fix(mission-control): find Chrome or Chromium on Linux for the code map

.claude-plugin/marketplace.json

@@ -118,7 +118,7 @@
     {
       "name": "mission-control",
       "description": "/mission opens a live map of the main agent, its subagents and every tool call, plus a code map of the files they touch.",
-      "version": "0.1.3",
+      "version": "0.1.4",
       "source": "./mods/mission-control",
       "category": "See what's happening",
       "tags": [

docs/mods.md

@@ -34,8 +34,8 @@ Shows every Claude Code subagent, tool call and touched file in a live pane.
 
 - Press `w` for Who, `c` for Code and `q` to close
 - `/mission code` opens straight to the code map, `/mission who` to the agents
-- Headless Chrome (`/Applications/Google Chrome.app`) draws the code map as an image, in a throwaway profile
-- The Code view is macOS only and needs a terminal that shows images (Ghostty, kitty, iTerm2)
+- Headless Chrome draws the code map as an image, in a throwaway profile. It uses the first of `/Applications/Google Chrome.app` (macOS), `google-chrome-stable`, `google-chrome`, `chromium-browser` or `chromium` in `/usr/bin` (Linux)
+- The Code view runs on macOS and Linux and needs a terminal that shows images (Ghostty, kitty, iTerm2)
 - A file glows blue while Claude reads it, orange while it edits it, and turns green with a check once changed
 - One Haiku call after each turn writes the line under each changed file
 

mods/mission-control/.claude-plugin/plugin.json

@@ -1,6 +1,6 @@
 {
   "name": "mission-control",
-  "version": "0.1.3",
+  "version": "0.1.4",
   "description": "/mission opens a live map of the main agent, its subagents and every tool call, plus a code map of the files they touch.",
   "author": {
     "name": "Hamza Zafar",

mods/mission-control/hooks/register.tsx

@@ -12,7 +12,14 @@ import { label, lines, summary } from './tree'
 import { bandsFile, parseOrder, stackBands } from './bands'
 
 const PANE = 'mission-control'
-const CHROME = '/Applications/Google Chrome.app/Contents/MacOS/Google Chrome'
+// The first of these that exists draws the code map: Chrome on macOS, then Linux builds.
+const CHROMES = [
+  '/Applications/Google Chrome.app/Contents/MacOS/Google Chrome',
+  '/usr/bin/google-chrome-stable',
+  '/usr/bin/google-chrome',
+  '/usr/bin/chromium-browser',
+  '/usr/bin/chromium',
+]
 const MAX_NODES = 300
 const MAX_FILES = 14
 const BAND_AFTER_MS = 30_000 // the band stays this long after a turn ends
@@ -315,8 +322,15 @@ async function renderSoon($: EngineInterface) {
 }
 
 async function renderMap($: EngineInterface) {
-  if (!(await $.fs.exists(CHROME))) {
-    draw.error = `The code map needs Google Chrome at ${CHROME}.`
+  let chrome = ''
+  for (const path of CHROMES) {
+    if (await $.fs.exists(path)) {
+      chrome = path
+      break
+    }
+  }
+  if (!chrome) {
+    draw.error = `The code map needs Google Chrome or Chromium at one of: ${CHROMES.join(', ')}.`
     await update($, now, () => Date.now()) // redraw the pane with the message
     return
   }
@@ -335,6 +349,11 @@ async function renderMap($: EngineInterface) {
     'mkdir -p "$(dirname "$2")"; rm -f "$2"; "$1" --headless=new --disable-gpu --hide-scrollbars --force-device-scale-factor=2 --no-first-run --no-default-browser-check ' +
     '--user-data-dir="$3" --window-size="$4" --screenshot="$2" "$5" >/dev/null 2>&1 & pid=$!; ' +
     'i=0; while [ ! -s "$2" ] && [ $i -lt 150 ]; do sleep 0.1; i=$((i+1)); done; sleep 0.2; pkill -P $pid 2>/dev/null; kill $pid 2>/dev/null; [ -s "$2" ]'
-  const r = await $.process.run(['sh', '-c', script, 'mission-control', CHROME, png, `${dir}/chrome`, `${width},${height}`, `file://${encodeURI(svgPath)}`], { timeoutMs: 20_000 })
-  if (r.exitCode === 0) await update($, frame, () => ({ file: png, n }))
+  const r = await $.process.run(['sh', '-c', script, 'mission-control', chrome, png, `${dir}/chrome`, `${width},${height}`, `file://${encodeURI(svgPath)}`], { timeoutMs: 20_000 })
+  if (r.exitCode === 0) {
+    await update($, frame, () => ({ file: png, n }))
+    return
+  }
+  draw.error = `${chrome} could not draw the code map.`
+  await update($, now, () => Date.now()) // redraw the pane with the message
 }

mods/mission-control/tests/mission-control.test.tsx

@@ -9,7 +9,7 @@ const PANE = { component: 'Pane', requestId: 'mission-control', props: { title:
 const BAND = { component: 'AbovePrompt', props: { hasSurvey: false, isWorking: true, maxRows: 10, bodyColumns: 120 } }
 
 // Stands for the engine beneath the mod.
-function engine(on: any, opts: { noChrome?: boolean; bands?: string; beneath?: unknown } = {}) {
+function engine(on: any, opts: { noChrome?: boolean; chromeAt?: string; renderFails?: boolean; bands?: string; beneath?: unknown } = {}) {
   const runs: string[][] = []
   resetBandOrder()
   const writes: Record<string, string> = {}
@@ -23,9 +23,9 @@ function engine(on: any, opts: { noChrome?: boolean; bands?: string; beneath?: u
   on('tool.call', () => ({ result: {}, text: 'ok' }))
   on('fs.read', (_$: any, e: any) => ({ value: e.path.endsWith('login.tsx') ? "import { start } from '../auth/session'\n" : e.path.endsWith('/bands.json') ? opts.bands : '' }))
   on('fs.write', (_$: any, e: any) => ((writes[e.path] = e.text), { value: undefined }))
-  on('fs.exists', (_$: any, e: any) => ({ value: e.path.endsWith('/bands.json') ? opts.bands !== undefined : !opts.noChrome }))
+  on('fs.exists', (_$: any, e: any) => ({ value: e.path.endsWith('/bands.json') ? opts.bands !== undefined : opts.chromeAt !== undefined ? e.path === opts.chromeAt : !opts.noChrome }))
   on('env.get', () => ({ value: '/tmp/' }))
-  on('process.run', (_$: any, e: any) => (runs.push(e.argv), { value: { exitCode: 0, stdout: '', stderr: '' } }))
+  on('process.run', (_$: any, e: any) => (runs.push(e.argv), { value: { exitCode: opts.renderFails && e.argv[0] === 'sh' ? 1 : 0, stdout: '', stderr: '' } }))
   on('ui.open', () => ({ value: { isPlaced: true } }))
   on('ui.panes', () => ({ value: [{ id: 'mission-control', title: 'Mission Control', isShown: true, isFocused: true, isPlaced: true }] }))
   on('model.complete', () => ({ value: { isAnswered: true, text: '["tokens now expire after an hour"]', usage: { input_tokens: 1, output_tokens: 1 } } }))
@@ -73,6 +73,32 @@ describe('mission-control', () => {
     await pane.unmount()
   })
 
+  test('on Linux the code map uses Chromium when that is the browser installed', async ($, on) => {
+    const { runs } = engine(on, { chromeAt: '/usr/bin/chromium-browser' })
+    await $.session.start({ surface: 'terminal', isInteractive: true, cwd: '/repo' } as any)
+    await $.turn.start({ text: 'go', turnId: 't1' } as any)
+    await $.command.run({ command: 'mission', args: 'code' } as any)
+    const pane = await $.ui.mount({ plugin: 'mission-control', surface: 'terminal', ...PANE } as any)
+    await $.tool.call({ tool: 'Read', file_path: '/repo/src/a.ts' } as any)
+    await mockClock.advance(800)
+    expect(await pane.find({ type: 'Text', text: /needs Google Chrome/ })).toBeUndefined()
+    expect(runs.some(a => a[0] === 'sh' && a.includes('/usr/bin/chromium-browser'))).toBe(true)
+    await pane.unmount()
+  })
+
+  test('a browser that exists but cannot draw says so instead of drawing forever', async ($, on) => {
+    engine(on, { chromeAt: '/usr/bin/chromium-browser', renderFails: true })
+    await $.session.start({ surface: 'terminal', isInteractive: true, cwd: '/repo' } as any)
+    await $.turn.start({ text: 'go', turnId: 't1' } as any)
+    await $.command.run({ command: 'mission', args: 'code' } as any)
+    const pane = await $.ui.mount({ plugin: 'mission-control', surface: 'terminal', ...PANE } as any)
+    await $.tool.call({ tool: 'Read', file_path: '/repo/src/a.ts' } as any)
+    await mockClock.advance(800)
+    expect(await pane.find({ type: 'Text', text: /\/usr\/bin\/chromium-browser could not draw the code map/ })).toBeDefined()
+    expect(await pane.find({ type: 'Image' })).toBeUndefined()
+    await pane.unmount()
+  })
+
   test('a background agent still running keeps its open calls when main ends', async ($, on) => {
     engine(on)
     await $.session.start({ surface: 'terminal', isInteractive: true, cwd: '/repo' } as any)