add hexai-tmux-edit: tmux popup editor for AI agent prompts

New tool that opens $EDITOR in a tmux popup for composing longer prompts
when working with AI CLI agents (Claude Code, Cursor, Amp, Aider, etc.).
Captures existing prompt text from the target pane, pre-fills the editor,
and sends edited text back via tmux send-keys. Config-driven agent
detection via regex patterns in [tmux_edit] config section.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

2 files changed, 190 insertions, 0 deletions

diff --git a/internal/appconfig/config.go b/internal/appconfig/config.go
index 8ec29ae..b21a4de 100644
--- a/internal/appconfig/config.go
+++ b/internal/appconfig/config.go
@@ -118,6 +118,12 @@ type App struct {
 	IgnoreGitignore     *bool    `json:"-" toml:"-"`
 	IgnoreExtraPatterns []string `json:"-" toml:"-"`
 	IgnoreLSPNotify     *bool    `json:"-" toml:"-"`
+
+	// TmuxEdit: popup editor settings for hexai-tmux-edit
+	TmuxEditPopupWidth   string             `json:"-" toml:"-"`
+	TmuxEditPopupHeight  string             `json:"-" toml:"-"`
+	TmuxEditDefaultAgent string             `json:"-" toml:"-"`
+	TmuxEditAgents       []TmuxEditAgentCfg `json:"-" toml:"-"`
 }
 
 // CustomAction describes a user-defined code action.
@@ -132,6 +138,20 @@ type CustomAction struct {
 	User        string // optional; if set, render with available vars
 }
 
+// TmuxEditAgentCfg describes an AI agent's detection and interaction patterns
+// for the tmux popup editor (hexai-tmux-edit).
+type TmuxEditAgentCfg struct {
+	Name          string
+	DisplayName   string
+	DetectPattern string
+	PromptPattern string
+	StripPatterns []string
+	ClearFirst    *bool
+	ClearKeys     string
+	NewlineKeys   string
+	SubmitKeys    string
+}
+
 // Constructor: defaults for App (kept first among functions)
 func newDefaultConfig() App {
 	// Coding-friendly default temperature across providers
@@ -281,6 +301,7 @@ type fileConfig struct {
 	Tmux       sectionTmux       `toml:"tmux"`
 	Stats      sectionStats      `toml:"stats"`
 	Ignore     sectionIgnore     `toml:"ignore"`
+	TmuxEdit   sectionTmuxEdit   `toml:"tmux_edit"`
 }
 
 type sectionGeneral struct {
@@ -333,6 +354,27 @@ type sectionIgnore struct {
 	LSPNotifyIgnored *bool    `toml:"lsp_notify_ignored"`
 }
 
+// sectionTmuxEdit configures the tmux popup editor feature (hexai-tmux-edit).
+type sectionTmuxEdit struct {
+	PopupWidth   string                 `toml:"popup_width"`
+	PopupHeight  string                 `toml:"popup_height"`
+	DefaultAgent string                 `toml:"default_agent"`
+	Agents       []sectionTmuxEditAgent `toml:"agents"`
+}
+
+// sectionTmuxEditAgent defines detection and interaction patterns for one AI agent.
+type sectionTmuxEditAgent struct {
+	Name          string   `toml:"name"`
+	DisplayName   string   `toml:"display_name"`
+	DetectPattern string   `toml:"detect_pattern"`
+	PromptPattern string   `toml:"prompt_pattern"`
+	StripPatterns []string `toml:"strip_patterns"`
+	ClearFirst    *bool    `toml:"clear_first"`
+	ClearKeys     string   `toml:"clear_keys"`
+	NewlineKeys   string   `toml:"newline_keys"`
+	SubmitKeys    string   `toml:"submit_keys"`
+}
+
 type sectionOpenAI struct {
 	Model       string            `toml:"model"`
 	BaseURL     string            `toml:"base_url"`
@@ -659,9 +701,42 @@ func (fc *fileConfig) toApp() App {
 		out.mergeBasics(&tmp)
 	}
 
+	// tmux_edit
+	fc.applyTmuxEdit(&out)
+
 	return out
 }
 
+// applyTmuxEdit converts the [tmux_edit] section into App fields.
+func (fc *fileConfig) applyTmuxEdit(out *App) {
+	te := fc.TmuxEdit
+	if strings.TrimSpace(te.PopupWidth) != "" {
+		out.TmuxEditPopupWidth = strings.TrimSpace(te.PopupWidth)
+	}
+	if strings.TrimSpace(te.PopupHeight) != "" {
+		out.TmuxEditPopupHeight = strings.TrimSpace(te.PopupHeight)
+	}
+	if strings.TrimSpace(te.DefaultAgent) != "" {
+		out.TmuxEditDefaultAgent = strings.TrimSpace(te.DefaultAgent)
+	}
+	for _, a := range te.Agents {
+		if strings.TrimSpace(a.Name) == "" {
+			continue
+		}
+		out.TmuxEditAgents = append(out.TmuxEditAgents, TmuxEditAgentCfg{
+			Name:          strings.TrimSpace(a.Name),
+			DisplayName:   strings.TrimSpace(a.DisplayName),
+			DetectPattern: strings.TrimSpace(a.DetectPattern),
+			PromptPattern: strings.TrimSpace(a.PromptPattern),
+			StripPatterns: a.StripPatterns,
+			ClearFirst:    a.ClearFirst,
+			ClearKeys:     strings.TrimSpace(a.ClearKeys),
+			NewlineKeys:   strings.TrimSpace(a.NewlineKeys),
+			SubmitKeys:    strings.TrimSpace(a.SubmitKeys),
+		})
+	}
+}
+
 func loadFromFile(path string, logger *log.Logger) (*App, error) {
 	b, err := os.ReadFile(path)
 	if err != nil {
@@ -900,6 +975,7 @@ func (a *App) mergeWith(other *App) {
 	a.mergeProviderFields(other)
 	a.mergeSurfaceModels(other)
 	a.mergePrompts(other)
+	a.mergeTmuxEdit(other)
 }
 
 // mergeBasics merges general (non-provider) fields.
@@ -1060,6 +1136,22 @@ func (a *App) mergePrompts(other *App) {
 }
 
 // Validate checks custom actions and tmux settings for duplicates and consistency.
+// mergeTmuxEdit copies non-empty tmux edit settings from other.
+func (a *App) mergeTmuxEdit(other *App) {
+	if s := strings.TrimSpace(other.TmuxEditPopupWidth); s != "" {
+		a.TmuxEditPopupWidth = s
+	}
+	if s := strings.TrimSpace(other.TmuxEditPopupHeight); s != "" {
+		a.TmuxEditPopupHeight = s
+	}
+	if s := strings.TrimSpace(other.TmuxEditDefaultAgent); s != "" {
+		a.TmuxEditDefaultAgent = s
+	}
+	if len(other.TmuxEditAgents) > 0 {
+		a.TmuxEditAgents = append([]TmuxEditAgentCfg{}, other.TmuxEditAgents...)
+	}
+}
+
 func (a App) Validate() error {
 	// Normalize and check duplicates for IDs and hotkeys
 	seenID := make(map[string]struct{})
diff --git a/internal/appconfig/config_test.go b/internal/appconfig/config_test.go
index b9dfe3a..6b8ee5b 100644
--- a/internal/appconfig/config_test.go
+++ b/internal/appconfig/config_test.go
@@ -893,3 +893,101 @@ gitignore = false
 		t.Error("expected IgnoreLSPNotify to remain true (default)")
 	}
 }
+
+func TestTmuxEditConfig_FromFile(t *testing.T) {
+	clearHexaiEnv(t)
+	dir := t.TempDir()
+	cfgPath := filepath.Join(dir, "config.toml")
+	writeFile(t, cfgPath, `
+[tmux_edit]
+popup_width = "90%"
+popup_height = "85%"
+default_agent = "claude"
+
+[[tmux_edit.agents]]
+name = "claude"
+display_name = "Claude Code"
+detect_pattern = "(?i)(claude|anthropic)"
+prompt_pattern = '(?s)>\s*(.+?)$'
+clear_first = true
+clear_keys = "C-u"
+newline_keys = "S-Enter"
+submit_keys = "Enter"
+
+[[tmux_edit.agents]]
+name = "cursor"
+display_name = "Cursor"
+detect_pattern = "(?i)cursor"
+prompt_pattern = '(?s)│\s*(.+?)$'
+strip_patterns = ["INSERT", "Add a follow-up"]
+clear_first = true
+clear_keys = "C-u"
+newline_keys = "S-Enter"
+submit_keys = "Enter"
+`)
+	cfg := LoadWithOptions(newLogger(), LoadOptions{ConfigPath: cfgPath})
+	if cfg.TmuxEditPopupWidth != "90%" {
+		t.Errorf("PopupWidth = %q, want 90%%", cfg.TmuxEditPopupWidth)
+	}
+	if cfg.TmuxEditPopupHeight != "85%" {
+		t.Errorf("PopupHeight = %q, want 85%%", cfg.TmuxEditPopupHeight)
+	}
+	if cfg.TmuxEditDefaultAgent != "claude" {
+		t.Errorf("DefaultAgent = %q, want claude", cfg.TmuxEditDefaultAgent)
+	}
+	if len(cfg.TmuxEditAgents) != 2 {
+		t.Fatalf("got %d agents, want 2", len(cfg.TmuxEditAgents))
+	}
+	a := cfg.TmuxEditAgents[0]
+	if a.Name != "claude" || a.DisplayName != "Claude Code" {
+		t.Errorf("agent[0] = %q/%q, want claude/Claude Code", a.Name, a.DisplayName)
+	}
+	if a.ClearFirst == nil || !*a.ClearFirst {
+		t.Error("expected ClearFirst = true for claude agent")
+	}
+	b := cfg.TmuxEditAgents[1]
+	if b.Name != "cursor" {
+		t.Errorf("agent[1].Name = %q, want cursor", b.Name)
+	}
+	if len(b.StripPatterns) != 2 {
+		t.Errorf("agent[1].StripPatterns = %v, want 2 entries", b.StripPatterns)
+	}
+}
+
+func TestTmuxEditConfig_Merge(t *testing.T) {
+	clearHexaiEnv(t)
+	a := newDefaultConfig()
+	b := App{
+		TmuxEditPopupWidth:   "70%",
+		TmuxEditDefaultAgent: "amp",
+		TmuxEditAgents: []TmuxEditAgentCfg{
+			{Name: "amp", DisplayName: "Amp"},
+		},
+	}
+	a.mergeWith(&b)
+	if a.TmuxEditPopupWidth != "70%" {
+		t.Errorf("PopupWidth = %q, want 70%%", a.TmuxEditPopupWidth)
+	}
+	if a.TmuxEditDefaultAgent != "amp" {
+		t.Errorf("DefaultAgent = %q, want amp", a.TmuxEditDefaultAgent)
+	}
+	if len(a.TmuxEditAgents) != 1 || a.TmuxEditAgents[0].Name != "amp" {
+		t.Errorf("Agents = %v, want single amp", a.TmuxEditAgents)
+	}
+}
+
+func TestTmuxEditConfig_SkipsEmptyName(t *testing.T) {
+	clearHexaiEnv(t)
+	dir := t.TempDir()
+	cfgPath := filepath.Join(dir, "config.toml")
+	writeFile(t, cfgPath, `
+[tmux_edit]
+[[tmux_edit.agents]]
+name = ""
+display_name = "Empty"
+`)
+	cfg := LoadWithOptions(newLogger(), LoadOptions{ConfigPath: cfgPath})
+	if len(cfg.TmuxEditAgents) != 0 {
+		t.Errorf("got %d agents, want 0 (empty name should be skipped)", len(cfg.TmuxEditAgents))
+	}
+}