diagrams-mcp-server 0.1.0

MCP server for rendering diagrams using mingrammer/diagrams, Mermaid, and PlantUML

diagrams-mcp-server

MCP server for generating cloud architecture diagrams, flowcharts, sequence diagrams, and more — powered by three rendering engines: mingrammer/diagrams, Mermaid, and PlantUML.

Getting Started

Hosted (Recommended)

Connect to the public hosted server — no installation required. All rendering engines and dependencies are pre-installed.

Add to your MCP client configuration:

{
  "mcpServers": {
    "diagrams-mcp": {
      "url": "https://diagrams-mcp-production.up.railway.app/mcp"
    }
  }
}

That's it — you're ready to generate diagrams.

Local Installation

Prerequisites

Graphviz is required for the core diagram rendering engine. Mermaid CLI and PlantUML are optional — install them only if you need those specific rendering engines.

Dependency	Required for	Install
Graphviz	render_diagram (cloud architecture)	brew install graphviz
Mermaid CLI	render_mermaid (flowcharts, sequence, etc.)	npm install -g @mermaid-js/mermaid-cli
Java + PlantUML	render_plantuml (UML diagrams)	brew install openjdk + download plantuml.jar

Note: The hosted server has all dependencies pre-installed. Local prerequisites only apply if you're running the server yourself.

Install the server

Via uvx (recommended):

uvx diagrams-mcp-server

Via pip:

pip install diagrams-mcp-server

From source:

pip install git+https://github.com/ByteOverDev/diagrams-mcp.git

Configure your MCP client

After installing, add to your MCP client configuration:

{
  "mcpServers": {
    "diagrams-mcp": {
      "command": "uvx",
      "args": ["diagrams-mcp-server"]
    }
  }
}

Or if installed via pip:

{
  "mcpServers": {
    "diagrams-mcp": {
      "command": "diagrams-mcp-server"
    }
  }
}

Available Tools

Discovery

• list_providers() → list[str] — List all diagram providers (aws, gcp, k8s, azure, onprem, etc.)
• list_services(provider) → list[str] — List service categories within a provider (e.g. aws → compute, database, network)
• list_nodes(provider, service) → list[dict] — List node classes for a provider.service pair with import paths
• search_nodes(query) → list[dict] — Search for nodes by keyword across all providers (e.g. "postgres", "lambda")

Rendering

• render_diagram(code) → Image (PNG) — Execute a Python script using mingrammer/diagrams in a sandboxed subprocess. Returns a rendered cloud architecture diagram.
• render_mermaid(definition) → Image (PNG/SVG) — Render a Mermaid diagram definition (flowcharts, sequence, class, ER, state, Gantt, and more).
• render_plantuml(definition) → Image (PNG) — Render a PlantUML diagram definition (sequence, class, component, activity, state, deployment).

Cross-Provider Equivalence

• find_equivalent(node, target_provider?) → dict — Find equivalent services across cloud providers (e.g. EC2 → ComputeEngine on GCP).
• list_categories() → list[dict] — List all 30 infrastructure role categories with mapped nodes across providers.

Resources

The server provides reference documentation accessible via MCP resource URIs:

URI	Description
diagrams://reference/diagram	Diagram constructor parameters, defaults, and usage
diagrams://reference/edge	Edge operators, labels, styling, and chaining
diagrams://reference/cluster	Cluster nesting, styling, and graph attributes
diagrams://reference/mermaid	Mermaid syntax examples for 6 diagram types
diagrams://reference/plantuml	PlantUML syntax examples for 6 diagram types

Examples

Cloud Architecture (mingrammer/diagrams)

"Draw an AWS architecture with an ALB routing to two ECS services, backed by RDS and ElastiCache"

from diagrams import Diagram, Cluster
from diagrams.aws.network import ALB
from diagrams.aws.compute import ECS
from diagrams.aws.database import RDS, ElastiCache

with Diagram("ECS Service", direction="LR"):
    lb = ALB("ALB")

    with Cluster("ECS Cluster"):
        services = [ECS("Web"), ECS("API")]

    lb >> services
    services[0] >> ElastiCache("Cache")
    services[1] >> RDS("Database")

Flowchart (Mermaid)

"Create a flowchart showing a CI/CD pipeline"

graph LR
    A[Push to main] --> B[Run Tests]
    B --> C{Tests pass?}
    C -->|Yes| D[Build Image]
    C -->|No| E[Notify Team]
    D --> F[Deploy to Staging]
    F --> G[Deploy to Production]

Sequence Diagram (PlantUML)

"Show the authentication flow between a client, API gateway, and auth service"

@startuml
Client -> "API Gateway": POST /login
"API Gateway" -> "Auth Service": Validate credentials
"Auth Service" --> "API Gateway": JWT token
"API Gateway" --> Client: 200 OK + token
Client -> "API Gateway": GET /data (Bearer token)
"API Gateway" -> "Auth Service": Verify token
"Auth Service" --> "API Gateway": Valid
"API Gateway" --> Client: 200 OK + data
@enduml

Development

# Clone and install
git clone https://github.com/ByteOverDev/diagrams-mcp.git
cd diagrams-mcp
pip install -e ".[dev]"

# Run tests
pytest

# Lint and format
ruff check .
ruff format .

# Run the MCP server locally (stdio mode)
diagrams-mcp-server

Supported Providers

The render_diagram tool supports all providers from the mingrammer/diagrams library, including:

AWS, GCP, Azure, Kubernetes, On-Premise, AlibabaCloud, OCI, OpenStack, DigitalOcean, Elastic, Outscale, Generic, and Custom nodes.

Use list_providers() and search_nodes(query) to discover available nodes.

License

MIT