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>

1 files changed, 17 insertions, 0 deletions

diff --git a/internal/tmuxedit/capture.go b/internal/tmuxedit/capture.go
new file mode 100644
index 0000000..2af5698
--- /dev/null
+++ b/internal/tmuxedit/capture.go
@@ -0,0 +1,17 @@
+package tmuxedit
+
+import (
+	"fmt"
+	"strings"
+)
+
+// capturePane retrieves the visible content of a tmux pane via
+// `tmux capture-pane -p -t <paneID>`. The -p flag prints to stdout
+// instead of to a paste buffer.
+var capturePane = func(paneID string) (string, error) {
+	out, err := runCommand("tmux", "capture-pane", "-p", "-t", paneID)
+	if err != nil {
+		return "", fmt.Errorf("capture-pane failed for %s: %w", paneID, err)
+	}
+	return strings.TrimRight(string(out), "\n"), nil
+}