diff --git a/CHANGELOG.md b/CHANGELOG.md
index adcc97a..3ae6812 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -38,6 +38,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   non-existent `~/.claude/hooks/ck/` directory after the `ck` -> `specwright` rename.
 - `/sd:setup` Phase 7 (and Phase 1.5) now verify every hook `command` path in
   `.claude/settings.json` resolves to a file on disk, warning loudly when a hook is not firing.
+- `hooks/powershell/subagent-retro.ps1`, `prompt-router.ps1`, and `spec-gate.ps1` no longer assign
+  parsed hook JSON to `$input` - PowerShell's reserved automatic pipeline variable. Assigning to it
+  threw a non-terminating `ParameterBindingException` on every real (piped/redirected) stdin
+  invocation, leaving it unbound and causing every PowerShell hook to exit silently before reading
+  any input. Renamed to `$hookInput` in all three files.
 
 ---
 
diff --git a/hooks/powershell/prompt-router.ps1 b/hooks/powershell/prompt-router.ps1
index 8103e80..de3bf48 100644
--- a/hooks/powershell/prompt-router.ps1
+++ b/hooks/powershell/prompt-router.ps1
@@ -173,11 +173,11 @@ function Get-InProgressSpecs {
 
 # ---- main ----
 
-$input = Read-StdinJson
-if ($null -eq $input) { exit 0 }
+$hookInput = Read-StdinJson
+if ($null -eq $hookInput) { exit 0 }
 
-$prompt = $input.prompt
-$cwd    = $input.cwd
+$prompt = $hookInput.prompt
+$cwd    = $hookInput.cwd
 if ([string]::IsNullOrWhiteSpace($prompt) -or [string]::IsNullOrWhiteSpace($cwd)) { exit 0 }
 if (-not (Test-Path -LiteralPath $cwd)) { exit 0 }
 
diff --git a/hooks/powershell/spec-gate.ps1 b/hooks/powershell/spec-gate.ps1
index 3ba4e72..97fcd41 100644
--- a/hooks/powershell/spec-gate.ps1
+++ b/hooks/powershell/spec-gate.ps1
@@ -166,13 +166,13 @@ function Write-BlockDecision {
 
 # ---- main ----
 
-$input = Read-StdinJson
-if ($null -eq $input) { exit 0 }
+$hookInput = Read-StdinJson
+if ($null -eq $hookInput) { exit 0 }
 
-$toolName = $input.tool_name
+$toolName = $hookInput.tool_name
 if ($toolName -ne 'Edit' -and $toolName -ne 'Write' -and $toolName -ne 'MultiEdit') { exit 0 }
 
-$cwd = $input.cwd
+$cwd = $hookInput.cwd
 if ([string]::IsNullOrWhiteSpace($cwd)) { $cwd = (Get-Location).Path }
 
 $config = Get-ProjectConfig -Cwd $cwd
@@ -188,7 +188,7 @@ $mode = 'warn'
 try { if ($config.hooks.specGate.mode) { $mode = [string]$config.hooks.specGate.mode } } catch { }
 if ($mode -eq 'off') { exit 0 }
 
-$filePath = $input.tool_input.file_path
+$filePath = $hookInput.tool_input.file_path
 if ([string]::IsNullOrWhiteSpace($filePath)) { exit 0 }
 
 $rel = ConvertTo-RelativePath -Cwd $cwd -FilePath $filePath
diff --git a/hooks/powershell/subagent-retro.ps1 b/hooks/powershell/subagent-retro.ps1
index 229d0ae..c9f9c35 100644
--- a/hooks/powershell/subagent-retro.ps1
+++ b/hooks/powershell/subagent-retro.ps1
@@ -156,14 +156,14 @@ function Remove-StaleStateFiles {
 
 # ---- main ----
 
-$input = Read-StdinJson
-if ($null -eq $input) { exit 0 }
+$hookInput = Read-StdinJson
+if ($null -eq $hookInput) { exit 0 }
 
-$cwd = $input.cwd
+$cwd = $hookInput.cwd
 if ([string]::IsNullOrWhiteSpace($cwd)) { $cwd = (Get-Location).Path }
 if (-not (Test-Path -LiteralPath $cwd)) { exit 0 }
 
-$sessionId = $input.session_id
+$sessionId = $hookInput.session_id
 if ([string]::IsNullOrWhiteSpace($sessionId)) { $sessionId = 'no-session' }
 
 $config = Get-ProjectConfig -Cwd $cwd