diagram-mcp
Server Configuration
Describes the environment variables required to run the server.
| Name | Required | Description | Default |
|---|---|---|---|
| DIAGRAM_MCP_OUTPUT_DIR | No | Directory where rendered diagrams are saved. Defaults to ~/Documents/diagram-renders. | ~/Documents/diagram-renders |
| DIAGRAM_MCP_ALLOW_ANY_OUTPUT_PATH | No | When true, allows explicit outputPath values outside the output directory or working directory. | false |
Instructions
Guidance the server publishes about itself, which clients place ahead of the tool catalog so the model reads it before choosing anything.
This server publishes no instructions, or was last inspected before Glama recorded them.
Capabilities
Features and capabilities supported by this server
Protocol revision2025-11-25
| Capability | Details |
|---|---|
| tools | {
"listChanged": true
} |
Tools
Functions exposed to the LLM to take actions
| Name | Description |
|---|---|
| render_diagramA | Render diagram-as-code text to a PNG file and return the path. Runs locally with no browser and no network. Returns an error listing the offending line numbers if the code does not parse. |
| validate_diagramA | Parse diagram code and report errors and warnings with line numbers, without writing any file. |
| preview_diagramA | Draw the diagram as text art so it can be shown directly in the conversation. Writes no file. Use render_diagram when a PNG is needed. |
| diagram_syntaxA | Return the full diagram-as-code language reference, with shapes, options and a worked example. |
Prompts
Interactive templates invoked by user choice
| Name | Description |
|---|---|
No prompts | |
Resources
Contextual data attached and managed by the client
| Name | Description |
|---|---|
No resources | |
TDQS
Scored across 4 tools
Each tool has a distinct purpose: syntax reference, validation, text preview, and PNG rendering. The descriptions clearly differentiate the outputs, and render_diagram explicitly notes when to use it over preview_diagram.
Three tools follow the verb_diagram pattern (render_diagram, validate_diagram, preview_diagram), while diagram_syntax reverses the order. The convention is still readable and consistent in style, with only a minor deviation.
Four tools is well-scoped for a diagram-as-code server. Each tool covers a necessary part of the workflow without redundancy or unnecessary bulk.
The toolset covers the full authoring loop: learn the syntax, validate the code, preview as text, and render to a PNG file. There are no obvious missing operations for the stated local rendering purpose.