context-bar by MattLewin: Claude Code mod code and design

What it does

Draws a band above the prompt
Adds /context-bar
Hooks session.compact, session.measure, session.start
Keeps its own state between turns

Good points

No network calls
Starts no processes
Small: 277 lines
Written in TypeScript

Code to start from

Two kinds: a starter modscode writes from the design above, and the lines of the mod's own code that draw it.

Starter (register.tsx)

import type { Register } from 'claude-code'

// Drawn like context-bar by MattLewin (band), as modscode read it from the mod's code:
// https://modscode.com/gallery/mattlewin-context-bar/
// Written by modscode from that reading, not copied from the mod: use it as you like.
// Each value below stands for one the mod works out at run time; put in your own.
export const register: Register = on => {
  // the band above the prompt; what else goes there is drawn under it
  on('ui.render', { component: 'AbovePrompt' }, async ($, e, next) => {
    const { Box, Text } = $.ui.resolve(e)
    const glyph = '…'
    const glyph2 = '…'
    const glyph3 = '…'
    const label = '…'
    const glyph4 = '…'
    const name = '…'
    const tokens = '…'
    const percent = '…'
    const glyph5 = '…'
    const name2 = '…'
    const tokens2 = '…'
    const percent2 = '…'
    const glyph6 = '…'
    const name3 = '…'
    const tokens3 = '…'
    const percent3 = '…'
    return (
      <Box flexDirection="column">
        <Box flexDirection="row">
          <Text>
            {glyph}
          </Text>
          <Text>
            {glyph2}
          </Text>
          <Text>
            {glyph3}
          </Text>
          <Text dimColor>
            {label}
          </Text>
        </Box>
        <Box flexDirection="row">
          <Text>
            {glyph4}
            {" "}
          </Text>
          <Text>
            {name}
            {" "}
          </Text>
          <Text dimColor>
            {tokens}
            {" tokens "}
          </Text>
          <Text>
            {percent}
          </Text>
        </Box>
        <Box flexDirection="row">
          <Text>
            {glyph5}
            {" "}
          </Text>
          <Text>
            {name2}
            {" "}
          </Text>
          <Text dimColor>
            {tokens2}
            {" tokens "}
          </Text>
          <Text>
            {percent2}
          </Text>
        </Box>
        <Box flexDirection="row">
          <Text>
            {glyph6}
            {" "}
          </Text>
          <Text>
            {name3}
            {" "}
          </Text>
          <Text dimColor>
            {tokens3}
            {" tokens "}
          </Text>
          <Text>
            {percent3}
          </Text>
        </Box>
        {await next(e)}
      </Box>
    )
  })
}

The mod's own code

Shown under the mod's licence (Unlicense); its text is below. Keep the notice if you copy these lines.

misc/dot-claude/mods/context-bar/hooks/register.tsx lines 105–156 · Band

misc/dot-claude/mods/context-bar/hooks/register.tsx:105

  on('ui.render', { component: 'AbovePrompt' }, async ($, e, next) => {
    const shown = await read($, mode)
    if (e.props.hasSurvey || shown === 'off') {
      return next(e)
    }
    const snap = await read($, snapshot)
    if (!snap) {
      return next(e)
    }

    const { Box, Text } = $.ui.resolve(e)
    const label = ` ${snap.percentage}% ${compact(snap.totalTokens)}/${compact(snap.maxTokens)}`
    const width = Math.max(10, e.props.bodyColumns - label.length - 1)
    const segments = layout(snap.categories, snap.maxTokens, width)
    const bar = (
      <Box key="bar" flexDirection="row">
        {segments.map(s => (
          <Text
            key={s.name}
            color={s.color}
            dimColor={s.kind === 'free'}
          >
            {glyph(s.kind).repeat(s.cells)}
          </Text>
        ))}
        <Text dimColor>{label}</Text>
      </Box>
    )
    if (shown === 'on') {
      return bar
    }

    const rows = details(snap.categories, snap.maxTokens)
    const nameWidth = Math.max(...rows.map(r => r.name.length))
    const tokenWidth = Math.max(...rows.map(r => r.tokens.length))

    return (
      <Box flexDirection="column">
        {bar}
        {rows.map(r => (
          <Box key={r.name} flexDirection="row">
            <Text color={r.color} dimColor={r.kind === 'free'}>
              {glyph(r.kind).repeat(2)}{' '}
            </Text>
            <Text>{r.name.padEnd(nameWidth)}  </Text>
            <Text dimColor>{r.tokens.padStart(tokenWidth)} tokens  </Text>
            <Text>{r.percent.padStart(6)}</Text>
          </Box>
        ))}
      </Box>
    )
  })

Licence text (Unlicense)

This is free and unencumbered software released into the public domain.

Anyone is free to copy, modify, publish, use, compile, sell, or
distribute this software, either in source code form or as a compiled
binary, for any purpose, commercial or non-commercial, and by any
means.

In jurisdictions that recognize copyright laws, the author or authors
of this software dedicate any and all copyright interest in the
software to the public domain. We make this dedication for the benefit
of the public at large and to the detriment of our heirs and
successors. We intend this dedication to be an overt act of
relinquishment in perpetuity of all present and future rights to this
software under copyright law.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.

For more information, please refer to <http://unlicense.org>

What its code calls

remembers

The design, read from code

Claude — Code

●●●build

● build 12.4 tokens 42%

Ask Claude…

Drawn from the mod's source at the commit read, not from a run: a list is drawn three times, a condition takes its first branch that draws in the desktop app, and a value only the run time knows is shown as a made-up sample (dotted underline) or left out. Colours and type are this site's.

What its code shows

Read from the source at commit 23230af14f49 on 2026-10-06. The first group decides whether a mod is listed; the rest is for you to weigh. A later commit is not read until the next crawl.

Decides the listing: code you can check
Entry read	Every module hooks/hooks.json names was read.misc/dot-claude/mods/context-bar/hooks/register.tsx
Parses	Every file parses as TypeScript or JavaScript.2 files parsed
All its code is in the mod	Every import is a file of the mod or the engine's own module; no packages, no require.all its code is in the mod
Readable	No minified lines, no eval or new Function, no import of a computed path, no encoded blobs.no minified code, no eval, no encoded blobs
Calls in the open	Network and programs are reached as $.http.fetch and $.process.run in place, never passed around.every call outside goes through $ in the open
For you to weigh before installing
Where it draws	The terminal, the desktop app, both, or nothing (hooks only: a guard or a prompt rewriter), as its code says. Shown, never a reason to leave a mod out.draws in the terminal and the desktop app, the same in both
Install line	Whether its repository's own .claude-plugin/marketplace.json lists it, so it installs from that marketplace with the lines on its page.its repository's .claude-plugin/marketplace.json does not list it: no install line to give
Programs on Windows	Whether every program it starts through $.process exists on Windows (tail, date, open, osascript, /usr/… do not).runs no program a Windows PC lacks
Network	Whether every fetch names its https host in the code.no network
Programs	Whether every program it starts is named in the code and is not a shell, an interpreter or a network tool.starts no programs
Reads and sends	Whether it both reads files or environment variables and reaches the network.reaches no network
Keys in the source	Whether the source holds what looks like an API key or a private key.no keys in the source
Licence	An open licence (MIT, Apache-2.0, BSD, ISC, Unlicense, 0BSD, CC0) with its text lets modscode show its code; otherwise the code is linked.Unlicense

This is a reading of the code text, not a security review: it does not run the mod, and it cannot see what a program the mod starts does. The check before installing is yours. How mods are chosen

Install it

Check it yourself before you install it. Mods run unsandboxed, with your permissions, and modscode does not vouch for what this code does. Read the code below (or run claude plugin validate . in its folder), weigh what it reaches, and install the commit you read.

Its repository's .claude-plugin/marketplace.json does not list it, so there is no install line to give. Read it as code, or follow its author's README.

Ask Claude about it

With the modscode connector added, Claude can read this design, what its code reaches and its code, and build on them. Ask it like this:

Read the modscode design "mattlewin-context-bar" with its code and make me a pane like it

Search them from Claude: the MCP connector