uml-mcp-mermaid git:20261031.29f3c13A

Immutable. This exact content never changes and is served at /api/v1/blob/cb264676e7f1ae87.

---
name: uml-mcp-mermaid
description: Render readable complex Mermaid flowcharts and sequences, preserving labels, themes and playground links.
---

# Complex Mermaid

Follow `skill://uml-mcp-diagrams/SKILL.md`. Confirm Mermaid in the live catalog.
Build a component and directed-edge inventory before translating another format.
Use short stable IDs and quoted human labels; keep all relationships unless the
user explicitly narrows the view. Split large graphs into overview/detail views.

```mermaid
flowchart LR
  web["Frontend Web App"] -->|"REST / JSON"| api["API Gateway"]
  api -->|"API requests"| backend["Backend Services"]
  backend -->|"CRUD"| db[("Primary Database")]
```

For sequences, put every participant, message, activation and control statement
on its own line. Balance `activate`/`deactivate` and `alt`/`end`. Validate with
`validate_uml(..., strict=true)` before rendering. Label yes/no decision branches;
use subgraphs for boundaries rather than duplicating nodes. Escape punctuation
inside labels instead of changing the architecture to satisfy the parser.

Use `generate_uml_image` with `diagram_type: mermaid`, `output_format: svg` for
MCP Apps. Kroki is the default service; a Mermaid request alone does not select
mermaid.ink. Use a catalog-supported theme and replace the previous theme when
re-rendering, avoiding conflicting init and frontmatter theme declarations.

Check readable labels and edge endpoints in the actual SVG. When only a compact
PNG is initially available, let the App retrieve full SVG rather than enlarging
the raster. Inspect the new result after changing format or theme. Use the
returned Mermaid Live playground link; never fabricate its encoded state.
In plain clients, provide one image and the returned links. In Apps, keep the
chat confirmation short and use the viewer's source and download controls.