Diagrams.so

Official

by RedHold · JavaScript

Generate and edit AWS, Azure, GCP and Kubernetes architecture diagrams as editable draw.io files.

The io.github.RedHold/diagrams-so-mcp MCP server generates and edits AWS, Azure, GCP, and Kubernetes architecture diagrams as editable draw.io files. It is exposed for use with the Model Context Protocol (MCP) and is relevant to developers working with cloud architecture diagramming workflows.

🛠️ Key Features

Generate and edit architecture diagrams
Output format: editable draw.io files
Targets: AWS, Azure, GCP, Kubernetes
MCP support: model-context-protocol (MCP)

🚀 Use Cases

Create or update cloud architecture diagrams for AWS, Azure, and GCP
Maintain Kubernetes architecture documentation using editable diagrams
Standardize diagram assets in draw.io format

⚡ Developer Benefits

Produces editable draw.io files for ongoing diagram refinement
Fits MCP-based tooling using the mcp-server model

⚠️ Limitations

Scope is limited to diagram generation/editing for AWS, Azure, GCP, and Kubernetes
Provided metadata does not describe additional capabilities beyond draw.io editing

Topics

aiarchitectureawsclaudecursordiagramsdrawiomcpmcp-servermodel-context-protocol

README.md11 KBView on GitHub

@diagrams-so/mcp

The Diagrams.so MCP server — generate, edit, and manage cloud architecture diagrams from any MCP client (Claude Desktop, Claude Code, Cursor). It's a thin stdio client over the public Diagrams.so API (/api/v2); every tool is one REST call.

Quick start

Needs Node ≥ 18. No API key to copy: you connect by approving in a browser.

bash

# 1. add the server to Claude Code
claude mcp add diagrams-so -- npx -y @diagrams-so/mcp

# 2. connect this machine (a browser opens, press Approve)
npx @diagrams-so/mcp login

Restart your client, then ask: "Generate an AWS 3-tier web app diagram and show me the warnings." Run /mcp if you want to confirm all 23 tools registered first.

Using it a lot? Install once and the command gets shorter:

bash

npm i -g @diagrams-so/mcp
diagrams-so login

The server talks to production (https://api.diagrams.so/api/v2) by default. Point it at a local or self-hosted API with DIAGRAMS_API_BASE.

Using Claude Desktop or Cursor instead of the CLI? See Add it to your MCP client. Prefer a one-click, no-terminal install? See One-click install (MCPB).

No terminal at all (Claude Desktop)

Add the server to your client config (below), then just ask for a diagram. Because the machine isn't connected yet, the first tool call replies with a link. Open it, press Approve, and ask again. Nothing to install or type.

Generating a diagram from Claude

login only connects the machine. It never generates anything itself, so there is no generate command to type in a terminal. You write the prompt in your assistant's normal chat box and it calls the tools for you.

Client	Where you type the prompt
Claude Code	the terminal chat, same place you ask anything else
Claude Desktop	the normal message box
Cursor	the chat or composer panel

MCP servers load at startup, so restart your client after adding it. Then run /mcp and confirm diagrams-so shows 23 tools.

Now just ask, in plain English:

Generate an AWS three-tier web app with an ALB, EC2 Auto Scaling and RDS Multi-AZ. Show me the design warnings, then export it as draw.io.

Behind that one sentence the assistant calls generate_diagram, then get_warnings, then export_diagram. You never name a tool or write JSON.

More things worth asking, once you have a diagram:

The warnings mention no encryption in transit. Fix that one and show me the new score.

Add a CloudFront distribution in front of the ALB.

Re-export it as SVG so I can drop it in the README.

Each reply carries the credit cost and your remaining balance. Generating, editing, fixing and re-laying-out spend credits; reading, warnings and every export are free.

The .drawio file the assistant saves opens at app.diagrams.net or in the desktop app, fully editable — it is real draw.io XML, not a picture.

Prefer not to use an assistant at all? diagrams.so/create has the same thing as a web page: type the prompt in the box. No install, no login, no MCP.

Tools (23)

Create & change (mutating)

Tool	What it does	Cost
`generate_diagram`	Create a diagram from a prompt → id + draw.io XML + warnings + score	credits
`edit_diagram`	Apply a natural-language change (new version)	credits
`fix_warning`	Resolve one Well-Architected warning	credits
`relayout_diagram`	AI re-arrange the layout (async; first 2/diagram free, then confirm)	credits*
`import_diagram`	Import existing draw.io XML as a new diagram	free
`update_diagram`	Rename / change visibility / replace XML	free
`revert_diagram`	Revert to an earlier version	free
`delete_diagram`	Soft-delete a diagram (destructive)	free
`fork_template`	Copy a public/library diagram into your account (private)	free

Read (free)

Tool	What it does
`get_diagram`	Fetch a diagram's XML + score
`list_diagrams`	List your diagrams (cursor-paginated)
`get_warnings`	Well-Architected findings for a diagram
`export_diagram`	Raw `drawio` or `svg` file (SVG is a paid feature)
`list_versions`	Version history (with `is_current`)
`get_version`	A specific version's XML + score
`get_relayout_status`	Poll an async re-layout job
`search_gallery`	Search public community + curated library diagrams
`enhance_prompt`	Turn a rough idea into a detailed prompt
`clarify_prompt`	Get clarifying questions for a vague prompt
`get_usage`	Plan + credits + cost estimates
`get_usage_history`	Itemized credit ledger per task (action, credits, diagram, surface) with filters + a live session tally
`whoami`	Account, plan, scopes, live/test mode
`list_capabilities`	Valid diagram types / providers / export formats

Reads and exports are free; generate / edit / fix / relayout cost credits, and delete is destructive. relayout asks for confirm=true before it charges.

CLI

Commands

Installing the package puts diagrams-so on your PATH. The longer diagrams-so-mcp name still works, and npx @diagrams-so/mcp <command> works without installing anything.

bash

npm i -g @diagrams-so/mcp

diagrams-so login          # connect this machine (a browser opens, press Approve)
diagrams-so whoami         # which account is this machine connected as
diagrams-so logout         # remove the local credential
diagrams-so install        # print client config to paste

Environment

Var	Required	Default
`DIAGRAMS_API_KEY`	❌	— (CI and headless only; `login` is the normal path)
`DIAGRAMS_API_BASE`	❌	`https://api.diagrams.so/api/v2` (production; override for local/self-hosted)
`DIAGRAMS_API_TIMEOUT_MS`	❌	`450000` (per-request safety-net; sits above the API's full server-side timeout ladder)
`DIAGRAMS_BROWSER`	❌	— (`login` opens your default browser; set e.g. `Google Chrome` when your Diagrams.so session lives in a non-default browser)
`DIAGRAMS_NO_BROWSER`	❌	— (set to any value to stop `login` opening a browser; the URL is always printed)
`DIAGRAMS_NO_AUTO_LOGIN`	❌	— (set to any value to disable in-tool connect; unauthenticated tools then just say to run `login`)

Add it to your MCP client

The published package runs straight from npm, so there is no path to fill in and no key in the config. Run npx @diagrams-so/mcp install to print these blocks for your client.

Claude Code (CLI)

bash

claude mcp add diagrams-so -- npx -y @diagrams-so/mcp
npx @diagrams-so/mcp login

Claude Desktop / Cursor (`claude_desktop_config.json` / `mcp.json`)

jsonc

{
  "mcpServers": {
    "diagrams-so": {
      "command": "npx",
      "args": ["-y", "@diagrams-so/mcp"]
      // optional: "env": { "DIAGRAMS_API_BASE": "http://localhost:8000/api/v2" } for a local API
    }
  }
}

Connect either by running npx @diagrams-so/mcp login once, or by asking for a diagram and clicking the link the first tool call gives you. Set DIAGRAMS_API_KEY instead only for CI and headless machines, where no browser can open.

Restart the client, then ask: "Generate an AWS 3-tier web app diagram and show me the warnings."

One-click install (MCPB)

Download diagrams-so.mcpb from the latest release and drag it into Claude Desktop. No terminal, and it no longer asks for an API key: install it, then connect on first use by clicking the link the first tool call gives you.

Building the bundle yourself is a contributor step, see Developing locally.

Verify it works

bash

DIAGRAMS_API_KEY=dgz_live_your_key node test-smoke.mjs

Runs the full flow (connect → list tools → whoami → generate → warnings → fix → export → error handling).

Continuous integration & releases

Workflow	Trigger	What it does
CI (`ci.yml`)	every push / PR	`npm ci` + `npm run build` on Node 18/20/22, then a free smoke (`scripts/ci-smoke.mjs`) that launches the built server and asserts all 23 tools register. No API calls, no credits.
Live smoke (`live-smoke.yml`)	nightly + manual	the full end-to-end flow (`test-smoke.mjs`) against the real API. Spends credits — runs only when the `DIAGRAMS_API_KEY` secret is set.
Release (`release.yml`)	tag `vX.Y.Z`	build → `npm prune --omit=dev` → pack `diagrams-so.mcpb` → attach to a GitHub Release. Publishes to npm too if an `NPM_TOKEN` secret is set.

Cut a release:

bash

# bump "version" in package.json + manifest.json to match, commit, then:
git tag v1.2.0 && git push origin v1.2.0

The tag must match package.json's version (the workflow enforces this). The .mcpb bundle appears on the GitHub Release; manual workflow_dispatch produces it as a downloadable artifact without publishing (handy for testing a bundle).

Repo secrets/variables (optional): DIAGRAMS_API_KEY (live smoke), NPM_TOKEN (npm publish), DIAGRAMS_API_BASE variable (non-prod live-smoke target).

Notes

stdout is the MCP channel — the server logs only to stderr.
Errors come back as clean MCP tool errors carrying the API's code, HTTP status, and request_id.
The server never talks to internal services or the database — only the public /api/v2.
Long-running tools stay alive past client timeouts. generate / edit / fix / relayout / enhance_prompt / clarify_prompt emit a notifications/progress every 10s while running, so MCP clients that reset their request timeout on progress (resetTimeoutOnProgress) won't abort a slow generation at the SDK's 60s default. If your client doesn't reset on progress, raise its per-call timeout for these tools.

Developing locally

Only needed if you are changing the server itself. Users should install from npm, see Quick start.

bash

git clone https://github.com/RedHold/diagrams-mcp-app-core.git
cd diagrams-mcp-app-core
npm install                  # installs deps and builds dist/ via the prepare hook
node scripts/ci-smoke.mjs    # all 23 tools register; no API calls, no credits

# point a client at your working copy
claude mcp add diagrams-so-dev -- node "$(pwd)/dist/index.js"

# build the MCPB bundle
npm run build && npx @anthropic-ai/mcpb pack

Install

Configuration

Environment variables

DIAGRAMS_API_KEYsecret

Diagrams.so API key (dgz_live_... or dgz_test_...). Optional since 1.4.0: run `npx @diagrams-so/mcp login` once instead. Or create a key at https://diagrams.so under Settings then AI Provider.

DIAGRAMS_API_BASEdefault https://api.diagrams.so/api/v2

API base URL. Defaults to production; override only for a local or self-hosted API.

DIAGRAMS_API_TIMEOUT_MSdefault 450000

Per-request timeout in milliseconds for slow generate/edit/fix calls.

Add to VS Code Add to Cursor

claude_desktop_config.json

json

{
  "mcpServers": {
    "diagrams-so-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "@diagrams-so/mcp@1.4.2"
      ],
      "env": {
        "DIAGRAMS_API_KEY": "<YOUR_DIAGRAMS_API_KEY>",
        "DIAGRAMS_API_BASE": "https://api.diagrams.so/api/v2",
        "DIAGRAMS_API_TIMEOUT_MS": "450000"
      }
    }
  }
}

🛠️ Key Features

🚀 Use Cases

⚡ Developer Benefits

⚠️ Limitations

Topics

@diagrams-so/mcp

Quick start

Generating a diagram from Claude

Tools (23)

CLI

Commands

Environment

Add it to your MCP client

Claude Code (CLI)

Claude Desktop / Cursor (claude_desktop_config.json / mcp.json)

One-click install (MCPB)

Verify it works

Continuous integration & releases

Notes

Developing locally

Install

Configuration

Claude Desktop / Cursor (`claude_desktop_config.json` / `mcp.json`)