Night Market Skill — ported from claude-night-market/cartograph. For the full experience with agents, hooks, and commands, install the Claude Code plugin.

Data Flow Diagram#

Generate a Mermaid sequence diagram showing how data moves between components in a codebase.

When To Use#

• Tracing how a request flows through the system
• Understanding data transformation pipelines
• Documenting API call chains
• Answering "what happens when X is called?"

Workflow#

Step 1: Explore the Codebase#

Dispatch the codebase explorer agent:

text

Agent(cartograph:codebase-explorer)
Prompt: Explore [scope] and return a structural model.
Focus on function calls, data transformations, and
inter-module communication for a data flow diagram.

Step 2: Generate Mermaid Syntax#

Transform the structural model into a Mermaid sequence diagram.

Rules for data flow diagrams:

• Use sequenceDiagram for request/response flows
• Participants are modules or components (not functions)
• Arrows show data direction: ->> for calls, -->> for returns
• Use activate/ deactivate for long-running operations
• Add Note over for data transformations
• Limit to 8-10 participants maximum
• Use alt/ else for conditional flows
• Handle circular calls by showing them once with a note

Example output:

Rendering diagram...

Step 3: Render via MCP#

Call the Mermaid Chart MCP to render:

text

mcp__claude_ai_Mermaid_Chart__validate_and_render_mermaid_diagram
  prompt: "Data flow diagram of [scope/feature]"
  mermaidCode: [generated syntax]
  diagramType: "sequenceDiagram"
  clientName: "claude-code"

If rendering fails, fix syntax and retry (max 2 retries).

Step 4: Present Results#

Show the rendered diagram with a brief description of the flow depicted (2-3 sentences).