mermaid-architect

name	mermaid-architect
description	Scan a codebase and auto-generate relevant diagrams from its structure
argument-hint	["path"]
allowed-tools	Read, Bash, Glob, Grep, Write, Edit

/mermaid-architect

User request: "$ARGUMENTS"

Task

Analyze a codebase or project path and generate a relevant suite of Mermaid diagrams (typically 3-5 types based on what's found).

Difference from /mermaid-diagram

• /mermaid-diagram generates one diagram from a text description
• /mermaid-architect generates multiple diagrams from actual code/files at a given path

Process

Step 1: Resolve Plugin Path

find "$HOME/.claude/plugins/cache" -type d -name "mermaid" -path "*/skills/mermaid" 2>/dev/null | head -1

If empty:

find "$HOME" -maxdepth 8 -type d -name "mermaid" -path "*/skills/mermaid" 2>/dev/null | head -1

Step 2: Ensure Dependencies

bash "$PLUGIN_DIR/scripts/ensure-deps.sh"

If .claude/mermaid.json does not exist, display a one-time nudge before continuing:

First time using the mermaid plugin? Run /mermaid-config to pick a theme and output settings. Using defaults for now (zinc-light, ./diagrams).

Step 3: Read Config

If .claude/mermaid.json exists, read output_directory, theme, auto_validate, auto_render.

Resolve output path:

• If output_directory is "same" AND an input path is known: OUTPUT_DIR=$(dirname {input_file}) (for a directory argument, use the directory itself)
• If output_directory is "same" AND no argument was provided: OUTPUT_DIR=./diagrams
• Otherwise: OUTPUT_DIR=<output_directory from config>

Theme-First Rule

Respect the configured theme/themeVariables as the visual source of truth.

• Do not emit hardcoded classDef fill/stroke/color by default.
• Only add explicit color overrides if the user asks for a custom palette or semantic color coding.

Step 4: Resolve Target Path

• If no argument, use current directory.
• If argument is a file, analyze that single file.
• If argument is a directory, explore it.

Step 5: Explore Codebase

Run these to understand what's present:

find {path} \( -name "*.py" -o -name "*.ts" -o -name "*.js" -o -name "*.rb" -o -name "*.go" \) | grep -v node_modules | head -50
find {path} \( -name "*.sql" -o -name "*.prisma" -o -name "*schema*" \) | grep -v node_modules | head -20
find {path} \( -name "routes*" -o -name "router*" -o -name "urls*" \) | grep -v node_modules | head -20

Read key files to understand the domain (models, routes, services, main entry point).

Step 6: Infer Diagram Types

Based on what's found:

Found	Generates
Database models / ORM / schema files	ER diagram
API routes / controllers / endpoints	Sequence diagram (request flow)
Service classes / modules	Architecture diagram
State/lifecycle fields (status, state)	State diagram
Config / deployment files (docker, k8s, cloud)	Deployment diagram
Class files with inheritance	Class diagram

Select 3-5 most relevant types. Do not generate all 7 unless the codebase clearly warrants it.

Step 7: Generate Each Diagram

For each selected type, load the specialist:

cat "$PLUGIN_DIR/specialists/mermaid-{type}.md"

Follow the specialist's Process section using the actual code found in Step 4 as input. Generate diagram content from real code, not hypothetical examples.

Theme handling for rendering

When rendering diagrams in Step 9:

• If theme == "custom" and themeVariables is present in config: Pass --custom-theme '{serialized themeVariables JSON}' to the render script.

• If theme == "custom" but themeVariables is absent from config: Render without custom theme and display a note:

  Custom theme configured but no themeVariables found — run /mermaid-config → option 6 to define colors.

• Otherwise: pass --theme {theme} to the render script.

Step 8: Validate

For each generated diagram:

node "$PLUGIN_DIR/scripts/extract_mermaid.js" {output_file} --validate

Fix any errors using $PLUGIN_DIR/references/guides/troubleshooting.md.

Step 9: Render (if auto_render=true or user requests)

Apply theme handling from the section above:

# Named theme:
node "$PLUGIN_DIR/scripts/resilient_diagram.js" {file} --output-dir $OUTPUT_DIR --theme {theme}
# Custom theme:
node "$PLUGIN_DIR/scripts/resilient_diagram.js" {file} --output-dir $OUTPUT_DIR --custom-theme '{serialized themeVariables JSON}'

If the script fails (Node.js not found, node_modules missing): stop and tell the user to run /mermaid-config → option 7 (health check) to diagnose missing dependencies.

Step 10: Report

Analyzed: {path}
Generated {N} diagrams:

  ✅ $OUTPUT_DIR/er-{name}-{timestamp}.mmd       (ER — 5 entities, 7 relationships)
  ✅ $OUTPUT_DIR/sequence-{name}-{timestamp}.mmd  (Sequence — 4 actors, 8 messages)
  ✅ $OUTPUT_DIR/architecture-{name}-{timestamp}.mmd (Architecture — 6 components)

Validation: all passed

Step 11: Offer design document (opt-in)

If 3 or more diagrams were generated, offer to assemble them into a system design document:

💡 Generated {N} diagrams — want me to assemble them into a system design document?
   I'll use the system-design-template and embed each diagram in the relevant section.

If user accepts:

1. Read $PLUGIN_DIR/assets/system-design-template.md
2. Embed each generated diagram in its matching section (architecture → Architecture Overview, ER → Data Architecture, sequence → API Flow, etc.)
3. Fill metadata placeholders with the analyzed path and codebase context
4. Save to $OUTPUT_DIR/{project-name}-system-design.md

If fewer than 3 diagrams: skip silently.

Common Mistakes

• Generating all 7 diagram types when the codebase only warrants 3-4. Select only the types that have clear evidence in the code.
• Empty PLUGIN_DIR — if both find commands return nothing, stop and report: "Plugin not found. Is it installed? Run /plugin install mermaid@claude-toolshed."
• Analyzing node_modules or build directories — always exclude with -not -path "*/node_modules/*" and -not -path "*/dist/*".
• Generating from file headers only — read actual function bodies, model fields, and route handlers before inferring diagram type. Surface-level file names can mislead.