- |
| API | [openapi.json](https://startupbuilder.dev/openapi.json): one route per operation at `https://api.sb/{namespace}` |
| SDK | [startup-builder.d.ts](https://startupbuilder.dev/startup-builder.d.ts): the types of `$`, in `startup-builder@1` |
| CLI | [CLI spec](/code/cli/spec): commands, flags and exit codes of `npx startup-builder` |
| MCP | [MCP](/code/mcp): the `search`, `fetch` and `do` tools at `https://api.sb/mcp` |
| Errors | [Error catalog](/code/api/errors): every problem type, with its fix |

## How changes land
[Versioning](/code/api/guides/versioning) defines which changes are breaking. An additive change joins version 1 as it ships. A breaking change opens the next version and a new package major, and `startup-builder@1` keeps calling version 1.