diff --git a/src/commands.ts b/src/commands.ts
index 57b522b..e604458 100644
--- a/src/commands.ts
+++ b/src/commands.ts
@@ -13,6 +13,7 @@ import { addTraceFile, getWorkspacePath, openTerminal, openTraceDirectoryExterna
 import { addTraceDiagnostics, clearTaceDiagnostics } from './traceDiagnostics'
 import { setStatusBarState } from './statusBar'
 import { afterWatches, projectPath, saveName, state, traceFiles, traceRunning } from './appState'
+import { buildTraceCommand, resolveTraceShell } from './shell'
 
 const readdir = promisify(readdirC)
 
@@ -128,9 +129,11 @@ async function runTrace(args?: unknown[]) {
       return
     }
 
-    const quotedTraceDir = `'${traceDir}'`
-    // eslint-disable-next-line no-template-curly-in-string
-    const fullCmd = `(cd '${newDirName ?? workspacePath}'; ${traceCmd.replace('${traceDir}', quotedTraceDir)})`
+    const shell = resolveTraceShell(process.env.SHELL)
+    const fullCmd = buildTraceCommand(traceCmd, traceDir, {
+      platform: process.platform,
+      shell: typeof shell === 'string' ? shell : undefined,
+    })
 
     log(fullCmd)
 
@@ -147,8 +150,8 @@ async function runTrace(args?: unknown[]) {
 
     setStatusBarState('traceError', false)
 
-    log(`shell: ${process.env.SHELL}`)
-    const cmdProcess = spawn(fullCmd, [], { cwd: newProjectPath, shell: process.env.SHELL })
+    log(`shell: ${typeof shell === 'string' ? shell : '<default>'}`)
+    const cmdProcess = spawn(fullCmd, [], { cwd: newProjectPath, shell })
 
     let err = ''
     cmdProcess.stderr.on('data', data => err += data.toString())
diff --git a/src/shell.ts b/src/shell.ts
new file mode 100644
index 0000000..f245e09
--- /dev/null
+++ b/src/shell.ts
@@ -0,0 +1,29 @@
+import process from 'node:process'
+
+const posixShellPattern = /(?:^|[\\/])(?:bash|dash|fish|ksh|sh|zsh)(?:\.exe)?$/i
+const traceDirPlaceholder = '${' + 'traceDir}'
+
+export function shouldUsePosixQuoting(platform: NodeJS.Platform, shell?: string) {
+  if (shell && posixShellPattern.test(shell))
+    return true
+
+  return platform !== 'win32'
+}
+
+export function quoteForShell(value: string, opts?: { platform?: NodeJS.Platform, shell?: string }) {
+  const platform = opts?.platform ?? process.platform
+  const shell = opts?.shell
+
+  if (!shouldUsePosixQuoting(platform, shell))
+    return `"${value.replace(/"/g, '""')}"`
+
+  return `'${value.replace(/'/g, `'\\''`)}'`
+}
+
+export function buildTraceCommand(traceCmd: string, traceDir: string, opts?: { platform?: NodeJS.Platform, shell?: string }) {
+  return traceCmd.replace(traceDirPlaceholder, quoteForShell(traceDir, opts))
+}
+
+export function resolveTraceShell(shell?: string): string | true {
+  return shell || true
+}
diff --git a/test/index.test.ts b/test/index.test.ts
index 401553c..00e8c71 100644
--- a/test/index.test.ts
+++ b/test/index.test.ts
@@ -1,7 +1,36 @@
 import { describe, expect, it } from 'vitest'
+import { buildTraceCommand, quoteForShell, resolveTraceShell, shouldUsePosixQuoting } from '../src/shell'
 
-describe('should', () => {
-  it('exported', () => {
-    expect(1).toEqual(1)
+describe('shell helpers', () => {
+  const traceCmd = 'npx tsc --generateTrace ' + '${' + 'traceDir}'
+
+  it('uses default Windows quoting when no explicit shell is configured', () => {
+    expect(buildTraceCommand(traceCmd, 'C:\\Users\\me\\trace dir', { platform: 'win32' }))
+      .toBe('npx tsc --generateTrace "C:\\Users\\me\\trace dir"')
+  })
+
+  it('uses POSIX quoting when the configured shell is bash on Windows', () => {
+    expect(buildTraceCommand(traceCmd, 'C:\\Users\\me\\trace dir', {
+      platform: 'win32',
+      shell: 'C:\\Program Files\\Git\\bin\\bash.exe',
+    })).toBe(`npx tsc --generateTrace 'C:\\Users\\me\\trace dir'`)
+  })
+
+  it('escapes single quotes for POSIX shells', () => {
+    expect(quoteForShell(`/tmp/it's here`, { platform: 'linux' })).toBe(`'/tmp/it'\\''s here'`)
+  })
+
+  it('falls back to the platform default shell when SHELL is absent', () => {
+    expect(resolveTraceShell()).toBe(true)
+  })
+
+  it('keeps an explicit shell path when provided', () => {
+    expect(resolveTraceShell('/bin/zsh')).toBe('/bin/zsh')
+  })
+
+  it('detects POSIX shells from the shell executable path', () => {
+    expect(shouldUsePosixQuoting('win32', 'C:\\Program Files\\Git\\bin\\bash.exe')).toBe(true)
+    expect(shouldUsePosixQuoting('linux')).toBe(true)
+    expect(shouldUsePosixQuoting('win32')).toBe(false)
   })
 })