menu bar app: live agent states from tmux pane options

single-file appkit status item (menubar/main.swift, LSUIElement) polling
@agent/@agent_state pane options every 2s: counts in the bar, per-pane
rows with click-to-focus via switch-client. daemon now also writes an
@agent label per pane so the menu bar and tmux status-right can render
agent names without duplicating identification logic.

2 files changed, 28 insertions, 8 deletions

diff --git a/crates/dinggerd/src/tmux.rs b/crates/dinggerd/src/tmux.rs
index e833e3c..edd44aa 100644
--- a/crates/dinggerd/src/tmux.rs
+++ b/crates/dinggerd/src/tmux.rs
@@ -4,7 +4,6 @@ use std::process::Command;
 
 use detect_core::manifest::agent_state_label;
 use detect_core::{identify_agent, Agent, AgentState};
-use tracing::debug;
 
 #[derive(Debug, Clone)]
 pub struct Pane {
@@ -25,6 +24,8 @@ pub struct Pane {
     /// The `@agent_state` user option previously written for this pane,
     /// read straight from the pane format.
     pub written_state: String,
+    /// The `@agent` user option (agent label) previously written, if any.
+    pub written_agent: String,
 }
 
 impl Pane {
@@ -68,13 +69,14 @@ pub fn list_panes() -> Result<Vec<Pane>, String> {
         "#{session_attached}\t",
         "#{pane_start_command}\t",
         "#{pane_pid}\t",
-        "#{@agent_state}"
+        "#{@agent_state}\t",
+        "#{@agent}"
     );
     let out = run_tmux(&["list-panes", "-a", "-F", format])?;
     let mut panes = Vec::new();
     for line in out.lines() {
         let fields: Vec<&str> = line.split('\t').collect();
-        if fields.len() < 10 {
+        if fields.len() < 11 {
             continue;
         }
         let current_command = fields[2].to_string();
@@ -101,6 +103,7 @@ pub fn list_panes() -> Result<Vec<Pane>, String> {
             session_attached: fields[6] != "0",
             agent,
             written_state: fields[9].to_string(),
+            written_agent: fields[10].to_string(),
         });
     }
     Ok(panes)
@@ -180,3 +183,10 @@ pub fn set_agent_state(pane_id: &str, state: AgentState) -> Result<(), String> {
     ])
     .map(|_| ())
 }
+
+/// Label the pane with the agent running in it, for tmux status-line and
+/// menu-bar rendering; clears the label when the pane stops running one.
+pub fn set_agent(pane_id: &str, agent: Option<Agent>) -> Result<(), String> {
+    let label = agent.map(detect_core::agent_label).unwrap_or("");
+    run_tmux(&["set-option", "-p", "-t", pane_id, "@agent", label]).map(|_| ())
+}
diff --git a/crates/dinggerd/src/watcher.rs b/crates/dinggerd/src/watcher.rs
index 56107d6..f039456 100644
--- a/crates/dinggerd/src/watcher.rs
+++ b/crates/dinggerd/src/watcher.rs
@@ -113,6 +113,20 @@ impl Watcher {
                 debug!(target = %pane.target, "observation skipped (viewer screen)");
                 continue;
             };
+
+            // Keep the pane's agent label current even when the state is
+            // unchanged (e.g. an agent swap between two idle panes).
+            let agent_label = pane
+                .agent
+                .map(detect_core::agent_label)
+                .unwrap_or("")
+                .to_string();
+            if pane.written_agent != agent_label {
+                if let Err(err) = tmux::set_agent(&pane.pane_id, pane.agent) {
+                    warn!(target = %pane.target, %err, "failed to write @agent");
+                }
+            }
+
             if new_state == prev_state {
                 continue;
             }
@@ -123,11 +137,7 @@ impl Watcher {
                 warn!(target = %pane.target, %err, "failed to write @agent_state");
             }
 
-            let agent_label = pane
-                .agent
-                .map(detect_core::agent_label)
-                .unwrap_or("agent")
-                .to_string();
+
             if let Some(kind) = notification_kind_for_transition(prev_state, new_state) {
                 if pane.suppresses_notifications() {
                     debug!(target = %pane.target, "suppressed (active pane)");