> ## Documentation Index
> Fetch the complete documentation index at: https://cactal.ai/docs/llms.txt
> Use this file to discover all available pages before exploring further.
# How Cactal works
> The Cactal mental model: organizations own websites, every website has a draft head version and a published version, and every operation is available through the dashboard (including the built-in Cactal agent), the REST API, and MCP.
Cactal is a website platform where organizations own websites, and every operation on a website is available to humans and agents through the same three interfaces. The dashboard also ships the built-in [Cactal agent](/docs/agents/cactal-agent), which runs these same operations from a conversation beside your site.
## The resource model
An organization is the unit of ownership and billing. It holds members, API keys, an audit log, and websites. A website belongs to exactly one organization and bundles everything one site needs:
| Resource | What it holds | Concept page |
| ----------- | ------------------------------------------------ | ---------------------------------------- |
| Source code | Versioned pages, components, and site-wide files | [Source code](/docs/concepts/source-code) |
| CMS | Collections, fields, and content items | [CMS](/docs/concepts/cms) |
| Assets | Uploaded images and files, served from the CDN | [Assets](/docs/concepts/assets) |
| Domains | The platform subdomain and custom domains | [Domains](/docs/concepts/domains) |
| Analytics | Traffic stats for the published site | [Read analytics](/docs/guides/read-analytics) |
Access to all of it flows through one capability-based permission model. See [Access control](/docs/concepts/access-control).
## Draft head and published version
Every website tracks two version numbers. `headVersion` is the draft: every source edit advances it by one, append-only. `publishedVersion` is the version the live site serves, and it only moves when you publish or roll back.
This split means edits are never live until you decide. List the files that differ between head and published with `GET /v1/websiteSourceCode/changes`, inspect selected files with `GET /v1/websiteSourceCode/files/diff`, and discard drafts or restore any historical version with `POST /v1/websiteSourceCode/head/restore`. See [Publishing](/docs/concepts/publishing).
A new website starts at `headVersion: 1` with `publishedVersion: null`. Nothing is publicly served until the first publish, so you can build the entire site as a draft on any plan.
## Three interfaces, one operation set
The dashboard, the REST API, and MCP all invoke the same underlying operations with the same authorization, rate limits, and audit pipeline. The built-in Cactal agent drives them from the dashboard on your behalf, and anything you can do in the dashboard, an outside agent can do with an API key.
| Interface | Endpoint | Authentication |
| --------- | ----------------------------------- | ------------------------------------------ |
| Dashboard | `https://app.cactal.ai` | Email and password, or email one-time code |
| REST API | `https://api.cactal.ai/v1` | `Authorization: Bearer $CACTAL_API_KEY` |
| MCP | `POST https://api.cactal.ai/v1/mcp` | `Authorization: Bearer $CACTAL_API_KEY` |
The MCP server is stateless Streamable HTTP: `POST /v1/mcp` handles every message, and `GET` or `DELETE` on that path return `405`. Each public REST endpoint appears as one MCP tool, named from its operation id — `websites.create` becomes the `websites_create` tool. `tools/list` only returns tools the key's capabilities allow.
The same website list, fetched over REST:
```bash theme={null}
curl "https://api.cactal.ai/v1/websites" \
-H "Authorization: Bearer $CACTAL_API_KEY"
```
```json theme={null}
{
"items": [
{
"id": "V1StGXR8_Z5jdHi6B-myT",
"organizationId": "kX9dQ2mNpL4wRt7vYc3Ub",
"name": "Acme Marketing Site",
"slug": "acme-marketing-site",
"headVersion": 42,
"publishedVersion": 40,
"primaryHostname": "www.acme.com",
"createdAt": "2026-06-01T12:00:00.000Z",
"updatedAt": "2026-07-08T09:30:00.000Z"
}
],
"nextCursor": null
}
```
## Control plane and content plane
Cactal keeps product surfaces and customer content on separate domain families. The control plane (`cactal.ai`) carries trusted product traffic; the content plane (`cactal.app`) carries public customer output.
| Host | Plane | Role |
| --------------------------- | ------- | ------------------------------------------------------------------- |
| `docs.cactal.ai` | Control | Permanent alias for the canonical documentation at `cactal.ai/docs` |
| `app.cactal.ai` | Control | Dashboard and session-authenticated app traffic |
| `api.cactal.ai` | Control | Public API and MCP; API-key auth only, no session cookies |
| `cactal.app` | Content | Permanent alias for the marketing site at `cactal.ai` |
| `