feat: config name case insensitivity

internal/cli/attach_cmd.go

@@ -33,12 +33,12 @@ func runAttach(cmd *cobra.Command, args []string) error {
 			return err
 		}
 
-		item, exists := allConfig[key]
+		item, actualKey, exists := allConfig.Get(key)
 		if !exists {
 			return NewUserError("tmux config item '" + key + "' not found")
 		}
 
-		parsed := config.ParseConfig(key, item)
+		parsed := config.ParseConfig(actualKey, item)
 
 		if !tmux.SessionExists(opts, parsed.Name) {
 			return NewUserError("tmux session '" + parsed.Name + "' does not exist")

internal/cli/main_cmd.go

@@ -34,10 +34,11 @@ func runMain(cmd *cobra.Command, args []string) error {
 			return err
 		}
 
-		if _, exists := info.Merged.Config[selected]; !exists {
+		if _, actualKey, exists := info.Merged.Config.Get(selected); !exists {
 			return NewUserError("tmux config item '" + selected + "' not found")
+		} else {
+			key = actualKey
 		}
-		key = selected
 	}
 
 	// Get config
@@ -46,12 +47,12 @@ func runMain(cmd *cobra.Command, args []string) error {
 		return err
 	}
 
-	item, exists := allConfig[key]
+	item, actualKey, exists := allConfig.Get(key)
 	if !exists {
 		return NewUserError("tmux config item '" + key + "' not found")
 	}
 
-	parsed := config.ParseConfig(key, item)
+	parsed := config.ParseConfig(actualKey, item)
 
 	// Check if session exists
 	if tmux.SessionExists(opts, parsed.Name) {

internal/cli/main_cmd_test.go

@@ -58,6 +58,41 @@ testproject:
 	}
 }
 
+func TestRunMain_CaseInsensitiveKey(t *testing.T) {
+	// Create a temp directory with a config file
+	tmpDir := t.TempDir()
+	configPath := filepath.Join(tmpDir, ".tmux.yaml")
+
+	content := `
+Notes:
+  root: /tmp/notes
+  windows:
+    - ./src
+`
+	err := os.WriteFile(configPath, []byte(content), 0644)
+	if err != nil {
+		t.Fatalf("failed to write temp config: %v", err)
+	}
+
+	// Set XDG_CONFIG_HOME to temp directory so config is found
+	oldXDG := os.Getenv("XDG_CONFIG_HOME")
+	_ = os.Setenv("XDG_CONFIG_HOME", tmpDir)
+	defer func() { _ = os.Setenv("XDG_CONFIG_HOME", oldXDG) }()
+
+	dry = true
+	defer func() { dry = false }()
+
+	// Should succeed with different casings
+	for _, key := range []string{"Notes", "notes", "NOTES", "nOtEs"} {
+		t.Run(key, func(t *testing.T) {
+			err := runMain(nil, []string{key})
+			if err != nil {
+				t.Errorf("expected no error for key %q, got %v", key, err)
+			}
+		})
+	}
+}
+
 func TestRunMain_InvalidKey(t *testing.T) {
 	// Create a temp directory with a config file
 	tmpDir := t.TempDir()

internal/cli/remove_cmd.go

@@ -33,11 +33,12 @@ func runRemove(cmd *cobra.Command, args []string) error {
 		return err
 	}
 
-	if _, exists := allConfig[key]; !exists {
+	_, actualKey, exists := allConfig.Get(key)
+	if !exists {
 		return NewUserError("tmux config item '" + key + "' not found")
 	}
 
-	err = config.RemoveConfigFromFile(key, removeLocal, opts.Dry)
+	err = config.RemoveConfigFromFile(actualKey, removeLocal, opts.Dry)
 	if err != nil {
 		return err
 	}

internal/cli/show_cmd.go

@@ -49,12 +49,12 @@ func runShow(cmd *cobra.Command, args []string) error {
 		key = selected
 	}
 
-	item, exists := allConfig[key]
+	item, actualKey, exists := allConfig.Get(key)
 	if !exists {
 		return NewUserError("tmux config item '" + key + "' not found")
 	}
 
-	parsed := config.ParseConfig(key, item)
+	parsed := config.ParseConfig(actualKey, item)
 
 	if showJSON {
 		data, err := json.Marshal(parsed)

internal/config/types.go

@@ -1,6 +1,8 @@
 package config
 
 import (
+	"strings"
+
 	"gopkg.in/yaml.v3"
 )
 
@@ -15,6 +17,23 @@ type GlobalConfig struct {
 // ConfigFile represents the top-level config file: map of session name -> config
 type ConfigFile map[string]TmuxConfigItemInput
 
+// Get performs a case-insensitive lookup of a key in the config file.
+// It returns the config item, the actual key as stored in the config, and whether it was found.
+func (c ConfigFile) Get(key string) (TmuxConfigItemInput, string, bool) {
+	// Try exact match first
+	if item, ok := c[key]; ok {
+		return item, key, true
+	}
+	// Fall back to case-insensitive match
+	lower := strings.ToLower(key)
+	for k, v := range c {
+		if strings.ToLower(k) == lower {
+			return v, k, true
+		}
+	}
+	return TmuxConfigItemInput{}, "", false
+}
+
 // TmuxConfigItemInput represents a single tmux session configuration
 type TmuxConfigItemInput struct {
 	Root        string            `yaml:"root"`

internal/config/types_test.go

@@ -180,6 +180,102 @@ another:
 	}
 }
 
+func TestConfigFile_Get_ExactMatch(t *testing.T) {
+	config := ConfigFile{
+		"notes": {Root: "/tmp/notes"},
+		"work":  {Root: "/tmp/work"},
+	}
+
+	item, actualKey, ok := config.Get("notes")
+	if !ok {
+		t.Fatal("expected to find 'notes'")
+	}
+	if actualKey != "notes" {
+		t.Errorf("expected actualKey 'notes', got %q", actualKey)
+	}
+	if item.Root != "/tmp/notes" {
+		t.Errorf("expected Root '/tmp/notes', got %q", item.Root)
+	}
+}
+
+func TestConfigFile_Get_CaseInsensitive(t *testing.T) {
+	config := ConfigFile{
+		"Notes": {Root: "/tmp/notes"},
+		"work":  {Root: "/tmp/work"},
+	}
+
+	tests := []struct {
+		lookup    string
+		wantKey   string
+		wantFound bool
+	}{
+		{"Notes", "Notes", true},
+		{"notes", "Notes", true},
+		{"NOTES", "Notes", true},
+		{"nOtEs", "Notes", true},
+		{"work", "work", true},
+		{"Work", "work", true},
+		{"WORK", "work", true},
+		{"missing", "", false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.lookup, func(t *testing.T) {
+			_, actualKey, ok := config.Get(tt.lookup)
+			if ok != tt.wantFound {
+				t.Errorf("Get(%q): found=%v, want %v", tt.lookup, ok, tt.wantFound)
+			}
+			if ok && actualKey != tt.wantKey {
+				t.Errorf("Get(%q): actualKey=%q, want %q", tt.lookup, actualKey, tt.wantKey)
+			}
+		})
+	}
+}
+
+func TestConfigFile_Get_ExactMatchTakesPrecedence(t *testing.T) {
+	// If both "notes" and "Notes" exist, exact match should win
+	config := ConfigFile{
+		"notes": {Root: "/tmp/lower"},
+		"Notes": {Root: "/tmp/upper"},
+	}
+
+	_, actualKey, ok := config.Get("notes")
+	if !ok {
+		t.Fatal("expected to find 'notes'")
+	}
+	if actualKey != "notes" {
+		t.Errorf("expected exact match 'notes', got %q", actualKey)
+	}
+
+	_, actualKey, ok = config.Get("Notes")
+	if !ok {
+		t.Fatal("expected to find 'Notes'")
+	}
+	if actualKey != "Notes" {
+		t.Errorf("expected exact match 'Notes', got %q", actualKey)
+	}
+}
+
+func TestConfigFile_Get_NotFound(t *testing.T) {
+	config := ConfigFile{
+		"notes": {Root: "/tmp/notes"},
+	}
+
+	_, _, ok := config.Get("missing")
+	if ok {
+		t.Error("expected not found for 'missing'")
+	}
+}
+
+func TestConfigFile_Get_EmptyConfig(t *testing.T) {
+	config := ConfigFile{}
+
+	_, _, ok := config.Get("anything")
+	if ok {
+		t.Error("expected not found in empty config")
+	}
+}
+
 func TestDefaultEmptyLayout(t *testing.T) {
 	if DefaultEmptyLayout.Cwd != "." {
 		t.Errorf("expected Cwd to be '.', got %q", DefaultEmptyLayout.Cwd)

internal/config/writer.go

@@ -37,7 +37,7 @@ func AddSimpleConfigToFile(config ParsedTmuxConfigItem, local bool, dryRun bool)
 		return err
 	}
 
-	if _, exists := allConfigs[config.Name]; exists && !dryRun {
+	if _, _, exists := allConfigs.Get(config.Name); exists && !dryRun {
 		return fmt.Errorf("%w: '%s'", ErrConfigItemExists, config.Name)
 	}