diff --git a/.changeset/calm-powershell-alerts.md b/.changeset/calm-powershell-alerts.md
new file mode 100644
index 000000000000..ac702a7abc8c
--- /dev/null
+++ b/.changeset/calm-powershell-alerts.md
@@ -0,0 +1,6 @@
+---
+"@kilocode/cli": patch
+"kilo-code": patch
+---
+
+Run Windows PowerShell tool commands without `-EncodedCommand` to reduce antivirus false positives.
diff --git a/packages/opencode/src/kilocode/shell/shell.ts b/packages/opencode/src/kilocode/shell/shell.ts
index 34db598e5305..b134c43376a1 100644
--- a/packages/opencode/src/kilocode/shell/shell.ts
+++ b/packages/opencode/src/kilocode/shell/shell.ts
@@ -1,16 +1,124 @@
-import { Buffer } from "node:buffer"
-
 export function args(command: string) {
-  return ["-NoLogo", "-NoProfile", "-NonInteractive", "-EncodedCommand", encoded(command)]
+  return ["-NoLogo", "-NoProfile", "-NonInteractive", "-Command", script(command)]
 }
 
-function encoded(command: string) {
-  const payload = Buffer.from(command, "utf8").toString("base64")
-  return Buffer.from(
-    `[Console]::InputEncoding = [System.Text.UTF8Encoding]::new($false);
+const setup = `[Console]::InputEncoding = [System.Text.UTF8Encoding]::new($false);
 [Console]::OutputEncoding = [System.Text.UTF8Encoding]::new($false);
 $OutputEncoding = [Console]::OutputEncoding;
-& ([scriptblock]::Create([System.Text.Encoding]::UTF8.GetString([System.Convert]::FromBase64String('${payload}'))))`,
-    "utf16le",
-  ).toString("base64")
+`
+
+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 attr = attrs(command, pos)
+  const body = command.slice(attr)
+  const match = /^param\s*\(/i.exec(body)
+  if (!match) return pos
+
+  const start = attr + match[0].lastIndexOf("(")
+  const end = block(command, start, "(", ")")
+  if (end === undefined) return pos
+  return end
+}
+
+function attrs(command: string, start: number) {
+  let pos = start
+  while (pos < command.length) {
+    const next = scan(command, pos)
+    if (command[next] !== "[") return next
+    const end = block(command, next, "[", "]")
+    if (end === undefined) return start
+    pos = end
+  }
+  return pos
+}
+
+function scan(command: string, start: number) {
+  let pos = start
+  while (pos < command.length) {
+    const next = trivia(command, pos)
+    if (next !== pos) {
+      pos = next
+      continue
+    }
+    const end = line(command, pos)
+    const value = command.slice(pos, end)
+    if (/^using\s+(?:assembly|module|namespace|type)\b/i.test(value)) {
+      pos = end
+      continue
+    }
+    return pos
+  }
+  return pos
+}
+
+function trivia(command: string, start: number) {
+  let pos = start
+  while (pos < command.length) {
+    while (/\s/.test(command[pos] ?? "")) pos++
+    if (command[pos] === "#") {
+      pos = line(command, pos)
+      continue
+    }
+    if (command.startsWith("<#", pos)) {
+      const end = command.indexOf("#>", pos + 2)
+      if (end === -1) return command.length
+      pos = end + 2
+      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, open: string, close: string) {
+  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 (command.startsWith("<#", pos)) {
+      const end = command.indexOf("#>", pos + 2)
+      if (end === -1) return
+      pos = end + 1
+      continue
+    }
+    if (char === "#") {
+      pos = line(command, pos) - 1
+      continue
+    }
+    if (char === open) depth++
+    if (char === close) {
+      depth--
+      if (depth === 0) return pos + 1
+    }
+  }
 }
diff --git a/packages/opencode/src/shell/shell.ts b/packages/opencode/src/shell/shell.ts
index c51a0426efe6..a7d7ec3bf704 100644
--- a/packages/opencode/src/shell/shell.ts
+++ b/packages/opencode/src/shell/shell.ts
@@ -1,5 +1,5 @@
 import { Flag } from "@opencode-ai/core/flag/flag"
-import * as PowerShell from "@/kilocode/shell/shell" // kilocode_change - encoded PowerShell args
+import * as PowerShell from "@/kilocode/shell/shell" // kilocode_change - PowerShell args
 import { lazy } from "@/util/lazy"
 import { Filesystem } from "@/util/filesystem"
 import { which } from "@/util/which"
@@ -189,7 +189,7 @@ export function args(file: string, command: string, cwd: string) {
     ]
   }
   if (n === "cmd") return ["/c", command]
-  if (ps(file)) return PowerShell.args(command) // kilocode_change - encoded PowerShell args
+  if (ps(file)) return PowerShell.args(command) // kilocode_change - PowerShell args
   return ["-c", command]
 }
 
diff --git a/packages/opencode/src/tool/shell.ts b/packages/opencode/src/tool/shell.ts
index f6d2fa71ba84..18f974c8955a 100644
--- a/packages/opencode/src/tool/shell.ts
+++ b/packages/opencode/src/tool/shell.ts
@@ -312,7 +312,7 @@ const ask = Effect.fn("ShellTool.ask")(function* (
 
 function cmd(shell: string, command: string, cwd: string, env: NodeJS.ProcessEnv) {
   if (process.platform === "win32" && Shell.ps(shell)) {
-    // kilocode_change start - encoded PowerShell args
+    // kilocode_change start - PowerShell args
     return ChildProcess.make(shell, Shell.args(shell, command, cwd), {
       // kilocode_change end
       cwd,
diff --git a/packages/opencode/test/kilocode/shell/shell.test.ts b/packages/opencode/test/kilocode/shell/shell.test.ts
index 99eac3ecb029..57aa989fffca 100644
--- a/packages/opencode/test/kilocode/shell/shell.test.ts
+++ b/packages/opencode/test/kilocode/shell/shell.test.ts
@@ -1,31 +1,48 @@
 import { describe, expect, test } from "bun:test"
-import { Buffer } from "node:buffer"
 import * as PowerShell from "@/kilocode/shell/shell"
 import { Shell } from "@/shell/shell"
 
 const command = `Write-Output "こんにちは 😀"; Write-Output '$value'; Write-Output \`tick\`
 Write-Output "done"`
 
-function script(args: string[]) {
-  return Buffer.from(args[4], "base64").toString("utf16le")
-}
-
 describe("PowerShell arguments", () => {
-  test("transports commands through UTF-8 inside EncodedCommand", () => {
+  test("transports commands in plaintext with UTF-8 console setup", () => {
     const args = PowerShell.args(command)
-    const value = script(args)
-    const payload = value.match(/FromBase64String\('([^']+)'\)/)?.[1]
+    const value = args[4]
 
-    expect(args.slice(0, 4)).toEqual(["-NoLogo", "-NoProfile", "-NonInteractive", "-EncodedCommand"])
+    expect(args.slice(0, 4)).toEqual(["-NoLogo", "-NoProfile", "-NonInteractive", "-Command"])
     expect(args).toHaveLength(5)
     expect(value).toContain("[Console]::InputEncoding = [System.Text.UTF8Encoding]::new($false)")
     expect(value).toContain("[Console]::OutputEncoding = [System.Text.UTF8Encoding]::new($false)")
     expect(value).toContain("$OutputEncoding = [Console]::OutputEncoding")
-    expect(payload).toBeDefined()
-    expect(Buffer.from(payload!, "base64").toString("utf8")).toBe(command)
+    expect(value).toContain(command)
+    expect(args).not.toContain("-EncodedCommand")
+    expect(value).not.toContain("FromBase64String")
   })
 
   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
+<#
+Block comment before attributes.
+#>
+[CmdletBinding()]
+[OutputType([string])]
+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(value.slice(0, setup)).toContain("[CmdletBinding()]")
+    expect(value.slice(0, setup)).toContain("[OutputType([string])]")
+    expect(value.slice(0, setup)).toContain("param(")
+    expect(setup).toBeLessThan(value.indexOf("Write-Output"))
+  })
 })