claude-context-bar

A Claude Code mod that draws the context window as a stacked bar under the prompt.

• Header: tokens used, the window's size, where autocompaction starts, and the share used. The share's badge is green, then yellow from 60% of the way to compaction, then red from 85%.
• Bar: one coloured run per /context category, then the free space, a mark where autocompaction starts, and the buffer held back beyond it. Boundaries fall on half cells.
• Legend: each category with its token count and share of the window, then the free space and the autocompact buffer.

The bar grows from empty when it appears and slides to its new values when the context changes. While a compaction runs, the messages dim; when it is done, they take their colour back as the bar slides down to what is left.

Install

Run this in a terminal:

claude plugin marketplace add ContextLab/claude-context-bar && claude plugin install context-bar@claude-context-bar

Then start a new Claude Code session. The bar appears under the prompt.

Use

• The bar updates as the context changes.
• During a compaction (/compact or an automatic one) the messages dim, and the bar moves to the compacted size as soon as it is done.
• /context-bar hides the bar; running it again shows it.

The token counts are Claude Code's local estimates (the same summary /context starts from), so the mod sends no extra requests.

Claude Code clips what is drawn under the prompt on a short terminal, so the mod draws less there: the whole box from about 24 rows, the box without its legend from 20, and the header and bar alone below that. A change in the terminal's height takes effect the next time the bar redraws.

The category colours are fixed; the free space and buffer follow a light or dark theme.

Uninstall

claude plugin uninstall context-bar@claude-context-bar && claude plugin marketplace remove claude-context-bar

Develop

The mod is a hooks module with no build step and no dependencies.

Path	What it holds
hooks/register.tsx	The hooks: the /context-bar command, the refresh on context changes and compactions, the animation, and the drawing
hooks/cells.ts	Splitting the bar's width among categories, half-cell painting, colour blending, formatting, easing, and fitting the drawing to the terminal's height
hooks/register.test.ts	Tests
types/index.d.ts	The mod's state contract
.claude-plugin/	The plugin manifest and the marketplace file that makes this repository installable

Run it from a clone, then test and validate:

claude --plugin-dir .      # load the mod from this folder for one session
claude plugin test .       # run the tests
claude plugin validate .   # check the manifests and the hooks module

Loading the mod writes Claude Code's type definitions to .claude-plugin/types/ (git-ignored); after that, npx -p typescript tsc -p . type-checks it.

Credit

The idea for this mod comes from the "Claude Code Mods" documentation, Getting started with Claude Code mods. The context bar example is no longer on that page; it appeared in the newsletter version of the post.