feat(maestro): rename a session from the web sidebar

Right-clicking a card opens a custom context menu (rename, spawn similar,
kill). Rename swaps the name for an inline field; Enter commits, Escape and
blur cancel. The tree stops rebuilding while the field is open, so a catalog
delta cannot replace what is being typed into.

Refs #125

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

crates/maestro-daemon/src/local_api.rs

@@ -20,7 +20,7 @@ use axum::{Json, Router};
 use maestro_config::SpawnPreset;
 use maestro_protocol::{
     routes, ApiError, CatalogEvent, CreateSessionRequest, DaemonInfo, GitRoot, NameBatch,
-    ReportActivityRequest, Session, PROTOCOL_VERSION,
+    RenameSessionRequest, ReportActivityRequest, Session, PROTOCOL_VERSION,
 };
 use serde::Deserialize;
 use uuid::Uuid;
@@ -47,7 +47,10 @@ pub fn router(state: LocalApiState) -> Router {
     Router::new()
         .route(routes::SESSIONS, get(list_sessions).post(create_session))
         .route(routes::patterns::SESSION_ACTIVITY, post(report_activity))
-        .route(routes::patterns::SESSION, delete(kill_session))
+        .route(
+            routes::patterns::SESSION,
+            delete(kill_session).patch(rename_session),
+        )
         .route(routes::DIRS, get(list_dir))
         .route(routes::RECENT_DIRS, get(recent_dirs))
         .route(routes::PROJECTS, get(projects))
@@ -213,6 +216,28 @@ async fn kill_session(
     }
 }
 
+/// `PATCH /api/sessions/:id` (#125): rename a session. The name is trimmed
+/// and capped server-side; a blank one clears `metadata.name` so the session
+/// falls back to its command. Answers with the updated session, which also
+/// goes out as `SessionUpdated` to every events subscriber.
+async fn rename_session(
+    State(s): State<LocalApiState>,
+    Path(id): Path<Uuid>,
+    Json(body): Json<RenameSessionRequest>,
+) -> Response {
+    match s.manager.rename(id, &body.name).await {
+        Ok(session) => (StatusCode::OK, Json(session)).into_response(),
+        Err(e) => {
+            let info = e.to_error_info();
+            error_response(
+                session_error_status(&info.code),
+                info.code.as_str(),
+                info.message.as_str(),
+            )
+        }
+    }
+}
+
 /// `GET /api/worktrees` (#80): every retained worktree, with the in-the-way
 /// breakdown recomputed at read time — never stored, so a tree whose work has
 /// since been committed or pushed says so. Entries whose directory somebody

crates/maestro-daemon/src/session.rs

@@ -716,6 +716,38 @@ impl SessionManager {
             .map_err(SessionError::Tmux)
     }
 
+    /// Rename a session (#125): set `metadata.name`, or clear it when the
+    /// requested name is blank so the session falls back to its command.
+    ///
+    /// The new name is persisted to the sidecar before the event goes out — a
+    /// rename the operator can see but that a daemon restart would undo is
+    /// worse than one that failed outright.
+    pub async fn rename(&self, id: Uuid, name: &str) -> Result<Session, SessionError> {
+        // The sidecar write happens under the sessions lock so what is on disk
+        // and what is in memory can never disagree about the newest rename.
+        let session = {
+            let mut sessions = self.inner.sessions.lock().await;
+            let rec = sessions.get_mut(&id).ok_or(SessionError::NotFound(id))?;
+            let mut renamed = rec.session.clone();
+            match maestro_protocol::normalize_session_name(name) {
+                Some(name) => renamed
+                    .metadata
+                    .insert("name".into(), serde_json::Value::String(name)),
+                None => renamed.metadata.remove("name"),
+            };
+            self.inner
+                .sidecar
+                .write(&renamed)
+                .map_err(SessionError::Sidecar)?;
+            rec.session = renamed.clone();
+            renamed
+        };
+        let _ = self.inner.events.send(CatalogEvent::SessionUpdated {
+            session: session.clone(),
+        });
+        Ok(session)
+    }
+
     /// Accept an agent-reported activity state (#105), the only path that can
     /// produce `ActivityState::Error`. The report outranks the activity pass's
     /// own inference until its TTL lapses — so an agent that dies mid-run

crates/maestro-daemon/tests/local_api.rs

@@ -323,6 +323,48 @@ async fn delete_unknown_session_returns_404() {
     assert_eq!(resp.status(), reqwest::StatusCode::NOT_FOUND);
 }
 
+/// #125: the rename endpoint answers with the updated session, and the name
+/// it stored is the trimmed one.
+#[tokio::test]
+async fn patch_session_renames_it() {
+    let h = spawn("naps-laptop").await;
+    let session = h
+        .manager
+        .create(CreateSessionRequest {
+            cwd: "/tmp".into(),
+            command: "sleep 60".into(),
+            env: HashMap::new(),
+            metadata: HashMap::new(),
+            worktree: None,
+        })
+        .await
+        .unwrap();
+    let resp = reqwest::Client::new()
+        .patch(url(h.addr, &format!("/api/sessions/{}", session.id)))
+        .json(&serde_json::json!({ "name": "  crimson-otter " }))
+        .send()
+        .await
+        .unwrap();
+    assert_eq!(resp.status(), reqwest::StatusCode::OK);
+    let updated: Session = resp.json().await.unwrap();
+    assert_eq!(
+        updated.metadata.get("name").and_then(|v| v.as_str()),
+        Some("crimson-otter")
+    );
+}
+
+#[tokio::test]
+async fn patch_unknown_session_returns_404() {
+    let h = spawn("naps-laptop").await;
+    let resp = reqwest::Client::new()
+        .patch(url(h.addr, &format!("/api/sessions/{}", Uuid::new_v4())))
+        .json(&serde_json::json!({ "name": "nope" }))
+        .send()
+        .await
+        .unwrap();
+    assert_eq!(resp.status(), reqwest::StatusCode::NOT_FOUND);
+}
+
 #[tokio::test]
 async fn delete_owned_session_kills_it() {
     let h = spawn("naps-laptop").await;

crates/maestro-daemon/tests/rename.rs

@@ -0,0 +1,138 @@
+//! Renaming a live session (#125): `SessionManager::rename` semantics —
+//! what lands in `metadata.name`, what reaches the sidecar, and what goes out
+//! on the event stream.
+
+mod common;
+
+use std::sync::Arc;
+
+use common::TmuxFixture;
+use maestro_daemon::sidecar::SidecarStore;
+use maestro_daemon::worktree::WorktreeManager;
+use maestro_daemon::SessionManager;
+use maestro_protocol::{CatalogEvent, CreateSessionRequest, MAX_SESSION_NAME_LEN};
+use tempfile::TempDir;
+use uuid::Uuid;
+
+struct Fixture {
+    manager: SessionManager,
+    sidecar: SidecarStore,
+    _tmux: TmuxFixture,
+    _state_dir: TempDir,
+}
+
+fn fixture() -> Fixture {
+    let tmux = TmuxFixture::new();
+    let state_dir = TempDir::new().unwrap();
+    let sidecar = SidecarStore::new(state_dir.path().join("sessions"));
+    let manager = SessionManager::new(
+        Arc::new(tmux.tmux.clone()),
+        sidecar.clone(),
+        WorktreeManager::new(None),
+        state_dir.path().join("fifos"),
+    );
+    Fixture {
+        manager,
+        sidecar,
+        _tmux: tmux,
+        _state_dir: state_dir,
+    }
+}
+
+async fn spawn_named(manager: &SessionManager, name: Option<&str>) -> Uuid {
+    let metadata = match name {
+        Some(n) => std::collections::HashMap::from([(
+            "name".to_string(),
+            serde_json::Value::String(n.to_string()),
+        )]),
+        None => Default::default(),
+    };
+    manager
+        .create(CreateSessionRequest {
+            cwd: "/tmp".into(),
+            command: "sleep 60".into(),
+            env: Default::default(),
+            metadata,
+            worktree: None,
+        })
+        .await
+        .unwrap()
+        .id
+}
+
+fn name_of(session: &maestro_protocol::Session) -> Option<&str> {
+    session.metadata.get("name").and_then(|v| v.as_str())
+}
+
+#[tokio::test]
+async fn rename_on_unknown_session_is_not_found() {
+    let fx = fixture();
+    let err = fx
+        .manager
+        .rename(Uuid::new_v4(), "whatever")
+        .await
+        .unwrap_err();
+    assert!(matches!(err, maestro_daemon::SessionError::NotFound(_)));
+}
+
+#[tokio::test]
+async fn rename_sets_the_name_in_memory_and_on_disk() {
+    let fx = fixture();
+    let id = spawn_named(&fx.manager, Some("amber-falcon")).await;
+
+    let renamed = fx.manager.rename(id, "  crimson-otter  ").await.unwrap();
+    assert_eq!(name_of(&renamed), Some("crimson-otter"));
+
+    let snapshot = fx.manager.snapshot().await;
+    let live = snapshot.iter().find(|s| s.id == id).unwrap();
+    assert_eq!(name_of(live), Some("crimson-otter"));
+
+    // A rename a daemon restart would undo is worse than one that failed.
+    let persisted = fx.sidecar.read(id).unwrap().unwrap();
+    assert_eq!(name_of(&persisted), Some("crimson-otter"));
+}
+
+#[tokio::test]
+async fn a_blank_rename_clears_the_name() {
+    let fx = fixture();
+    let id = spawn_named(&fx.manager, Some("amber-falcon")).await;
+
+    let renamed = fx.manager.rename(id, "   ").await.unwrap();
+    assert_eq!(name_of(&renamed), None);
+    // Line 1 falls back to the command, per docs/SIDEBAR.md.
+    assert_eq!(renamed.command, "sleep 60");
+    assert_eq!(name_of(&fx.sidecar.read(id).unwrap().unwrap()), None);
+}
+
+#[tokio::test]
+async fn rename_caps_a_long_name() {
+    let fx = fixture();
+    let id = spawn_named(&fx.manager, None).await;
+    let long = "x".repeat(MAX_SESSION_NAME_LEN + 20);
+    let renamed = fx.manager.rename(id, &long).await.unwrap();
+    assert_eq!(
+        name_of(&renamed).unwrap().chars().count(),
+        MAX_SESSION_NAME_LEN
+    );
+}
+
+#[tokio::test]
+async fn rename_broadcasts_a_session_update() {
+    let fx = fixture();
+    let id = spawn_named(&fx.manager, Some("amber-falcon")).await;
+    let mut events = fx.manager.events();
+
+    fx.manager.rename(id, "crimson-otter").await.unwrap();
+
+    let event = tokio::time::timeout(std::time::Duration::from_secs(5), events.recv())
+        .await
+        .expect("an update within the timeout")
+        .expect("the event channel stays open");
+    match event {
+        CatalogEvent::SessionUpdated { session } => {
+            assert_eq!(session.id, id);
+            assert_eq!(name_of(&session), Some("crimson-otter"));
+        }
+        other => panic!("expected SessionUpdated, got {other:?}"),
+    }
+}

crates/maestro-protocol/src/client.rs

@@ -16,7 +16,8 @@ use uuid::Uuid;
 use crate::routes::{self, UrlError};
 use crate::{
     ApiError, BranchInfo, CreateSessionRequest, DaemonInfo, DirListing, ErrorInfo, GitRoot,
-    KillOutcome, Project, RecentDirs, ReportActivityRequest, RetainedWorktree, Session,
+    KillOutcome, Project, RecentDirs, RenameSessionRequest, ReportActivityRequest,
+    RetainedWorktree, Session,
 };
 
 /// Time budget for establishing a TCP connection to the daemon.
@@ -134,6 +135,17 @@ impl DaemonClient {
         json(resp).await
     }
 
+    /// `PATCH /api/sessions/:id` (#125): rename a live session. A blank name
+    /// clears the custom one, so the session falls back to its command. The
+    /// daemon trims and caps the name and answers with the updated session.
+    pub async fn rename_session(&self, id: Uuid, name: &str) -> Result<Session, ClientError> {
+        let req = RenameSessionRequest { name: name.into() };
+        let resp = self
+            .send(Method::PATCH, &routes::session(id), &[], Some(&req))
+            .await?;
+        json(check(resp).await?).await
+    }
+
     /// `POST /api/sessions/:id/activity` (#105): report an agent-observed
     /// state. The daemon holds it above its own inference for a TTL, then
     /// resumes inference. Answers `204 No Content`.

crates/maestro-protocol/src/lib.rs

@@ -495,6 +495,31 @@ pub struct NameBatch {
     pub names: Vec<String>,
 }
 
+/// Longest session name the daemon stores (#125), in characters. A name is a
+/// sidebar card's line 1; past this it only truncates on every client anyway.
+pub const MAX_SESSION_NAME_LEN: usize = 64;
+
+/// HTTP `PATCH /api/sessions/:id` body (#125): rename a live session.
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+pub struct RenameSessionRequest {
+    pub name: String,
+}
+
+/// Trim a requested session name and cap it at [`MAX_SESSION_NAME_LEN`]
+/// characters. `None` when nothing is left — that clears `metadata.name` and
+/// the card falls back to the command, the same rule the spawn form uses when
+/// its name field is blank.
+///
+/// Shared so the daemon and every Rust client agree on what a name becomes;
+/// `web/src/types.ts` carries the same function for the browser.
+pub fn normalize_session_name(name: &str) -> Option<String> {
+    let trimmed = name.trim();
+    if trimmed.is_empty() {
+        return None;
+    }
+    Some(trimmed.chars().take(MAX_SESSION_NAME_LEN).collect())
+}
+
 // ---------------------------------------------------------------------------
 // Catalog events (`WS /api/events`)
 // ---------------------------------------------------------------------------
@@ -964,4 +989,42 @@ mod tests {
             assert_eq!(c, round_trip(&c));
         }
     }
+
+    /// #125: a rename request is trimmed and capped; a blank one clears the
+    /// name so the card falls back to the command.
+    #[test]
+    fn session_names_are_trimmed_capped_and_blankable() {
+        assert_eq!(
+            normalize_session_name("  amber-falcon  "),
+            Some("amber-falcon".into())
+        );
+        assert_eq!(normalize_session_name(""), None);
+        assert_eq!(normalize_session_name("   \t "), None);
+        let long = "x".repeat(MAX_SESSION_NAME_LEN + 10);
+        assert_eq!(
+            normalize_session_name(&long).unwrap().chars().count(),
+            MAX_SESSION_NAME_LEN
+        );
+    }
+
+    /// The cap counts characters, not bytes — a multi-byte name must not be
+    /// sliced mid-codepoint.
+    #[test]
+    fn session_name_cap_counts_characters() {
+        let name = "é".repeat(MAX_SESSION_NAME_LEN + 5);
+        let capped = normalize_session_name(&name).unwrap();
+        assert_eq!(capped.chars().count(), MAX_SESSION_NAME_LEN);
+    }
+
+    #[test]
+    fn rename_request_round_trips() {
+        let req = RenameSessionRequest {
+            name: "amber-falcon".into(),
+        };
+        assert_eq!(req, round_trip(&req));
+        assert_eq!(
+            serde_json::to_value(&req).unwrap(),
+            serde_json::json!({"name": "amber-falcon"})
+        );
+    }
 }

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") {
-        name.clone()
-    } else {
-        s.command.clone()
+    custom_name_for(s).unwrap_or_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"

docs/SIDEBAR.md

@@ -20,6 +20,13 @@ A card is always two lines: **line 1** and **line 2**.
 Line 1 carries no badges. The `⚠ blocked work` badge (#83) and the `exited`
 badge move off this row into line 2.
 
+The name is editable in place (#125). In the web client, right-clicking a card
+opens a context menu whose **rename** entry swaps the name for a text field —
+Enter commits, Escape cancels. The TUI opens the same edit as a prompt, bound
+to `r` in the sidebar by default. Both send `PATCH /api/sessions/:id`; both
+start from the session's own name, never from the command it falls back to,
+and an empty field clears the name so the fallback resumes.
+
 ## Line 2 — meta line (adaptive)
 
 Line 2 always renders — never an empty placeholder row either, since its

web/src/api.ts

@@ -44,6 +44,20 @@ export async function createSession(req: CreateSessionRequest): Promise<Session>
   );
 }
 
+/** Rename a session (#125). An empty name clears the custom one, so the card
+ * falls back to the command. The daemon trims and caps what it stores and
+ * broadcasts the update, so callers need not patch the store themselves. */
+export async function renameSession(id: Uuid, name: string): Promise<Session> {
+  return jsonOrError(
+    await fetch(routes.session(id), {
+      method: "PATCH",
+      credentials: "same-origin",
+      headers: { "content-type": "application/json" },
+      body: JSON.stringify({ name }),
+    }),
+  );
+}
+
 export async function killSession(id: Uuid): Promise<void> {
   await jsonOrError(
     await fetch(routes.session(id), {

web/src/catalog.ts

@@ -1,9 +1,18 @@
 import { escapeHtml } from "./html.js";
-import { getDaemonInfo, killSession } from "./api.js";
+import { getDaemonInfo, killSession, renameSession } from "./api.js";
+import { openContextMenu } from "./contextMenu.js";
 import { HUD_TOGGLE_EVENT, isHudEnabled, toggleHud } from "./debug.js";
 import { CatalogStore } from "./events.js";
 import type { Session } from "./types.js";
-import { abbreviateFolderName, formatInTheWay, sessionBlockers, sessionName } from "./types.js";
+import {
+  abbreviateFolderName,
+  customSessionName,
+  formatInTheWay,
+  MAX_SESSION_NAME_LEN,
+  normalizeSessionName,
+  sessionBlockers,
+  sessionName,
+} from "./types.js";
 import {
   activityColorSlug,
   activityDurationLabel,
@@ -23,6 +32,11 @@ export function requestOpenSpawn(): void {
 
 const collapsed = new Set<string>();
 
+/** Session whose card is currently being renamed inline (#125). The tree
+ * re-renders on every catalog delta, and an activity update arriving mid-edit
+ * would otherwise replace the field the user is typing into. */
+let renamingId: string | null = null;
+
 // docs/SIDEBAR.md: the state word is never rendered — the dot's colour carries
 // it. It survives only in tooltips/aria labels so meaning is not colour-only.
 const STATE_WORDS: Record<string, string> = {
@@ -124,24 +138,96 @@ function renderNode(node: TreeNode, depth: number): HTMLElement {
     document.dispatchEvent(new CustomEvent("catalog-spawn-similar", { detail: s }));
   });
   const killBtn = row.querySelector(".leaf-kill") as HTMLButtonElement;
-  killBtn.addEventListener("click", async (ev) => {
+  killBtn.addEventListener("click", (ev) => {
     ev.preventDefault();
     ev.stopPropagation();
-    // #83: the confirm restates the warning at the moment of decision.
-    const blockers = sessionBlockers(s);
-    const question = blockers
-      ? `Kill session "${name}"? Its worktree still has ${formatInTheWay(blockers)} — the kill will be refused unless forced.`
-      : `Kill session "${name}"?`;
-    if (!confirm(question)) return;
-    try {
-      await killSession(s.id);
-    } catch (e) {
-      alert(`Failed to kill: ${(e as Error).message}`);
-    }
+    void confirmAndKill(s, name);
+  });
+  row.addEventListener("contextmenu", (ev) => {
+    ev.preventDefault();
+    ev.stopPropagation();
+    openContextMenu(ev.clientX, ev.clientY, [
+      { label: "Rename…", onSelect: () => beginRename(row, s) },
+      {
+        label: "Spawn similar",
+        onSelect: () =>
+          document.dispatchEvent(new CustomEvent("catalog-spawn-similar", { detail: s })),
+      },
+      { label: "Kill session", danger: true, onSelect: () => void confirmAndKill(s, name) },
+    ]);
   });
   return row;
 }
 
+/** #83: the confirm restates the warning at the moment of decision. */
+async function confirmAndKill(s: Session, name: string): Promise<void> {
+  const blockers = sessionBlockers(s);
+  const question = blockers
+    ? `Kill session "${name}"? Its worktree still has ${formatInTheWay(blockers)} — the kill will be refused unless forced.`
+    : `Kill session "${name}"?`;
+  if (!confirm(question)) return;
+  try {
+    await killSession(s.id);
+  } catch (e) {
+    alert(`Failed to kill: ${(e as Error).message}`);
+  }
+}
+
+/**
+ * Swap the card's name for a text field (#125). Enter commits, Escape and
+ * blur cancel. An emptied field clears the name, so the card falls back to
+ * the command — the same rule the spawn form's blank name field follows.
+ */
+function beginRename(row: HTMLElement, s: Session): void {
+  const nameEl = row.querySelector<HTMLElement>(".leaf-name");
+  if (!nameEl) return;
+  const input = document.createElement("input");
+  input.type = "text";
+  input.className = "leaf-name leaf-rename";
+  input.value = customSessionName(s) ?? "";
+  input.maxLength = MAX_SESSION_NAME_LEN;
+  input.setAttribute("aria-label", `Rename ${sessionName(s)}`);
+  // The card is an <a>, and the tree starts a drag on pointerdown: without
+  // these, clicking into the field navigates away or begins dragging the row.
+  for (const type of ["click", "pointerdown", "dblclick"]) {
+    input.addEventListener(type, (ev) => {
+      ev.preventDefault();
+      ev.stopPropagation();
+      input.focus();
+    });
+  }
+
+  renamingId = s.id;
+  let settled = false;
+  const finish = () => {
+    if (settled) return false;
+    settled = true;
+    renamingId = null;
+    document.dispatchEvent(new CustomEvent("catalog-rerender"));
+    return true;
+  };
+
+  input.addEventListener("keydown", (ev) => {
+    if (ev.key === "Enter") {
+      ev.preventDefault();
+      // Normalised here so what is sent is what the daemon will store.
+      const name = normalizeSessionName(input.value);
+      if (!finish()) return;
+      void renameSession(s.id, name).catch((e: Error) => {
+        alert(`Failed to rename: ${e.message}`);
+      });
+    } else if (ev.key === "Escape") {
+      ev.preventDefault();
+      finish();
+    }
+  });
+  input.addEventListener("blur", () => finish());
+
+  nameEl.replaceWith(input);
+  input.focus();
+  input.select();
+}
+
 function renderStatusbar(sessions: Session[]): HTMLElement {
   const wrap = document.createElement("div");
   wrap.className = "statusbar";
@@ -402,6 +488,8 @@ export function renderSidebar(store: CatalogStore, opts: SidebarOptions = {}): S
   };
 
   const refresh = () => {
+    // Rebuilding the tree now would blow away the field being typed into.
+    if (renamingId !== null) return;
     const state = store.snapshot();
     const sessions = [...state.sessions.values()];
     const tree = buildTree(sessions, homeDir, filter);
@@ -458,6 +546,9 @@ export function renderSidebar(store: CatalogStore, opts: SidebarOptions = {}): S
     },
     dispose() {
       clearInterval(clock);
+      // An unfinished rename would otherwise leave every later sidebar
+      // refusing to refresh.
+      renamingId = null;
       document.removeEventListener("catalog-rerender", rerenderHandler);
       unsubscribe();
     },

web/src/contextMenu.test.ts

@@ -0,0 +1,58 @@
+// @vitest-environment happy-dom
+import { afterEach, describe, expect, it, vi } from "vitest";
+
+import { closeContextMenu, openContextMenu } from "./contextMenu.js";
+
+afterEach(() => {
+  closeContextMenu();
+  document.body.replaceChildren();
+});
+
+function labels(): string[] {
+  return [...document.querySelectorAll(".context-menu-item")].map((b) => b.textContent ?? "");
+}
+
+describe("context menu (#125)", () => {
+  it("renders one item per entry, in order", () => {
+    openContextMenu(10, 20, [
+      { label: "Rename…", onSelect: () => {} },
+      { label: "Kill session", onSelect: () => {}, danger: true },
+    ]);
+    expect(labels()).toEqual(["Rename…", "Kill session"]);
+    expect(document.querySelector(".context-menu-item.is-danger")?.textContent).toBe(
+      "Kill session",
+    );
+  });
+
+  it("runs the selected entry and closes", () => {
+    const chosen = vi.fn();
+    openContextMenu(0, 0, [{ label: "Rename…", onSelect: chosen }]);
+    (document.querySelector(".context-menu-item") as HTMLButtonElement).click();
+    expect(chosen).toHaveBeenCalledOnce();
+    expect(document.querySelector(".context-menu")).toBeNull();
+  });
+
+  it("opening a second menu replaces the first", () => {
+    openContextMenu(0, 0, [{ label: "first", onSelect: () => {} }]);
+    openContextMenu(0, 0, [{ label: "second", onSelect: () => {} }]);
+    expect(document.querySelectorAll(".context-menu")).toHaveLength(1);
+    expect(labels()).toEqual(["second"]);
+  });
+
+  it("closes on Escape and on a press outside it", () => {
+    openContextMenu(0, 0, [{ label: "Rename…", onSelect: () => {} }]);
+    window.dispatchEvent(new KeyboardEvent("keydown", { key: "Escape" }));
+    expect(document.querySelector(".context-menu")).toBeNull();
+
+    openContextMenu(0, 0, [{ label: "Rename…", onSelect: () => {} }]);
+    document.body.dispatchEvent(new Event("pointerdown", { bubbles: true }));
+    expect(document.querySelector(".context-menu")).toBeNull();
+  });
+
+  it("stays open for a press inside itself", () => {
+    openContextMenu(0, 0, [{ label: "Rename…", onSelect: () => {} }]);
+    const menu = document.querySelector(".context-menu") as HTMLElement;
+    menu.dispatchEvent(new Event("pointerdown", { bubbles: true }));
+    expect(document.querySelector(".context-menu")).not.toBeNull();
+  });
+});

web/src/contextMenu.ts

@@ -0,0 +1,81 @@
+/** Custom right-click menu (#125).
+ *
+ * One menu exists at a time: opening a second closes the first. The menu is
+ * appended to `<body>` rather than to the row it belongs to, so an overflowing
+ * sidebar cannot clip it.
+ */
+
+export interface ContextMenuItem {
+  label: string;
+  onSelect: () => void;
+  /** Renders the entry in the destructive style. */
+  danger?: boolean;
+}
+
+let open: { el: HTMLElement; dispose: () => void } | null = null;
+
+/** Close the menu that is currently up, if any. */
+export function closeContextMenu(): void {
+  open?.dispose();
+}
+
+/**
+ * Open a menu at viewport coordinates `x`/`y`. The menu closes on selection,
+ * on Escape, on a pointer press anywhere outside it, and on scroll or resize —
+ * a menu anchored to coordinates goes stale the moment the page moves under it.
+ */
+export function openContextMenu(x: number, y: number, items: ContextMenuItem[]): HTMLElement {
+  closeContextMenu();
+
+  const el = document.createElement("div");
+  el.className = "context-menu";
+  el.setAttribute("role", "menu");
+  for (const item of items) {
+    const btn = document.createElement("button");
+    btn.type = "button";
+    btn.className = item.danger ? "context-menu-item is-danger" : "context-menu-item";
+    btn.setAttribute("role", "menuitem");
+    btn.textContent = item.label;
+    btn.addEventListener("click", (ev) => {
+      ev.preventDefault();
+      ev.stopPropagation();
+      closeContextMenu();
+      item.onSelect();
+    });
+    el.appendChild(btn);
+  }
+  document.body.appendChild(el);
+
+  // Nudge back inside the viewport when the click was near an edge. happy-dom
+  // reports 0 for every measurement, which lands the menu at the click point —
+  // the same place it would sit with room to spare.
+  const rect = el.getBoundingClientRect();
+  const maxX = window.innerWidth - rect.width;
+  const maxY = window.innerHeight - rect.height;
+  el.style.left = `${Math.max(0, Math.min(x, maxX))}px`;
+  el.style.top = `${Math.max(0, Math.min(y, maxY))}px`;
+
+  const onPointerDown = (ev: Event) => {
+    if (!el.contains(ev.target as Node)) closeContextMenu();
+  };
+  const onKeyDown = (ev: KeyboardEvent) => {
+    if (ev.key === "Escape") closeContextMenu();
+  };
+  const dispose = () => {
+    if (open?.el !== el) return;
+    open = null;
+    el.remove();
+    window.removeEventListener("pointerdown", onPointerDown, true);
+    window.removeEventListener("keydown", onKeyDown, true);
+    window.removeEventListener("scroll", closeContextMenu, true);
+    window.removeEventListener("resize", closeContextMenu);
+  };
+  window.addEventListener("pointerdown", onPointerDown, true);
+  window.addEventListener("keydown", onKeyDown, true);
+  window.addEventListener("scroll", closeContextMenu, true);
+  window.addEventListener("resize", closeContextMenu);
+
+  open = { el, dispose };
+  (el.firstElementChild as HTMLElement | null)?.focus();
+  return el;
+}

web/src/rename.test.ts

@@ -0,0 +1,178 @@
+// @vitest-environment happy-dom
+import { afterEach, beforeAll, describe, expect, it, vi } from "vitest";
+
+import { renderSidebar } from "./catalog.js";
+import { closeContextMenu } from "./contextMenu.js";
+import type { CatalogListener, CatalogStore } from "./events.js";
+import type { Session } from "./types.js";
+import { normalizeSessionName } from "./types.js";
+
+beforeAll(() => {
+  Object.defineProperty(window, "localStorage", {
+    value: { getItem: () => null, setItem: () => {} },
+  });
+});
+
+let mounted: { el: HTMLElement; dispose: () => void } | null = null;
+
+afterEach(() => {
+  closeContextMenu();
+  mounted?.dispose();
+  mounted = null;
+  vi.unstubAllGlobals();
+});
+
+function session(overrides: Partial<Session> = {}): Session {
+  return {
+    id: "aaaaaaaa-0000-0000-0000-0000000000ff",
+    cwd: "/home/naps/tea/maestro",
+    command: "claude",
+    env: {},
+    metadata: { name: "amber-falcon" },
+    status: "Running",
+    created_at: "2026-08-24T10:00:00Z",
+    ...overrides,
+  };
+}
+
+function storeWith(sessions: Session[]): CatalogStore {
+  const state = { sessions: new Map(sessions.map((s) => [s.id, s])) };
+  return {
+    snapshot: () => state,
+    subscribe: (fn: CatalogListener) => {
+      fn(state);
+      return () => {};
+    },
+  } as unknown as CatalogStore;
+}
+
+/** Mount a sidebar with one session; the handle is disposed after each test. */
+function mount(s: Session): HTMLElement {
+  vi.stubGlobal(
+    "fetch",
+    vi.fn(() => Promise.reject(new Error("offline"))),
+  );
+  const handle = renderSidebar(storeWith([s]));
+  mounted = handle;
+  return handle.el;
+}
+
+function cardIn(el: HTMLElement, s: Session): HTMLElement {
+  return el.querySelector<HTMLElement>(`[data-session-id="${s.id}"]`) as HTMLElement;
+}
+
+/** Mount a sidebar with one session and right-click its card. */
+function openCardMenu(s: Session): { el: HTMLElement; row: HTMLElement } {
+  const el = mount(s);
+  const row = cardIn(el, s);
+  row.dispatchEvent(new Event("contextmenu", { bubbles: true, cancelable: true }));
+  return { el, row };
+}
+
+function menuItem(label: string): HTMLButtonElement {
+  const found = [...document.querySelectorAll<HTMLButtonElement>(".context-menu-item")].find(
+    (b) => b.textContent === label,
+  );
+  if (!found) throw new Error(`no "${label}" entry in the context menu`);
+  return found;
+}
+
+describe("session name normalisation (#125)", () => {
+  it("trims, and treats a blank name as a clear", () => {
+    expect(normalizeSessionName("  amber-falcon ")).toBe("amber-falcon");
+    expect(normalizeSessionName("   ")).toBe("");
+  });
+
+  it("caps at the daemon's limit, counting code points", () => {
+    expect(normalizeSessionName("x".repeat(80))).toHaveLength(64);
+    expect([...normalizeSessionName("é".repeat(80))]).toHaveLength(64);
+  });
+});
+
+describe("sidebar card context menu (#125)", () => {
+  it("suppresses the browser menu and offers rename, spawn similar and kill", () => {
+    const s = session();
+    const row = cardIn(mount(s), s);
+    const ev = new Event("contextmenu", { bubbles: true, cancelable: true });
+    row.dispatchEvent(ev);
+    expect(ev.defaultPrevented).toBe(true);
+    expect([...document.querySelectorAll(".context-menu-item")].map((b) => b.textContent)).toEqual([
+      "Rename…",
+      "Spawn similar",
+      "Kill session",
+    ]);
+  });
+
+  it("spawn similar dispatches the same event the ⧉ button does", () => {
+    const s = session();
+    openCardMenu(s);
+    const seen = vi.fn();
+    document.addEventListener("catalog-spawn-similar", seen);
+    menuItem("Spawn similar").click();
+    document.removeEventListener("catalog-spawn-similar", seen);
+    expect(seen).toHaveBeenCalledOnce();
+  });
+});
+
+describe("inline rename (#125)", () => {
+  it("pre-fills the field with the session's own name", () => {
+    const { row } = openCardMenu(session());
+    menuItem("Rename…").click();
+    const input = row.querySelector<HTMLInputElement>("input.leaf-rename");
+    expect(input?.value).toBe("amber-falcon");
+    expect(row.querySelector("span.leaf-name")).toBeNull();
+  });
+
+  it("starts empty for a session that has no name of its own", () => {
+    const { row } = openCardMenu(session({ metadata: {} }));
+    menuItem("Rename…").click();
+    expect(row.querySelector<HTMLInputElement>("input.leaf-rename")?.value).toBe("");
+  });
+
+  it("holds the tree still while the field is open", () => {
+    const s = session();
+    const { el, row } = openCardMenu(s);
+    menuItem("Rename…").click();
+    const input = row.querySelector<HTMLInputElement>("input.leaf-rename");
+    // A catalog delta mid-edit must not rebuild the row out from under it.
+    document.dispatchEvent(new CustomEvent("catalog-rerender"));
+    expect(cardIn(el, s).querySelector("input.leaf-rename")).toBe(input);
+  });
+
+  it("Enter PATCHes the session with the typed name", () => {
+    const s = session();
+    const { row } = openCardMenu(s);
+    menuItem("Rename…").click();
+    const input = row.querySelector<HTMLInputElement>("input.leaf-rename") as HTMLInputElement;
+    input.value = "crimson-otter";
+
+    const fetchMock = vi.fn(() =>
+      Promise.resolve(new Response(JSON.stringify(s), { status: 200 })),
+    );
+    vi.stubGlobal("fetch", fetchMock);
+    input.dispatchEvent(new KeyboardEvent("keydown", { key: "Enter", bubbles: true }));
+
+    expect(fetchMock).toHaveBeenCalledOnce();
+    const [url, init] = fetchMock.mock.calls[0] as unknown as [string, RequestInit];
+    expect(url).toBe(`/api/sessions/${s.id}`);
+    expect(init.method).toBe("PATCH");
+    expect(JSON.parse(init.body as string)).toEqual({ name: "crimson-otter" });
+  });
+
+  it("Escape cancels without a request and restores the name", () => {
+    const s = session();
+    const { el, row } = openCardMenu(s);
+    menuItem("Rename…").click();
+    const input = row.querySelector<HTMLInputElement>("input.leaf-rename") as HTMLInputElement;
+    input.value = "discarded";
+
+    const fetchMock = vi.fn(() => Promise.reject(new Error("offline")));
+    vi.stubGlobal("fetch", fetchMock);
+    input.dispatchEvent(new KeyboardEvent("keydown", { key: "Escape", bubbles: true }));
+
+    expect(fetchMock).not.toHaveBeenCalled();
+    // The row is rebuilt from the store, so the old name comes back.
+    expect(cardIn(el, s).querySelector(".leaf-name")?.textContent).toBe("amber-falcon");
+    expect(cardIn(el, s).querySelector("input.leaf-rename")).toBeNull();
+  });
+});

web/src/styles.css

@@ -814,6 +814,68 @@ textarea {
   white-space: nowrap;
 }
 
+/* Inline rename field (#125): sits exactly where the name it replaces did, so
+   the card does not jump when the edit starts. */
+input.leaf-rename {
+  font: inherit;
+  font-weight: 500;
+  font-size: var(--fs-13);
+  color: var(--ink);
+  background: var(--surface-2);
+  border: 1px solid var(--accent-ring);
+  border-radius: var(--r-2);
+  padding: 0 var(--sp-1);
+  min-width: 0;
+}
+
+input.leaf-rename:focus {
+  outline: none;
+  box-shadow: 0 0 0 3px var(--accent-tint);
+}
+
+/* Right-click menu on a session card (#125). Positioned from the click point,
+   so it is fixed to the viewport rather than to the scrolling sidebar. */
+.context-menu {
+  position: fixed;
+  z-index: var(--z-modal);
+  display: flex;
+  flex-direction: column;
+  min-width: 168px;
+  padding: var(--sp-1);
+  background: var(--surface-2);
+  border: 1px solid var(--border-strong);
+  border-radius: var(--r-3);
+  box-shadow: var(--shadow-2);
+}
+
+.context-menu-item {
+  appearance: none;
+  background: none;
+  border: 0;
+  border-radius: var(--r-2);
+  color: var(--ink);
+  font: inherit;
+  font-size: var(--fs-13);
+  text-align: left;
+  padding: var(--sp-1) var(--sp-2);
+  cursor: pointer;
+}
+
+.context-menu-item:hover,
+.context-menu-item:focus-visible {
+  background: var(--surface-3);
+  outline: none;
+}
+
+.context-menu-item.is-danger {
+  color: var(--danger);
+}
+
+.context-menu-item.is-danger:hover,
+.context-menu-item.is-danger:focus-visible {
+  background: var(--danger-tint);
+}
+
 /* Line 2 — dot + duration in the state's colour, then muted fragments. The
    state word itself is never spelled out here; the colour carries it. */
 .card-line2 {

web/src/types.ts

@@ -244,10 +244,29 @@ export interface ApiError {
 }
 
 export function sessionName(s: Session): string {
+  return customSessionName(s) ?? s.command;
+}
+
+/** The session's own name, without the command fallback (#125): `undefined`
+ * for a session that was never given one. */
+export function customSessionName(s: Session): string | undefined {
   const meta = s.metadata as Record<string, unknown>;
   const name = meta?.name;
   if (typeof name === "string" && name.length > 0) return name;
-  return s.command;
+  return undefined;
+}
+
+/** Longest session name the daemon stores (#125), in characters. Mirrors
+ * `maestro_protocol::MAX_SESSION_NAME_LEN`. */
+export const MAX_SESSION_NAME_LEN = 64;
+
+/** Trim a requested session name and cap it at {@link MAX_SESSION_NAME_LEN}
+ * characters. Empty means "clear the name", so the card falls back to the
+ * command. Mirrors `maestro_protocol::normalize_session_name` — the daemon
+ * applies the same rule, this only keeps the UI honest about what it will
+ * get back. Uses the spread so the cap counts code points, not UTF-16 units. */
+export function normalizeSessionName(name: string): string {
+  return [...name.trim()].slice(0, MAX_SESSION_NAME_LEN).join("");
 }
 
 /** The directory a session lives in: its live `current_cwd` if the daemon has