diff --git a/adapters/claude/config/settings.json b/adapters/claude/config/settings.json
index 5c72ea9..bd239a4 100644
--- a/adapters/claude/config/settings.json
+++ b/adapters/claude/config/settings.json
@@ -4,12 +4,7 @@
     "allow": [
       "Agent"
     ],
-    "deny": [
-      "Bash(git reset --hard*)",
-      "Bash(git clean*)",
-      "Bash(rm -rf*)",
-      "Bash(Remove-Item -Recurse*)"
-    ]
+    "deny": __CLAUDE_DENY_RULES__
   },
   "sandbox": __CLAUDE_SANDBOX__,
   "env": {
diff --git a/scripts/commands/build.ps1 b/scripts/commands/build.ps1
index eedf6c5..e61e4e0 100644
--- a/scripts/commands/build.ps1
+++ b/scripts/commands/build.ps1
@@ -4,6 +4,12 @@ $ErrorActionPreference = 'Stop'
 $root = Split-Path (Split-Path $PSScriptRoot -Parent) -Parent
 $shared = Join-Path $root 'shared'
 $output = Join-Path $root 'generated'
+$sandboxSupported = [Environment]::OSVersion.Platform -eq [PlatformID]::Unix
+if ($sandboxSupported) {
+    $kernel = (& uname -r 2>$null | Out-String).Trim()
+    if ($kernel -match '(?i)microsoft') { $sandboxSupported = $kernel -match '(?i)microsoft-standard-WSL2' }
+}
+$claudeSandbox = if ($sandboxSupported) { '{"enabled": true, "allowUnsandboxedCommands": false, "failIfUnavailable": true}' } else { '{"enabled": false}' }
 $pluginManifest = Join-Path $root 'adapters/plugins.tsv'
 $capabilityManifest = Join-Path $root 'adapters/claude/capabilities.tsv'
 
@@ -173,10 +179,15 @@ foreach ($shell in @('powershell','bash')) {
         $script = if ($shell -eq 'powershell') { 'flashbang.ps1' } else { 'flashbang.sh' }
         $statusLineScript = if ($shell -eq 'powershell') { 'statusline.ps1' } else { 'statusline.sh' }
         $content = Get-Content -LiteralPath $path -Raw
-        $sandbox = if ($shell -eq 'powershell') { '{"enabled": false}' } else { '{"enabled": true, "allowUnsandboxedCommands": false, "failIfUnavailable": true}' }
+        $denyRules = if ($shell -eq 'powershell') {
+            @('PowerShell(git reset --hard*)','PowerShell(git clean*)','PowerShell(Remove-Item *-Recurse*)')
+        } else {
+            @('Bash(git reset --hard*)','Bash(git clean*)','Bash(rm -rf*)')
+        }
+        $denyRulesJson = ConvertTo-Json -InputObject $denyRules -Compress
         $compactScript = if ($shell -eq 'powershell') { 'Record-Compact.ps1' } else { 'record-compact.sh' }
         $pointerScript = if ($shell -eq 'powershell') { 'Show-SessionStatePointer.ps1' } else { 'show-session-state-pointer.sh' }
-        $content = $content.Replace('__HOOK_COMMAND__', $command).Replace('__POWERSHELL_HOOK_COMMAND__', $command).Replace('__HOOK_SCRIPT__', $script).Replace('__POWERSHELL_HOOK_SCRIPT__', $script).Replace('__COMPACT_SCRIPT__', $compactScript).Replace('__SESSION_POINTER_SCRIPT__', $pointerScript).Replace('__STATUSLINE_COMMAND__', $command).Replace('__STATUSLINE_SCRIPT__', $statusLineScript).Replace('__CLAUDE_SANDBOX__', $sandbox)
+        $content = $content.Replace('__HOOK_COMMAND__', $command).Replace('__POWERSHELL_HOOK_COMMAND__', $command).Replace('__HOOK_SCRIPT__', $script).Replace('__POWERSHELL_HOOK_SCRIPT__', $script).Replace('__COMPACT_SCRIPT__', $compactScript).Replace('__SESSION_POINTER_SCRIPT__', $pointerScript).Replace('__STATUSLINE_COMMAND__', $command).Replace('__STATUSLINE_SCRIPT__', $statusLineScript).Replace('__CLAUDE_SANDBOX__', $claudeSandbox).Replace('__CLAUDE_DENY_RULES__', $denyRulesJson)
         Set-Content -LiteralPath $path -Value $content -Encoding UTF8
     }
 
@@ -192,7 +203,7 @@ $leftoverPlaceholders = @(Get-ChildItem $output -File -Recurse | ForEach-Object
     # expected to remain in generated output. -cmatch keeps this case-sensitive so Python
     # dunder names (__main__, __name__) in flashbang.sh are not mistaken for placeholders.
     $content = (Get-Content -LiteralPath $_.FullName -Raw) -replace '__AI_CONFIG_ROOT__|__POWERSHELL_COMMAND__|__CLAUDE_CODE_MAX_TOOL_USE_CONCURRENCY__', ''
-    if ($content -cmatch '__[A-Z0-9_]+__') { $_.FullName }
+    if ($content -cmatch '__[A-Z0-9_]*[A-Z0-9][A-Z0-9_]*__') { $_.FullName }
 })
 if ($leftoverPlaceholders.Count) { throw "Unresolved template placeholders in: $($leftoverPlaceholders -join ', ')" }
 
diff --git a/scripts/commands/build.sh b/scripts/commands/build.sh
index 889972f..c7472d3 100644
--- a/scripts/commands/build.sh
+++ b/scripts/commands/build.sh
@@ -11,6 +11,20 @@ done
 root=$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")/../.." && pwd)
 shared="$root/shared"
 output="$root/generated"
+sandbox_supported=false
+platform=$(uname -s 2>/dev/null || true)
+case "$platform" in
+  Darwin) sandbox_supported=true ;;
+  Linux)
+    kernel=$(uname -r 2>/dev/null || true)
+    case "$kernel" in
+      *microsoft*) [[ "$kernel" == *microsoft-standard-WSL2* ]] && sandbox_supported=true ;;
+      *) sandbox_supported=true ;;
+    esac
+    ;;
+esac
+sandbox='{"enabled": false}'
+[ "$sandbox_supported" != true ] || sandbox='{"enabled": true, "allowUnsandboxedCommands": false, "failIfUnavailable": true}'
 plugin_manifest="$root/adapters/plugins.tsv"
 capability_manifest="$root/adapters/claude/capabilities.tsv"
 
@@ -158,8 +172,11 @@ for client in codex claude; do
   fi
   path="$output/$client-$shell/$file"
   content=$(<"$path")
-  sandbox='{"enabled": true, "allowUnsandboxedCommands": false, "failIfUnavailable": true}'
-  [ "$shell" != powershell ] || sandbox='{"enabled": false}'
+  if [ "$shell" = powershell ]; then
+    deny_rules='["PowerShell(git reset --hard*)","PowerShell(git clean*)","PowerShell(Remove-Item *-Recurse*)"]'
+  else
+    deny_rules='["Bash(git reset --hard*)","Bash(git clean*)","Bash(rm -rf*)"]'
+  fi
   content=${content//__HOOK_COMMAND__/$command}
   content=${content//__POWERSHELL_HOOK_COMMAND__/$command}
   content=${content//__HOOK_SCRIPT__/$script}
@@ -169,6 +186,7 @@ for client in codex claude; do
   content=${content//__STATUSLINE_COMMAND__/$command}
   content=${content//__STATUSLINE_SCRIPT__/$statusline_script}
   content=${content//__CLAUDE_SANDBOX__/$sandbox}
+  content=${content//__CLAUDE_DENY_RULES__/$deny_rules}
   printf '%s\n' "$content" > "$path"
 done
 
@@ -191,9 +209,9 @@ done
 # __AI_CONFIG_ROOT__ is resolved at install time, once the destination is known; it is
 # expected to remain in generated output, so it is excluded from the leftover check. A
 # single tree-wide grep (rather than one process per file) keeps this fast.
-leftover_tokens=$(grep -RohE '__[A-Z0-9_]+__' "$output" 2>/dev/null | sort -u | grep -Ev '^(__AI_CONFIG_ROOT__|__POWERSHELL_COMMAND__|__CLAUDE_CODE_MAX_TOOL_USE_CONCURRENCY__)$' || true)
+leftover_tokens=$(grep -RohE '__[A-Z0-9_]*[A-Z0-9][A-Z0-9_]*__' "$output" 2>/dev/null | sort -u | grep -Ev '^(__AI_CONFIG_ROOT__|__POWERSHELL_COMMAND__|__CLAUDE_CODE_MAX_TOOL_USE_CONCURRENCY__)$' || true)
 if [ -n "$leftover_tokens" ]; then
-  offending_files=$(grep -RlE '__[A-Z0-9_]+__' "$output" 2>/dev/null | tr '\n' ' ')
+  offending_files=$(grep -RlE '__[A-Z0-9_]*[A-Z0-9][A-Z0-9_]*__' "$output" 2>/dev/null | tr '\n' ' ')
   printf 'Unresolved template placeholders (%s) in: %s\n' "$(printf '%s' "$leftover_tokens" | tr '\n' ' ')" "$offending_files" >&2
   exit 1
 fi