name	diagram-generation
description	Generate self-contained HTML architecture diagrams. Use when creating visual diagrams for PRs, task plans, or architectural explanations.

Diagram Generation

Generate self-contained HTML diagrams that visualize code changes, data flows, and architecture decisions.

When to Use

Visualizing PR changes for code review
Explaining architectural decisions
Documenting data/request flows
Illustrating before/after comparisons

Output

Self-contained HTML file at {MAIN_REPO_ROOT}/diagrams/opik-{TICKET_NUMBER}-diagram.html — always resolved against the main repo root (via git rev-parse --git-common-dir), even when the session runs inside a worktree, so the file outlives the worktree
Includes "Copy as image" button for sharing in Slack, Jira, PR descriptions
Dark GitHub theme, semantic color coding, responsive layout

How to Generate

Follow the style guide in style-guide.md and use the HTML template in template.md.

Required Sections (pick what applies)

Request / Data Flow — how data moves through layers
Why This Approach — problem vs solution comparison
Files Changed by Layer — grid of affected files grouped by component
Key Design Decisions — numbered guards, trade-offs, or constraints

Section Selection

Bug fix: Focus on before/after flow, root cause, safety guards
New feature: Focus on data flow, architecture, files changed
Refactor: Focus on before/after architecture, files changed
Cross-component: Show all layers with connecting flows

Reference Files

style-guide.md — Semantic colors, box themes, section labels, flow patterns, architecture trees
template.md — Base HTML structure, copy-as-image script, section recipes

Common Gotchas

SRI hash on CDN scripts: The html2canvas <script> tag must include integrity and crossorigin attributes — see template.md for the current hash
Absolute paths for Playwright screenshots: Playwright saves relative to its own CWD, not the repo root — always use absolute paths when calling browser_take_screenshot
Max 4 sections: More than 4 sections makes diagrams too tall for screenshots and hard to scan visually
No raw diff content: Diagrams show high-level summaries (component names, file names, flow descriptions) — never embed verbatim diff hunks or Jira comments
toBlob can return null: The Canvas toBlob call in the copy-as-image script needs a null check — see template.md

Diagram Generation

Generate self-contained HTML diagrams that visualize code changes, data flows, and architecture decisions.

When to Use

Visualizing PR changes for code review

Explaining architectural decisions

Documenting data/request flows

Illustrating before/after comparisons

Output

Self-contained HTML file at {MAIN_REPO_ROOT}/diagrams/opik-{TICKET_NUMBER}-diagram.html — always resolved against the main repo root (via git rev-parse --git-common-dir), even when the session runs inside a worktree, so the file outlives the worktree

Includes "Copy as image" button for sharing in Slack, Jira, PR descriptions

Dark GitHub theme, semantic color coding, responsive layout

How to Generate

Follow the style guide in style-guide.md and use the HTML template in template.md.

Required Sections (pick what applies)

Request / Data Flow — how data moves through layers

Why This Approach — problem vs solution comparison

Files Changed by Layer — grid of affected files grouped by component

Key Design Decisions — numbered guards, trade-offs, or constraints

Section Selection

Bug fix: Focus on before/after flow, root cause, safety guards

New feature: Focus on data flow, architecture, files changed

Refactor: Focus on before/after architecture, files changed

Cross-component: Show all layers with connecting flows

Reference Files

style-guide.md — Semantic colors, box themes, section labels, flow patterns, architecture trees

template.md — Base HTML structure, copy-as-image script, section recipes

Common Gotchas

SRI hash on CDN scripts: The html2canvas <script> tag must include integrity and crossorigin attributes — see template.md for the current hash

Absolute paths for Playwright screenshots: Playwright saves relative to its own CWD, not the repo root — always use absolute paths when calling browser_take_screenshot

Max 4 sections: More than 4 sections makes diagrams too tall for screenshots and hard to scan visually

No raw diff content: Diagrams show high-level summaries (component names, file names, flow descriptions) — never embed verbatim diff hunks or Jira comments

toBlob can return null: The Canvas toBlob call in the copy-as-image script needs a null check — see template.md

diagram-generation