MCP server - Melius

The Melius MCP server lets an AI agent (Claude Desktop, Claude Code, or any MCP-compatible client) read and write to your projects: create canvases, drop nodes, wire edges, run generations, upload files, and download outputs — all without leaving the agent chat.

Connection options

Connection	Endpoint	Auth	When to use
Claude connector (recommended)	`https://mcp.melius.com/mcp`	Sign in with Melius	One-click connect for Claude — no API key to create or paste.
Remote HTTP	`https://api.melius.com/mcp`	API key	Default. Works with Claude Desktop, Claude Code, and any HTTP MCP client.
Local stdio	`mel-mcp` binary	API key	When you need a local-only connection — air-gapped, custom base URL, or stdio-only clients.

All three speak the same MCP protocol and expose the same tools.

Connect via Claude (recommended)
Connect with an API key

The Claude connector signs you in with your Melius account — no API key to paste. Use this for Claude.ai, Claude Desktop, and Claude Code.

Connect Claude Desktop

Open Claude

Go to Customize → Connectors → Add (+) → Custom.

Name your connector

Set the name to Melius.

Paste the endpoint

https://mcp.melius.com/mcp

Claude opens a Melius login page in your browser. Sign in (or use your existing session), pick the team you want Claude to work in, and click Authorize. Melius creates a connector key for Claude on your behalf — you don’t need to create or paste anything. Claude is connected immediately.

Set tool permissions

Go to Tool Permissions and select Always Allow for everything.

Claude Code

Add the connector

claude mcp add melius --transport http https://mcp.melius.com/mcp --scope user

Authenticate

Run claude, type /mcp, select melius, and follow the browser prompt. Sign in to Melius and pick a team.

Disconnect

The connector key Melius created during authorize is listed in Team settings → Integrations under your API keys, named claude-…-mcp. To remove Claude’s access at any time, delete that row. Claude loses access immediately.

API Keys

Generate an API key from Team settings → Integrations in the Melius app. Each key:

Is shown once at creation time — copy it before closing the modal.
Can be named (Claude, prod-bot, etc.).
Is scoped to a single team.
Can be given an expiry or marked no expiry.
Can be revoked at any time from the same settings page.

Connect Claude Desktop

Open Claude

Go to Customize → Connectors → Add (+) → Custom.

Name your connector

Set the name to Melius.

Paste the endpoint

https://api.melius.com/mcp

Paste your API key

Use a key from Team settings → Integrations. Save the connection.

Set tool permissions

Go to Tool Permissions and select Always Allow for everything.

Claude Code

Add the connector

claude mcp add melius --transport http https://api.melius.com/mcp --scope user

Authenticate

Run claude, type /mcp, select melius, and follow the browser prompt.

Local stdio (`mel-mcp`)

mel-mcp ships with the Melius CLI. Configure your MCP client to run the binary with the right env:

MEL_API_KEY=mel_...   # required
MEL_BASE_URL=https://api.melius.com   # optional; override for self-hosted
mel-mcp

If MEL_API_KEY isn’t set, mel-mcp falls back to ~/.mel/config.json (the file mel auth login writes). MEL_BASE_URL defaults to https://api.melius.com.Example Claude Desktop claude_desktop_config.json:

{
  "mcpServers": {
    "melius": {
      "command": "mel-mcp",
      "env": {
        "MEL_API_KEY": "mel_..."
      }
    }
  }
}

Verify the connection

In a new chat, send:

“Create a new project called Hello World in Melius”

If the agent calls project_create and reports a new project ID, you’re connected.

Uploading images

Image upload is a three-step flow:

Call file_upload — returns a signed URL.
PUT the file bytes to the URL.
Call file_upload_complete — finalizes the asset and creates the file node.

In a sandboxed Claude environment, the sandbox must allow network egress to *.melius.com:

Open Organization Settings

Go to Organization Settings → Capabilities → Code execution.

Enable code execution and egress

Turn on Cloud code execution and file creation and Allow network egress.

Allowlist *.melius.com

Add this exactly to the network egress allowlist:

*.melius.com

Video uploads are not supported. Video has to be generated on the canvas via a video node — agents should not attempt to upload .mp4 files.

Inline canvas previews

The MCP server can render a live image of the canvas inline in the agent chat via display_canvas. Useful for confirming layout before the agent commits to a big bulk-run.

Troubleshooting

Melius tools aren’t showing up

If your agent reports “Melius tools aren’t available through the connected MCP servers” or in Claude connectors you see “This connector has no tools available,” the client connected before the tool list finished loading. Refresh the tools list to fix it.

Open the connector menu

Click the triple-dot (⋯) menu on the Melius connector in Claude.

Refresh the tools list

Select Refresh to reload the tools list. The Melius tools appear once the refresh completes.

If the tools still don’t appear, confirm your endpoint and credentials are correct (see Connection options) and that your connection in Melius hasn’t been revoked.

Full tool reference

See Tool reference for every tool and what it does.

Data and permissions

The Melius MCP server reads from and writes to your Melius account. Specifically:

Reads your projects, canvases, nodes, edges, runs, comments, presets, teams, and models you have access to.
Writes new projects, canvases, nodes, edges, runs, uploads, comments, and team skills you ask it to create.
Deletes projects, canvases, nodes, and edges you ask it to delete.
Generates images, video, audio, and text on the canvas via Melius’s existing third-party model providers. All generation is initiated by explicit tool calls.
Does not read your Claude chat history, conversation summaries, Claude memory, or files outside the canvas. The server only operates on data the agent provides through tool calls and the canvases it explicitly opens.

The connector is scoped to the single Melius team you pick during authorize.

External links and origins

The display_canvas MCP App opens links to your Melius canvas via ui/open-link. The only origin it opens is the Melius web app:

https://app.melius.com/projects/*/canvas/*

Tested surfaces

The Melius MCP server is tested with Claude.ai, Claude Desktop, and Claude Code. Other MCP-compatible clients work as long as they speak Streamable HTTP MCP.

​Connection options

​Connect Claude Desktop

​Claude Code

​Disconnect

​API Keys

​Connect Claude Desktop

​Claude Code

​Local stdio (mel-mcp)

​Verify the connection

​Uploading images

​Inline canvas previews

​Troubleshooting

​Melius tools aren’t showing up

​Full tool reference

​Data and permissions

​External links and origins

​Tested surfaces

Connection options

Connect Claude Desktop

Claude Code

Disconnect

API Keys

Connect Claude Desktop

Claude Code

Local stdio (`mel-mcp`)

Verify the connection

Uploading images

Inline canvas previews

Troubleshooting

Melius tools aren’t showing up

Full tool reference

Data and permissions

External links and origins

Tested surfaces