feat(maestro): rename the highlighted session from the TUI sidebar

`r` opens a prompt pre-filled with the session's own name — empty when it
has none, so Enter cannot pin the command as the name. Enter saves, Escape
cancels, and an emptied field clears the name.

Refs #125

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

crates/maestro-tui/src/action.rs

@@ -48,6 +48,9 @@ pub enum Action {
     /// resolved; unresolvable defaults open a pre-filled draft instead.
     FastForwardSpawn,
     KillHighlighted,
+    /// Rename the highlighted session (#125): opens a prompt pre-filled with
+    /// its current name.
+    RenameHighlighted,
     /// Open the retained-worktrees view (#85).
     ShowWorktrees,
 
@@ -92,6 +95,7 @@ impl Action {
             Action::NewDraftPane => "Create a session".into(),
             Action::FastForwardSpawn => "Create session with defaults".into(),
             Action::KillHighlighted => "Kill selected session".into(),
+            Action::RenameHighlighted => "Rename selected session".into(),
             Action::ShowWorktrees => "Show retained worktrees".into(),
             Action::ToggleSidebar => "Show or hide sidebar".into(),
             Action::ShowHelp => "Show help".into(),
@@ -118,6 +122,7 @@ impl Action {
             "NewDraftPane" => return Ok(Action::NewDraftPane),
             "FastForwardSpawn" => return Ok(Action::FastForwardSpawn),
             "KillHighlighted" => return Ok(Action::KillHighlighted),
+            "RenameHighlighted" => return Ok(Action::RenameHighlighted),
             "ShowWorktrees" => return Ok(Action::ShowWorktrees),
             "ToggleSidebar" => return Ok(Action::ToggleSidebar),
             "ShowHelp" => return Ok(Action::ShowHelp),
@@ -223,10 +228,24 @@ mod tests {
         assert_eq!(Action::FastForwardSpawn.to_string(), "FastForwardSpawn");
     }
 
+    #[test]
+    fn rename_action_round_trips() {
+        assert_eq!(
+            Action::parse("RenameHighlighted").unwrap(),
+            Action::RenameHighlighted
+        );
+        assert_eq!(Action::RenameHighlighted.to_string(), "RenameHighlighted");
+        assert_eq!(
+            Action::RenameHighlighted.help_label(),
+            "Rename selected session"
+        );
+    }
+
     #[test]
     fn display_round_trips() {
         for a in [
             Action::EnterInsert,
+            Action::RenameHighlighted,
             Action::Quit,
             Action::NewDraftPane,
             Action::ScrollPanePageDown,

crates/maestro-tui/src/app.rs

@@ -40,6 +40,7 @@ use crate::render::{draw, RegionMap, RenderInputs};
 use crate::session_task::{SessionInput, SessionTask};
 use crate::sidebar::Sidebar;
 use crate::state::{AppState, Focus, OverlayKind, PaneRef, SidebarItem};
+use crate::text_input::TextInput;
 use crate::worktrees::WorktreesView;
 use crate::TuiError;
 
@@ -75,6 +76,9 @@ pub struct App {
     /// Entries of the retained-worktrees view (#85). Daemon data, kept here
     /// rather than in `AppState` so the overlay kind stays payload-free.
     worktrees: WorktreesView,
+    /// Edit buffer behind [`OverlayKind::Rename`] (#125), kept here for the
+    /// same reason the worktree entries are.
+    rename_input: TextInput,
     region: RegionMap,
     last_sent_size: HashMap<Uuid, (u16, u16)>,
     clicks: ClickTracker,
@@ -123,6 +127,12 @@ pub enum Effect {
     /// Reclaim one retained worktree (#85) — removes its directory; the
     /// branch is never deleted.
     ReclaimWorktree(Uuid),
+    /// Rename a session (#125). An empty name clears the custom one, so the
+    /// card falls back to the command.
+    Rename {
+        id: Uuid,
+        name: String,
+    },
 }
 
 impl App {
@@ -148,6 +158,7 @@ impl App {
             daemon,
             http,
             worktrees: WorktreesView::default(),
+            rename_input: TextInput::default(),
             draft_tx,
             draft_rx,
             region: RegionMap::default(),
@@ -284,6 +295,7 @@ impl App {
                 Effect::LoadBranches(tab) => self.spawn_load_branches(tab),
                 Effect::LoadWorktrees => self.spawn_load_worktrees(),
                 Effect::ReclaimWorktree(id) => self.submit_reclaim(id).await,
+                Effect::Rename { id, name } => self.submit_rename(id, &name).await,
                 Effect::Forward { id, bytes } => {
                     if let Some(handle) = self.emulators.get(id) {
                         let _ = handle.tx.send(SessionInput::Bytes(bytes)).await;
@@ -306,6 +318,21 @@ impl App {
                 }
                 _ => (OverlayDecision::Consumed, Vec::new()),
             },
+            Some(OverlayKind::Rename(id)) => match key {
+                InputKey::Enter => {
+                    let name = self.rename_input.value().to_string();
+                    self.state.dismiss_overlay();
+                    (OverlayDecision::Consumed, vec![Effect::Rename { id, name }])
+                }
+                InputKey::Esc => {
+                    self.state.dismiss_overlay();
+                    (OverlayDecision::Consumed, Vec::new())
+                }
+                other => {
+                    self.rename_input.handle_key(other);
+                    (OverlayDecision::Consumed, Vec::new())
+                }
+            },
             Some(OverlayKind::Worktrees) => match key {
                 InputKey::Char { c: 'j', .. } | InputKey::Down => {
                     self.worktrees.move_highlight(1);
@@ -430,6 +457,23 @@ impl App {
                     self.state.show_overlay(OverlayKind::KillConfirm(sid));
                 }
             }
+            Action::RenameHighlighted => {
+                if let Some(sid) = self.pick_sidebar_target() {
+                    // Pre-fill with the custom name only: a session that has
+                    // none starts empty rather than with its command already
+                    // typed in, which Enter would then pin as the name.
+                    self.rename_input = TextInput::with_value(
+                        self.catalog
+                            .snapshot()
+                            .sessions
+                            .iter()
+                            .find(|s| s.id == sid)
+                            .and_then(crate::sidebar::custom_name_for)
+                            .unwrap_or_default(),
+                    );
+                    self.state.show_overlay(OverlayKind::Rename(sid));
+                }
+            }
             Action::ShowWorktrees => {
                 self.state.show_overlay(OverlayKind::Worktrees);
                 effects.push(Effect::LoadWorktrees);
@@ -928,6 +972,14 @@ impl App {
         }
     }
 
+    /// Rename a session (#125). The catalog updates from the daemon's
+    /// `SessionUpdated` broadcast, so nothing is patched locally here.
+    async fn submit_rename(&mut self, sid: Uuid, name: &str) {
+        if let Err(e) = self.daemon.rename_session(sid, name).await {
+            self.state.toast(format!("rename failed: {e}"));
+        }
+    }
+
     /// Fetch the retained-worktree store without blocking the loop (#85) —
     /// same off-loop pattern as the draft loaders.
     fn spawn_load_worktrees(&self) {
@@ -1008,6 +1060,7 @@ impl App {
             draft,
             help: &self.help,
             worktrees: Some(&self.worktrees),
+            rename_input: &self.rename_input,
         };
 
         let mut new_region = RegionMap::default();
@@ -2035,6 +2088,117 @@ mod tests {
         assert!(matches!(app.state.overlay(), Some(OverlayKind::KillConfirm(s)) if *s == sid));
     }
 
+    // -- rename (#125) ------------------------------------------------------
+
+    fn seed_session(app: &mut App, sid: Uuid, name: Option<&str>) {
+        use chrono::Utc;
+        use maestro_protocol::{CatalogEvent, Session, SessionStatus};
+        let metadata = match name {
+            Some(n) => {
+                HashMap::from([("name".to_string(), serde_json::Value::String(n.to_string()))])
+            }
+            None => Default::default(),
+        };
+        app.catalog.apply_event(CatalogEvent::Snapshot {
+            sessions: vec![Session {
+                id: sid,
+                command: "bash".into(),
+                cwd: std::path::PathBuf::from("/"),
+                env: Default::default(),
+                metadata,
+                worktree: None,
+                status: SessionStatus::Running,
+                created_at: Utc::now(),
+                foreground: None,
+                activity: Default::default(),
+                activity_detail: None,
+                last_activity_at: Utc::now(),
+                activity_since: Utc::now(),
+                current_cwd: None,
+                blocked_work: None,
+            }],
+        });
+    }
+
+    #[test]
+    fn rename_highlighted_opens_a_prompt_prefilled_with_the_current_name() {
+        let mut app = make_app();
+        let sid = Uuid::from_u128(7);
+        seed_session(&mut app, sid, Some("amber-falcon"));
+        app.dispatch(Action::RenameHighlighted);
+        assert!(matches!(app.state.overlay(), Some(OverlayKind::Rename(s)) if *s == sid));
+        assert_eq!(app.rename_input.value(), "amber-falcon");
+    }
+
+    /// A session with no name of its own opens an empty field: pre-filling
+    /// with the command would let Enter pin the command as the name.
+    #[test]
+    fn rename_prompt_starts_empty_for_an_unnamed_session() {
+        let mut app = make_app();
+        seed_session(&mut app, Uuid::from_u128(7), None);
+        app.dispatch(Action::RenameHighlighted);
+        assert_eq!(app.rename_input.value(), "");
+    }
+
+    #[test]
+    fn typing_then_enter_submits_the_edited_name() {
+        let mut app = make_app();
+        let sid = Uuid::from_u128(7);
+        seed_session(&mut app, sid, Some("amber"));
+        app.dispatch(Action::RenameHighlighted);
+        for c in "-fox".chars() {
+            let (decision, effects) = app.handle_overlay_input(&InputKey::Char {
+                c,
+                ctrl: false,
+                alt: false,
+                shift: false,
+            });
+            assert_eq!(decision, OverlayDecision::Consumed);
+            assert!(effects.is_empty());
+        }
+        let (decision, effects) = app.handle_overlay_input(&InputKey::Enter);
+        assert_eq!(decision, OverlayDecision::Consumed);
+        assert_eq!(
+            effects,
+            vec![Effect::Rename {
+                id: sid,
+                name: "amber-fox".into()
+            }]
+        );
+        assert!(app.state.overlay().is_none());
+    }
+
+    #[test]
+    fn escape_cancels_the_rename_without_an_effect() {
+        let mut app = make_app();
+        seed_session(&mut app, Uuid::from_u128(7), Some("amber"));
+        app.dispatch(Action::RenameHighlighted);
+        let (decision, effects) = app.handle_overlay_input(&InputKey::Esc);
+        assert_eq!(decision, OverlayDecision::Consumed);
+        assert!(effects.is_empty());
+        assert!(app.state.overlay().is_none());
+    }
+
+    /// Clearing the field and submitting is how the name is dropped, so the
+    /// card falls back to the command.
+    #[test]
+    fn an_emptied_field_submits_a_blank_name() {
+        let mut app = make_app();
+        let sid = Uuid::from_u128(7);
+        seed_session(&mut app, sid, Some("ab"));
+        app.dispatch(Action::RenameHighlighted);
+        app.handle_overlay_input(&InputKey::Backspace);
+        app.handle_overlay_input(&InputKey::Backspace);
+        let (_, effects) = app.handle_overlay_input(&InputKey::Enter);
+        assert_eq!(
+            effects,
+            vec![Effect::Rename {
+                id: sid,
+                name: String::new()
+            }]
+        );
+    }
+
     // -- retained worktrees (#85) -------------------------------------------
 
     fn sample_worktree(id: u128) -> maestro_protocol::RetainedWorktree {

crates/maestro-tui/src/config.rs

@@ -53,6 +53,7 @@ const DEFAULT_NORMAL: &[(&str, &str)] = &[
     // thing with every default resolved and no form.
     ("S", "FastForwardSpawn"),
     ("x", "KillHighlighted"),
+    ("r", "RenameHighlighted"),
     ("w", "ShowWorktrees"),
     // Focus
     ("ctrl-w h", "FocusSidebar"),

crates/maestro-tui/src/overlays.rs

@@ -1,4 +1,5 @@
-//! Overlay widgets: kill-confirm prompt, help overlay, transient toast.
+//! Overlay widgets: kill-confirm prompt, rename prompt, help overlay,
+//! transient toast.
 //!
 //! The spawn form is no longer an overlay (issue #63) — it lives in draft
 //! panes ([`crate::draft::DraftPane`]).
@@ -7,10 +8,13 @@
 //! `Clear` widget wipes the underlying buffer before drawing.
 
 use ratatui::layout::Rect;
+use ratatui::style::Style;
 use ratatui::text::Line;
 use ratatui::widgets::{Block, Borders, Clear, List, ListItem, Paragraph};
 use ratatui::Frame;
 
+use crate::text_input::TextInput;
+
 #[derive(Debug, Clone)]
 pub struct KillConfirm {
     pub label: String,
@@ -39,6 +43,50 @@ impl KillConfirm {
     }
 }
 
+/// Rename prompt for the highlighted session (#125).
+///
+/// Borrows its text buffer rather than owning it: the buffer lives on `App`
+/// alongside the worktrees view's entries, so [`crate::state::OverlayKind`]
+/// stays a plain comparable enum.
+#[derive(Debug)]
+pub struct RenamePrompt<'a> {
+    /// What the card shows today — the session's name, or the command it
+    /// falls back to when it has none.
+    pub current: &'a str,
+    pub input: &'a TextInput,
+}
+
+impl RenamePrompt<'_> {
+    /// Draws the prompt and returns where the terminal cursor belongs.
+    pub fn render(&self, f: &mut Frame, parent: Rect) -> Option<(u16, u16)> {
+        let area = centered(parent, 64, 7);
+        f.render_widget(Clear, area);
+        let block = Block::default().title(" rename ").borders(Borders::ALL);
+        let inner = block.inner(area);
+        f.render_widget(block, area);
+        if inner.height < 4 || inner.width == 0 {
+            return None;
+        }
+        let row = |offset: u16| Rect {
+            x: inner.x,
+            y: inner.y + offset,
+            width: inner.width,
+            height: 1,
+        };
+        f.render_widget(
+            Paragraph::new(Line::from(format!("Rename {}", self.current))),
+            row(0),
+        );
+        let field = row(1);
+        let col = self.input.render(field, f.buffer_mut(), Style::default());
+        f.render_widget(
+            Paragraph::new(Line::from("[enter] save   [esc] cancel")),
+            row(3),
+        );
+        Some((col, field.y))
+    }
+}
+
 #[derive(Debug, Clone)]
 pub struct HelpOverlay {
     pub lines: Vec<String>,
@@ -151,6 +199,22 @@ mod tests {
         assert!(rendered.contains("refused"), "{rendered}");
     }
 
+    #[test]
+    fn rename_prompt_shows_the_current_name_and_the_edit_buffer() {
+        let input = TextInput::with_value("crimson-otter");
+        let prompt = RenamePrompt {
+            current: "amber-falcon",
+            input: &input,
+        };
+        let rendered = render_to_string(70, 12, |f| {
+            prompt.render(f, f.area());
+        });
+        assert!(rendered.contains("Rename amber-falcon"), "{rendered}");
+        assert!(rendered.contains("crimson-otter"), "{rendered}");
+        assert!(rendered.contains("[enter] save"), "{rendered}");
+        assert!(rendered.contains("[esc] cancel"), "{rendered}");
+    }
+
     #[test]
     fn help_overlay_lists_lines() {
         let help = HelpOverlay {

crates/maestro-tui/src/render.rs

@@ -10,7 +10,7 @@ use ratatui::Frame;
 
 use crate::input::Region;
 use crate::keymap::Mode;
-use crate::overlays::{HelpOverlay, KillConfirm, Toast};
+use crate::overlays::{HelpOverlay, KillConfirm, RenamePrompt, Toast};
 use crate::palette;
 use crate::pane::Pane;
 use crate::sidebar::Sidebar;
@@ -84,6 +84,8 @@ pub struct RenderInputs<'a> {
     pub help: &'a HelpOverlay,
     /// Retained-worktree entries for the worktrees view (#85).
     pub worktrees: Option<&'a WorktreesView>,
+    /// Edit buffer behind the rename prompt (#125).
+    pub rename_input: &'a crate::text_input::TextInput,
 }
 
 /// Draw one frame. Returns the `RegionMap` the input router will consult for
@@ -170,6 +172,23 @@ pub fn draw(f: &mut Frame, inputs: RenderInputs<'_>) -> RegionMap {
             kc.render(f, area);
             map.modal = Some(area);
         }
+        Some(OverlayKind::Rename(id)) => {
+            let current = inputs
+                .sidebar
+                .sessions
+                .iter()
+                .find(|s| &s.id == id)
+                .map(crate::sidebar::name_for)
+                .unwrap_or_else(|| id.to_string());
+            let prompt = RenamePrompt {
+                current: &current,
+                input: inputs.rename_input,
+            };
+            if let Some((x, y)) = prompt.render(f, area) {
+                f.set_cursor_position((x, y));
+            }
+            map.modal = Some(area);
+        }
         Some(OverlayKind::Help) => {
             inputs.help.render(f, area);
             map.modal = Some(area);
@@ -354,6 +373,7 @@ mod tests {
             state: &state,
             help: &help,
             worktrees: None,
+            rename_input: &crate::text_input::TextInput::default(),
         };
 
         let backend = ratatui::backend::TestBackend::new(80, 24);
@@ -407,6 +427,7 @@ mod tests {
                 state: &state,
                 help: &help,
                 worktrees: None,
+                rename_input: &crate::text_input::TextInput::default(),
             };
             let backend = ratatui::backend::TestBackend::new(80, 24);
             let mut terminal = ratatui::Terminal::new(backend).unwrap();
@@ -446,6 +467,7 @@ mod tests {
                 state: &state,
                 help: &help,
                 worktrees: None,
+                rename_input: &crate::text_input::TextInput::default(),
             };
             let backend = ratatui::backend::TestBackend::new(80, 24);
             let mut terminal = ratatui::Terminal::new(backend).unwrap();

crates/maestro-tui/src/sidebar.rs

@@ -382,10 +382,15 @@ fn pad_to_width(mut spans: Vec<Span<'static>>, width: usize, base: Style) -> Vec
 
 /// `metadata.name` if present, else the command line.
 pub(crate) fn name_for(s: &Session) -> String {
-    if let Some(serde_json::Value::String(name)) = s.metadata.get("name") {
+    custom_name_for(s).unwrap_or_else(|| s.command.clone())
-        name.clone()
+}
-    } else {
+
-        s.command.clone()
+/// The session's own name, without the command fallback (#125): `None` for a
+/// session that was never given one.
+pub(crate) fn custom_name_for(s: &Session) -> Option<String> {
+    match s.metadata.get("name") {
+        Some(serde_json::Value::String(name)) => Some(name.clone()),
+        _ => None,
     }
 }
 

crates/maestro-tui/src/state.rs

@@ -60,6 +60,9 @@ impl Tab {
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub enum OverlayKind {
     KillConfirm(Uuid),
+    /// Rename prompt for this session (#125). The edit buffer lives on `App`,
+    /// like the worktrees view's entries, so this stays comparable.
+    Rename(Uuid),
     Help,
     Toast(String),
     /// The retained-worktrees view (#85); its entries live on `App` because

docs/INSTALL.md

@@ -142,6 +142,7 @@ chord_timeout_ms = 1000      # how long to hold a partial chord like `ctrl-w`
 "i"            = "EnterInsert"
 "s"            = "NewDraftPane"
 "x"            = "KillHighlighted"
+"r"            = "RenameHighlighted"
 "?"            = "ShowHelp"
 "ctrl-w h"     = "FocusSidebar"
 "enter"        = "AttachHighlighted"