Mermaid Plus is now an MCP server for AI agents
Mermaid diagrams won because they are text: they diff cleanly, they live in version control, and AI models are good at writing them. The MCP era should have been the moment every AI client learned to draw them. It half-happened — and the half that happened isn't the interesting half.
The Mermaid MCP ecosystem today: renderers, not editors
Search the MCP registries for "mermaid" and you'll find a handful of community servers. There is no official one — the Mermaid project ships the library, a CLI, and the mermaid.ink rendering service, but no MCP. The community servers are all variations on one pattern: take Mermaid code, launch a headless browser, render a PNG or SVG, hand the image back to the chat. Some are well built. As a category, they make your AI client a screensaver — it can show you a diagram, but the diagram evaporates when the conversation ends, and nothing your team maintains ever changes.
That's the gap. The diagrams worth editing don't live in chat windows. They live in your wiki, embedded in the architecture page someone's onboarding doc links to. An MCP server for Mermaid should be able to find and maintain those.
What we shipped
Mermaid Plus Diagrams & AI Agent for Confluence now ships a rovo:mcp module — Atlassian's bridge that turns Forge app actions into MCP tools. The same four actions that power the built-in Rovo agent are now exposed as an MCP server:
| Tool | What it does |
|---|---|
create-diagram | Renders a Mermaid diagram onto a page or blogpost — or creates a new page with it |
get-diagram | Reads back the diagram source and its version |
update-diagram | Replaces the diagram source with a version-checked write |
convert-diagram | Turns Mermaid code blocks already on the page into rendered diagrams, in place |
These aren't chat decorations. They edit the real macros on the real page: version locking prevents lost updates, an open editor draft is synced instead of clobbered, and every call runs with the invoking user's own Confluence permissions — the client can only see and change what that person could change in the editor.
Three ways to use it
1. In Confluence chat (already live). The Rovo agent picks up the page you're viewing — "make this diagram clearer" just works. This is the original surface and it's unchanged.
2. In agents you build in Rovo Studio. Create an agent, Add tools → Connected apps, and add the four Mermaid Plus tools — next to tools from any other app that exposes them. A release-notes agent that reads Jira and updates your architecture diagrams in the same conversation is now a configuration exercise, not an integration project.
3. In any MCP client. Claude Code, Cursor, or anything that speaks MCP can connect to:
https://mcp.atlassian.com/forge/0ddaf927-b00c-4186-8b1a-490be0cb7b69
Exposure is admin-controlled per site: external access is off by default, and a site admin flips it on under Apps → Sites → your site → Connected apps → Mermaid Plus → Tools in Atlassian Administration. Without that toggle the endpoint authenticates but shows no tools; with it, users approve their own connection through an OAuth 2.1 consent screen scoped to sites where the app is installed. (The built-in Rovo agent needs none of this — it's live the moment the app is installed.)
Connecting Claude Code, concretely:
# Register the server (--scope user = available in all your projects)
claude mcp add --scope user --transport http mermaid-plus \
https://mcp.atlassian.com/forge/0ddaf927-b00c-4186-8b1a-490be0cb7b69
Then start claude, run /mcp, select mermaid-plus → Authenticate, and approve the consent screen in the browser. claude mcp list flips from ! Needs authentication to ✔ Connected, and your first prompt can be as plain as:
Read the Mermaid diagram on https://your-site.atlassian.net/wiki/spaces/TEAM/pages/123456789/Architecture and suggest a clearer layout
Cursor users: add the same URL as a remote HTTP MCP server — the OAuth flow is identical. The full walkthrough, including the admin setup, lives in the user guide.
One behavioral difference worth knowing
In Confluence chat, "this page" means the page you're looking at — the context comes for free. Over MCP there is no open page, so you pass the numeric ID from the page URL (…/pages/123456789/Title → 123456789) or a space key. That's not a limitation we chose; it's the honest shape of working outside the wiki. Every one of our tools' errors will tell the client exactly this rather than guessing at a target — a wrong-page write is the one failure this feature must never have.
Why an app, not a standalone MCP server
A standalone Confluence MCP server would need you to hand a third party an API token with write access to your wiki. Ours rides on the Forge app you already installed: Atlassian hosts it, access goes through Atlassian's own OAuth and permission layer, and admin controls exposure per site. The MCP server is a capability of the app, not another vendor trust decision.
What's next
The four tools are the floor, not the ceiling — a search tool (find pages by title or space) is the obvious next one, once it can ship without a scope-change disruption for existing installs. If you're building agents on top of Confluence diagrams, we'd like to hear what's missing: the Marketplace listing takes feedback, and so does this blog.
Try Mermaid Plus Diagrams & AI Agent for Confluence
All 30 Mermaid diagram types plus a Rovo AI agent, with live preview and one-click templates — free for up to 10 users.
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