# Draw Io > Create, read, edit, and open draw.io (.drawio) files. Supports architecture diagrams, ER diagrams, flowcharts, domain model diagrams, and more. Use when requests include "create a diagram", "make a flowchart", "draw an architecture diagram", "create an ER diagram", "open a .drawio file", "what's in this diagram?", etc. Do NOT use for Mermaid or PlantUML generation. - Skill: `little-hands/draw-io` (Agent Skill, multi-file: 5 files) - Install (CLI): `npx skillmds@latest add little-hands/draw-io` - Raw SKILL.md: https://api.skillmd.com/api/skills/little-hands/draw-io/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: AI & ML - Author: little-hands (https://skillmd.com/u/little-hands) - Updated: 2026-09-22 - Page: https://skillmd.com/skills/little-hands/draw-io --- # draw.io Diagram Skill Create, read, and edit diagrams in draw.io format (.drawio). ## Supported Diagram Types (Examples) - Architecture diagrams - Domain model diagrams - Object diagrams - ER diagrams - Flowcharts - Wireframes - Sequence diagrams - Class diagrams Any other diagram type that can be expressed in draw.io is also supported. ## Workflow ### 1. Read (Reference during development) Read domain model or architecture diagrams and use them as development context. **Trigger examples:** "Check the domain model", "Read the design diagram", "Reference the architecture", "What's in this diagram?" **Steps:** 1. **Load reference files**: Read the following - [references/xml-reference.md](references/xml-reference.md) — mxCell patterns, parsing examples 2. Use `Glob` to search for `.drawio` files 3. Use `Read` to load the XML 4. Extract information from `mxCell` attributes: - `value` attribute: labels (entity names, method names, etc.) - `parent` attribute: parent-child relationships (group membership) - `source`/`target` attributes: edge connections - `fillColor` in `style` attribute: element classification (color-based) 5. Output a structured summary ### 2. Create / Edit Create new diagrams or update existing `.drawio` files. **Trigger examples:** "Create a diagram", "Make a flowchart", "Draw an architecture diagram", "Create an ER diagram", "Update the diagram", "Add an entity", "Change a relationship" **Steps:** 1. **Clarify requirements**: Confirm the diagram type and elements to include with the user 2. **Load reference files**: **Always** load the following before starting work - [references/xml-reference.md](references/xml-reference.md) — mxCell patterns, styles, color palette - [references/layout-guide.md](references/layout-guide.md) — layout principles, coordinate calculations 3. **Check existing files**: Use `Glob` to search for the target `.drawio` file - **File exists** → Use `Read` to get the XML and check existing IDs - **No file** → Proceed as a new creation 4. **List elements**: Enumerate boxes, relationships, and groups 5. **Generate / Edit XML**: - **New creation**: Combine the base structure template with mxCells, and save as `.drawio` using `Write` - **Editing existing**: Assign new IDs that don't conflict with existing ones, and update the XML using `Edit` 6. **Show path**: Display the file path to the user (do not open automatically) ### 3. Open in Desktop App **Trigger examples:** "Open this file", "Open the .drawio file", "Open the diagram" **Steps:** 1. Identify the file path (if not specified, use `Glob` to search for `.drawio` files) 2. Run `open -a "draw.io" ` using `Bash` Prerequisite: draw.io must be installed via `brew install --cask drawio` ## XML Base Structure **Important:** Always specify `darkMode="0"`. This disables Adaptive Colors, preventing color inversion when opened in a dark-mode editor, and maintains light-mode colors during SVG/PNG export. ```xml ``` For multiple pages, add multiple `` elements. Specify `darkMode="0"` in each ``. ## Important Constraints - **Always specify `darkMode="0"`** — omitting it causes color inversion in dark mode - **Keep IDs unique** — manage with prefixes like `box1`, `edge1` - **Use ` ` for line breaks** — for text line breaks within XML - **Specify parent-child relationships with the `parent` attribute** — coordinates of child elements within a group are relative to the parent - **`vertex="1"` for shapes, `edge="1"` for edges** - **Do not open after editing** — only display the file path; open only when the user explicitly asks - **Do not include `--` in XML comments** — ` Customer -->` causes an XML error; write as `` ## Troubleshooting ### XML Parse Error **Cause:** `--` is included in a comment **Fix:** Avoid `--` as in ``. See the beginning of [references/xml-reference.md](references/xml-reference.md) for details ### Colors Inverted in Dark Mode **Cause:** Missing `darkMode="0"` specification **Fix:** Add `darkMode="0"` to ``. For multiple pages, specify it on all pages ### Shapes Overlapping / Edges Crossing **Cause:** Layout calculation issues **Fix:** Check layout principles in [references/layout-guide.md](references/layout-guide.md). Distribute edge connection points using `exitX`/`exitY`/`entryX`/`entryY` ### Rendering Broken Due to Duplicate IDs **Cause:** Multiple mxCells with the same ID exist **Fix:** Check existing IDs before editing and assign unique IDs ### draw.io App Won't Open **Cause:** draw.io desktop app is not installed **Fix:** Install with `brew install --cask drawio` ## Reference Files - **XML Patterns & Styles** → [references/xml-reference.md](references/xml-reference.md) Contents: mxCell patterns (rectangle, text, edge, group, DB, stack layout), style attributes, color palette, edge styles, custom properties, connection points, parsing examples for reading **Load for reading, creating, and editing** - **Layout Guide** → [references/layout-guide.md](references/layout-guide.md) Contents: Layout principles, coordinate calculations, placement patterns, boundary coordinate calculations **Load for creating and editing**