Claude: resolve CLI executable across npm and native installers

Probe PATH for claude.cmd / claude.exe / claude rather than hardcoding
claude.cmd, so the native installer's claude.exe also works.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: PostSharpAgent

src/PostSharp.Engineering.BuildTools/Resources/RunClaude.ps1

@@ -210,8 +210,20 @@ if ($Prompt)
     # Stream JSON output for human-readable real-time monitoring
     $processArgs = "-p --output-format stream-json --verbose --model $Model --dangerously-skip-permissions $mcpConfigArg"
 
+    # Resolve the Claude CLI launcher: npm ships claude.cmd on Windows, the native installer ships
+    # claude.exe, and on Linux/macOS the binary is plain "claude". Get-Command honors PATHEXT so
+    # asking for "claude" without an extension finds whichever variant is on PATH.
+    $claudeCommand = Get-Command claude.cmd -ErrorAction SilentlyContinue
+    if (-not $claudeCommand) { $claudeCommand = Get-Command claude.exe -ErrorAction SilentlyContinue }
+    if (-not $claudeCommand) { $claudeCommand = Get-Command claude -ErrorAction SilentlyContinue }
+    if (-not $claudeCommand) {
+        Write-Error "Claude CLI not found on PATH. Install it via 'npm i -g @anthropic-ai/claude-code' or the native installer."
+        exit 1
+    }
+    Write-Host "Using Claude executable: $($claudeCommand.Source)" -ForegroundColor Cyan
+
     $psi = [System.Diagnostics.ProcessStartInfo]::new()
-    $psi.FileName = "claude.cmd"
+    $psi.FileName = $claudeCommand.Source
     $psi.Arguments = $processArgs
     $psi.RedirectStandardInput = $true
     $psi.RedirectStandardOutput = $true

src/PostSharp.Engineering.BuildTools/Utilities/ClaudeCodeHelper.cs

@@ -3,8 +3,10 @@
 using System;
 using System.Collections.Generic;
 using System.Collections.Immutable;
+using System.IO;
 using System.Linq;
 using System.Reflection;
+using System.Runtime.InteropServices;
 using System.Text;
 using System.Text.Json;
 using System.Text.RegularExpressions;
@@ -139,10 +141,23 @@ void HandleOutput( string line )
             }
         }
 
+        // Resolve the Claude CLI executable on PATH. The npm install ships claude.cmd on Windows;
+        // the native installer ships claude.exe; on Unix it is plain "claude".
+        if ( !TryResolveClaudeExecutable( out var claudeExecutable ) )
+        {
+            console.WriteError(
+                "Claude CLI not found on PATH. Install it via 'npm i -g @anthropic-ai/claude-code' or the native installer from https://claude.com/claude-code." );
+            prBodyText = "";
+
+            return false;
+        }
+
+        console.WriteMessage( $"Using Claude executable: {claudeExecutable}" );
+
         // Invoke claude with custom output handler
         var success = ToolInvocationHelper.InvokeTool(
             console,
-            "claude.cmd",
+            claudeExecutable,
             claudeArgs,
             workingDirectory,
             out var exitCode,
@@ -511,4 +526,48 @@ This conclusion will be extracted and placed at the TOP of the PR description.
                 Begin now.
                 """;
     }
+
+    /// <summary>
+    /// Probes PATH for a Claude CLI launcher. The npm package installs <c>claude.cmd</c> on Windows,
+    /// the native installer ships <c>claude.exe</c>, and on Unix the binary is named <c>claude</c>.
+    /// Returns the resolved absolute path so <see cref="System.Diagnostics.Process"/> doesn't have to
+    /// rely on PATHEXT (which is not consulted when <c>UseShellExecute</c> is false).
+    /// </summary>
+    private static bool TryResolveClaudeExecutable( out string path )
+    {
+        var candidates = RuntimeInformation.IsOSPlatform( OSPlatform.Windows )
+            ? new[] { "claude.cmd", "claude.exe", "claude.bat", "claude" }
+            : new[] { "claude" };
+
+        var pathEnv = Environment.GetEnvironmentVariable( "PATH" ) ?? "";
+
+        foreach ( var dir in pathEnv.Split( Path.PathSeparator, StringSplitOptions.RemoveEmptyEntries ) )
+        {
+            foreach ( var candidate in candidates )
+            {
+                string fullPath;
+
+                try
+                {
+                    fullPath = Path.Combine( dir.Trim().Trim( '"' ), candidate );
+                }
+                catch ( ArgumentException )
+                {
+                    // Skip malformed PATH entries.
+                    continue;
+                }
+
+                if ( File.Exists( fullPath ) )
+                {
+                    path = fullPath;
+
+                    return true;
+                }
+            }
+        }
+
+        path = "";
+
+        return false;
+    }
 }