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Fermium

What Fermium is

A shared store of documents for your team and its agents, reached through an MCP server and read at stable links.

Fermium gives your agent a place to put the things it makes. Claude Code, Cursor, Codex or any MCP client connects to one server at https://fermium.app/mcp, and from then on the agent can publish a page, a markdown document, a code snippet, an image, a PDF or a video and hand you back a link. The link does not change when the content does.

The pieces

An MCP server. This is the product. It exposes tools such as publish_html, publish_markdown, publish_file, update_html, set_visibility and list_docs. Your agent picks the tool from a plain request like "publish this as a page and keep it forever". You never copy content around.

A content host. Everything you publish is served from https://fermiumusercontent.app/d/<slug>/, or from your own hostname if you set one up. That host serves only documents, inside a strict browser sandbox. The app, the API and sign-in stay on fermium.app. The split is deliberate; see Two origins.

A web app. At fermium.app/app you browse what has been published, change who can open a link, set expiry, sort documents into folders and tag them, edit a document's files in the browser, manage tokens, members, billing and custom domains. Nothing in the app is required for publishing.

Roots, agents and a wiki. Documents live in your private My documents, in the workspace's General root, or in shared roots with their own access lists; a document in a shared root belongs to the team and stays when its author leaves. An agent is memory your agents load before working on a concern: instructions, skills, workflows and what earlier sessions learned, kept as files people can read and review. Any folder can be published as a read-oriented site, on the content host or on your own domain, with search and opt-in search-engine indexing. See Roots and folders, Agents and Wiki.

What a document is

A document is a folder of files with a stable secret URL. The entry point is index.html. An HTML page can have stylesheets, scripts and images next to it; a markdown document keeps its source.md; a snippet keeps source.<ext>; a file share holds the file plus a generated viewer page. Every update writes a new immutable version. Identical content is a no-op.

Each document has:

  • Visibility: restricted (the default: sign-in plus explicit permission), unlisted (anyone with the link) or password (HTTP Basic). A Restricted document can be shared with people, groups or the whole workspace.
  • Retention: how many days it is kept after the last update. Default 30; 0 means keep forever.
  • Listing: private (only you see it in the app) or team (listed for everyone in your workspace).
  • Folder: where the document lives, one path like Customers/Acme. Moving it never changes its URL.
  • Tags: lowercase topic labels that cut across folders, such as customer-facing.

Every tool response includes the URL, expires_at, visibility, listing, folder, tags and version, so the agent can tell you exactly what it did.

Workspaces and plans

Every account belongs to a workspace. Signing in for the first time creates a personal one. A company workspace on a paid plan can claim an email domain, and people who sign in with that domain join it automatically.

Plans are Free, Team, Business and Enterprise. Free is limited by storage (1 GiB) and lacks the company features: groups, custom domains, and the controls that arrive with Business. Details are in Plans and limits.

Where to go next

Next Connect Claude Code