Show Diagram

Draw the thing the conversation is about, check the result, open it beside this pane.

1. Pick the source from context

Content	Source	Produces
Graph, dataflow, callstack, branch ladder	mermaid .mmd, rendered by ~/.claude/skills/charting-code-chains/scripts/render_mermaid.sh -i X.mmd -o X.png	.png
Numbers, curves, distributions, trajectories	matplotlib script run with whatever the project uses (Bazel in the monorepo, uv run elsewhere)	.png
Existing image (a plot, screenshot, render)	nothing, open it as is	the file
Small structure where the text is the picture	ASCII in a .md code block	.md

For mermaid, follow charting-code-chains for shape, labels and palette. For plots, follow dataviz. dot, d2 and plantuml aren't installed, so don't reach for them.

Build it from facts in this conversation or read from source. Mark untraced links (dashed edge, ?) instead of guessing at them.

2. Look before opening

Read the PNG back. Fix overlaps, clipped labels and mid-phrase wraps, then render again.

3. Open it

Write to the session scratchpad and keep the source next to the output. Then:

~/.claude/skills/show-diagram/scripts/open_in_pane.sh /abs/path/X.png      # beside
~/.claude/skills/show-diagram/scripts/open_in_pane.sh /abs/path/X.png -v   # below

Use -v when the image is much wider than tall. nvim shows the PNG through image.nvim: +/- zoom, hjkl pan, 0 fit. tmux resize-pane -Z gives it the full screen.

4. Report

Give the absolute path and one line on what the diagram makes obvious that the code or text doesn't. Offer to move the files into the repo; don't do it unasked.