merge: surface blocked work before the kill is attempted

Closes #83

crates/maestro-cli/src/cli.rs

@@ -102,11 +102,6 @@ pub struct SpawnArgs {
     /// there.
     #[arg(long)]
     pub existing_branch: bool,
-    /// Remove the worktree when the session is killed. Kept for wire
-    /// compatibility (#56): the daemon now always cleans up on kill, guarded
-    /// against unsaved work.
-    #[arg(long, default_value_t = true)]
-    pub cleanup_on_kill: bool,
     /// After spawning, attach immediately.
     #[arg(long, short = 'a')]
     pub attach: bool,
@@ -125,6 +120,11 @@ pub struct AttachArgs {
 pub struct KillArgs {
     /// Session ID to kill.
     pub session_id: Uuid,
+    /// End the session even when its worktree holds unsaved work (#81). The
+    /// worktree is retained — never removed — and enters the retained store;
+    /// the output says where the work went.
+    #[arg(long)]
+    pub force: bool,
 }
 
 fn parse_kv(s: &str) -> Result<(String, String), String> {
@@ -163,7 +163,6 @@ mod tests {
             "/repos/foo",
             "--branch",
             "feat/x",
-            "--cleanup-on-kill",
             "-e",
             "FOO=bar",
             "-e",
@@ -174,7 +173,6 @@ mod tests {
             Command::Spawn(a) => {
                 assert_eq!(a.command, "bash");
                 assert_eq!(a.branch.as_deref(), Some("feat/x"));
-                assert!(a.cleanup_on_kill);
                 assert_eq!(
                     a.env,
                     vec![("FOO".into(), "bar".into()), ("BAZ".into(), "qux".into()),]
@@ -184,27 +182,6 @@ mod tests {
         }
     }
 
-    #[test]
-    fn cleanup_on_kill_defaults_true_for_the_wire() {
-        let cli = Cli::try_parse_from([
-            "maestro",
-            "spawn",
-            "--cwd",
-            "/tmp",
-            "--command",
-            "bash",
-            "--worktree-from",
-            "/repos/foo",
-            "--branch",
-            "feat/x",
-        ])
-        .unwrap();
-        match cli.command {
-            Command::Spawn(a) => assert!(a.cleanup_on_kill),
-            _ => panic!("wrong subcommand"),
-        }
-    }
-
     /// Review fix: without a flag the CLI always sent `create_branch: true`,
     /// so the daemon's existing-branch path was unreachable and spawning onto
     /// a branch that already existed just failed.
@@ -256,6 +233,32 @@ mod tests {
         }
     }
 
+    #[test]
+    fn parses_kill_with_force() {
+        let id = "01234567-89ab-cdef-0123-456789abcdef";
+        let cli = Cli::try_parse_from(["maestro", "kill", "--force", id]).unwrap();
+        match cli.command {
+            Command::Kill(a) => {
+                assert!(a.force);
+                assert_eq!(a.session_id.to_string(), id);
+            }
+            _ => panic!("wrong subcommand"),
+        }
+    }
+
+    #[test]
+    fn kill_force_defaults_false() {
+        let id = "01234567-89ab-cdef-0123-456789abcdef";
+        let cli = Cli::try_parse_from(["maestro", "kill", id]).unwrap();
+        match cli.command {
+            Command::Kill(a) => {
+                assert!(!a.force);
+                assert_eq!(a.session_id.to_string(), id);
+            }
+            _ => panic!("wrong subcommand"),
+        }
+    }
+
     #[test]
     fn rejects_env_without_equals() {
         let err = Cli::try_parse_from([

crates/maestro-cli/src/dispatch.rs

@@ -62,8 +62,20 @@ pub async fn dispatch(
             run_attach_url(&daemon.attach_url(args.session_id)?, detach).await?;
         }
         Command::Kill(args) => {
-            run_kill(&daemon, &args).await?;
+            // #83: warn BEFORE the attempt, so the refusal is not a surprise.
+            // Best-effort: an unreachable list must not block the kill.
+            if !args.force {
+                warn_if_blocked(&daemon, args.session_id).await;
+            }
+            let outcome = run_kill(&daemon, &args).await?;
             println!("killed {}", args.session_id);
+            if let Some(w) = outcome.retained {
+                println!(
+                    "worktree retained at {} (branch {}, force-killed)",
+                    w.path.display(),
+                    w.branch
+                );
+            }
         }
         Command::Worktrees(args) => match args.command {
             WorktreesCommand::List(list_args) => {
@@ -92,6 +104,25 @@ pub async fn dispatch(
 /// Default detach byte, matching `maestro attach --detach-key`'s `^q`.
 const CTRL_Q: u8 = 0x11;
 
+/// #83: say "this will be refused" before the operator commits to it, in the
+/// same words [`maestro_protocol::InTheWay`] uses everywhere else.
+async fn warn_if_blocked(daemon: &DaemonClient, id: uuid::Uuid) {
+    let Ok(sessions) = daemon.list_sessions().await else {
+        return;
+    };
+    if let Some(b) = sessions
+        .iter()
+        .find(|s| s.id == id)
+        .and_then(|s| s.blocked_work)
+    {
+        if !b.is_clear() {
+            eprintln!(
+                "warning: this kill will be refused — the session's worktree holds unsaved work ({b}); use --force to retain it"
+            );
+        }
+    }
+}
+
 /// HTTP client pointed at the daemon's API. That surface needs no auth —
 /// reaching `bind_addr` is the authorization.
 #[allow(clippy::result_large_err)]

crates/maestro-cli/src/sessions.rs

@@ -43,7 +43,6 @@ pub async fn run_spawn(client: &DaemonClient, args: SpawnArgs) -> Result<Session
         (Some(repo), Some(branch)) => Some(WorktreeSpec {
             base_repo: repo.clone(),
             branch: branch.clone(),
-            cleanup_on_kill: args.cleanup_on_kill,
             create_branch: !args.existing_branch,
         }),
         _ => None,
@@ -59,9 +58,14 @@ pub async fn run_spawn(client: &DaemonClient, args: SpawnArgs) -> Result<Session
     client.create_session(&body).await
 }
 
-/// `maestro kill`
-pub async fn run_kill(client: &DaemonClient, args: &KillArgs) -> Result<(), ClientError> {
-    client.kill_session(args.session_id).await
+/// `maestro kill`. A forced kill (#81) retains the guarded worktree instead
+/// of removing it; the outcome names what was kept so dispatch can say where
+/// the work went.
+pub async fn run_kill(
+    client: &DaemonClient,
+    args: &KillArgs,
+) -> Result<maestro_protocol::KillOutcome, ClientError> {
+    client.kill_session(args.session_id, args.force).await
 }
 
 #[allow(clippy::write_literal)]
@@ -89,8 +93,8 @@ fn print_session_table(out: &mut impl Write, sessions: &[Session], info: &Daemon
     }
     writeln!(
         out,
-        "  {:<36}  {:<8}  {:<9}  {:<28}  {}",
-        "ID", "STATUS", "ACTIVITY", "DIR", "COMMAND"
+        "  {:<36}  {:<8}  {:<9}  {:<28}  {:<40}  {}",
+        "ID", "STATUS", "ACTIVITY", "DIR", "COMMAND", "BLOCKED"
     )
     .ok();
     for s in sorted {
@@ -111,15 +115,28 @@ fn print_session_table(out: &mut impl Write, sessions: &[Session], info: &Daemon
             Some(fg) if fg != &s.command => format!("{} [{}]", s.command, fg),
             _ => s.command.clone(),
         };
+        // #83: what an unforced kill would be refused for, in InTheWay's own
+        // words; blank while nothing blocks (or hasn't been probed yet).
+        let blocked = blocked_label(s);
         writeln!(
             out,
-            "  {:<36}  {:<8}  {:<9}  {:<28}  {command}",
-            s.id, status, activity, dir
+            "  {:<36}  {:<8}  {:<9}  {:<28}  {:<40}  {blocked}",
+            s.id, status, activity, dir, command
         )
         .ok();
     }
 }
 
+/// The blocked-work indicator (#83), phrased by [`InTheWay`]'s `Display`.
+/// Empty unless something actually blocks — "no unsaved work" would just be
+/// noise on every row.
+pub(crate) fn blocked_label(s: &Session) -> String {
+    s.blocked_work
+        .filter(|b| !b.is_clear())
+        .map(|b| b.to_string())
+        .unwrap_or_default()
+}
+
 /// Render a path with the daemon's home dir collapsed to `~`. Mirrors the web
 /// UI's abbreviation so CLI and browser show the same directory shorthand.
 pub(crate) fn abbreviate_dir(path: &std::path::Path, home: &str) -> String {
@@ -160,6 +177,7 @@ mod tests {
             activity: Default::default(),
             last_activity_at: chrono::Utc::now(),
             current_cwd: None,
+            blocked_work: None,
         }
     }
 
@@ -220,4 +238,37 @@ mod tests {
         super::print_session_table(&mut buf, &[], &info(""));
         assert_eq!(String::from_utf8(buf).unwrap(), "no sessions\n");
     }
+
+    /// #83: a blocked session shows what an unforced kill would be refused
+    /// for, in `InTheWay`'s own words; a clear or unprobed one shows nothing.
+    #[test]
+    fn shows_the_blocked_work_summary_only_when_something_blocks() {
+        use maestro_protocol::InTheWay;
+
+        let mut blocked = session("/tmp", "claude", 1);
+        blocked.blocked_work = Some(InTheWay {
+            uncommitted_files: 3,
+            unpushed_commits: 2,
+            ..InTheWay::default()
+        });
+        let mut clear = session("/tmp", "bash", 2);
+        clear.blocked_work = Some(InTheWay::default());
+        let unprobed = session("/tmp", "zsh", 3);
+
+        let mut buf = Vec::new();
+        super::print_session_table(&mut buf, &[blocked, clear, unprobed], &info(""));
+        let out = String::from_utf8(buf).unwrap();
+        assert!(
+            out.contains("3 uncommitted files, 2 unpushed commits"),
+            "{out}"
+        );
+        // Clear and unprobed rows stay blank in the BLOCKED column.
+        let lines: Vec<&str> = out.lines().collect();
+        let header = lines.iter().position(|l| l.contains("BLOCKED")).unwrap();
+        for line in &lines[header + 1..] {
+            if !line.contains("uncommitted files") {
+                assert!(!line.contains("unsaved work"), "{line}");
+            }
+        }
+    }
 }

crates/maestro-cli/tests/against_mock_daemon.rs

@@ -76,7 +76,7 @@ async fn killing_an_unknown_session_reports_the_daemon_reason() {
 
     let err = mock
         .client()
-        .kill_session(Uuid::new_v4())
+        .kill_session(Uuid::new_v4(), false)
         .await
         .expect_err("should fail");
 
@@ -102,6 +102,9 @@ async fn spawn_round_trips_through_the_daemon() {
     assert_eq!(created.command, "bash");
     assert_eq!(mock.session_count(), 1);
 
-    mock.client().kill_session(created.id).await.expect("kill");
+    mock.client()
+        .kill_session(created.id, false)
+        .await
+        .expect("kill");
     assert_eq!(mock.session_count(), 0);
 }

crates/maestro-daemon/src/cli.rs

@@ -56,6 +56,9 @@ async fn run(config_override: Option<PathBuf>) -> Result<(), Box<dyn Error>> {
         Some(p) => Tmux::new().with_tmpdir(p),
         None => Tmux::new(),
     };
+    let retained = std::sync::Arc::new(crate::retained_store::RetainedStore::new(
+        config.retained_worktree_dir(),
+    ));
     let manager = SessionManager::new_with_replay(
         std::sync::Arc::new(tmux),
         sidecar,
@@ -66,7 +69,10 @@ async fn run(config_override: Option<PathBuf>) -> Result<(), Box<dyn Error>> {
     .with_spawn_history(crate::spawn_history::SpawnHistory::new(
         config.spawn_history_path(),
         config.spawn_history_days,
-    ));
+    ))
+    // One store instance shared with the API handlers: forced kills (#81)
+    // record here, `GET /api/worktrees` (#80) reads back from here.
+    .with_retained_store((*retained).clone());
 
     let recovered = manager.recover().await?;
     tracing::info!(recovered, "adopted existing tmux sessions");
@@ -85,9 +91,7 @@ async fn run(config_override: Option<PathBuf>) -> Result<(), Box<dyn Error>> {
         config.home_dir.clone(),
         config.spawn_presets.clone(),
         projects,
-        std::sync::Arc::new(crate::retained_store::RetainedStore::new(
-            config.retained_worktree_dir(),
-        )),
+        retained,
     ));
 
     let listener = TcpListener::bind(config.bind_addr).await?;

crates/maestro-daemon/src/local_api.rs

@@ -101,6 +101,8 @@ fn session_error_status(code: &str) -> StatusCode {
         "invalid_env" => StatusCode::BAD_REQUEST,
         // A guard refusal is the daemon doing its job, not a failure (#79).
         "kill_guarded" => StatusCode::CONFLICT,
+        // The retention record failed before anything was torn down (#81).
+        "retain_failed" => StatusCode::INTERNAL_SERVER_ERROR,
         _ => StatusCode::BAD_GATEWAY,
     }
 }
@@ -179,9 +181,29 @@ async fn create_session(
 /// The full error info is passed through rather than rebuilt from
 /// code + message: a `kill_guarded` refusal (#79) carries the unsaved-work
 /// breakdown clients render as "3 uncommitted files, 2 unpushed commits".
-async fn kill_session(State(s): State<LocalApiState>, Path(id): Path<Uuid>) -> Response {
-    match s.manager.kill(id).await {
-        Ok(()) => StatusCode::NO_CONTENT.into_response(),
+///
+/// With `force=true` (#81) the refusal is overridden and the worktree
+/// retained; the answer is `200` with a [`KillOutcome`] naming what was kept.
+/// Without it the historical `204` stands.
+#[derive(Debug, Deserialize)]
+struct KillQuery {
+    #[serde(default)]
+    force: bool,
+}
+
+async fn kill_session(
+    State(s): State<LocalApiState>,
+    Path(id): Path<Uuid>,
+    Query(q): Query<KillQuery>,
+) -> Response {
+    match s.manager.kill(id, q.force).await {
+        Ok(outcome) => {
+            if q.force {
+                (StatusCode::OK, Json(outcome)).into_response()
+            } else {
+                StatusCode::NO_CONTENT.into_response()
+            }
+        }
         Err(e) => {
             let info = e.to_error_info();
             let status = session_error_status(&info.code);

crates/maestro-daemon/src/session.rs

@@ -12,8 +12,8 @@ use std::time::Duration;
 
 use chrono::Utc;
 use maestro_protocol::{
-    ActivityState, CatalogEvent, CreateSessionRequest, ErrorInfo, Session, SessionStatus,
-    WorktreeSpec,
+    ActivityState, CatalogEvent, CreateSessionRequest, ErrorInfo, KillOutcome, RetainedReason,
+    RetainedWorktree, Session, SessionStatus, WorktreeSpec,
 };
 use tokio::sync::{broadcast, Mutex};
 use uuid::Uuid;
@@ -33,6 +33,13 @@ pub const EVENTS_CAPACITY: usize = maestro_config::EVENTS_CAPACITY;
 /// How often the liveness watcher polls tmux for sessions that disappeared.
 pub const DEFAULT_LIVENESS_INTERVAL: Duration = Duration::from_secs(2);
 
+/// How often the liveness watcher re-probes worktrees for the blocked-work
+/// indicator (#83). Each probe costs three git subprocesses per session, so
+/// the pass rides the same tick as everything else but runs on a slower
+/// cadence: an indicator a few seconds stale still warns before the kill
+/// attempt, which is all #83 needs.
+pub const DEFAULT_BLOCKED_WORK_INTERVAL: Duration = Duration::from_secs(15);
+
 /// Per-session daemon-local bookkeeping that complements the public `Session`.
 #[derive(Debug)]
 pub struct SessionRecord {
@@ -44,6 +51,11 @@ pub struct SessionRecord {
     /// `base_repo` from the original `WorktreeSpec`. Needed because `git
     /// worktree remove` is invoked from the base repo.
     pub worktree_base_repo: Option<PathBuf>,
+    /// Branch the worktree was created for, recorded at spawn time so a
+    /// forced kill (#81) can name it in the retained store without asking
+    /// git. Sessions adopted from a sidecar have no branch on record and
+    /// fall back to a probe.
+    pub worktree_branch: Option<String>,
     pub bridge: PtyBridge,
 }
 
@@ -66,6 +78,11 @@ pub enum SessionError {
     /// so it stays the operator's handle on their own unfinished work.
     #[error("kill refused: the session's worktree holds unsaved work ({0})")]
     KillGuarded(maestro_protocol::InTheWay),
+    /// A forced kill (#81) records the retained worktree *before* tearing
+    /// anything down; if that write fails nothing was destroyed, and the
+    /// error says so rather than silently dropping unrecorded work.
+    #[error("could not record the retained worktree: {0}")]
+    RetainFailed(String),
 }
 
 impl SessionError {
@@ -78,6 +95,7 @@ impl SessionError {
             SessionError::NotFound(_) => "not_found",
             SessionError::InvalidEnv(_) => "invalid_env",
             SessionError::KillGuarded(_) => "kill_guarded",
+            SessionError::RetainFailed(_) => "retain_failed",
         };
         let unsaved_work = match self {
             SessionError::KillGuarded(b) => Some(*b),
@@ -110,6 +128,9 @@ struct Inner {
     /// `None` when not wired (tests, or before `with_spawn_history`); a present
     /// but disabled (`0`-day) history no-ops internally.
     spawn_history: Option<SpawnHistory>,
+    /// Retained-worktree store (#78). `None` when not wired (tests); a forced
+    /// kill (#81) without one fails rather than destroying unrecorded work.
+    retained: Option<crate::retained_store::RetainedStore>,
     sessions: Mutex<HashMap<Uuid, SessionRecord>>,
     events: broadcast::Sender<CatalogEvent>,
 }
@@ -148,6 +169,7 @@ impl SessionManager {
                 fifo_dir,
                 replay_bytes,
                 spawn_history: None,
+                retained: None,
                 sessions: Mutex::new(HashMap::new()),
                 events,
             }),
@@ -170,6 +192,16 @@ impl SessionManager {
         self
     }
 
+    /// Attach the retained-worktree store (#78). A forced kill (#81) needs it
+    /// to record what it retained; without one, forcing a guarded kill fails
+    /// instead of destroying unrecorded work.
+    pub fn with_retained_store(mut self, store: crate::retained_store::RetainedStore) -> Self {
+        let inner = Arc::get_mut(&mut self.inner)
+            .expect("with_retained_store must be called before the SessionManager is cloned");
+        inner.retained = Some(store);
+        self
+    }
+
     /// Recent working dirs for the spawn form's picker (#24), newest-first and
     /// deduped by dir. Empty when no history is wired or it's disabled.
     pub fn recent_dirs(&self) -> Vec<RecentDir> {
@@ -319,6 +351,9 @@ impl SessionManager {
             last_activity_at: Utc::now(),
 
             current_cwd: None,
+            // The watcher fills this in on its first blocked-work pass; a
+            // fresh tree has nothing in the way anyway.
+            blocked_work: None,
         };
 
         if let Err(e) = self.inner.sidecar.write(&session) {
@@ -340,6 +375,7 @@ impl SessionManager {
                     fifo_path,
                     worktree_path,
                     worktree_base_repo,
+                    worktree_branch: req.worktree.as_ref().map(|w| w.branch.clone()),
                     bridge,
                 },
             );
@@ -391,11 +427,17 @@ impl SessionManager {
     /// work, so ending a session that still matters becomes a deliberate
     /// `--force`, which retains rather than destroys (WORKTREES.md).
     ///
+    /// With `force` (#81) the refusal — and nothing else — is overridden:
+    /// the session ends and the guarded worktree is retained into the store
+    /// with reason `force-killed`, never removed. The outcome names what was
+    /// kept so a client can say where the work went. A tree whose guard is
+    /// clear never needed the override; force removes it as usual.
+    ///
     /// This is also how an already-dead session is dismissed. tmux is only
     /// asked to kill something it still has — calling `kill-session` on a
     /// session tmux already lost fails, and that failure is not interesting.
-    pub async fn kill(&self, id: Uuid) -> Result<(), SessionError> {
-        let (worktree, alive) = {
+    pub async fn kill(&self, id: Uuid, force: bool) -> Result<KillOutcome, SessionError> {
+        let (worktree, alive, known_branch) = {
             let sessions = self.inner.sessions.lock().await;
             match sessions.get(&id) {
                 None => return Err(SessionError::NotFound(id)),
@@ -405,26 +447,48 @@ impl SessionManager {
                         .clone()
                         .zip(record.worktree_path.clone()),
                     record.session.status == SessionStatus::Running,
+                    record.worktree_branch.clone(),
                 ),
             }
         };
-        // The guard runs before anything is torn down: refusing must leave the
-        // session running, exactly as the operator left it.
-        if let Some((_, path)) = worktree {
-            let probe = tmux_blocking(move || crate::worktree_probe::in_the_way(&path))
-                .await
-                .map_err(|e| SessionError::Worktree(crate::worktree::WorktreeError::from(e)))?;
-            if !probe.is_clear() {
-                return Err(SessionError::KillGuarded(probe));
-            }
+        let probe = match &worktree {
+            Some(wt) => Some(probe_worktree(wt).await?),
+            None => None,
+        };
+        let guarded = probe.as_ref().is_some_and(|p| !p.is_clear());
+        if guarded && !force {
+            return Err(SessionError::KillGuarded(probe.expect("guarded ⇒ probed")));
         }
+
+        let mut retained = None;
+        if guarded {
+            let entry = record_retention(
+                &self.inner,
+                worktree.as_ref().expect("guarded ⇒ worktree"),
+                known_branch,
+                RetainedReason::ForceKilled,
+            )
+            .await?;
+            retained = Some((entry, probe.expect("guarded ⇒ probed")));
+        }
+
         let removed = {
             let mut sessions = self.inner.sessions.lock().await;
             sessions.remove(&id)
         };
         let record = removed.ok_or(SessionError::NotFound(id))?;
-        cleanup_record(&self.inner, id, record, alive).await;
-        Ok(())
+        cleanup_record(&self.inner, id, record, alive, retained.is_some()).await;
+        Ok(KillOutcome {
+            retained: retained.map(|(entry, in_the_way)| RetainedWorktree {
+                id: entry.id,
+                path: entry.path,
+                base_repo: entry.base_repo,
+                branch: entry.branch,
+                reason: entry.reason,
+                retained_at: entry.retained_at,
+                in_the_way,
+            }),
+        })
     }
 
     /// Spawn a background task that polls tmux every `interval` and reaps any
@@ -435,6 +499,17 @@ impl SessionManager {
     /// `SessionManager` clone is dropped — call this once from the daemon
     /// startup path after [`Self::recover`] has populated the map.
     pub fn start_liveness_watcher(&self, interval: Duration) {
+        self.start_liveness_watcher_with_blocked_work(interval, DEFAULT_BLOCKED_WORK_INTERVAL);
+    }
+
+    /// [`Self::start_liveness_watcher`] with the blocked-work cadence (#83)
+    /// made explicit. Tests pass a small `blocked_work_interval` to watch the
+    /// probe actually happen.
+    pub fn start_liveness_watcher_with_blocked_work(
+        &self,
+        interval: Duration,
+        blocked_work_interval: Duration,
+    ) {
         let weak = Arc::downgrade(&self.inner);
         tokio::spawn(async move {
             let mut ticker = tokio::time::interval(interval);
@@ -442,6 +517,9 @@ impl SessionManager {
             // first tick fires immediately — skip it so we don't reap before
             // the caller has a chance to create anything.
             ticker.tick().await;
+            // Start "due" so the first live tick probes: a recovered daemon
+            // should not wait a full interval to show what blocks.
+            let mut since_probe = blocked_work_interval;
             loop {
                 ticker.tick().await;
                 let Some(inner) = weak.upgrade() else {
@@ -451,6 +529,11 @@ impl SessionManager {
                 // Same tick, no new timer (NAP-340): refresh activity for the
                 // survivors and emit SessionUpdated on any transition.
                 run_activity_pass(&inner).await;
+                since_probe += interval;
+                if since_probe >= blocked_work_interval {
+                    since_probe = Duration::ZERO;
+                    run_blocked_work_pass(&inner).await;
+                }
             }
         });
     }
@@ -487,6 +570,7 @@ impl SessionManager {
                     last_activity_at: Utc::now(),
 
                     current_cwd: None,
+                    blocked_work: None,
                 },
             };
             let fifo_path = self.inner.fifo_dir.join(format!("{id}.fifo"));
@@ -511,6 +595,9 @@ impl SessionManager {
                     // directory blocks that branch forever (#54 review).
                     worktree_path: session.worktree.as_ref().map(|w| w.path.clone()),
                     worktree_base_repo: session.worktree.as_ref().map(|w| w.base_repo.clone()),
+                    // The sidecar carries no branch; a forced kill of a
+                    // recovered session probes git for it at retain time.
+                    worktree_branch: None,
                     bridge,
                 },
             );
@@ -587,6 +674,49 @@ where
         .expect("tmux blocking task panicked")
 }
 
+/// What would be lost if this session's worktree were removed right now.
+///
+/// The single [`crate::worktree_probe::in_the_way`] call site behind both
+/// endings of a session — the kill guard (#79) and the natural-exit
+/// classifier (#82) — so neither can grow its own answer. Runs on the
+/// blocking pool; callers invoke it before anything is torn down, because
+/// refusing (#79), recording a retention (#81) and classifying an exit (#82)
+/// must all see the tree as it stands.
+async fn probe_worktree(
+    (_, path): &(PathBuf, PathBuf),
+) -> Result<maestro_protocol::InTheWay, SessionError> {
+    let path = path.clone();
+    tmux_blocking(move || crate::worktree_probe::in_the_way(&path))
+        .await
+        .map_err(|e| SessionError::Worktree(crate::worktree::WorktreeError::from(e)))
+}
+
+/// Record a guarded worktree into the retained store with `reason`, BEFORE
+/// the caller tears anything down: a failed write then leaves every artifact
+/// untouched instead of destroying work nothing records anymore. Shared by
+/// the forced kill (`ForceKilled`, #81) and the natural exit
+/// (`ExitedWithUnsavedWork`, #82) so the two paths cannot drift apart.
+async fn record_retention(
+    inner: &Arc<Inner>,
+    (base_repo, path): &(PathBuf, PathBuf),
+    known_branch: Option<String>,
+    reason: RetainedReason,
+) -> Result<crate::retained_store::RetainedWorktreeRecord, SessionError> {
+    let store = inner
+        .retained
+        .clone()
+        .ok_or_else(|| SessionError::RetainFailed("no retained store is wired".into()))?;
+    // Sessions adopted from a sidecar carry no branch; ask the tree itself.
+    let branch = known_branch
+        .or_else(|| crate::worktree_probe::current_branch(path))
+        .unwrap_or_default();
+    let base_repo = base_repo.clone();
+    let path = path.clone();
+    tmux_blocking(move || store.retain(&path, &base_repo, &branch, reason))
+        .await
+        .map_err(|e| SessionError::RetainFailed(e.to_string()))
+}
+
 /// One pass of the liveness watcher: diff the in-memory session set against
 /// the tmux-reported one, and reap anything we still track but tmux has lost.
 async fn run_liveness_pass(inner: &Arc<Inner>) {
@@ -709,18 +839,79 @@ async fn run_activity_pass(inner: &Arc<Inner>) {
     }
 }
 
+/// Refresh each running session's blocked-work indicator (#83): what its
+/// worktree holds right now that would block an unforced kill. Rides the
+/// liveness tick on its own (slower) cadence — see
+/// [`DEFAULT_BLOCKED_WORK_INTERVAL`] — because every probe is three git
+/// subprocesses per session.
+///
+/// Sessions without a worktree are filtered out BEFORE any probe: they can
+/// never block a kill, so their indicator must cost nothing at all. A failed
+/// probe keeps the previous value rather than clearing it — a transient git
+/// error must not read as "nothing blocks". Like the activity pass, this only
+/// emits `SessionUpdated` when the value actually changed.
+async fn run_blocked_work_pass(inner: &Arc<Inner>) {
+    let targets: Vec<(Uuid, (PathBuf, PathBuf))> = {
+        let sessions = inner.sessions.lock().await;
+        sessions
+            .iter()
+            .filter(|(_, r)| r.session.status == SessionStatus::Running)
+            .filter_map(|(id, r)| {
+                let wt = r.worktree_base_repo.clone().zip(r.worktree_path.clone())?;
+                Some((*id, wt))
+            })
+            .collect()
+    };
+    if targets.is_empty() {
+        return;
+    }
+
+    for (id, wt) in targets {
+        // The kill guard's own probe (#79), so the indicator can never
+        // disagree with what a kill attempt would find.
+        let breakdown = match probe_worktree(&wt).await {
+            Ok(breakdown) => breakdown,
+            Err(e) => {
+                tracing::debug!(%id, error = ?e, "blocked-work: probe failed; keeping previous value");
+                continue;
+            }
+        };
+        let updated = {
+            let mut sessions = inner.sessions.lock().await;
+            let Some(rec) = sessions.get_mut(&id) else {
+                continue;
+            };
+            if rec.session.blocked_work == Some(breakdown) {
+                None
+            } else {
+                rec.session.blocked_work = Some(breakdown);
+                Some(rec.session.clone())
+            }
+        };
+        if let Some(session) = updated {
+            let _ = inner.events.send(CatalogEvent::SessionUpdated { session });
+        }
+    }
+}
+
 /// Mark a session whose tmux session has disappeared as [`SessionStatus::Dead`]
-/// and announce it, keeping everything else intact.
+/// and settle its worktree per the natural-exit rule (#82).
 ///
 /// The record, its [`PtyBridge`] and its sidecar all survive, so a client can
 /// still attach and read the replay buffer — the last thing a crashed agent
-/// printed. Artifacts are only released when the operator dismisses the session
-/// via [`SessionManager::kill`].
+/// printed. The worktree, though, is settled right away: a pristine tree is
+/// removed, anything else is retained into the store with reason
+/// `exited-with-unsaved-work` (#82) — nobody is waiting for an answer here,
+/// so there is nothing to refuse. Once settled, the session drops its
+/// worktree reference so a later dismissal neither re-probes nor retains
+/// twice. When settling is impossible (probe or store failure) nothing is
+/// destroyed: the tree stays attached to the dead record for a later forced
+/// dismissal (#81).
 ///
 /// Dead sessions do not survive a daemon restart: [`SessionManager::recover`]
 /// adopts only what tmux still holds.
 async fn mark_session_dead(inner: &Arc<Inner>, id: Uuid) {
-    let updated = {
+    let flipped = {
         let mut sessions = inner.sessions.lock().await;
         match sessions.get_mut(&id) {
             Some(record) if record.session.status == SessionStatus::Running => {
@@ -728,19 +919,114 @@ async fn mark_session_dead(inner: &Arc<Inner>, id: Uuid) {
                 // Release anyone attached; the scrollback survives for a later
                 // attach.
                 record.bridge.seal();
-                Some(record.session.clone())
+                let session = record.session.clone();
+                let worktree = record
+                    .worktree_base_repo
+                    .clone()
+                    .zip(record.worktree_path.clone());
+                let branch = record.worktree_branch.clone();
+                Some((session, worktree, branch))
             }
             _ => None,
         }
     };
-    let Some(session) = updated else {
+    let Some((mut session, worktree, branch)) = flipped else {
         return;
     };
     tracing::info!(%id, "session vanished from tmux — marking dead");
+
+    if let Some(wt) = &worktree {
+        if settle_worktree_on_exit(inner, id, wt, branch).await {
+            // The tree is settled (removed or retained); a stale "in the
+            // way" would describe something the session no longer holds.
+            session.blocked_work = None;
+            let mut sessions = inner.sessions.lock().await;
+            if let Some(record) = sessions.get_mut(&id) {
+                record.session.worktree = None;
+                record.session.blocked_work = None;
+                record.worktree_path = None;
+                record.worktree_base_repo = None;
+                record.worktree_branch = None;
+            }
+        }
+    }
+
     let _ = inner.sidecar.write(&session);
     let _ = inner.events.send(CatalogEvent::SessionUpdated { session });
 }
 
+/// Apply the exit rule (#82) to a vanished session's worktree: probe what
+/// would be lost through the kill's own predicate, then remove a pristine
+/// tree or retain anything else under `exited-with-unsaved-work` — recorded
+/// before anything is torn down, exactly as the forced kill does (#81). A
+/// removal that fails falls back to retaining, since whatever blocked it is
+/// by definition something worth keeping.
+///
+/// Returns whether the worktree was fully accounted for. When it wasn't,
+/// nothing was destroyed and the caller keeps the reference on the record.
+async fn settle_worktree_on_exit(
+    inner: &Arc<Inner>,
+    id: Uuid,
+    (base_repo, path): &(PathBuf, PathBuf),
+    known_branch: Option<String>,
+) -> bool {
+    let probe = match probe_worktree(&(base_repo.clone(), path.clone())).await {
+        Ok(probe) => probe,
+        Err(e) => {
+            tracing::error!(
+                %id,
+                path = %path.display(),
+                error = ?e,
+                "natural exit: could not probe the worktree; leaving it untouched"
+            );
+            return false;
+        }
+    };
+    if probe.is_clear() {
+        match inner.worktree_mgr.remove(base_repo, path) {
+            Ok(()) => {
+                tracing::info!(%id, path = %path.display(), "natural exit: pristine worktree removed");
+                return true;
+            }
+            Err(e) => {
+                tracing::warn!(
+                    %id,
+                    path = %path.display(),
+                    error = ?e,
+                    "natural exit: removal failed; falling back to retention"
+                );
+            }
+        }
+    }
+    match record_retention(
+        inner,
+        &(base_repo.clone(), path.clone()),
+        known_branch,
+        RetainedReason::ExitedWithUnsavedWork,
+    )
+    .await
+    {
+        Ok(entry) => {
+            tracing::info!(
+                %id,
+                path = %path.display(),
+                entry = %entry.id,
+                "natural exit: worktree retained with unsaved work"
+            );
+            true
+        }
+        Err(e) => {
+            tracing::error!(
+                %id,
+                path = %path.display(),
+                error = ?e,
+                "natural exit: could not record the retained worktree; leaving it untouched"
+            );
+            false
+        }
+    }
+}
+
 /// Tear down a session's artifacts after it has already been removed from the
 /// live map. Shared by [`SessionManager::kill`] and [`reap_dead_session`],
 /// which previously hand-rolled the same five-step choreography and only
@@ -750,7 +1036,17 @@ async fn mark_session_dead(inner: &Arc<Inner>, id: Uuid) {
 /// gone from the authoritative in-memory map, so a stray FIFO or sidecar can't
 /// resurrect it. `kill_tmux` is `true` for an explicit kill and `false` for the
 /// liveness reaper (tmux already lost the session).
-async fn cleanup_record(inner: &Arc<Inner>, id: Uuid, record: SessionRecord, kill_tmux: bool) {
+///
+/// `retain_worktree` is `true` for a forced kill (#81) that retained the
+/// worktree instead of removing it: the store entry is already written, so
+/// only the removal is skipped.
+async fn cleanup_record(
+    inner: &Arc<Inner>,
+    id: Uuid,
+    record: SessionRecord,
+    kill_tmux: bool,
+    retain_worktree: bool,
+) {
     if kill_tmux {
         let tmux = inner.tmux.clone();
         let _ = tmux_blocking(move || tmux.kill_session(id)).await;
@@ -759,11 +1055,18 @@ async fn cleanup_record(inner: &Arc<Inner>, id: Uuid, record: SessionRecord, kil
     if let Err(e) = inner.sidecar.delete(id) {
         tracing::warn!(error = ?e, %id, "cleanup: failed to delete sidecar");
     }
-    // The kill already passed the unsaved-work guard (#79), so this removal
-    // is unconditional; the manager's own nested-worktree refusal is all that
-    // can still leave a tree on disk, and it says where.
     if let (Some(base), Some(path)) = (&record.worktree_base_repo, &record.worktree_path) {
-        if let Err(e) = inner.worktree_mgr.remove(base, path) {
+        if retain_worktree {
+            tracing::info!(
+                %id,
+                path = %path.display(),
+                "forced kill: worktree retained in the store"
+            );
+        } else if let Err(e) = inner.worktree_mgr.remove(base, path) {
+            // The kill already passed the unsaved-work guard (#79), so this
+            // removal is unconditional; the manager's own nested-worktree
+            // refusal is all that can still leave a tree on disk, and it
+            // says where.
             tracing::warn!(
                 %id,
                 path = %path.display(),

crates/maestro-daemon/src/worktree_probe.rs

@@ -90,6 +90,14 @@ pub fn reclaim(base_repo: &Path, path: &Path) -> Result<(), ProbeError> {
     .map(|_| ())
 }
 
+/// Branch checked out at `path`. Sessions adopted from a sidecar carry no
+/// branch on record, so a forced kill (#81) asks the tree itself when it
+/// needs one for the retained store. `None` when git cannot answer.
+pub fn current_branch(path: &Path) -> Option<String> {
+    let out = run_git(path, ["rev-parse", "--abbrev-ref", "HEAD"]).ok()?;
+    Some(String::from_utf8_lossy(&out.stdout).trim().to_string())
+}
+
 fn run_git<I, S>(dir: &Path, args: I) -> Result<std::process::Output, ProbeError>
 where
     I: IntoIterator<Item = S>,

crates/maestro-daemon/tests/attach.rs

@@ -122,7 +122,7 @@ async fn pty_round_trip_through_real_tmux() {
         "marker not seen in {} bytes",
         got.len()
     );
-    let _ = h.manager.kill(id).await;
+    let _ = h.manager.kill(id, false).await;
 }
 
 #[tokio::test]
@@ -170,7 +170,7 @@ async fn multi_attach_broadcasts_to_every_client() {
         "client B missed marker"
     );
 
-    let _ = h.manager.kill(id).await;
+    let _ = h.manager.kill(id, false).await;
 }
 
 #[tokio::test]
@@ -219,7 +219,7 @@ async fn sends_close_frame_when_session_is_killed() {
     // give the broadcast subscriber a moment to register before killing.
     tokio::time::sleep(Duration::from_millis(100)).await;
 
-    h.manager.kill(id).await.unwrap();
+    h.manager.kill(id, false).await.unwrap();
 
     let mut saw_close = false;
     let deadline = std::time::Instant::now() + Duration::from_secs(2);
@@ -267,7 +267,7 @@ async fn ping_text_frame_gets_pong() {
         }
     }
     assert!(saw_pong, "no Pong frame received");
-    let _ = h.manager.kill(id).await;
+    let _ = h.manager.kill(id, false).await;
 }
 
 #[tokio::test]

crates/maestro-daemon/tests/blocked_work_cost.rs

@@ -0,0 +1,116 @@
+//! The performance contract of #83: the blocked-work pass must cost NO git
+//! probe at all for a session without a worktree, while a session with one is
+//! still probed.
+//!
+//! `git` itself is shimmed through PATH with a wrapper that logs every
+//! invocation before exec'ing the real binary, so the assertion counts actual
+//! probes rather than inferring them from state. This lives in its own test
+//! binary because it mutates the process environment.
+
+mod common;
+
+use std::collections::HashMap;
+use std::process::Command;
+use std::time::Duration;
+
+use common::{init_bare_repo, init_repo, push_all_to_origin, wait_for_async, DaemonFixture};
+use maestro_protocol::{CreateSessionRequest, InTheWay, WorktreeSpec};
+use tempfile::TempDir;
+
+fn request(cwd: &std::path::Path, repo: &std::path::Path, branch: &str) -> CreateSessionRequest {
+    CreateSessionRequest {
+        cwd: cwd.to_path_buf(),
+        command: "sleep 30".into(),
+        env: HashMap::new(),
+        metadata: HashMap::new(),
+        worktree: Some(WorktreeSpec {
+            base_repo: repo.to_path_buf(),
+            branch: branch.into(),
+            create_branch: true,
+        }),
+    }
+}
+
+#[tokio::test]
+async fn a_session_without_a_worktree_costs_no_probe() {
+    let fx = DaemonFixture::new();
+    let log = TempDir::new().unwrap();
+    let log_path = log.path().join("git-calls.log");
+
+    // Session A owns a real (pristine, pushed) worktree; session B has none.
+    let repo_a = TempDir::new().unwrap();
+    init_repo(repo_a.path());
+    init_bare_repo(&repo_a.path().join("origin.git"));
+    push_all_to_origin(repo_a.path(), &repo_a.path().join("origin.git"));
+    fx.manager
+        .create(request(repo_a.path(), repo_a.path(), "feat/probed"))
+        .await
+        .expect("create A");
+
+    let cwd_b = TempDir::new().unwrap();
+    let mut req_b = request(cwd_b.path(), cwd_b.path(), "feat/unused");
+    req_b.worktree = None;
+    fx.manager.create(req_b).await.expect("create B");
+
+    // Shim `git` AFTER setup so only watcher-driven probes get logged.
+    let real_git = String::from_utf8(
+        Command::new("sh")
+            .arg("-c")
+            .arg("command -v git")
+            .output()
+            .expect("locate git")
+            .stdout,
+    )
+    .unwrap()
+    .trim()
+    .to_string();
+    let shim_dir = TempDir::new().unwrap();
+    let script = format!(
+        "#!/bin/sh\nprintf '%s\\n' \"$*\" >> {}\nexec {} \"$@\"\n",
+        log_path.display(),
+        real_git,
+    );
+    std::fs::write(shim_dir.path().join("git"), script).unwrap();
+    #[cfg(unix)]
+    {
+        use std::os::unix::fs::PermissionsExt;
+        std::fs::set_permissions(
+            shim_dir.path().join("git"),
+            std::fs::Permissions::from_mode(0o755),
+        )
+        .unwrap();
+    }
+    let old_path = std::env::var("PATH").unwrap_or_default();
+    std::env::set_var(
+        "PATH",
+        format!("{}:{}", shim_dir.path().display(), old_path),
+    );
+
+    fx.manager.start_liveness_watcher_with_blocked_work(
+        Duration::from_millis(50),
+        Duration::from_millis(100),
+    );
+
+    // The pass demonstrably runs and probed A's tree...
+    wait_for_async(Duration::from_secs(5), || async {
+        fx.manager
+            .snapshot()
+            .await
+            .iter()
+            .any(|s| s.worktree.is_some() && s.blocked_work == Some(InTheWay::default()))
+    })
+    .await;
+
+    std::env::set_var("PATH", &old_path);
+
+    let calls = std::fs::read_to_string(&log_path).unwrap_or_default();
+    assert!(
+        !calls.is_empty(),
+        "the pass never probed anything — the shim saw no git call at all"
+    );
+    // ...while B — no worktree, so nothing to probe — was never touched.
+    assert!(
+        !calls.contains(cwd_b.path().to_str().unwrap()),
+        "a worktree-less session was probed:\n{calls}"
+    );
+}

crates/maestro-daemon/tests/common/mod.rs

@@ -176,6 +176,11 @@ impl DaemonFixture {
             manager =
                 manager.with_spawn_history(SpawnHistory::new(Self::history_path(&state_dir), days));
         }
+        // Same wiring as production: the manager records retained worktrees
+        // into the same dir the API reads back from (#78/#81).
+        let retained =
+            maestro_daemon::retained_store::RetainedStore::new(Self::retained_path(&state_dir));
+        manager = manager.with_retained_store(retained.clone());
         Self {
             tmux,
             manager,
@@ -187,6 +192,10 @@ impl DaemonFixture {
         state_dir.path().join("spawn-history.jsonl")
     }
 
+    fn retained_path(state_dir: &TempDir) -> PathBuf {
+        state_dir.path().join("retained-worktrees")
+    }
+
     pub fn spawn_history_path(&self) -> PathBuf {
         Self::history_path(&self.state_dir)
     }

crates/maestro-daemon/tests/local_api.rs

@@ -25,6 +25,13 @@ struct Harness {
     _fx: DaemonFixture,
 }
 
+impl Harness {
+    /// Store over the same dir the manager records into.
+    fn fx_retained(&self) -> maestro_daemon::retained_store::RetainedStore {
+        self._fx.retained_store()
+    }
+}
+
 async fn spawn(hostname: &str) -> Harness {
     spawn_with(
         hostname,
@@ -356,7 +363,6 @@ async fn delete_a_session_whose_worktree_holds_unsaved_work_returns_409_with_the
             worktree: Some(WorktreeSpec {
                 base_repo: repo.path().to_path_buf(),
                 branch: "feat/guarded".into(),
-                cleanup_on_kill: true,
                 create_branch: true,
             }),
         })
@@ -386,6 +392,61 @@ async fn delete_a_session_whose_worktree_holds_unsaved_work_returns_409_with_the
     assert!(h.manager.has(session.id).await, "the session keeps running");
 }
 
+/// `?force=true` on the wire (#81): the refusal is overridden, the session
+/// ends, and the answer is 200 with the retained worktree named — path,
+/// branch, reason — while the directory survives on disk.
+#[tokio::test]
+async fn delete_with_force_ends_the_session_and_answers_what_was_retained() {
+    let h = spawn("naps-laptop").await;
+    let repo = tempfile::TempDir::new().unwrap();
+    common::init_repo(repo.path());
+    let wt_path = repo
+        .path()
+        .join("worktrees")
+        .join("feat")
+        .join("guarded")
+        .to_path_buf();
+    let session = h
+        .manager
+        .create(CreateSessionRequest {
+            cwd: repo.path().to_path_buf(),
+            command: "sleep 60".into(),
+            env: HashMap::new(),
+            metadata: HashMap::new(),
+            worktree: Some(WorktreeSpec {
+                base_repo: repo.path().to_path_buf(),
+                branch: "feat/guarded".into(),
+                create_branch: true,
+            }),
+        })
+        .await
+        .unwrap();
+    std::fs::write(wt_path.join("README"), b"unsaved edits\n").unwrap();
+
+    let resp = reqwest::Client::new()
+        .delete(url(h.addr, &format!("/api/sessions/{}", session.id)))
+        .query(&[("force", "true")])
+        .send()
+        .await
+        .unwrap();
+    assert_eq!(resp.status(), reqwest::StatusCode::OK);
+    let body: maestro_protocol::KillOutcome = resp.json().await.unwrap();
+    let retained = body.retained.expect("force names what was kept");
+    assert_eq!(retained.path, wt_path);
+    assert_eq!(retained.branch, "feat/guarded");
+    assert_eq!(
+        retained.reason,
+        maestro_protocol::RetainedReason::ForceKilled
+    );
+
+    // The tree would have blocked; force must not have removed it.
+    assert!(wt_path.exists(), "a forced kill never removes the worktree");
+    // And the store entry exists, so reclaim can find it (#80).
+    let all = h.fx_retained().load_all().unwrap();
+    assert_eq!(all.len(), 1);
+    assert_eq!(all[0].id, retained.id);
+}
+
 #[tokio::test]
 async fn attach_ws_streams_pty_bytes() {
     let h = spawn("naps-laptop").await;
@@ -476,7 +537,7 @@ async fn events_ws_sends_a_snapshot_then_streams_deltas() {
         other => panic!("expected SessionAdded, got {other:?}"),
     }
 
-    h.manager.kill(created.id).await.expect("kill");
+    h.manager.kill(created.id, false).await.expect("kill");
 
     // Activity ticks may interleave; the removal is what we are waiting for.
     let deadline = tokio::time::Instant::now() + Duration::from_secs(5);

crates/maestro-daemon/tests/session_decisions.rs

@@ -211,7 +211,7 @@ async fn killing_a_dead_session_dismisses_it_without_touching_tmux() {
     fx.manager.start_liveness_watcher(Duration::from_millis(25));
     wait_for_status(&fx.manager, s.id, SessionStatus::Dead).await;
 
-    fx.manager.kill(s.id).await.expect("dismiss");
+    fx.manager.kill(s.id, false).await.expect("dismiss");
 
     assert!(fx.manager.snapshot().await.is_empty());
     assert!(
@@ -371,7 +371,7 @@ async fn killing_an_unknown_session_is_reported_as_not_found() {
     let fx = Fx::new();
     let err = fx
         .manager
-        .kill(uuid::Uuid::new_v4())
+        .kill(uuid::Uuid::new_v4(), false)
         .await
         .expect_err("should fail");
     assert_eq!(err.to_error_info().code, "not_found");

crates/maestro-daemon/tests/session_manager.rs

@@ -8,7 +8,9 @@ use std::process::Command;
 use std::sync::Arc;
 use std::time::Duration;
 
-use common::{init_bare_repo, init_repo, push_all_to_origin, wait_for_async, DaemonFixture};
+use common::{
+    init_bare_repo, init_repo, push_all_to_origin, wait_for_async, DaemonFixture, TmuxFixture,
+};
 use maestro_daemon::SessionError;
 use maestro_protocol::CreateSessionRequest;
 use maestro_protocol::{CatalogEvent, SessionStatus, WorktreeSpec};
@@ -44,7 +46,7 @@ async fn create_then_kill_round_trip() {
     // FIFO should also exist
     assert!(fx.fifo_dir().join(format!("{}.fifo", session.id)).exists());
 
-    fx.manager.kill(session.id).await.expect("kill");
+    fx.manager.kill(session.id, false).await.expect("kill");
     assert!(!fx.manager.has(session.id).await);
     assert!(!fx
         .sidecar_dir()
@@ -79,7 +81,7 @@ async fn create_appends_to_spawn_history() {
     assert_eq!(recents[0].cwd, cwd.path());
     assert_eq!(recents[0].last_command, "sleep 30");
 
-    fx.manager.kill(session.id).await.expect("kill");
+    fx.manager.kill(session.id, false).await.expect("kill");
     // History is durable — it survives the kill that deletes the sidecar.
     assert_eq!(fx.manager.recent_dirs().len(), 1);
 }
@@ -185,7 +187,7 @@ async fn create_captures_initial_output_in_replay_buffer() {
         "first-line marker never reached the replay buffer — pipe-pane raced past the child's initial output",
     );
 
-    fx.manager.kill(s.id).await.unwrap();
+    fx.manager.kill(s.id, false).await.unwrap();
 }
 
 /// Regression for NAP-228: after `recover`, PTY output must reach new
@@ -251,7 +253,7 @@ async fn recover_re_pipes_pane_so_output_reaches_subscribers() {
         String::from_utf8_lossy(&buf),
     );
 
-    revived.kill(s.id).await.unwrap();
+    revived.kill(s.id, false).await.unwrap();
 }
 
 #[tokio::test]
@@ -300,7 +302,7 @@ async fn pty_broadcast_delivers_bytes_to_subscribers() {
     assert!(buf_a.windows(want.len()).any(|w| w == want), "A missed");
     assert!(buf_b.windows(want.len()).any(|w| w == want), "B missed");
 
-    fx.manager.kill(s.id).await.unwrap();
+    fx.manager.kill(s.id, false).await.unwrap();
     let _ = (cwd, PathBuf::from("/"));
 }
 
@@ -359,12 +361,73 @@ async fn liveness_watcher_marks_dead_sessions_and_keeps_them_until_dismissed() {
     );
 
     // Dismissing it is what finally releases the artifacts.
-    fx.manager.kill(s.id).await.expect("dismiss");
+    fx.manager.kill(s.id, false).await.expect("dismiss");
     assert!(!fx.manager.has(s.id).await);
     assert!(!fx.sidecar_dir().join(format!("{}.json", s.id)).exists());
     assert!(!fx.fifo_dir().join(format!("{}.fifo", s.id)).exists());
 }
 
+/// #83: the watcher refreshes `Session.blocked_work` on its own cadence —
+/// first "nothing blocks" for a pristine tree, then the breakdown once the
+/// tree picks up unsaved work, so clients can warn before the kill attempt.
+#[tokio::test]
+async fn watcher_refreshes_the_blocked_work_indicator() {
+    let fx = DaemonFixture::new();
+    let repo = TempDir::new().unwrap();
+    init_repo(repo.path());
+    let wt_path = repo.path().join("worktrees").join("feat").join("indicator");
+
+    fx.manager
+        .create(CreateSessionRequest {
+            cwd: repo.path().to_path_buf(),
+            command: "sleep 30".into(),
+            env: HashMap::new(),
+            metadata: HashMap::new(),
+            worktree: Some(WorktreeSpec {
+                base_repo: repo.path().to_path_buf(),
+                branch: "feat/indicator".into(),
+                create_branch: true,
+            }),
+        })
+        .await
+        .expect("create");
+
+    // Pushed and clean: nothing in the way, and the indicator must say so.
+    let origin = TempDir::new().unwrap();
+    init_bare_repo(origin.path());
+    push_all_to_origin(repo.path(), origin.path());
+
+    fx.manager.start_liveness_watcher_with_blocked_work(
+        Duration::from_millis(50),
+        Duration::from_millis(100),
+    );
+
+    wait_for_async(Duration::from_secs(5), || async {
+        fx.manager.snapshot().await[0].blocked_work == Some(maestro_protocol::InTheWay::default())
+    })
+    .await;
+
+    // Unsaved work appears; the next pass must surface it.
+    std::fs::write(wt_path.join("README"), b"unsaved edits\n").unwrap();
+    std::fs::write(wt_path.join("notes.txt"), b"untracked\n").unwrap();
+    wait_for_async(Duration::from_secs(5), || async {
+        matches!(
+            &fx.manager.snapshot().await[0].blocked_work,
+            Some(b) if b.uncommitted_files >= 1 && b.untracked_files >= 1
+        )
+    })
+    .await;
+
+    // A steady state must not re-emit every tick (#83 change-detection).
+    let mut events = fx.manager.events();
+    while events.try_recv().is_ok() {}
+    tokio::time::sleep(Duration::from_millis(400)).await;
+    assert!(
+        !matches!(events.try_recv(), Ok(CatalogEvent::SessionUpdated { .. })),
+        "an unchanged worktree must not re-emit SessionUpdated"
+    );
+}
+
 /// Cleanup on kill is unconditional once the guard passes (#79): even a spec
 /// that says "don't clean up" loses its worktree — the branch was pushed, so
 /// nothing in the tree is unique and removal goes ahead.
@@ -385,7 +448,6 @@ async fn kill_removes_worktree_even_when_spec_says_keep() {
             worktree: Some(WorktreeSpec {
                 base_repo: repo.path().to_path_buf(),
                 branch: "feat/keep".into(),
-                cleanup_on_kill: false,
                 create_branch: true,
             }),
         })
@@ -398,7 +460,7 @@ async fn kill_removes_worktree_even_when_spec_says_keep() {
     init_bare_repo(origin.path());
     push_all_to_origin(repo.path(), origin.path());
 
-    fx.manager.kill(s.id).await.expect("kill");
+    fx.manager.kill(s.id, false).await.expect("kill");
     assert!(!wt_path.exists(), "worktree must be removed on kill");
 }
 
@@ -423,7 +485,6 @@ async fn killing_refuses_a_worktree_with_unsaved_work_and_keeps_the_session() {
             worktree: Some(WorktreeSpec {
                 base_repo: repo.path().to_path_buf(),
                 branch: "feat/guarded".into(),
-                cleanup_on_kill: true,
                 create_branch: true,
             }),
         })
@@ -432,7 +493,11 @@ async fn killing_refuses_a_worktree_with_unsaved_work_and_keeps_the_session() {
     std::fs::write(wt_path.join("README"), b"unsaved edits\n").unwrap();
     std::fs::write(wt_path.join("notes.txt"), b"untracked\n").unwrap();
 
-    let err = fx.manager.kill(s.id).await.expect_err("kill must refuse");
+    let err = fx
+        .manager
+        .kill(s.id, false)
+        .await
+        .expect_err("kill must refuse");
     let SessionError::KillGuarded(breakdown) = err else {
         panic!("expected KillGuarded, got {err:?}");
     };
@@ -456,7 +521,10 @@ async fn killing_refuses_a_worktree_with_unsaved_work_and_keeps_the_session() {
     let origin = TempDir::new().unwrap();
     init_bare_repo(origin.path());
     push_all_to_origin(repo.path(), origin.path());
-    fx.manager.kill(s.id).await.expect("kill after saving");
+    fx.manager
+        .kill(s.id, false)
+        .await
+        .expect("kill after saving");
     assert!(!fx.manager.has(s.id).await);
 }
 
@@ -480,14 +548,17 @@ async fn killing_refuses_until_the_branch_is_pushed() {
             worktree: Some(WorktreeSpec {
                 base_repo: repo.path().to_path_buf(),
                 branch: "feat/pushed".into(),
-                cleanup_on_kill: true,
                 create_branch: true,
             }),
         })
         .await
         .expect("create");
 
-    let err = fx.manager.kill(s.id).await.expect_err("unpushed blocks");
+    let err = fx
+        .manager
+        .kill(s.id, false)
+        .await
+        .expect_err("unpushed blocks");
     let SessionError::KillGuarded(breakdown) = err else {
         panic!("expected KillGuarded, got {err:?}");
     };
@@ -499,11 +570,116 @@ async fn killing_refuses_until_the_branch_is_pushed() {
     init_bare_repo(origin.path());
     push_all_to_origin(repo.path(), origin.path());
 
-    fx.manager.kill(s.id).await.expect("pushed branch kills");
+    fx.manager
+        .kill(s.id, false)
+        .await
+        .expect("pushed branch kills");
     assert!(!wt_path.exists());
     assert!(!fx.manager.has(s.id).await);
 }
 
+/// `--force` overrides the refusal and nothing else (#81): the session ends,
+/// but the guarded worktree is RETAINED — never removed — and enters the
+/// retained store with reason `force-killed`. The outcome names what was
+/// kept, so a client can say where the work went.
+#[tokio::test]
+async fn force_killing_a_guarded_worktree_retains_it_in_the_store() {
+    let fx = DaemonFixture::new();
+    let repo = TempDir::new().unwrap();
+    init_repo(repo.path());
+    let wt_path = repo.path().join("worktrees").join("feat").join("forced");
+
+    let s = fx
+        .manager
+        .create(CreateSessionRequest {
+            cwd: repo.path().to_path_buf(),
+            command: "sleep 30".into(),
+            env: HashMap::new(),
+            metadata: HashMap::new(),
+            worktree: Some(WorktreeSpec {
+                base_repo: repo.path().to_path_buf(),
+                branch: "feat/forced".into(),
+                create_branch: true,
+            }),
+        })
+        .await
+        .expect("create");
+    std::fs::write(wt_path.join("README"), b"unsaved edits\n").unwrap();
+
+    // Without force the same kill is refused (#79).
+    assert!(fx.manager.kill(s.id, false).await.is_err());
+
+    let outcome = fx
+        .manager
+        .kill(s.id, true)
+        .await
+        .expect("force overrides the refusal");
+
+    // The tree would have blocked, so force must NOT have removed it...
+    assert!(
+        wt_path.exists(),
+        "a forced kill never removes a tree that would have blocked"
+    );
+    // ...but the session itself still ends.
+    assert!(!fx.manager.has(s.id).await);
+    assert!(!fx.sidecar_dir().join(format!("{}.json", s.id)).exists());
+
+    let retained = outcome.retained.expect("the outcome names what was kept");
+    assert_eq!(retained.path, wt_path);
+    assert_eq!(retained.branch, "feat/forced");
+    assert_eq!(
+        retained.reason,
+        maestro_protocol::RetainedReason::ForceKilled
+    );
+    assert!(
+        retained.in_the_way.uncommitted_files >= 1,
+        "the outcome carries what blocked the unforced kill"
+    );
+
+    // The store holds the same entry, so reclaim can find it later (#80).
+    let all = fx.retained_store().load_all().expect("load_all");
+    assert_eq!(all.len(), 1);
+    assert_eq!(all[0].id, retained.id);
+    assert_eq!(all[0].path, wt_path);
+    assert_eq!(all[0].branch, "feat/forced");
+}
+
+/// Force overrides the *refusal*, not ordinary cleanup (#81): a tree whose
+/// guard is clear never needed the override, so a forced kill removes it as
+/// usual and retains nothing.
+#[tokio::test]
+async fn force_on_a_clear_worktree_removes_it_as_usual() {
+    let fx = DaemonFixture::new();
+    let repo = TempDir::new().unwrap();
+    init_repo(repo.path());
+    let wt_path = repo.path().join("worktrees").join("feat").join("clear");
+
+    let s = fx
+        .manager
+        .create(CreateSessionRequest {
+            cwd: repo.path().to_path_buf(),
+            command: "sleep 30".into(),
+            env: HashMap::new(),
+            metadata: HashMap::new(),
+            worktree: Some(WorktreeSpec {
+                base_repo: repo.path().to_path_buf(),
+                branch: "feat/clear".into(),
+                create_branch: true,
+            }),
+        })
+        .await
+        .expect("create");
+
+    let origin = TempDir::new().unwrap();
+    init_bare_repo(origin.path());
+    push_all_to_origin(repo.path(), origin.path());
+
+    let outcome = fx.manager.kill(s.id, true).await.expect("kill");
+    assert!(!wt_path.exists(), "a clear tree needs no override");
+    assert_eq!(outcome.retained, None);
+    assert!(fx.retained_store().load_all().unwrap().is_empty());
+}
+
 /// Ignored files NEVER block (#79): build output like `target/` exists in
 /// every Rust checkout, and an ignored-only worktree stays killable.
 #[tokio::test]
@@ -530,7 +706,6 @@ async fn killing_an_ignored_only_worktree_succeeds() {
             worktree: Some(WorktreeSpec {
                 base_repo: repo.path().to_path_buf(),
                 branch: "feat/rusty".into(),
-                cleanup_on_kill: true,
                 create_branch: true,
             }),
         })
@@ -543,13 +718,196 @@ async fn killing_an_ignored_only_worktree_succeeds() {
     push_all_to_origin(repo.path(), origin.path());
 
     fx.manager
-        .kill(s.id)
+        .kill(s.id, false)
         .await
         .expect("ignored files never block");
     assert!(!wt_path.exists());
     assert!(!fx.manager.has(s.id).await);
 }
 
+/// Natural exit (#82): a session that ends on its own never reaches the kill
+/// path, so the watcher applies the kill's rule itself. A worktree holding
+/// unsaved work is RETAINED into the store with reason
+/// `exited-with-unsaved-work`; the session stays in the catalog marked dead
+/// until dismissed — and dismissing it afterwards neither refuses nor
+/// retains a second time.
+#[tokio::test]
+async fn natural_exit_of_a_guarded_worktree_retains_it_in_the_store() {
+    let fx = DaemonFixture::new();
+    let repo = TempDir::new().unwrap();
+    init_repo(repo.path());
+    let wt_path = repo.path().join("worktrees").join("feat").join("exited");
+
+    let s = fx
+        .manager
+        .create(CreateSessionRequest {
+            cwd: repo.path().to_path_buf(),
+            command: "sleep 30".into(),
+            env: HashMap::new(),
+            metadata: HashMap::new(),
+            worktree: Some(WorktreeSpec {
+                base_repo: repo.path().to_path_buf(),
+                branch: "feat/exited".into(),
+                create_branch: true,
+            }),
+        })
+        .await
+        .expect("create");
+    std::fs::write(wt_path.join("README"), b"unsaved edits\n").unwrap();
+
+    // The command finishes / the operator types exit: tmux loses the session.
+    fx.tmux.tmux.kill_session(s.id).expect("kill tmux directly");
+    fx.manager.start_liveness_watcher(Duration::from_millis(50));
+    wait_for_async(Duration::from_secs(3), || async {
+        fx.manager.status(s.id).await == Some(SessionStatus::Dead)
+    })
+    .await;
+
+    // The tree would have blocked a kill, so the exit kept it...
+    assert!(
+        wt_path.exists(),
+        "a dirty worktree must be retained on natural exit"
+    );
+    // ...in the store, under the exit reason.
+    let all = fx.retained_store().load_all().expect("load_all");
+    assert_eq!(all.len(), 1);
+    assert_eq!(all[0].path, wt_path);
+    assert_eq!(all[0].branch, "feat/exited");
+    assert_eq!(
+        all[0].reason,
+        maestro_protocol::RetainedReason::ExitedWithUnsavedWork
+    );
+
+    // The session itself stays until dismissed; its worktree reference is
+    // settled, so dismissal is neither refused nor retained twice.
+    // (`Dead` is observable a moment before the settle step finishes.)
+    wait_for_async(Duration::from_secs(3), || async {
+        let s = &fx.manager.snapshot().await[0];
+        s.worktree.is_none() && s.blocked_work.is_none()
+    })
+    .await;
+    let snap = fx.manager.snapshot().await;
+    assert_eq!(snap.len(), 1);
+    assert_eq!(snap[0].worktree, None);
+
+    fx.manager.kill(s.id, false).await.expect("dismiss");
+    assert!(!fx.manager.has(s.id).await);
+    assert!(
+        wt_path.exists(),
+        "dismissal must not remove what was retained"
+    );
+    assert_eq!(
+        fx.retained_store().load_all().unwrap().len(),
+        1,
+        "dismissal must not record a second entry for the same tree"
+    );
+}
+
+/// Natural exit (#82), pristine side of the same rule: nothing in the tree,
+/// nothing to keep — the worktree is removed and no store entry appears.
+#[tokio::test]
+async fn natural_exit_of_a_pristine_worktree_removes_it() {
+    let fx = DaemonFixture::new();
+    let repo = TempDir::new().unwrap();
+    init_repo(repo.path());
+    let wt_path = repo.path().join("worktrees").join("feat").join("clean");
+
+    let s = fx
+        .manager
+        .create(CreateSessionRequest {
+            cwd: repo.path().to_path_buf(),
+            command: "sleep 30".into(),
+            env: HashMap::new(),
+            metadata: HashMap::new(),
+            worktree: Some(WorktreeSpec {
+                base_repo: repo.path().to_path_buf(),
+                branch: "feat/clean".into(),
+                create_branch: true,
+            }),
+        })
+        .await
+        .expect("create");
+
+    // Push everything so the branch has no unpushed commits: fully pristine.
+    let origin = TempDir::new().unwrap();
+    init_bare_repo(origin.path());
+    push_all_to_origin(repo.path(), origin.path());
+
+    fx.tmux.tmux.kill_session(s.id).expect("kill tmux directly");
+    fx.manager.start_liveness_watcher(Duration::from_millis(50));
+    wait_for_async(Duration::from_secs(3), || async {
+        fx.manager.status(s.id).await == Some(SessionStatus::Dead)
+    })
+    .await;
+
+    assert!(
+        !wt_path.exists(),
+        "a pristine worktree leaves nothing behind"
+    );
+    assert!(
+        fx.retained_store().load_all().unwrap().is_empty(),
+        "nothing was retained"
+    );
+    assert!(
+        fx.manager.has(s.id).await,
+        "the session stays until dismissed"
+    );
+}
+
+/// When nothing can be recorded — here: no retained store wired — the exit
+/// destroys nothing. The tree stays on disk AND stays attached to the dead
+/// record, where dismissing it later still goes through #81's forced-kill
+/// retention. Losing the store must not lose the work.
+#[tokio::test]
+async fn natural_exit_without_a_retained_store_destroys_nothing() {
+    let tmux = TmuxFixture::new();
+    let state_dir = TempDir::new().unwrap();
+    let manager = maestro_daemon::SessionManager::new(
+        Arc::new(tmux.tmux.clone()),
+        maestro_daemon::sidecar::SidecarStore::new(state_dir.path().join("sessions")),
+        maestro_daemon::worktree::WorktreeManager::new(None),
+        state_dir.path().join("fifos"),
+    );
+    // Deliberately NO with_retained_store.
+
+    let repo = TempDir::new().unwrap();
+    init_repo(repo.path());
+    let wt_path = repo.path().join("worktrees").join("feat").join("nostore");
+
+    let s = manager
+        .create(CreateSessionRequest {
+            cwd: repo.path().to_path_buf(),
+            command: "sleep 30".into(),
+            env: HashMap::new(),
+            metadata: HashMap::new(),
+            worktree: Some(WorktreeSpec {
+                base_repo: repo.path().to_path_buf(),
+                branch: "feat/nostore".into(),
+                create_branch: true,
+            }),
+        })
+        .await
+        .expect("create");
+    std::fs::write(wt_path.join("README"), b"unsaved edits\n").unwrap();
+
+    tmux.tmux.kill_session(s.id).expect("kill tmux directly");
+    manager.start_liveness_watcher(Duration::from_millis(50));
+    wait_for_async(Duration::from_secs(3), || async {
+        manager.status(s.id).await == Some(SessionStatus::Dead)
+    })
+    .await;
+
+    assert!(
+        wt_path.exists(),
+        "nothing may be destroyed when it cannot be recorded"
+    );
+    let snap = manager.snapshot().await;
+    assert!(
+        snap[0].worktree.is_some(),
+        "the tree must stay attached to the record so a later forced kill can retain it"
+    );
+}
+
 fn run_git_in(dir: &std::path::Path, args: &[&str]) {
     let out = Command::new("git")
         .arg("-C")
@@ -587,5 +945,5 @@ async fn liveness_watcher_leaves_running_sessions_alone() {
     tokio::time::sleep(Duration::from_millis(400)).await;
     assert!(fx.manager.has(s.id).await, "live session got reaped");
 
-    fx.manager.kill(s.id).await.unwrap();
+    fx.manager.kill(s.id, false).await.unwrap();
 }

crates/maestro-daemon/tests/sidecar.rs

@@ -28,6 +28,7 @@ fn sample(id: Uuid) -> Session {
         activity: Default::default(),
         last_activity_at: chrono::Utc::now(),
         current_cwd: Some(PathBuf::from("/tmp/work/crates")),
+        blocked_work: None,
     }
 }
 

crates/maestro-e2e/src/client.rs

@@ -12,7 +12,8 @@ use std::time::Duration;
 
 use futures_util::{SinkExt, StreamExt};
 use maestro_protocol::{
-    BranchInfo, CatalogEvent, CreateSessionRequest, DaemonClient, Project, Session,
+    BranchInfo, CatalogEvent, CreateSessionRequest, DaemonClient, KillOutcome, Project,
+    RetainedWorktree, Session,
 };
 use tokio_tungstenite::tungstenite::client::IntoClientRequest;
 use tokio_tungstenite::tungstenite::Message as WsMessage;
@@ -61,7 +62,21 @@ impl TestClient {
     }
 
     pub async fn kill_session(&self, id: Uuid) -> Result<(), ClientError> {
-        Ok(self.daemon.kill_session(id).await?)
+        Ok(self.daemon.kill_session(id, false).await.map(|_| ())?)
+    }
+
+    /// Kill with `force=true`: overrides a kill refusal and retains the
+    /// guarded worktree (#81). Answers with what was kept.
+    pub async fn kill_session_forced(&self, id: Uuid) -> Result<KillOutcome, ClientError> {
+        Ok(self.daemon.kill_session(id, true).await?)
+    }
+
+    pub async fn list_worktrees(&self) -> Result<Vec<RetainedWorktree>, ClientError> {
+        Ok(self.daemon.list_worktrees().await?)
+    }
+
+    pub async fn reclaim_worktree(&self, id: Uuid) -> Result<(), ClientError> {
+        Ok(self.daemon.reclaim_worktree(id).await?)
     }
 
     pub async fn list_projects(&self) -> Result<Vec<Project>, ClientError> {

crates/maestro-e2e/tests/e2e.rs

@@ -35,6 +35,17 @@ fn create_req(cwd: &std::path::Path, command: &str) -> CreateSessionRequest {
     }
 }
 
+/// A worktree spec built through its wire shape. The daemon and clients ship
+/// together (#87 dropped `cleanup_on_kill` from the struct), so the JSON
+/// object carries only the fields the lifecycle actually honours.
+fn worktree_spec(base_repo: &std::path::Path, branch: &str, create_branch: bool) -> WorktreeSpec {
+    WorktreeSpec {
+        base_repo: base_repo.to_path_buf(),
+        branch: branch.into(),
+        create_branch,
+    }
+}
+
 /// Spawn request carrying a worktree spec against `base`.
 fn worktree_req(base: &std::path::Path, branch: &str, create_branch: bool) -> CreateSessionRequest {
     CreateSessionRequest {
@@ -42,12 +53,7 @@ fn worktree_req(base: &std::path::Path, branch: &str, create_branch: bool) -> Cr
         command: "sleep 30".into(),
         env: HashMap::new(),
         metadata: HashMap::new(),
-        worktree: Some(WorktreeSpec {
-            base_repo: base.to_path_buf(),
-            branch: branch.into(),
-            cleanup_on_kill: true,
-            create_branch,
-        }),
+        worktree: Some(worktree_spec(base, branch, create_branch)),
     }
 }
 
@@ -141,12 +147,7 @@ async fn kill_removes_clean_worktree() {
         command: "sleep 30".into(),
         env: HashMap::new(),
         metadata: HashMap::new(),
-        worktree: Some(WorktreeSpec {
-            base_repo: base.path().to_path_buf(),
-            branch: "feature/e2e".into(),
-            cleanup_on_kill: true,
-            create_branch: true,
-        }),
+        worktree: Some(worktree_spec(base.path(), "feature/e2e", true)),
     };
 
     let s = client.spawn_session(&req).await.expect("spawn worktree");
@@ -160,7 +161,7 @@ async fn kill_removes_clean_worktree() {
         "expected a worktree for feature/e2e under <repo>/worktrees, got: {worktrees:?}"
     );
 
-    push_to_throwaway_origin(base.path());
+    let _origin = throwaway_origin(base.path());
     client.kill_session(s.id).await.expect("kill");
 
     // Give the daemon a moment to remove the worktree, then verify.
@@ -199,12 +200,7 @@ async fn kill_refuses_worktree_with_uncommitted_changes() {
         command: "sleep 30".into(),
         env: HashMap::new(),
         metadata: HashMap::new(),
-        worktree: Some(WorktreeSpec {
-            base_repo: base.path().to_path_buf(),
-            branch: "feature/unsaved".into(),
-            cleanup_on_kill: true,
-            create_branch: true,
-        }),
+        worktree: Some(worktree_spec(base.path(), "feature/unsaved", true)),
     };
 
     let s = client.spawn_session(&req).await.expect("spawn worktree");
@@ -262,12 +258,7 @@ async fn spawn_on_existing_branch_checks_it_out() {
         command: "sleep 30".into(),
         env: HashMap::new(),
         metadata: HashMap::new(),
-        worktree: Some(WorktreeSpec {
-            base_repo: base.path().to_path_buf(),
-            branch: "feature/existing".into(),
-            cleanup_on_kill: true,
-            create_branch: false,
-        }),
+        worktree: Some(worktree_spec(base.path(), "feature/existing", false)),
     };
 
     let s = client
@@ -280,7 +271,7 @@ async fn spawn_on_existing_branch_checks_it_out() {
         "expected a worktree checked out at feature/existing, got: {worktrees:?}"
     );
 
-    push_to_throwaway_origin(base.path());
+    let _origin = throwaway_origin(base.path());
     client.kill_session(s.id).await.expect("kill");
 }
 
@@ -328,7 +319,7 @@ async fn spawn_new_branch_creates_worktree_and_runs_in_it() {
     )
     .await;
 
-    push_to_throwaway_origin(base.path());
+    let _origin = throwaway_origin(base.path());
     client.kill_session(s.id).await.expect("kill");
 }
 
@@ -376,7 +367,7 @@ async fn second_spawn_on_same_branch_is_rejected() {
         "original worktree must be untouched"
     );
 
-    push_to_throwaway_origin(base.path());
+    let _origin = throwaway_origin(base.path());
     client.kill_session(first.id).await.expect("kill");
 }
 
@@ -419,10 +410,481 @@ async fn spawn_from_linked_worktree_places_in_main_checkout() {
         "worktrees must never nest inside another worktree"
     );
 
-    push_to_throwaway_origin(base.path());
+    let _origin = throwaway_origin(base.path());
     client.kill_session(s.id).await.expect("kill");
 }
 
+// ---------------------------------------------------------------------------
+// Worktree lifecycle: collisions, retention, reclaim (#88)
+// ---------------------------------------------------------------------------
+
+/// #77/#88: the target path `<repo>/worktrees/<branch>` is occupied by a real
+/// registered worktree the operator made by hand. The daemon sidesteps to the
+/// suffixed directory and never touches the occupant — and both trees keep
+/// working: two registered worktrees, two sessions, each running in its own.
+#[tokio::test(flavor = "multi_thread")]
+async fn occupied_path_gets_suffixed_directory_and_both_worktrees_work() {
+    let (_daemon, client) = bring_up().await;
+
+    let base = TempDir::new().unwrap();
+    init_repo(base.path());
+
+    // An operator-made worktree sits exactly where `feature/collide` would go.
+    // Its branch is a different one, so the requested branch stays creatable.
+    let squatter = base
+        .path()
+        .join("worktrees")
+        .join("feature")
+        .join("collide");
+    run_git(
+        &[
+            "worktree",
+            "add",
+            "-q",
+            "-b",
+            "operator/manual",
+            &squatter.to_string_lossy(),
+        ],
+        base.path(),
+    );
+
+    let s = client
+        .spawn_session(&worktree_req(base.path(), "feature/collide", true))
+        .await
+        .expect("spawn onto occupied path");
+
+    let suffixed = base
+        .path()
+        .join("worktrees")
+        .join("feature")
+        .join("collide-2");
+    assert_eq!(
+        s.cwd, suffixed,
+        "the daemon must take the suffixed directory, not the occupied one"
+    );
+    assert!(suffixed.is_dir(), "suffixed worktree must exist on disk");
+
+    // Both trees are registered, distinct, and the squatter is byte-intact.
+    let registrations = git_worktree_list(base.path());
+    assert!(
+        registrations
+            .iter()
+            .any(|l| l == &format!("worktree {}", squatter.canonicalize().unwrap().display())),
+        "operator's worktree must stay registered: {registrations:?}"
+    );
+    assert!(
+        registrations.iter().any(|l| l.contains("collide-2")),
+        "suffixed worktree must be registered too: {registrations:?}"
+    );
+
+    // Both sessions run inside their own tree at the same time.
+    let sessions = client.list_sessions().await.expect("list");
+    assert!(
+        sessions.iter().any(|x| x.id == s.id && x.cwd == suffixed),
+        "session must keep running in its suffixed tree"
+    );
+
+    let _origin = throwaway_origin(base.path());
+    client.kill_session(s.id).await.expect("kill");
+
+    // Only the daemon-made trees go; the operator's manual one survives.
+    let after = git_worktree_list(base.path());
+    assert!(
+        after
+            .iter()
+            .any(|l| l == &format!("worktree {}", squatter.canonicalize().unwrap().display())),
+        "operator's worktree must outlive the sessions: {after:?}"
+    );
+}
+
+/// #77/#88: the target path holds a plain directory the daemon never made and
+/// git has never heard of. The daemon neither adopts it nor errors — it builds
+/// beside it and leaves every byte of it alone.
+#[tokio::test(flavor = "multi_thread")]
+async fn foreign_directory_is_sidestepped_never_adopted() {
+    let (_daemon, client) = bring_up().await;
+
+    let base = TempDir::new().unwrap();
+    init_repo(base.path());
+
+    let squatter = base
+        .path()
+        .join("worktrees")
+        .join("feature")
+        .join("foreign");
+    std::fs::create_dir_all(&squatter).unwrap();
+    std::fs::write(squatter.join("operator-notes.txt"), b"mine\n").unwrap();
+
+    let s = client
+        .spawn_session(&worktree_req(base.path(), "feature/foreign", true))
+        .await
+        .expect("spawn must sidestep, not adopt or fail");
+
+    let suffixed = base
+        .path()
+        .join("worktrees")
+        .join("feature")
+        .join("foreign-2");
+    assert_eq!(s.cwd, suffixed, "session must run in the suffixed tree");
+    assert_eq!(
+        std::fs::read(squatter.join("operator-notes.txt")).unwrap(),
+        b"mine\n",
+        "the foreign directory must be untouched"
+    );
+    let registrations = git_worktree_list(base.path());
+    let registered_paths: Vec<&str> = registrations
+        .iter()
+        .filter_map(|l| l.strip_prefix("worktree "))
+        .collect();
+    assert!(
+        !registered_paths
+            .iter()
+            .any(|p| *p == squatter.canonicalize().unwrap().display().to_string()),
+        "a plain directory must never be adopted as a worktree: {registered_paths:?}"
+    );
+
+    let _origin = throwaway_origin(base.path());
+    client.kill_session(s.id).await.expect("kill");
+    assert!(squatter.join("operator-notes.txt").exists());
+}
+
+/// #79/#88: killing with uncommitted changes is refused; committing and
+/// pushing that work clears the guard and the very same kill then succeeds
+/// and removes the tree. The session is the handle on the work: while it is
+/// unsaved the session stays, once it is saved the tree goes.
+#[tokio::test(flavor = "multi_thread")]
+async fn guarded_kill_then_commit_and_push_makes_the_same_kill_succeed() {
+    let (_daemon, client) = bring_up().await;
+
+    let base = TempDir::new().unwrap();
+    init_repo(base.path());
+    let _origin = throwaway_origin(base.path());
+
+    let wt = base.path().join("worktrees").join("feature").join("guard");
+    let s = client
+        .spawn_session(&worktree_req(base.path(), "feature/guard", true))
+        .await
+        .expect("spawn");
+    std::fs::write(wt.join("README"), b"work in progress\n").unwrap();
+
+    // Refused: the edit is uncommitted.
+    let err = client
+        .kill_session(s.id)
+        .await
+        .expect_err("kill must refuse");
+    match err {
+        maestro_e2e::ClientError::Api(maestro_protocol::ClientError::Api { info, .. }) => {
+            assert_eq!(info.code, "kill_guarded", "{info:?}");
+            let breakdown = info.unsaved_work.expect("breakdown on the wire");
+            assert_eq!(breakdown.uncommitted_files, 1);
+            assert_eq!(breakdown.unpushed_commits, 0);
+        }
+        other => panic!("expected a kill_guarded refusal, got {other:?}"),
+    }
+    assert!(
+        client
+            .list_sessions()
+            .await
+            .unwrap()
+            .iter()
+            .any(|x| x.id == s.id),
+        "a refused kill keeps the session running"
+    );
+    assert_eq!(
+        std::fs::read(wt.join("README")).unwrap(),
+        b"work in progress\n",
+        "the worktree is untouched by the refusal"
+    );
+
+    // The operator does exactly what the refusal asked for: save and push.
+    commit_all(&wt, "wip");
+    push_all(base.path());
+
+    client.kill_session(s.id).await.expect("kill after saving");
+
+    let deadline = Instant::now() + Duration::from_secs(5);
+    while Instant::now() < deadline {
+        if !wt.exists() {
+            break;
+        }
+        tokio::time::sleep(Duration::from_millis(100)).await;
+    }
+    assert!(
+        !wt.exists(),
+        "a cleared worktree must be removed after kill"
+    );
+    let registrations = git_worktree_list(base.path());
+    assert!(
+        !registrations.iter().any(|l| l.contains("feature/guard")),
+        "removal must deregister the tree: {registrations:?}"
+    );
+}
+
+/// #81/#88: commits that no remote has refuse the kill; `--force` ends the
+/// session anyway but RETAINS the worktree — force never destroys blocked
+/// work, it parks it in the retained store with reason `force-killed`.
+#[tokio::test(flavor = "multi_thread")]
+async fn unpushed_commits_block_kill_and_force_retains_the_tree() {
+    let (_daemon, client) = bring_up().await;
+
+    let base = TempDir::new().unwrap();
+    init_repo(base.path());
+    let _origin = throwaway_origin(base.path());
+
+    let wt = base.path().join("worktrees").join("feature").join("local");
+    let s = client
+        .spawn_session(&worktree_req(base.path(), "feature/local", true))
+        .await
+        .expect("spawn");
+    std::fs::write(wt.join("README"), b"local only\n").unwrap();
+    commit_all(&wt, "not pushed yet");
+
+    // Refused: the commit is on no remote-tracking ref.
+    let err = client
+        .kill_session(s.id)
+        .await
+        .expect_err("kill must refuse");
+    match err {
+        maestro_e2e::ClientError::Api(maestro_protocol::ClientError::Api { info, .. }) => {
+            assert_eq!(info.code, "kill_guarded", "{info:?}");
+            let breakdown = info.unsaved_work.expect("breakdown on the wire");
+            assert_eq!(breakdown.unpushed_commits, 1);
+            assert_eq!(breakdown.uncommitted_files, 0);
+        }
+        other => panic!("expected a kill_guarded refusal, got {other:?}"),
+    }
+
+    // Force overrides the refusal and nothing else: session gone, tree kept.
+    let outcome = client.kill_session_forced(s.id).await.expect("forced kill");
+    let retained = outcome
+        .retained
+        .expect("force must retain the guarded tree");
+    assert_eq!(
+        retained.reason,
+        maestro_protocol::RetainedReason::ForceKilled
+    );
+    assert_eq!(retained.path, wt);
+    assert_eq!(retained.branch, "feature/local");
+    assert_eq!(retained.in_the_way.unpushed_commits, 1);
+
+    assert!(
+        !client
+            .list_sessions()
+            .await
+            .unwrap()
+            .iter()
+            .any(|x| x.id == s.id),
+        "the forced kill ends the session"
+    );
+    assert!(wt.is_dir(), "a force-retained worktree must stay on disk");
+    assert!(
+        git_worktree_list(base.path())
+            .iter()
+            .any(|l| l.contains("feature/local")),
+        "the retained tree stays registered in git"
+    );
+}
+
+/// #82/#88: a session that exits on its own never reaches the kill path, but
+/// its worktree follows the same rule. Dirty → retained with reason
+/// `exited-with-unsaved-work`; pristine → removed, leaving nothing behind.
+#[tokio::test(flavor = "multi_thread")]
+async fn natural_exit_settles_dirty_and_pristine_worktrees_differently() {
+    let (_daemon, client) = bring_up().await;
+
+    // Two repos so the two cases cannot see each other's state.
+    let dirty_repo = TempDir::new().unwrap();
+    init_repo(dirty_repo.path());
+    let _origin = throwaway_origin(dirty_repo.path());
+    let pristine_repo = TempDir::new().unwrap();
+    init_repo(pristine_repo.path());
+    let _origin_pristine = throwaway_origin(pristine_repo.path());
+
+    let dirty_wt = dirty_repo
+        .path()
+        .join("worktrees")
+        .join("feature")
+        .join("messy");
+    let pristine_wt = pristine_repo
+        .path()
+        .join("worktrees")
+        .join("feature")
+        .join("tidy");
+
+    let _dirty = client
+        .spawn_session(&CreateSessionRequest {
+            cwd: dirty_repo.path().to_path_buf(),
+            command: "sh -c 'echo unsaved > scratch.txt'".into(),
+            env: HashMap::new(),
+            metadata: HashMap::new(),
+            worktree: Some(worktree_spec(dirty_repo.path(), "feature/messy", true)),
+        })
+        .await
+        .expect("spawn dirty");
+    let _pristine = client
+        .spawn_session(&create_req_cmd(
+            pristine_repo.path(),
+            "true",
+            "feature/tidy",
+        ))
+        .await
+        .expect("spawn pristine");
+
+    assert!(dirty_wt.is_dir() && pristine_wt.is_dir());
+
+    // The watcher reaps dead tmux sessions every couple of ticks and settles
+    // each worktree accordingly. Poll for both outcomes.
+    wait_for_async(
+        "dirty exit retains its worktree",
+        Duration::from_secs(20),
+        || {
+            let client = client.clone();
+            let path = dirty_wt.clone();
+            async move {
+                client
+                    .list_worktrees()
+                    .await
+                    .ok()
+                    .map(|wts| {
+                        wts.iter().any(|w| {
+                            w.path == path
+                                && w.reason
+                                    == maestro_protocol::RetainedReason::ExitedWithUnsavedWork
+                        })
+                    })
+                    .unwrap_or(false)
+            }
+        },
+    )
+    .await;
+    wait_for_async(
+        "pristine exit removes its worktree entirely",
+        Duration::from_secs(20),
+        || {
+            let client = client.clone();
+            let repo = pristine_repo.path().to_path_buf();
+            let path = pristine_wt.clone();
+            async move {
+                if path.exists() {
+                    return false;
+                }
+                let listed = client.list_worktrees().await.ok();
+                let listed_clear = listed
+                    .map(|wts| !wts.iter().any(|w| w.path == path))
+                    .unwrap_or(false);
+                let registered = git_worktree_list(&repo);
+                !registered.iter().any(|l| l.contains("feature/tidy")) && listed_clear
+            }
+        },
+    )
+    .await;
+
+    // The dirty tree is still fully there, file included.
+    assert!(dirty_wt.is_dir());
+    assert_eq!(
+        std::fs::read(dirty_wt.join("scratch.txt")).unwrap(),
+        b"unsaved\n"
+    );
+}
+
+fn create_req_cmd(cwd: &std::path::Path, command: &str, branch: &str) -> CreateSessionRequest {
+    CreateSessionRequest {
+        cwd: cwd.to_path_buf(),
+        command: command.into(),
+        env: HashMap::new(),
+        metadata: HashMap::new(),
+        worktree: Some(worktree_spec(cwd, branch, true)),
+    }
+}
+
+/// #80/#88: `GET /api/worktrees` lists what the daemon is holding, with the
+/// reason and a live in-the-way breakdown; reclaim removes the directory and
+/// the store entry but NEVER the branch — its commits outlive the reclaim.
+#[tokio::test(flavor = "multi_thread")]
+async fn worktrees_endpoint_lists_reasons_and_reclaim_keeps_the_branch() {
+    let (_daemon, client) = bring_up().await;
+
+    let base = TempDir::new().unwrap();
+    init_repo(base.path());
+    let _origin = throwaway_origin(base.path());
+
+    let wt = base.path().join("worktrees").join("feature").join("parked");
+    let s = client
+        .spawn_session(&worktree_req(base.path(), "feature/parked", true))
+        .await
+        .expect("spawn");
+    std::fs::write(wt.join("README"), b"worth keeping\n").unwrap();
+    commit_all(&wt, "worth keeping");
+    let sha = branch_sha(&wt, "feature/parked");
+
+    let outcome = client.kill_session_forced(s.id).await.expect("force kill");
+    assert!(outcome.retained.is_some());
+
+    let listed = client.list_worktrees().await.expect("list worktrees");
+    assert_eq!(listed.len(), 1, "exactly one retained entry: {listed:?}");
+    let entry = &listed[0];
+    assert_eq!(entry.path, wt);
+    assert_eq!(entry.branch, "feature/parked");
+    assert_eq!(entry.reason, maestro_protocol::RetainedReason::ForceKilled);
+    assert_eq!(entry.in_the_way.unpushed_commits, 1);
+
+    client.reclaim_worktree(entry.id).await.expect("reclaim");
+    assert!(!wt.exists(), "reclaim removes the directory");
+    assert!(
+        client.list_worktrees().await.unwrap().is_empty(),
+        "reclaim drops the store entry"
+    );
+
+    // The whole point of reclaim: the branch and its commits survive.
+    assert_eq!(
+        branch_sha(base.path(), "feature/parked"),
+        sha,
+        "the branch must keep pointing at the same commit after reclaim"
+    );
+}
+
+/// The retained store is state-dir backed (#80): a daemon restart must not
+/// orphan the trees it is holding — they are still on disk with entries
+/// pointing at them, and still reclaimable afterwards.
+#[tokio::test(flavor = "multi_thread")]
+async fn retained_store_survives_a_daemon_restart() {
+    let (mut daemon, client) = bring_up().await;
+
+    let base = TempDir::new().unwrap();
+    init_repo(base.path());
+    let _origin = throwaway_origin(base.path());
+
+    let wt = base
+        .path()
+        .join("worktrees")
+        .join("feature")
+        .join("durable");
+    let s = client
+        .spawn_session(&worktree_req(base.path(), "feature/durable", true))
+        .await
+        .expect("spawn");
+    std::fs::write(wt.join("README"), b"survives restarts\n").unwrap();
+    commit_all(&wt, "survives restarts");
+    client.kill_session_forced(s.id).await.expect("force kill");
+
+    daemon.restart().await;
+
+    let listed = client.list_worktrees().await.expect("list after restart");
+    assert_eq!(listed.len(), 1, "store must survive restart: {listed:?}");
+    assert_eq!(listed[0].path, wt);
+    assert_eq!(
+        listed[0].reason,
+        maestro_protocol::RetainedReason::ForceKilled
+    );
+    assert!(wt.is_dir(), "the tree itself must survive the restart too");
+
+    client
+        .reclaim_worktree(listed[0].id)
+        .await
+        .expect("reclaim");
+    assert!(!wt.exists());
+}
+
 // ---------------------------------------------------------------------------
 // GET /api/projects + /api/branches (#54/#55/#66)
 // ---------------------------------------------------------------------------
@@ -788,10 +1250,12 @@ fn git_worktree_list(dir: &std::path::Path) -> Vec<String> {
         .collect()
 }
 
-/// Push every branch of `repo` to a throwaway bare remote, so its commits are
-/// reachable from remote-tracking refs. Without one the kill guard (#79)
-/// reads every commit as unpushed, and any worktree session refuses to die.
-fn push_to_throwaway_origin(repo: &std::path::Path) {
+/// Bare remote registered as `origin` on `repo`, seeded with every current
+/// branch, so existing commits are reachable from remote-tracking refs.
+/// Without one the kill guard (#79) reads every commit as unpushed, and any
+/// worktree session refuses to die. The caller must keep the `TempDir` alive
+/// while the remote is still needed; later pushes go through [`push_all`].
+fn throwaway_origin(repo: &std::path::Path) -> TempDir {
     let origin = tempfile::TempDir::new().unwrap();
     run_git(
         &["init", "-q", "--bare", origin.path().to_str().unwrap()],
@@ -803,9 +1267,34 @@ fn push_to_throwaway_origin(repo: &std::path::Path) {
         .args(["remote", "add", "origin", origin.path().to_str().unwrap()])
         .output()
         .expect("git remote add");
+    push_all(repo);
+    origin
+}
+
+fn push_all(repo: &std::path::Path) {
     run_git(&["push", "-q", "--all", "origin"], repo);
 }
 
+fn commit_all(dir: &std::path::Path, message: &str) {
+    run_git(&["add", "-A"], dir);
+    run_git(&["commit", "-q", "-m", message], dir);
+}
+
+fn branch_sha(repo: &std::path::Path, branch: &str) -> String {
+    let out = Command::new("git")
+        .arg("-C")
+        .arg(repo)
+        .args(["rev-parse", "--verify", &format!("refs/heads/{branch}")])
+        .output()
+        .expect("git rev-parse");
+    assert!(
+        out.status.success(),
+        "branch {branch} missing: {}",
+        String::from_utf8_lossy(&out.stderr)
+    );
+    String::from_utf8_lossy(&out.stdout).trim().to_string()
+}
+
 #[tokio::test(flavor = "multi_thread")]
 async fn daemon_events_ws_streams_snapshot_then_session_added() {
     // NAP-248: subscribe to the daemon's WS /api/events, expect an initial

crates/maestro-protocol/src/client.rs

@@ -16,7 +16,7 @@ use uuid::Uuid;
 use crate::routes::{self, UrlError};
 use crate::{
     ApiError, BranchInfo, CreateSessionRequest, DaemonInfo, DirListing, ErrorInfo, GitRoot,
-    Project, RecentDirs, RetainedWorktree, Session,
+    KillOutcome, Project, RecentDirs, RetainedWorktree, Session,
 };
 
 /// Time budget for establishing a TCP connection to the daemon.
@@ -114,12 +114,24 @@ impl DaemonClient {
         self.post(routes::SESSIONS, req).await
     }
 
-    pub async fn kill_session(&self, id: Uuid) -> Result<(), ClientError> {
+    /// Kill a session. With `force`, the daemon overrides the kill refusal
+    /// (#79) and retains the worktree instead of removing it (#81); the
+    /// outcome then names what was kept and where.
+    pub async fn kill_session(&self, id: Uuid, force: bool) -> Result<KillOutcome, ClientError> {
+        let query: &[(&str, &str)] = if force {
+            &[(routes::FORCE_QUERY, "true")]
+        } else {
+            &[]
+        };
         let resp = self
-            .send(Method::DELETE, &routes::session(id), &[], None::<&()>)
+            .send(Method::DELETE, &routes::session(id), query, None::<&()>)
             .await?;
-        check(resp).await?;
-        Ok(())
+        let resp = check(resp).await?;
+        // An unforced kill keeps its historical `204 No Content`.
+        if resp.status() == reqwest::StatusCode::NO_CONTENT {
+            return Ok(KillOutcome { retained: None });
+        }
+        json(resp).await
     }
 
     pub async fn daemon_info(&self) -> Result<DaemonInfo, ClientError> {

crates/maestro-protocol/src/lib.rs

@@ -87,6 +87,13 @@ pub struct Session {
     /// from daemons that predate the field.
     #[serde(default)]
     pub current_cwd: Option<PathBuf>,
+    /// Whether the session's worktree currently holds anything that would
+    /// block an unforced kill (#83), summarised by [`InTheWay`]'s `Display`.
+    /// Refreshed by the daemon's watcher; `None` for sessions without a
+    /// worktree and until the first probe. Defaults on the wire so payloads
+    /// from daemons that predate the field stay forward-compatible.
+    #[serde(default)]
+    pub blocked_work: Option<InTheWay>,
 }
 
 /// Default for [`Session::last_activity_at`] when an older payload omits it.
@@ -119,11 +126,6 @@ pub enum ActivityState {
 pub struct WorktreeSpec {
     pub base_repo: PathBuf,
     pub branch: String,
-    /// Kept on the wire for CLI compatibility (#56) but no longer a
-    /// user-facing choice: the daemon always cleans up on kill, guarded
-    /// against unsaved work. Defaults to `true`.
-    #[serde(default = "default_true")]
-    pub cleanup_on_kill: bool,
     /// When false, `branch` must already exist and is checked out as-is
     /// (#56); when true (the default, and what every payload meant before
     /// the field existed) the daemon creates it with `worktree add -b`.
@@ -195,6 +197,19 @@ pub struct RetainedWorktree {
     pub in_the_way: InTheWay,
 }
 
+/// Body of a successful forced `DELETE /api/sessions/:id?force=true` (#81).
+/// A forced kill ends the session and retains its worktree instead of
+/// removing it; this names what was kept, where, and why, so a client can say
+/// where the work went rather than leaving the operator to wonder.
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+pub struct KillOutcome {
+    /// Set when the worktree was retained with reason `force-killed`; `None`
+    /// when there was nothing to retain — no worktree at all, or one whose
+    /// guard was clear, which a forced kill removes as usual.
+    #[serde(default)]
+    pub retained: Option<RetainedWorktree>,
+}
+
 impl std::fmt::Display for InTheWay {
     /// "3 uncommitted files, 2 unpushed commits" — zero parts are omitted;
     /// all-zero renders "no unsaved work". This is the phrasing every client
@@ -523,6 +538,7 @@ mod tests {
                 .unwrap()
                 .with_timezone(&Utc),
             current_cwd: Some(PathBuf::from("/home/naps62/projects/maestro/crates")),
+            blocked_work: None,
         }
     }
 
@@ -542,6 +558,34 @@ mod tests {
         assert_eq!(s.activity, ActivityState::Idle);
         assert_eq!(s.last_activity_at, epoch());
         assert!(s.current_cwd.is_none());
+        assert!(s.blocked_work.is_none());
+    }
+
+    #[test]
+    fn blocked_work_defaults_to_none_on_legacy_payload() {
+        // A pre-#83 daemon omits the indicator; it must deserialize to `None`
+        // rather than failing, and a present value round-trips.
+        let json = serde_json::json!({
+            "id": Uuid::from_u128(1),
+            "cwd": "/tmp",
+            "command": "bash",
+            "status": "Running",
+            "created_at": "2026-05-24T12:00:00Z"
+        });
+        let s: Session = serde_json::from_value(json).unwrap();
+        assert_eq!(s.blocked_work, None);
+
+        let mut with_blocker = sample_session();
+        with_blocker.blocked_work = Some(InTheWay {
+            uncommitted_files: 3,
+            ..InTheWay::default()
+        });
+        assert_eq!(
+            with_blocker.clone().blocked_work,
+            serde_json::from_value::<Session>(serde_json::to_value(&with_blocker).unwrap())
+                .unwrap()
+                .blocked_work
+        );
     }
 
     #[test]
@@ -581,7 +625,6 @@ mod tests {
             worktree: Some(WorktreeSpec {
                 base_repo: PathBuf::from("/home/naps62/projects/maestro"),
                 branch: "feat/foo".into(),
-                cleanup_on_kill: true,
                 create_branch: true,
             }),
         };
@@ -611,7 +654,6 @@ mod tests {
         });
         let spec: WorktreeSpec = serde_json::from_value(json).unwrap();
         assert!(spec.create_branch);
-        assert!(spec.cleanup_on_kill);
     }
 
     #[test]
@@ -619,7 +661,6 @@ mod tests {
         let spec = WorktreeSpec {
             base_repo: PathBuf::from("/work"),
             branch: "feat/foo".into(),
-            cleanup_on_kill: true,
             create_branch: false,
         };
         assert_eq!(spec, round_trip(&spec));
@@ -679,6 +720,22 @@ mod tests {
         );
     }
 
+    #[test]
+    fn kill_outcome_round_trips_a_retained_worktree() {
+        let outcome = KillOutcome {
+            retained: Some(sample_retained_worktree()),
+        };
+        assert_eq!(outcome, round_trip(&outcome));
+    }
+
+    /// A kill with nothing to retain — no worktree, or a clean one removed as
+    /// usual — decodes from an absent field.
+    #[test]
+    fn kill_outcome_defaults_to_nothing_retained() {
+        let outcome: KillOutcome = serde_json::from_value(serde_json::json!({})).unwrap();
+        assert_eq!(outcome.retained, None);
+    }
+
     #[test]
     fn catalog_event_round_trips_and_tags() {
         let session = sample_session();

crates/maestro-protocol/src/routes.rs

@@ -38,6 +38,10 @@ pub const PATH_QUERY: &str = "path";
 /// Name of the query parameter [`NAMES`] takes.
 pub const COUNT_QUERY: &str = "count";
 
+/// Name of the boolean query parameter `DELETE /api/sessions/:id` takes (#81).
+/// `force=true` overrides the kill refusal and retains the worktree.
+pub const FORCE_QUERY: &str = "force";
+
 /// `DELETE /api/sessions/:id`.
 pub fn session(id: Uuid) -> String {
     format!("{SESSIONS}/{id}")

crates/maestro-testing/src/lib.rs

@@ -43,6 +43,7 @@ pub fn session(id: Uuid, cwd: &str, command: &str) -> Session {
         activity: Default::default(),
         last_activity_at: Utc::now(),
         current_cwd: None,
+        blocked_work: None,
     }
 }
 

crates/maestro-tui/src/app.rs

@@ -733,8 +733,14 @@ impl App {
     }
 
     async fn submit_kill(&mut self, sid: Uuid) {
-        match self.daemon.kill_session(sid).await {
-            Ok(()) => self.release_session(sid),
+        match self.daemon.kill_session(sid, false).await {
+            Ok(outcome) => {
+                if let Some(w) = outcome.retained {
+                    self.state
+                        .toast(format!("worktree retained: {}", w.path.display()));
+                }
+                self.release_session(sid)
+            }
             Err(e) => self.state.toast(format!("kill failed: {e}")),
         }
     }
@@ -1101,6 +1107,7 @@ mod tests {
                 activity: Default::default(),
                 last_activity_at: Utc::now(),
                 current_cwd: None,
+                blocked_work: None,
             }],
         });
         app.dispatch(Action::SidebarNext);
@@ -1608,6 +1615,7 @@ mod tests {
                 last_activity_at: chrono::Utc::now(),
 
                 current_cwd: None,
+                blocked_work: None,
             }],
         });
         app.dispatch(Action::KillHighlighted);

crates/maestro-tui/src/catalog.rs

@@ -195,6 +195,7 @@ mod tests {
             activity: Default::default(),
             last_activity_at: chrono::Utc::now(),
             current_cwd: None,
+            blocked_work: None,
         }
     }
 

crates/maestro-tui/src/draft.rs

@@ -549,7 +549,6 @@ impl DraftPane {
                 WorktreeSpec {
                     base_repo,
                     branch: branch.to_string(),
-                    cleanup_on_kill: true,
                     create_branch: true,
                 }
             }
@@ -562,7 +561,6 @@ impl DraftPane {
                 WorktreeSpec {
                     base_repo,
                     branch: name,
-                    cleanup_on_kill: true,
                     create_branch: false,
                 }
             }
@@ -1689,7 +1687,6 @@ mod tests {
         assert_eq!(wt.base_repo, PathBuf::from("/repos/maestro"));
         assert_eq!(wt.branch, "crimson-otter", "branch defaults to the name");
         assert!(wt.create_branch);
-        assert!(wt.cleanup_on_kill);
     }
 
     #[test]

crates/maestro-tui/src/fast_forward.rs

@@ -80,7 +80,6 @@ impl FastForwardDefaults {
                     .clone()
                     .unwrap_or_else(|| project.path.clone()),
                 branch: name.to_string(),
-                cleanup_on_kill: true,
                 create_branch: true,
             }),
         })

crates/maestro-tui/src/overlays.rs

@@ -14,23 +14,28 @@ use ratatui::Frame;
 #[derive(Debug, Clone)]
 pub struct KillConfirm {
     pub label: String,
+    /// #83: what the daemon's watcher last saw in the worktree, phrased by
+    /// [`maestro_protocol::InTheWay`]'s Display — so "this will be refused"
+    /// is visible before the attempt. `None` while nothing blocks.
+    pub blockers: Option<String>,
 }
 
 impl KillConfirm {
     pub fn render(&self, f: &mut Frame, parent: Rect) {
-        let area = centered(parent, 50, 5);
+        let area = centered(parent, 60, if self.blockers.is_some() { 6 } else { 5 });
         f.render_widget(Clear, area);
         let block = Block::default().title(" kill ").borders(Borders::ALL);
         let inner = block.inner(area);
         f.render_widget(block, area);
-        f.render_widget(
-            Paragraph::new(vec![
-                Line::from(format!("Kill session {}?", self.label)),
-                Line::from(""),
-                Line::from("[y] yes   [n] no"),
-            ]),
-            inner,
-        );
+        let mut lines = vec![Line::from(format!("Kill session {}?", self.label))];
+        if let Some(blockers) = &self.blockers {
+            // Same phrasing the reclaim confirmation uses for its own guard.
+            lines.push(Line::from(format!("Currently in the way: {blockers}")));
+            lines.push(Line::from("The kill will be refused unless forced."));
+        }
+        lines.push(Line::from(""));
+        lines.push(Line::from("[y] yes   [n] no"));
+        f.render_widget(Paragraph::new(lines), inner);
     }
 }
 
@@ -121,6 +126,7 @@ mod tests {
     fn kill_confirm_renders_prompt() {
         let modal = KillConfirm {
             label: "session-7".into(),
+            blockers: None,
         };
         let rendered = render_to_string(60, 10, |f| modal.render(f, f.area()));
         assert!(rendered.contains("Kill"));
@@ -129,6 +135,22 @@ mod tests {
         assert!(rendered.contains("no"));
     }
 
+    /// #83: when the worktree blocks, the confirm names it before the
+    /// operator commits — in `InTheWay`'s own words.
+    #[test]
+    fn kill_confirm_names_what_blocks() {
+        let modal = KillConfirm {
+            label: "session-7".into(),
+            blockers: Some("2 uncommitted files".into()),
+        };
+        let rendered = render_to_string(70, 10, |f| modal.render(f, f.area()));
+        assert!(
+            rendered.contains("Currently in the way: 2 uncommitted files"),
+            "{rendered}"
+        );
+        assert!(rendered.contains("refused"), "{rendered}");
+    }
+
     #[test]
     fn help_overlay_lists_lines() {
         let help = HelpOverlay {

crates/maestro-tui/src/render.rs

@@ -146,8 +146,19 @@ pub fn draw(f: &mut Frame, inputs: RenderInputs<'_>) -> RegionMap {
 
     match inputs.state.overlay() {
         Some(OverlayKind::KillConfirm(id)) => {
+            // #83: surface what the watcher last saw in the worktree, in
+            // InTheWay's own words, before the operator commits to the kill.
+            let blockers = inputs
+                .sidebar
+                .sessions
+                .iter()
+                .find(|s| &s.id == id)
+                .and_then(|s| s.blocked_work)
+                .filter(|b| !b.is_clear())
+                .map(|b| b.to_string());
             let kc = KillConfirm {
                 label: id.to_string(),
+                blockers,
             };
             kc.render(f, area);
             map.modal = Some(area);

crates/maestro-tui/src/sidebar.rs

@@ -52,6 +52,13 @@ impl Sidebar {
                 (SessionStatus::Running, false) => "○",
             };
             let label = name_for(s);
+            // #83: a session whose worktree blocks a kill gets a warning
+            // glyph; the kill confirm names the specifics.
+            let blocked = s
+                .blocked_work
+                .filter(|b| !b.is_clear())
+                .map(|_| " ⚠")
+                .unwrap_or_default();
             let style = if self.highlight == Some(s.id) {
                 Style::default().add_modifier(Modifier::REVERSED)
             } else {
@@ -59,7 +66,7 @@ impl Sidebar {
             };
             lines.push(Line::from(vec![
                 Span::raw("  "),
-                Span::styled(format!("{glyph} {label}"), style),
+                Span::styled(format!("{glyph} {label}{blocked}"), style),
             ]));
         }
         f.render_widget(Paragraph::new(lines), inner);
@@ -99,6 +106,7 @@ mod tests {
             activity: Default::default(),
             last_activity_at: chrono::Utc::now(),
             current_cwd: None,
+            blocked_work: None,
         }
     }
 
@@ -172,6 +180,40 @@ mod tests {
         assert!(line.contains('✗'), "expected dead glyph in: {line:?}");
     }
 
+    /// #83: a session whose worktree blocks a kill carries the warning glyph;
+    /// a clear or unprobed one does not.
+    #[test]
+    fn blocked_session_gets_a_warning_glyph() {
+        use maestro_protocol::InTheWay;
+
+        let mut blocked = session_named(1, "claude");
+        blocked.blocked_work = Some(InTheWay {
+            unpushed_commits: 4,
+            ..InTheWay::default()
+        });
+        let mut clear = session_named(2, "bash");
+        clear.blocked_work = Some(InTheWay::default());
+        let unprobed = session_named(3, "vim");
+        let sb = Sidebar {
+            sessions: vec![blocked, clear, unprobed],
+            highlight: None,
+            attached: Default::default(),
+        };
+        let rendered = render_to_string(&sb, 40, 8);
+        let line = rendered
+            .lines()
+            .find(|l| l.contains("claude"))
+            .expect("blocked row");
+        assert!(line.contains('⚠'), "expected warning glyph in: {line:?}");
+        for name in ["bash", "vim"] {
+            let line = rendered
+                .lines()
+                .find(|l| l.contains(name))
+                .expect("clear row");
+            assert!(!line.contains('⚠'), "{name} must not warn: {line:?}");
+        }
+    }
+
     #[test]
     fn falls_back_to_command_when_name_metadata_is_absent() {
         let s = Session {
@@ -188,6 +230,7 @@ mod tests {
             last_activity_at: chrono::Utc::now(),
 
             current_cwd: None,
+            blocked_work: None,
         };
         let sb = Sidebar {
             sessions: vec![s],

docs/WORKTREES.md

@@ -75,11 +75,16 @@ That is only safe because force retains.
 
 `--force` overrides the refusal and nothing else. It ends the session and
 **retains** the worktree, which enters the retained store with reason
-`force-killed`. Force never removes a tree that would have blocked.
+`force-killed`. Force never removes a tree that would have blocked. A tree
+whose guard is clear never needed the override, so a forced kill removes it as
+usual — force changes what happens to blocked work, not ordinary cleanup.
 
-Ending a session and destroying its work are two separate destructive acts. Each
-is chosen on its own, and the second one — reclaim — is chosen while looking at
-exactly what would be lost.
+Ending a session and destroying its work are two separate destructive acts.
+Each is chosen on its own, and the second one — reclaim — is chosen while
+looking at exactly what would be lost.
+
+A forced kill answers with what was retained and why, so a client can say where
+the work went rather than leaving the operator to wonder.
 
 ### Exiting on its own
 
@@ -92,6 +97,17 @@ Nobody is waiting for an answer here, so there is nothing to refuse; the choice
 only between removing and retaining. It uses the same predicate as the kill, from
 the same place, so the two paths cannot drift apart.
 
+The session itself stays in the catalog marked dead until it is dismissed — the
+replay buffer of a crashed agent outlives it — but its worktree is settled at
+once. Once settled, the session drops its worktree reference, so dismissing it
+afterwards neither refuses (there is no guard left to trip) nor records a second
+store entry.
+
+If settling is impossible — the probe fails, or the store cannot take the entry —
+nothing is destroyed. The tree stays on disk *and* stays attached to the dead
+record, where dismissing it later still goes through `--force`'s
+retain-before-teardown path. Losing the store must never mean losing the work.
+
 ## The retained store
 
 A `state_dir`-backed record of worktrees the daemon created that no longer have a

web/src/catalog.test.ts

@@ -0,0 +1,106 @@
+// @vitest-environment happy-dom
+import { beforeAll, describe, expect, it } from "vitest";
+
+import { renderSidebar } from "./catalog.js";
+import type { CatalogListener, CatalogStore } from "./events.js";
+import type { InTheWay, Session } from "./types.js";
+
+// happy-dom runs without a backing store; renderSidebar reads the persisted
+// sidebar width on mount.
+beforeAll(() => {
+  Object.defineProperty(window, "localStorage", {
+    value: { getItem: () => null, setItem: () => {} },
+  });
+  // No daemon here; renderSidebar treats a failed info fetch as "absolute
+  // paths are a fine fallback".
+  window.fetch = () => Promise.reject(new Error("offline"));
+});
+
+function session(overrides: Partial<Session>): Session {
+  return {
+    id: "11111111-2222-3333-4444-555555555555",
+    cwd: "/home/naps/tea/maestro",
+    command: "claude",
+    env: {},
+    metadata: {},
+    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,
+    // Like the real store, deliver an immediate snapshot so the sidebar
+    // renders its rows during construction.
+    subscribe: (fn: CatalogListener) => {
+      fn(state);
+      return () => {};
+    },
+  } as unknown as CatalogStore;
+}
+
+function rowFor(el: HTMLElement, id: string): HTMLElement | null {
+  return el.querySelector<HTMLElement>(`[data-session-id="${id}"]`);
+}
+
+describe("blocked-work indicator (#83)", () => {
+  it("marks the row of a blocked session with the shared phrasing", () => {
+    const blocked = session({
+      id: "aaaaaaaa-0000-0000-0000-000000000001",
+      blocked_work: { uncommitted_files: 3, unpushed_commits: 2 },
+    });
+    const el = renderSidebar(storeWith([blocked])).el;
+    const badge = rowFor(el, blocked.id)?.querySelector(".leaf-blocked");
+    expect(badge?.textContent).toContain("⚠");
+    expect(badge?.textContent).toContain("3 uncommitted files, 2 unpushed commits");
+  });
+
+  it("does not mark clear or unprobed sessions", () => {
+    const clear = session({
+      id: "aaaaaaaa-0000-0000-0000-000000000002",
+      blocked_work: {} as InTheWay,
+    });
+    const unprobed = session({
+      id: "aaaaaaaa-0000-0000-0000-000000000003",
+    });
+    const el = renderSidebar(storeWith([clear, unprobed])).el;
+    expect(rowFor(el, clear.id)?.querySelector(".leaf-blocked")).toBeNull();
+    expect(rowFor(el, unprobed.id)?.querySelector(".leaf-blocked")).toBeNull();
+  });
+
+  it("restates the warning at the kill confirm", async () => {
+    const confirmations: string[] = [];
+    window.confirm = (msg?: string) => {
+      confirmations.push(msg ?? "");
+      return false;
+    };
+    const blocked = session({
+      id: "aaaaaaaa-0000-0000-0000-000000000004",
+      command: "bash",
+      blocked_work: { untracked_files: 1 },
+    });
+    const el = renderSidebar(storeWith([blocked])).el;
+    const kill = rowFor(el, blocked.id)?.querySelector<HTMLButtonElement>(".leaf-kill");
+    kill?.click();
+    await Promise.resolve();
+    expect(confirmations).toHaveLength(1);
+    expect(confirmations[0]).toContain("1 untracked file");
+    expect(confirmations[0]).toContain("refused unless forced");
+  });
+
+  it("confirms plainly when nothing blocks", async () => {
+    const confirmations: string[] = [];
+    window.confirm = (msg?: string) => {
+      confirmations.push(msg ?? "");
+      return false;
+    };
+    const plain = session({ id: "aaaaaaaa-0000-0000-0000-000000000005" });
+    const el = renderSidebar(storeWith([plain])).el;
+    rowFor(el, plain.id)?.querySelector<HTMLButtonElement>(".leaf-kill")?.click();
+    await Promise.resolve();
+    expect(confirmations).toEqual(['Kill session "claude"?']);
+  });
+});

web/src/catalog.ts

@@ -3,7 +3,7 @@ import { getDaemonInfo, killSession } from "./api.js";
 import { HUD_TOGGLE_EVENT, isHudEnabled, toggleHud } from "./debug.js";
 import { CatalogStore } from "./events.js";
 import type { Session } from "./types.js";
-import { abbreviateFolderName, sessionName } from "./types.js";
+import { abbreviateFolderName, formatInTheWay, sessionBlockers, sessionName } from "./types.js";
 import type { TreeNode } from "./tree.js";
 import { buildTree } from "./tree.js";
 import { createThemeToggle } from "./theme.js";
@@ -64,10 +64,14 @@ function renderNode(node: TreeNode, depth: number): HTMLElement {
   // The directory is the enclosing folder, so only surface the command — and
   // only when it isn't already what the name shows.
   const showCmd = s.command !== name;
+  // #83: warn on the row itself, in `formatInTheWay`'s shared phrasing, so
+  // "this will be refused" is visible before the kill is attempted.
+  const blockers = sessionBlockers(s);
   row.innerHTML = `
     <span class="leaf-name">${escapeHtml(name)}</span>
     ${showCmd ? `<span class="leaf-meta"><span class="leaf-cmd">${escapeHtml(s.command)}</span></span>` : ""}
     ${running ? "" : `<span class="leaf-badge">exited</span>`}
+    ${blockers ? `<span class="leaf-badge leaf-blocked" title="Kill will be refused unless forced">⚠ ${escapeHtml(formatInTheWay(blockers))}</span>` : ""}
     <span class="leaf-actions">
       <button class="leaf-act leaf-clone" type="button" title="Spawn similar" aria-label="Spawn similar to ${escapeHtml(name)}">⧉</button>
       <button class="leaf-act leaf-kill" type="button" title="Kill session" aria-label="Kill ${escapeHtml(name)}">✕</button>
@@ -83,7 +87,12 @@ function renderNode(node: TreeNode, depth: number): HTMLElement {
   killBtn.addEventListener("click", async (ev) => {
     ev.preventDefault();
     ev.stopPropagation();
-    if (!confirm(`Kill session "${sessionName(s)}"?`)) return;
+    // #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) {

web/src/fastForward.test.ts

@@ -43,7 +43,6 @@ describe("resolveFastForward (#67)", () => {
     expect(req.worktree).toEqual({
       base_repo: "/repos/fresh",
       branch: "amber-falcon",
-      cleanup_on_kill: true,
       create_branch: true,
     });
   });

web/src/fastForward.ts

@@ -42,7 +42,6 @@ export function buildFastForwardRequest(
     worktree: {
       base_repo: project.base_repo ?? project.path,
       branch: name,
-      cleanup_on_kill: true,
       create_branch: true,
     },
   };

web/src/spawnForm.test.ts

@@ -38,7 +38,6 @@ describe("buildSpawnRequest", () => {
         worktree: {
           base_repo: "/home/user/project",
           branch: "feat/foo",
-          cleanup_on_kill: true,
           create_branch: true,
         },
       },
@@ -63,7 +62,6 @@ describe("buildSpawnRequest", () => {
         worktree: {
           base_repo: "/home/user/project",
           branch: "spawn-v2",
-          cleanup_on_kill: true,
           create_branch: false,
         },
       },

web/src/spawnForm.ts

@@ -75,9 +75,6 @@ export function buildSpawnRequest(
     req.worktree = {
       base_repo: baseRepo,
       branch,
-      // The daemon always cleans up, guarded against unsaved work (#56);
-      // the wire field stays for older daemons.
-      cleanup_on_kill: true,
       // Existing-mode picks must check out as-is; the daemon creates
       // anything else with `worktree add -b` (#56/#61).
       create_branch: mode !== "existing",

web/src/styles.css

@@ -831,6 +831,13 @@ textarea {
   flex: 0 0 auto;
 }
 
+/* #83: the session row's blocked-work warning — an unforced kill will be
+   refused, and the operator should see that before pressing the button. */
+.leaf-badge.leaf-blocked {
+  color: var(--warn, #b45309);
+  border-color: var(--warn, #b45309);
+}
+
 .leaf-actions {
   position: absolute;
   right: var(--sp-1);

web/src/types.ts

@@ -31,6 +31,11 @@ export interface Session {
    * observed it (`#{pane_current_path}`) — distinct from `cwd` (the spawn dir).
    * Drives the directory-based session tree. Absent until first observed. */
   current_cwd?: string | null;
+  /** What currently blocks an unforced kill of this session (#83), as the
+   * daemon's watcher last probed it. Absent until probed and for sessions
+   * without a worktree; all counts default to 0 on the wire for older
+   * daemons. */
+  blocked_work?: InTheWay | null;
 }
 
 /** One directory's immediate subdirectories (NAP-329). */
@@ -113,7 +118,6 @@ export type Projects = Project[];
 export interface WorktreeSpec {
   base_repo: string;
   branch: string;
-  cleanup_on_kill?: boolean;
   /** When false, `branch` already exists and is checked out as-is (#61).
    * Defaults to true (create a new branch) on older daemons. */
   create_branch?: boolean;
@@ -181,6 +185,19 @@ export function reasonLabel(reason: RetainedReason): string {
   return reason;
 }
 
+/** #83: this session's blocked-work breakdown when something actually blocks
+ * an unforced kill; `null` while clear or not yet probed. Render it with
+ * {@link formatInTheWay} so every client phrases it identically. */
+export function sessionBlockers(s: Session): InTheWay | null {
+  const w = s.blocked_work;
+  if (!w) return null;
+  const blocked =
+    (w.uncommitted_files ?? 0) > 0 ||
+    (w.untracked_files ?? 0) > 0 ||
+    (w.unpushed_commits ?? 0) > 0;
+  return blocked ? w : null;
+}
+
 export interface CreateSessionRequest {
   cwd: string;
   command: string;