cmd: add fallback for claude (#13892)

cmd/config/claude.go

@@ -4,6 +4,8 @@ import (
 	"fmt"
 	"os"
 	"os/exec"
+	"path/filepath"
+	"runtime"
 )
 
 // Claude implements Runner for Claude Code integration
@@ -18,12 +20,32 @@ func (c *Claude) args(model string) []string {
 	return nil
 }
 
+func (c *Claude) findPath() (string, error) {
+	if p, err := exec.LookPath("claude"); err == nil {
+		return p, nil
+	}
+	home, err := os.UserHomeDir()
+	if err != nil {
+		return "", err
+	}
+	name := "claude"
+	if runtime.GOOS == "windows" {
+		name = "claude.exe"
+	}
+	fallback := filepath.Join(home, ".claude", "local", name)
+	if _, err := os.Stat(fallback); err != nil {
+		return "", err
+	}
+	return fallback, nil
+}
+
 func (c *Claude) Run(model string) error {
-	if _, err := exec.LookPath("claude"); err != nil {
+	claudePath, err := c.findPath()
+	if err != nil {
 		return fmt.Errorf("claude is not installed, install from https://code.claude.com/docs/en/quickstart")
 	}
 
-	cmd := exec.Command("claude", c.args(model)...)
+	cmd := exec.Command(claudePath, c.args(model)...)
 	cmd.Stdin = os.Stdin
 	cmd.Stdout = os.Stdout
 	cmd.Stderr = os.Stderr

cmd/config/claude_test.go

@@ -1,6 +1,9 @@
 package config
 
 import (
+	"os"
+	"path/filepath"
+	"runtime"
 	"slices"
 	"testing"
 )
@@ -19,6 +22,62 @@ func TestClaudeIntegration(t *testing.T) {
 	})
 }
 
+func TestClaudeFindPath(t *testing.T) {
+	c := &Claude{}
+
+	t.Run("finds claude in PATH", func(t *testing.T) {
+		tmpDir := t.TempDir()
+		name := "claude"
+		if runtime.GOOS == "windows" {
+			name = "claude.exe"
+		}
+		fakeBin := filepath.Join(tmpDir, name)
+		os.WriteFile(fakeBin, []byte("#!/bin/sh\n"), 0o755)
+		t.Setenv("PATH", tmpDir)
+
+		got, err := c.findPath()
+		if err != nil {
+			t.Fatalf("unexpected error: %v", err)
+		}
+		if got != fakeBin {
+			t.Errorf("findPath() = %q, want %q", got, fakeBin)
+		}
+	})
+
+	t.Run("falls back to ~/.claude/local/claude", func(t *testing.T) {
+		tmpDir := t.TempDir()
+		setTestHome(t, tmpDir)
+		t.Setenv("PATH", t.TempDir()) // empty dir, no claude binary
+
+		name := "claude"
+		if runtime.GOOS == "windows" {
+			name = "claude.exe"
+		}
+		fallback := filepath.Join(tmpDir, ".claude", "local", name)
+		os.MkdirAll(filepath.Dir(fallback), 0o755)
+		os.WriteFile(fallback, []byte("#!/bin/sh\n"), 0o755)
+
+		got, err := c.findPath()
+		if err != nil {
+			t.Fatalf("unexpected error: %v", err)
+		}
+		if got != fallback {
+			t.Errorf("findPath() = %q, want %q", got, fallback)
+		}
+	})
+
+	t.Run("returns error when neither PATH nor fallback exists", func(t *testing.T) {
+		tmpDir := t.TempDir()
+		setTestHome(t, tmpDir)
+		t.Setenv("PATH", t.TempDir()) // empty dir, no claude binary
+
+		_, err := c.findPath()
+		if err == nil {
+			t.Fatal("expected error, got nil")
+		}
+	})
+}
+
 func TestClaudeArgs(t *testing.T) {
 	c := &Claude{}