cc-sidecar by HoshimuraYuto: Claude Code mod code and design

What it does

Draws a pane
Watches Bash calls and can refuse them
Hooks config.set, session.start, ui.press
Keeps its own state between turns

Good points

No network calls
Starts no processes
Written in TypeScript
Handles errors

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 cc-sidecar by HoshimuraYuto (pane), as modscode read it from the mod's code:
// https://modscode.com/gallery/hoshimurayuto-cc-sidecar/
// 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 pane: open it with $.ui.open({ id: 'my-pane', title: "Sidecar" })
  on('ui.render', { component: 'Pane', requestId: 'my-pane' }, async ($, e) => {
    const { Box, Text, Button } = $.ui.resolve(e)
    const glyph = '…'
    const index = '…'
    const label = '…'
    const mark = '…'
    const elapsed = '…'
    const steps = '…'
    const clamp = '…'
    const kindGlyph = '…'
    const clamp2 = '…'
    const glyph2 = '…'
    const mark2 = '…'
    const elapsed2 = '…'
    const steps2 = '…'
    const clamp3 = '…'
    const kindGlyph2 = '…'
    const clamp4 = '…'
    const glyph3 = '…'
    const mark3 = '…'
    const elapsed3 = '…'
    const steps3 = '…'
    const clamp5 = '…'
    const kindGlyph3 = '…'
    const clamp6 = '…'
    return (
      <Box flexDirection="column" paddingX={1}>
        <Box flexDirection="column">
          <Box flexDirection="row" gap={1}>
            <Text bold>
              {glyph}
            </Text>
            <Button plain hotkey={`${index}`} label={`${label}`} />
            <Text>
              {mark}
            </Text>
            <Text dimColor>
              {elapsed}
            </Text>
            <Text dimColor>
              {"· "}
              {steps}
            </Text>
            <Text dimColor>
              {"· "}
              {clamp}
            </Text>
          </Box>
          <Box flexDirection="row" gap={1} paddingLeft={2}>
            <Text dimColor>
              {kindGlyph}
            </Text>
            <Text wrap="wrap">
              {clamp2}
            </Text>
          </Box>
        </Box>
        <Box flexDirection="column">
          <Box flexDirection="row" gap={1}>
            <Text bold>
              {glyph2}
            </Text>
            <Button plain hotkey={`${index}`} label={`${label}`} />
            <Text>
              {mark2}
            </Text>
            <Text dimColor>
              {elapsed2}
            </Text>
            <Text dimColor>
              {"· "}
              {steps2}
            </Text>
            <Text dimColor>
              {"· "}
              {clamp3}
            </Text>
          </Box>
          <Box flexDirection="row" gap={1} paddingLeft={2}>
            <Text dimColor>
              {kindGlyph2}
            </Text>
            <Text wrap="wrap">
              {clamp4}
            </Text>
          </Box>
        </Box>
        <Box flexDirection="column">
          <Box flexDirection="row" gap={1}>
            <Text bold>
              {glyph3}
            </Text>
            <Button plain hotkey={`${index}`} label={`${label}`} />
            <Text>
              {mark3}
            </Text>
            <Text dimColor>
              {elapsed3}
            </Text>
            <Text dimColor>
              {"· "}
              {steps3}
            </Text>
            <Text dimColor>
              {"· "}
              {clamp5}
            </Text>
          </Box>
          <Box flexDirection="row" gap={1} paddingLeft={2}>
            <Text dimColor>
              {kindGlyph3}
            </Text>
            <Text wrap="wrap">
              {clamp6}
            </Text>
          </Box>
        </Box>
        <Text dimColor>
          1-9 open a run · esc back to the prompt
        </Text>
      </Box>
    )
  })
}

The mod's own code

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

hooks/hooks.tsx lines 759–870 · Pane

hooks/hooks.tsx:759

  on('ui.render', { component: 'Pane', requestId: PANE_ID }, ($, e) => {
    void announce($);
    const { Box, Text, Button } = $.ui.resolve(e);
    const props = (e.props as any) ?? {};
    const width = Math.max(30, (props.bodyColumns ?? 60) - 4);
    const detail = viewing ? runs.get(viewing) : undefined;

    if (detail) {
      const agent = agentOf(detail);
      const entries = detail.history.slice(-DETAIL_ROWS);
      const offset = detail.history.length - entries.length;
      return (
        <Box flexDirection="column" paddingX={1}>
          <Box flexDirection="row" gap={1}>
            <Button key="back" plain hotkey="b" label="← back" onPress={noop} />
            <Text color={agent.color} bold>
              {agent.glyph} {agent.label}
            </Text>
            <Text color={markColor(detail)}>{mark(detail)}</Text>
            <Text dimColor>{elapsed(detail)}</Text>
            {detail.steps > 0 ? <Text dimColor>· {steps(detail)}</Text> : null}
            {detail.model ? <Text dimColor>· {detail.model}</Text> : null}
          </Box>
          <Text dimColor wrap="truncate-end">
            {detail.command}
          </Text>
          {detail.threadId ? (
            <Text dimColor wrap="truncate-end">
              resume: {resumeLine(detail.key, detail.threadId)}
            </Text>
          ) : null}
          <Text> </Text>
          {entries.length === 0 ? (
            <Text dimColor>Nothing recorded yet.</Text>
          ) : (
            entries.map((entry, index) => (
              <Box flexDirection="row" gap={1}>
                <Text dimColor>
                  {String(offset + index + 1).padStart(3, ' ')}
                </Text>
                <Text dimColor>{kindGlyph(entry)}</Text>
                <Text
                  color={kindColor(entry)}
                  dimColor={entry.kind === 'think'}
                  wrap="wrap"
                >
                  {entry.text}
                </Text>
              </Box>
            ))
          )}
        </Box>
      );
    }

    const rows = live();
    return (
      <Box flexDirection="column" paddingX={1}>
        {rows.length === 0 ? (
          <Box flexDirection="column">
            <Text dimColor>No agent CLI is running.</Text>
            <Text dimColor>
              Runs of codex exec, claude -p and gemini -p show up here.
            </Text>
          </Box>
        ) : (
          rows.map((run, index) => {
            const agent = agentOf(run);
            return (
              <Box flexDirection="column">
                <Box flexDirection="row" gap={1}>
                  <Text color={agent.color} bold>
                    {agent.glyph}
                  </Text>
                  <Button
                    key={`row:${run.id}`}
                    plain
                    hotkey={index < 9 ? String(index + 1) : undefined}
                    label={agent.label.padEnd(8)}
                    onPress={noop}
                  />
                  <Text color={markColor(run)}>{mark(run)}</Text>
                  <Text dimColor>{elapsed(run)}</Text>
                  {run.steps > 0 ? <Text dimColor>· {steps(run)}</Text> : null}
                  {run.model ? (
                    <Text dimColor>· {clamp(run.model, 24)}</Text>
                  ) : null}
                </Box>
                <Box flexDirection="row" gap={1} paddingLeft={2}>
                  <Text dimColor>{kindGlyph(run.activity)}</Text>
                  <Text
                    color={kindColor(run.activity)}
                    dimColor={run.activity.kind === 'think'}
                    wrap="wrap"
                  >
                    {clamp(run.activity.text, width * 2 - 4)}
                  </Text>
                </Box>
              </Box>
            );
          })
        )}
        {rows.length > 0 ? (
          <Text dimColor>
            {props.isFocused === true
              ? '1-9 open a run · esc back to the prompt'
              : 'ctrl+x tab to focus · 1-9 open a run · /cc-sidecar for modes'}
          </Text>
        ) : null}
      </Box>
    );
  });

Licence text (MIT)

MIT License

Copyright (c) 2026 HoshimuraYuto

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

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 OR COPYRIGHT HOLDERS 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.

What its code calls

writes filesenv varstool callsremembers

What its code shows

Read from the source at commit eebf61210104 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.hooks/hooks.tsx
Parses	Every file parses as TypeScript or JavaScript.1 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.listed in its repository's .claude-plugin/marketplace.json: installs from there
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.MIT

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 is its marketplace. Add that marketplace (in the terminal with these commands, or in the desktop app's plugin settings) and install the mod from it:

/plugin marketplace add HoshimuraYuto/cc-sidecar

/plugin install cc-sidecar@cc-sidecar

This installs the marketplace's latest commit, which may not be the one read here (eebf61210104). Compare them before you install.

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 "hoshimurayuto-cc-sidecar" with its code and make me a pane like it

Search them from Claude: the MCP connector