fix(cli): preserve PowerShell prologues

packages/opencode/src/kilocode/shell/shell.ts

@@ -2,9 +2,81 @@ export function args(command: string) {
   return ["-NoLogo", "-NoProfile", "-NonInteractive", "-Command", script(command)]
 }
 
-function script(command: string) {
-  return `[Console]::InputEncoding = [System.Text.UTF8Encoding]::new($false);
+const setup = `[Console]::InputEncoding = [System.Text.UTF8Encoding]::new($false);
 [Console]::OutputEncoding = [System.Text.UTF8Encoding]::new($false);
 $OutputEncoding = [Console]::OutputEncoding;
-${command}`
+`
+
+function script(command: string) {
+  const pos = prologue(command)
+  const head = command.slice(0, pos)
+  const body = command.slice(pos)
+  const gap = head && !/[;\r\n]\s*$/.test(head) ? "\n" : ""
+  return `${head}${gap}${setup}${body}`
+}
+
+function prologue(command: string) {
+  const pos = scan(command, 0)
+  const body = command.slice(pos)
+  const match = /^\s*param\s*\(/i.exec(body)
+  if (!match) return pos
+
+  const start = match[0].lastIndexOf("(")
+  const end = block(body, start)
+  if (end === undefined) return pos
+  return pos + end
+}
+
+function scan(command: string, start: number) {
+  let pos = start
+  while (pos < command.length) {
+    const end = line(command, pos)
+    const value = command.slice(pos, end)
+    const text = value.trimStart()
+    if (text.trim() === "" || text.startsWith("#") || /^using\s+(?:assembly|module|namespace|type)\b/i.test(text)) {
+      pos = end
+      continue
+    }
+    return pos
+  }
+  return pos
+}
+
+function line(command: string, start: number) {
+  const index = command.indexOf("\n", start)
+  if (index === -1) return command.length
+  return index + 1
+}
+
+function block(command: string, start: number) {
+  let depth = 0
+  let quote: string | undefined
+  for (let pos = start; pos < command.length; pos++) {
+    const char = command[pos]
+    if (quote) {
+      if (quote === "'" && char === "'" && command[pos + 1] === "'") {
+        pos++
+        continue
+      }
+      if (quote === '"' && char === "`") {
+        pos++
+        continue
+      }
+      if (char === quote) quote = undefined
+      continue
+    }
+    if (char === "'" || char === '"') {
+      quote = char
+      continue
+    }
+    if (char === "#") {
+      pos = line(command, pos) - 1
+      continue
+    }
+    if (char === "(") depth++
+    if (char === ")") {
+      depth--
+      if (depth === 0) return pos + 1
+    }
+  }
 }

packages/opencode/test/kilocode/shell/shell.test.ts

@@ -23,4 +23,19 @@ describe("PowerShell arguments", () => {
   test.each(["powershell", "pwsh"])("routes %s through the Kilo argument builder", (shell) => {
     expect(Shell.args(shell, command, "/tmp")).toEqual(PowerShell.args(command))
   })
+
+  test("keeps script-level prologue before the UTF-8 console setup", () => {
+    const input = `#requires -Version 5.1
+using namespace System.Text
+param(
+  [string]$Name
+)
+Write-Output $Name`
+    const value = PowerShell.args(input)[4]
+    const setup = value.indexOf("[Console]::InputEncoding")
+
+    expect(value.startsWith("#requires -Version 5.1")).toBe(true)
+    expect(setup).toBeGreaterThan(value.indexOf(")"))
+    expect(setup).toBeLessThan(value.indexOf("Write-Output"))
+  })
 })