merge: base update from blitz/worktree-lifecycle

maestro worktrees list mirrors the sessions table shape: hostname header,
home-abbreviated paths, and the in-the-way breakdown recomputed by the
daemon at read time. reclaim takes a required explicit ID — no
reclaim-everything — and its confirmation says the branch survives.

crates/maestro-cli/src/cli.rs

@@ -41,6 +41,36 @@ pub enum Command {
     Attach(AttachArgs),
     /// Kill a session by ID.
     Kill(KillArgs),
+    /// List retained worktrees, or reclaim one by ID (#86).
+    Worktrees(WorktreesArgs),
+}
+
+/// `maestro worktrees <list|reclaim>`
+#[derive(Debug, clap::Args)]
+pub struct WorktreesArgs {
+    #[command(subcommand)]
+    pub command: WorktreesCommand,
+}
+
+#[derive(Debug, Subcommand)]
+pub enum WorktreesCommand {
+    /// List retained worktrees and what is in the way of reclaiming each.
+    List(ListWorktreesArgs),
+    /// Reclaim one retained worktree: removes the directory, never the branch.
+    Reclaim(ReclaimArgs),
+}
+
+#[derive(Debug, clap::Args)]
+pub struct ListWorktreesArgs {
+    /// Output as JSON instead of a table.
+    #[arg(long)]
+    pub json: bool,
+}
+
+#[derive(Debug, clap::Args)]
+pub struct ReclaimArgs {
+    /// Retained worktree ID to reclaim. Required — there is no reclaim-all.
+    pub id: Uuid,
 }
 
 #[derive(Debug, clap::Args)]
@@ -241,4 +271,56 @@ mod tests {
         .unwrap_err();
         assert!(err.to_string().contains("KEY=VALUE"));
     }
+
+    #[test]
+    fn parses_worktrees_list() {
+        let cli = Cli::try_parse_from(["maestro", "worktrees", "list", "--json"]).unwrap();
+        match cli.command {
+            Command::Worktrees(w) => match w.command {
+                WorktreesCommand::List(a) => assert!(a.json),
+                _ => panic!("wrong worktrees subcommand"),
+            },
+            _ => panic!("wrong subcommand"),
+        }
+    }
+
+    #[test]
+    fn parses_worktrees_reclaim() {
+        let id = "01234567-89ab-cdef-0123-456789abcdef";
+        let cli = Cli::try_parse_from(["maestro", "worktrees", "reclaim", id]).unwrap();
+        match cli.command {
+            Command::Worktrees(w) => match w.command {
+                WorktreesCommand::Reclaim(a) => assert_eq!(a.id.to_string(), id),
+                _ => panic!("wrong worktrees subcommand"),
+            },
+            _ => panic!("wrong subcommand"),
+        }
+    }
+
+    /// Contract rule: reclaim refuses to run without an explicit target.
+    /// There is no reclaim-everything convenience.
+    #[test]
+    fn reclaim_requires_an_explicit_target() {
+        let err = Cli::try_parse_from(["maestro", "worktrees", "reclaim"]).unwrap_err();
+        assert!(
+            matches!(
+                err.kind(),
+                clap::error::ErrorKind::InvalidSubcommand
+                    | clap::error::ErrorKind::MissingRequiredArgument
+            ),
+            "{err}"
+        );
+    }
+
+    #[test]
+    fn worktrees_without_subcommand_shows_help() {
+        let err = Cli::try_parse_from(["maestro", "worktrees"]).unwrap_err();
+        assert!(
+            matches!(
+                err.kind(),
+                clap::error::ErrorKind::DisplayHelpOnMissingArgumentOrSubcommand
+            ),
+            "{err}"
+        );
+    }
 }

crates/maestro-cli/src/dispatch.rs

@@ -9,8 +9,9 @@ use std::path::{Path, PathBuf};
 use maestro_protocol::DaemonClient;
 
 use crate::attach::{parse_detach_key, run_attach_url};
-use crate::cli::Command;
+use crate::cli::{Command, WorktreesCommand};
 use crate::sessions::{run_kill, run_list, run_spawn};
+use crate::worktrees::{run_list as run_worktree_list, run_reclaim as run_worktree_reclaim};
 use maestro_config::{default_config_path, MaestroConfigFile};
 
 #[derive(Debug, thiserror::Error)]
@@ -64,6 +65,26 @@ pub async fn dispatch(
             run_kill(&daemon, &args).await?;
             println!("killed {}", args.session_id);
         }
+        Command::Worktrees(args) => match args.command {
+            WorktreesCommand::List(list_args) => {
+                let mut stdout = std::io::stdout().lock();
+                run_worktree_list(&daemon, &list_args, &mut stdout).await?;
+            }
+            WorktreesCommand::Reclaim(reclaim_args) => {
+                // The daemon removes the directory and the store entry; the
+                // branch is never deleted — worth saying out loud (#86).
+                let entry = run_worktree_reclaim(&daemon, &reclaim_args).await?;
+                match entry {
+                    Some(wt) => println!(
+                        "reclaimed {} ({})\nbranch '{}' kept",
+                        wt.id,
+                        wt.path.display(),
+                        wt.branch
+                    ),
+                    None => println!("reclaimed {}\nbranch kept", reclaim_args.id),
+                }
+            }
+        },
     }
     Ok(())
 }

crates/maestro-cli/src/lib.rs

@@ -6,5 +6,6 @@ pub mod attach;
 pub mod cli;
 pub mod dispatch;
 pub mod sessions;
+pub mod worktrees;
 
 pub use dispatch::{dispatch, CliError};

crates/maestro-cli/src/sessions.rs

@@ -122,7 +122,7 @@ fn print_session_table(out: &mut impl Write, sessions: &[Session], info: &Daemon
 
 /// 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.
-fn abbreviate_dir(path: &std::path::Path, home: &str) -> String {
+pub(crate) fn abbreviate_dir(path: &std::path::Path, home: &str) -> String {
     let p = path.to_string_lossy();
     if !home.is_empty() {
         if p == home {

crates/maestro-cli/src/worktrees.rs

@@ -0,0 +1,204 @@
+//! `maestro worktrees list / reclaim` — the retained-store surface (#86).
+//!
+//! `reclaim` removes one directory; it never deletes the branch, which is
+//! said out loud in the output because "reclaim" otherwise sounds like it
+//! takes the commits too.
+
+use std::io::Write;
+
+use maestro_protocol::{ClientError, DaemonClient, DaemonInfo, InTheWay, RetainedWorktree};
+
+use crate::cli::{ListWorktreesArgs, ReclaimArgs};
+use crate::sessions::abbreviate_dir;
+
+/// `maestro worktrees list`
+pub async fn run_list(
+    client: &DaemonClient,
+    args: &ListWorktreesArgs,
+    out: &mut impl Write,
+) -> Result<(), ClientError> {
+    let worktrees = client.list_worktrees().await?;
+    let info = client.daemon_info().await.unwrap_or_default();
+
+    if args.json {
+        let body = serde_json::json!({ "worktrees": worktrees });
+        writeln!(out, "{}", serde_json::to_string_pretty(&body)?).ok();
+        return Ok(());
+    }
+
+    print_worktree_table(out, &worktrees, &info);
+    Ok(())
+}
+
+/// `maestro worktrees reclaim <id>`
+///
+/// Returns the entry as listed just before the reclaim, when it was found in
+/// the listing, so the confirmation can name what was removed.
+pub async fn run_reclaim(
+    client: &DaemonClient,
+    args: &ReclaimArgs,
+) -> Result<Option<RetainedWorktree>, ClientError> {
+    let listed = client
+        .list_worktrees()
+        .await?
+        .into_iter()
+        .find(|w| w.id == args.id);
+    client.reclaim_worktree(args.id).await?;
+    Ok(listed)
+}
+
+fn print_worktree_table(out: &mut impl Write, worktrees: &[RetainedWorktree], info: &DaemonInfo) {
+    if worktrees.is_empty() {
+        writeln!(out, "no retained worktrees").ok();
+        return;
+    }
+
+    let mut sorted: Vec<&RetainedWorktree> = worktrees.iter().collect();
+    sorted.sort_by_key(|w| w.retained_at);
+
+    if !info.hostname.is_empty() {
+        let warn = if maestro_protocol::is_compatible(&info.version) {
+            ""
+        } else {
+            "  (protocol mismatch)"
+        };
+        let version = if info.version.is_empty() {
+            String::new()
+        } else {
+            format!("  maestro {}{warn}", info.version)
+        };
+        writeln!(out, "\n{}{version}", info.hostname).ok();
+    }
+    writeln!(
+        out,
+        "  {:<36}  {:<24}  {:<28}  {:<24}  IN THE WAY",
+        "ID", "BRANCH", "PATH", "REASON"
+    )
+    .ok();
+    for w in sorted {
+        writeln!(
+            out,
+            "  {:<36}  {:<24}  {:<28}  {:<24}  {}",
+            w.id,
+            w.branch,
+            abbreviate_dir(&w.path, &info.home_dir),
+            reason_label(w.reason),
+            blocker_label(&w.in_the_way),
+        )
+        .ok();
+    }
+    // The branch survives every reclaim — see docs/WORKTREES.md.
+    writeln!(
+        out,
+        "\nreclaim removes the directory only; branches are never deleted"
+    )
+    .ok();
+}
+
+fn reason_label(reason: maestro_protocol::RetainedReason) -> &'static str {
+    match reason {
+        maestro_protocol::RetainedReason::ForceKilled => "force-killed",
+        maestro_protocol::RetainedReason::ExitedWithUnsavedWork => "exited-with-unsaved-work",
+    }
+}
+
+/// The same breakdown that blocks an unforced kill, as words: what is still
+/// in the way, or `clear` when the work has since been committed and pushed.
+fn blocker_label(in_the_way: &InTheWay) -> String {
+    if in_the_way.is_clear() {
+        return "clear".into();
+    }
+    let mut parts: Vec<String> = Vec::new();
+    if in_the_way.uncommitted_files > 0 {
+        parts.push(format!("{} uncommitted", in_the_way.uncommitted_files));
+    }
+    if in_the_way.untracked_files > 0 {
+        parts.push(format!("{} untracked", in_the_way.untracked_files));
+    }
+    if in_the_way.unpushed_commits > 0 {
+        parts.push(format!("{} unpushed", in_the_way.unpushed_commits));
+    }
+    parts.join(", ")
+}
+
+#[cfg(test)]
+mod tests {
+    use std::path::PathBuf;
+
+    use chrono::{TimeZone, Utc};
+    use maestro_protocol::{DaemonInfo, InTheWay, RetainedReason, RetainedWorktree};
+    use uuid::Uuid;
+
+    fn worktree(branch: &str, path: &str, id: u128) -> RetainedWorktree {
+        RetainedWorktree {
+            id: Uuid::from_u128(id),
+            path: PathBuf::from(path),
+            base_repo: PathBuf::from("/home/naps/maestro"),
+            branch: branch.into(),
+            reason: RetainedReason::ForceKilled,
+            retained_at: Utc.with_ymd_and_hms(2026, 8, 24, 10, 0, 0).unwrap(),
+            in_the_way: InTheWay::default(),
+        }
+    }
+
+    fn info(home: &str) -> DaemonInfo {
+        DaemonInfo {
+            hostname: "naps-laptop".into(),
+            home_dir: home.into(),
+            ..Default::default()
+        }
+    }
+
+    #[test]
+    fn formats_table() {
+        let mut w = worktree("feat/login", "/home/naps/maestro/worktrees/feat/login", 1);
+        w.in_the_way = InTheWay {
+            uncommitted_files: 2,
+            untracked_files: 1,
+            unpushed_commits: 3,
+        };
+        let mut buf = Vec::new();
+        super::print_worktree_table(&mut buf, &[w], &info("/home/naps"));
+        let s = String::from_utf8(buf).unwrap();
+        assert!(s.contains("naps-laptop"), "{s}");
+        assert!(s.contains("feat/login"), "{s}");
+        // Home dir collapses to ~ in the PATH column, like sessions' DIR.
+        assert!(s.contains("~/maestro/worktrees/feat/login"), "{s}");
+        assert!(s.contains("force-killed"), "{s}");
+        assert!(s.contains("2 uncommitted, 1 untracked, 3 unpushed"), "{s}");
+        assert!(s.contains("IN THE WAY"), "{s}");
+    }
+
+    /// Contract rule, visible to the operator: reclaiming a tree must not
+    /// throw away commits on its branch.
+    #[test]
+    fn says_the_branch_survives() {
+        let mut buf = Vec::new();
+        super::print_worktree_table(
+            &mut buf,
+            &[worktree("feat/x", "/repo/worktrees/feat/x", 1)],
+            &info(""),
+        );
+        let s = String::from_utf8(buf).unwrap();
+        assert!(s.contains("never deleted"), "{s}");
+    }
+
+    #[test]
+    fn clear_tree_says_clear() {
+        let mut buf = Vec::new();
+        super::print_worktree_table(
+            &mut buf,
+            &[worktree("main-ish", "/repo/worktrees/main-ish", 1)],
+            &info(""),
+        );
+        let s = String::from_utf8(buf).unwrap();
+        assert!(s.contains("clear"), "{s}");
+    }
+
+    #[test]
+    fn empty_store() {
+        let mut buf = Vec::new();
+        super::print_worktree_table(&mut buf, &[], &info(""));
+        assert_eq!(String::from_utf8(buf).unwrap(), "no retained worktrees\n");
+    }
+}

crates/maestro-daemon/src/dirlist.rs

@@ -111,6 +111,7 @@ fn io_error(dir: &Path, e: &std::io::Error) -> ErrorInfo {
     ErrorInfo {
         code: code.into(),
         message: format!("{message}: {}", dir.display()),
+        unsaved_work: None,
     }
 }
 

crates/maestro-daemon/src/local_api.rs

@@ -99,6 +99,8 @@ fn session_error_status(code: &str) -> StatusCode {
     match code {
         "not_found" => StatusCode::NOT_FOUND,
         "invalid_env" => StatusCode::BAD_REQUEST,
+        // A guard refusal is the daemon doing its job, not a failure (#79).
+        "kill_guarded" => StatusCode::CONFLICT,
         _ => StatusCode::BAD_GATEWAY,
     }
 }
@@ -173,16 +175,17 @@ async fn create_session(
 /// `kill` already reports a missing session as `SessionError::NotFound`, which
 /// maps to 404. Checking first would only add a window in which the liveness
 /// watcher reaps the session between the two awaits, turning a 404 into a 502.
+///
+/// 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(),
         Err(e) => {
             let info = e.to_error_info();
-            error_response(
-                session_error_status(&info.code),
-                info.code.as_str(),
-                info.message.as_str(),
-            )
+            let status = session_error_status(&info.code);
+            (status, Json(ApiError { error: info })).into_response()
         }
     }
 }
@@ -201,9 +204,7 @@ async fn list_worktrees(State(s): State<LocalApiState>) -> Response {
             .map(|entry| {
                 // A tree git cannot read (permissions, corrupt checkout)
                 // still gets listed; it just reports nothing in the way.
-                let in_the_way =
-                    crate::worktree_probe::in_the_way(&entry.path, &entry.base_repo, &entry.branch)
-                        .unwrap_or_default();
+                let in_the_way = crate::worktree_probe::in_the_way(&entry.path).unwrap_or_default();
                 Ok(maestro_protocol::RetainedWorktree {
                     id: entry.id,
                     path: entry.path.clone(),

crates/maestro-daemon/src/session.rs

@@ -38,8 +38,8 @@ pub const DEFAULT_LIVENESS_INTERVAL: Duration = Duration::from_secs(2);
 pub struct SessionRecord {
     pub session: Session,
     pub fifo_path: PathBuf,
-    /// Worktree we created at spawn time; removed on kill unless the
-    /// dirty-work guard refuses (#56).
+    /// Worktree we created at spawn time; removed on kill, but only after the
+    /// kill guard (#79) found nothing worth keeping in it.
     pub worktree_path: Option<PathBuf>,
     /// `base_repo` from the original `WorktreeSpec`. Needed because `git
     /// worktree remove` is invoked from the base repo.
@@ -61,6 +61,11 @@ pub enum SessionError {
     NotFound(Uuid),
     #[error("invalid environment variable name: {0:?}")]
     InvalidEnv(String),
+    /// The kill was refused (#79): the session's worktree holds unsaved work.
+    /// Nothing happened — the session keeps running and the tree is untouched,
+    /// 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),
 }
 
 impl SessionError {
@@ -72,10 +77,16 @@ impl SessionError {
             SessionError::Io(_) => "io_failed",
             SessionError::NotFound(_) => "not_found",
             SessionError::InvalidEnv(_) => "invalid_env",
+            SessionError::KillGuarded(_) => "kill_guarded",
+        };
+        let unsaved_work = match self {
+            SessionError::KillGuarded(b) => Some(*b),
+            _ => None,
         };
         ErrorInfo {
             code: code.into(),
             message: self.to_string(),
+            unsaved_work,
         }
     }
 }
@@ -370,20 +381,48 @@ impl SessionManager {
         }
     }
 
-    /// Kill a session and remove its on-disk artifacts. The worktree is
-    /// always pruned -- unless it holds uncommitted changes or commits not on
-    /// any other ref, in which case the guard leaves it on disk (#56).
+    /// Kill a session and remove its on-disk artifacts.
+    ///
+    /// Refused (#79) when the session's worktree holds unsaved work —
+    /// uncommitted tracked changes, untracked non-ignored files, or commits
+    /// reachable from no remote-tracking ref. Nothing is killed and nothing
+    /// is removed; the error names what blocked it and how much of it there
+    /// is. The session stays as the operator's handle on their own unfinished
+    /// work, so ending a session that still matters becomes a deliberate
+    /// `--force`, which retains rather than destroys (WORKTREES.md).
     ///
     /// 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) = {
+            let sessions = self.inner.sessions.lock().await;
+            match sessions.get(&id) {
+                None => return Err(SessionError::NotFound(id)),
+                Some(record) => (
+                    record
+                        .worktree_base_repo
+                        .clone()
+                        .zip(record.worktree_path.clone()),
+                    record.session.status == SessionStatus::Running,
+                ),
+            }
+        };
+        // 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 removed = {
             let mut sessions = self.inner.sessions.lock().await;
             sessions.remove(&id)
         };
         let record = removed.ok_or(SessionError::NotFound(id))?;
-        let alive = record.session.status == SessionStatus::Running;
         cleanup_record(&self.inner, id, record, alive).await;
         Ok(())
     }
@@ -720,10 +759,9 @@ 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");
     }
-    // Cleanup is unconditional now (#56): `cleanup_on_kill` is no longer a
-    // user-facing choice. The manager's guard is what protects unsaved work --
-    // when it refuses, leave the tree on disk and say where it is so the
-    // operator can find it.
+    // 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) {
             tracing::warn!(

crates/maestro-daemon/src/worktree.rs

@@ -10,11 +10,24 @@ pub enum WorktreeError {
     Spawn(#[from] std::io::Error),
     #[error("git exited with code {code}: {stderr}")]
     NonZero { code: i32, stderr: String },
-    /// The worktree holds unsaved work; removal was refused (#56).
+    /// A registered worktree lives under the tree about to be removed; git
+    /// hides its contents from `git status`, so removal would delete its
+    /// uncommitted work unseen (#54 review).
     #[error("left {} on disk: {}", .path.display(), .reason)]
     Guarded { path: PathBuf, reason: String },
 }
 
+impl From<crate::worktree_probe::ProbeError> for WorktreeError {
+    fn from(e: crate::worktree_probe::ProbeError) -> Self {
+        match e {
+            crate::worktree_probe::ProbeError::Spawn(io) => WorktreeError::Spawn(io),
+            crate::worktree_probe::ProbeError::NonZero { code, stderr } => {
+                WorktreeError::NonZero { code, stderr }
+            }
+        }
+    }
+}
+
 /// Runs `git worktree add` rooted at `base_repo`. By default worktrees land
 /// inside the repository itself at `<repo>/worktrees/<branch>` (#56) so they
 /// are findable from the repo; an operator-set root overrides that.
@@ -126,12 +139,13 @@ impl WorktreeManager {
         Ok(path)
     }
 
-    /// `git -C <base_repo> worktree remove <path>` — but only when the
-    /// worktree holds nothing unique (#56). A worktree with uncommitted
-    /// changes, or with commits reachable from no other ref, is refused and
-    /// left on disk so the operator can rescue it; cleanup is unconditional,
-    /// which makes this guard the only thing standing between a stray kill
-    /// and destroyed work.
+    /// `git -C <base_repo> worktree remove <path>`.
+    ///
+    /// Unconditional (#79): the guard moved off the worktree and onto the
+    /// kill, so by the time removal runs the caller has already chosen to
+    /// destroy the tree — the kill only gets here after
+    /// [`crate::worktree_probe::in_the_way`] came back clear. Still refused for a tree holding a
+    /// nested registered worktree, which `git status` cannot see.
     pub fn remove(&self, base_repo: &Path, path: &Path) -> Result<(), WorktreeError> {
         // Gone from disk already (operator `rm -rf`, or a create that failed
         // half-way). Probing it with git would fail and be misread as unsaved
@@ -147,12 +161,6 @@ impl WorktreeManager {
                 reason: format!("holds a nested worktree at {}", inner.display()),
             });
         }
-        if let Some(reason) = unsafe_to_remove(path)? {
-            return Err(WorktreeError::Guarded {
-                path: path.to_path_buf(),
-                reason,
-            });
-        }
         let out = Command::new("git")
             .arg("-C")
             .arg(base_repo)
@@ -251,24 +259,6 @@ fn branch_relpath(branch: &str) -> Option<PathBuf> {
     Some(candidate.to_path_buf())
 }
 
-/// `Some(reason)` when deleting `path` would destroy work.
-///
-/// Only an unclean working tree qualifies. `git worktree remove` deletes the
-/// checkout but keeps `refs/heads/<branch>`, so committed work — pushed or
-/// not — stays reachable and is never at risk. Guarding on "commits on no
-/// other ref" instead would refuse every ordinary unpushed feature branch,
-/// and because the path is deterministic that branch could then never be
-/// spawned again (#56 review).
-fn unsafe_to_remove(path: &Path) -> Result<Option<String>, WorktreeError> {
-    // `--ignored=no` keeps build output out of it; untracked sources count,
-    // since removal would delete them.
-    let status = run_git(path, ["status", "--porcelain", "--ignored=no"])?;
-    if !status.stdout.is_empty() {
-        return Ok(Some("has uncommitted changes".into()));
-    }
-    Ok(None)
-}
-
 /// `git -C <base_repo> worktree prune` — drops registrations whose directory
 /// no longer exists.
 fn prune(base_repo: &Path) -> Result<(), WorktreeError> {
@@ -280,22 +270,6 @@ fn prune(base_repo: &Path) -> Result<(), WorktreeError> {
     check(out)
 }
 
-fn run_git(
-    dir: &Path,
-    args: impl IntoIterator<Item = &'static str>,
-) -> Result<Output, WorktreeError> {
-    let mut cmd = Command::new("git");
-    cmd.arg("-C").arg(dir).args(args);
-    let out = cmd.output()?;
-    if !out.status.success() {
-        return Err(WorktreeError::NonZero {
-            code: out.status.code().unwrap_or(-1),
-            stderr: String::from_utf8_lossy(&out.stderr).into_owned(),
-        });
-    }
-    Ok(out)
-}
-
 fn check(out: Output) -> Result<(), WorktreeError> {
     if out.status.success() {
         Ok(())

crates/maestro-daemon/src/worktree_probe.rs

@@ -1,11 +1,14 @@
-//! Read-side git probes for retained worktrees (#80): what is currently in
-//! the way, and guard-free reclaim.
+//! The one git probe for what a worktree holds that would be lost, plus
+//! guard-free reclaim (#79, #80).
 //!
-//! The kill-refusal breakdown lives in `worktree.rs`, which this module must
-//! not touch (#77 owns it) and must not consult for reclaim — reclaim is the
-//! deliberate destructive act and never asks the guard. Issue #79 will factor
-//! the shared git plumbing out of `worktree.rs`; until then these probes are
-//! duplicated here on purpose.
+//! [`in_the_way`] is the single predicate behind all three paths: the kill
+//! refusal (#79), the natural-exit classifier (#82), and the retained list
+//! (#80). It lives here rather than in `worktree.rs` so that none of them can
+//! answer the question differently — #79 and #80 were built in parallel and
+//! each grew its own copy, which is exactly the drift this collapses.
+//!
+//! Reclaim never consults it: reclaim is the deliberate destructive act, and
+//! the operator chose it while looking at what was in the way.
 
 use std::path::Path;
 
@@ -25,9 +28,11 @@ pub enum ProbeError {
 /// `target/`, and counting those would put every tree permanently in the way.
 /// A directory that no longer exists reports nothing in the way: there is
 /// nothing left to lose, and the store's own pruning drops the entry.
-pub fn in_the_way(path: &Path, base_repo: &Path, branch: &str) -> Result<InTheWay, ProbeError> {
+pub fn in_the_way(path: &Path) -> Result<InTheWay, ProbeError> {
     let mut breakdown = InTheWay::default();
-    if !path.exists() {
+    // `symlink_metadata` rather than `exists`: a broken symlink is gone for
+    // our purposes, and following it would probe the wrong tree.
+    if std::fs::symlink_metadata(path).is_err() {
         return Ok(breakdown);
     }
     let status = run_git(
@@ -46,19 +51,15 @@ pub fn in_the_way(path: &Path, base_repo: &Path, branch: &str) -> Result<InTheWa
             breakdown.uncommitted_files += 1;
         }
     }
-    // Commits reachable from the branch but from no remote-tracking ref. A
-    // branch pushed anywhere counts as pushed; there is no "which remote"
-    // question to get wrong.
-    let unpushed = run_git(
-        base_repo,
-        [
-            "rev-list",
-            "--count",
-            &format!("refs/heads/{branch}"),
-            "--not",
-            "--glob=refs/remotes",
-        ],
-    )?;
+    // Resolved inside the worktree so a detached HEAD still has a starting
+    // point; asking the base repo for `refs/heads/<branch>` fails there.
+    let head = run_git(path, ["rev-parse", "--abbrev-ref", "HEAD"])?;
+    let branch = String::from_utf8_lossy(&head.stdout).trim().to_string();
+    let tip: &str = if branch == "HEAD" { "HEAD" } else { &branch };
+    // Commits reachable from the tip but from no remote-tracking ref. A branch
+    // pushed anywhere counts as pushed; there is no "which remote" question to
+    // get wrong.
+    let unpushed = run_git(path, ["rev-list", "--count", tip, "--not", "--remotes"])?;
     breakdown.unpushed_commits = String::from_utf8_lossy(&unpushed.stdout)
         .trim()
         .parse()
@@ -182,7 +183,7 @@ mod tests {
     fn a_clean_pushed_worktree_has_nothing_in_the_way() {
         let r = repo_with_worktree();
         git(&r.wt(), &["push", "-q", "-u", "origin", "feature"]);
-        let breakdown = in_the_way(&r.wt(), &r.repo, "feature").expect("probe");
+        let breakdown = in_the_way(&r.wt()).expect("probe");
         assert_eq!(breakdown, InTheWay::default());
         assert!(breakdown.is_clear());
     }
@@ -193,7 +194,7 @@ mod tests {
         std::fs::write(r.wt().join("README"), b"edited\n").unwrap();
         std::fs::write(r.wt().join("scratch.txt"), b"untracked\n").unwrap();
 
-        let dirty = in_the_way(&r.wt(), &r.repo, "feature").expect("probe");
+        let dirty = in_the_way(&r.wt()).expect("probe");
         assert_eq!(dirty.uncommitted_files, 1);
         assert_eq!(dirty.untracked_files, 1);
         assert_eq!(dirty.unpushed_commits, 0);
@@ -203,7 +204,7 @@ mod tests {
         git(&r.wt(), &["add", "README"]);
         git(&r.wt(), &["commit", "-qm", "wip"]);
 
-        let breakdown = in_the_way(&r.wt(), &r.repo, "feature").expect("probe");
+        let breakdown = in_the_way(&r.wt()).expect("probe");
         assert_eq!(breakdown.uncommitted_files, 0);
         assert_eq!(breakdown.untracked_files, 1);
         assert_eq!(breakdown.unpushed_commits, 1);
@@ -213,7 +214,7 @@ mod tests {
     fn tracked_edits_count_as_uncommitted() {
         let r = repo_with_worktree();
         std::fs::write(r.wt().join("README"), b"edited\n").unwrap();
-        let breakdown = in_the_way(&r.wt(), &r.repo, "feature").expect("probe");
+        let breakdown = in_the_way(&r.wt()).expect("probe");
         assert_eq!(breakdown.uncommitted_files, 1);
         assert_eq!(breakdown.untracked_files, 0);
     }
@@ -224,17 +225,17 @@ mod tests {
         std::fs::write(r.wt().join("new.txt"), b"x\n").unwrap();
         r.commit_in_wt("wip");
 
-        let before = in_the_way(&r.wt(), &r.repo, "feature").expect("probe");
+        let before = in_the_way(&r.wt()).expect("probe");
         assert_eq!(before.unpushed_commits, 1);
 
         git(&r.wt(), &["push", "-q", "-u", "origin", "feature"]);
         // Same stored entry, different tree: the breakdown must move with it.
-        let after = in_the_way(&r.wt(), &r.repo, "feature").expect("probe");
+        let after = in_the_way(&r.wt()).expect("probe");
         assert_eq!(after.unpushed_commits, 0);
         assert_eq!(after.untracked_files, 0);
 
         std::fs::write(r.wt().join("loose.txt"), b"x\n").unwrap();
-        let dirty = in_the_way(&r.wt(), &r.repo, "feature").expect("probe");
+        let dirty = in_the_way(&r.wt()).expect("probe");
         assert_eq!(dirty.untracked_files, 1);
     }
 
@@ -245,7 +246,7 @@ mod tests {
         std::fs::create_dir_all(r.wt().join("target")).unwrap();
         std::fs::write(r.wt().join("target/artifact"), b"x").unwrap();
 
-        let breakdown = in_the_way(&r.wt(), &r.repo, "feature").expect("probe");
+        let breakdown = in_the_way(&r.wt()).expect("probe");
         assert_eq!(
             breakdown,
             InTheWay {
@@ -260,7 +261,7 @@ mod tests {
     fn a_missing_directory_reports_nothing_in_the_way() {
         let r = repo_with_worktree();
         let gone = r.root.path().join("nowhere");
-        let breakdown = in_the_way(&gone, &r.repo, "feature").expect("probe");
+        let breakdown = in_the_way(&gone).expect("probe");
         assert!(breakdown.is_clear());
     }
 

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

@@ -93,6 +93,38 @@ fn run(cmd: &mut Command) {
     );
 }
 
+/// An empty bare repository at `dir`, usable as a push target (#79).
+pub fn init_bare_repo(dir: &Path) {
+    run(Command::new("git")
+        .arg("init")
+        .arg("-q")
+        .arg("--bare")
+        .arg(dir.to_str().expect("non-utf8 bare repo path")));
+}
+
+/// Push every branch of `repo` to `origin`, creating remote-tracking refs.
+///
+/// The unsaved-work probe (#79) counts commits reachable from no
+/// remote-tracking ref as unpushed, so tests that want a killable worktree
+/// must give its branch one. Safe to call again: re-adding an existing
+/// remote is ignored.
+pub fn push_all_to_origin(repo: &Path, origin: &Path) {
+    let _ = Command::new("git")
+        .arg("-C")
+        .arg(repo)
+        .args([
+            "remote",
+            "add",
+            "origin",
+            origin.to_str().expect("non-utf8 origin path"),
+        ])
+        .status();
+    run(Command::new("git")
+        .arg("-C")
+        .arg(repo)
+        .args(["push", "-q", "--all", "origin"]));
+}
+
 /// Async polling sibling of [`wait_for`] for tokio tests.
 pub async fn wait_for_async<F, Fut>(timeout: Duration, mut cond: F)
 where

crates/maestro-daemon/tests/local_api.rs

@@ -9,7 +9,7 @@ use std::time::Duration;
 use common::DaemonFixture;
 use futures_util::{SinkExt, StreamExt};
 use maestro_daemon::local_api;
-use maestro_protocol::{CreateSessionRequest, Session};
+use maestro_protocol::{ApiError, CreateSessionRequest, Session, WorktreeSpec};
 use tokio::net::TcpListener;
 use tokio::sync::oneshot;
 use tokio_tungstenite::tungstenite::Message as WsMessage;
@@ -339,6 +339,53 @@ async fn delete_owned_session_kills_it() {
     assert!(!h.manager.has(session.id).await);
 }
 
+/// The kill guard on the wire (#79): `DELETE /api/sessions/:id` answers 409
+/// with the structured breakdown, and the session keeps running.
+#[tokio::test]
+async fn delete_a_session_whose_worktree_holds_unsaved_work_returns_409_with_the_breakdown() {
+    let h = spawn("naps-laptop").await;
+    let repo = tempfile::TempDir::new().unwrap();
+    common::init_repo(repo.path());
+    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(),
+                cleanup_on_kill: true,
+                create_branch: true,
+            }),
+        })
+        .await
+        .unwrap();
+    std::fs::write(
+        repo.path()
+            .join("worktrees")
+            .join("feat")
+            .join("guarded")
+            .join("README"),
+        b"unsaved edits\n",
+    )
+    .unwrap();
+
+    let resp = reqwest::Client::new()
+        .delete(url(h.addr, &format!("/api/sessions/{}", session.id)))
+        .send()
+        .await
+        .unwrap();
+    assert_eq!(resp.status(), reqwest::StatusCode::CONFLICT);
+    let body: ApiError = resp.json().await.unwrap();
+    assert_eq!(body.error.code, "kill_guarded");
+    let breakdown = body.error.unsaved_work.expect("breakdown on the wire");
+    assert_eq!(breakdown.uncommitted_files, 1);
+
+    assert!(h.manager.has(session.id).await, "the session keeps running");
+}
+
 #[tokio::test]
 async fn attach_ws_streams_pty_bytes() {
     let h = spawn("naps-laptop").await;

crates/maestro-daemon/tests/session_manager.rs

@@ -4,10 +4,12 @@ mod common;
 
 use std::collections::HashMap;
 use std::path::PathBuf;
+use std::process::Command;
 use std::sync::Arc;
 use std::time::Duration;
 
-use common::{init_repo, wait_for_async, DaemonFixture};
+use common::{init_bare_repo, init_repo, push_all_to_origin, wait_for_async, DaemonFixture};
+use maestro_daemon::SessionError;
 use maestro_protocol::CreateSessionRequest;
 use maestro_protocol::{CatalogEvent, SessionStatus, WorktreeSpec};
 use tempfile::TempDir;
@@ -363,8 +365,9 @@ async fn liveness_watcher_marks_dead_sessions_and_keeps_them_until_dismissed() {
     assert!(!fx.fifo_dir().join(format!("{}.fifo", s.id)).exists());
 }
 
-/// Cleanup is unconditional (#56): even a spec that says "don't clean up"
-/// loses its worktree on kill — the guard, not the flag, protects work.
+/// 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.
 #[tokio::test]
 async fn kill_removes_worktree_even_when_spec_says_keep() {
     let fx = DaemonFixture::new();
@@ -390,14 +393,21 @@ async fn kill_removes_worktree_even_when_spec_says_keep() {
         .expect("create");
     assert!(wt_path.exists());
 
+    // Push the branch so its commits are reachable from a remote-tracking ref.
+    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");
     assert!(!wt_path.exists(), "worktree must be removed on kill");
 }
 
-/// The guard (#56): a worktree holding uncommitted changes survives the kill,
-/// left on disk where the operator can find it.
+/// The kill guard (#79): a worktree holding uncommitted changes refuses the
+/// kill outright. Nothing happens — the session keeps running as the
+/// operator's handle on their unfinished work, and the tree is untouched.
+/// The refusal names what blocked it and how much of it there is.
 #[tokio::test]
-async fn kill_leaves_worktree_with_unsaved_work_on_disk() {
+async fn killing_refuses_a_worktree_with_unsaved_work_and_keeps_the_session() {
     let fx = DaemonFixture::new();
     let repo = TempDir::new().unwrap();
     init_repo(repo.path());
@@ -420,13 +430,138 @@ async fn kill_leaves_worktree_with_unsaved_work_on_disk() {
         .await
         .expect("create");
     std::fs::write(wt_path.join("README"), b"unsaved edits\n").unwrap();
+    std::fs::write(wt_path.join("notes.txt"), b"untracked\n").unwrap();
 
-    fx.manager.kill(s.id).await.expect("kill");
+    let err = fx.manager.kill(s.id).await.expect_err("kill must refuse");
+    let SessionError::KillGuarded(breakdown) = err else {
+        panic!("expected KillGuarded, got {err:?}");
+    };
+    assert_eq!(breakdown.uncommitted_files, 1);
+    assert_eq!(breakdown.untracked_files, 1);
     assert!(
-        wt_path.exists(),
-        "dirty worktree must be left on disk, not destroyed"
+        breakdown.unpushed_commits >= 1,
+        "a fresh branch has no remote-tracking ref"
+    );
+    let message = breakdown.to_string();
+    assert!(message.contains("1 uncommitted file"), "{message}");
+    assert!(message.contains("1 untracked file"), "{message}");
+
+    // Nothing happened: the session survives and so does the tree.
+    assert!(fx.manager.has(s.id).await, "the session must keep running");
+    assert!(wt_path.exists(), "the worktree must be untouched");
+
+    // A second kill after the work is saved goes through.
+    run_git_in(&wt_path, &["add", "."]);
+    run_git_in(&wt_path, &["commit", "-q", "-m", "saved"]);
+    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");
+    assert!(!fx.manager.has(s.id).await);
+}
+
+/// Unpushed commits alone block the kill (#79): a feature branch almost
+/// always has them, which is why `--force` (which retains) is the ordinary
+/// way to end such a session.
+#[tokio::test]
+async fn killing_refuses_until_the_branch_is_pushed() {
+    let fx = DaemonFixture::new();
+    let repo = TempDir::new().unwrap();
+    init_repo(repo.path());
+    let wt_path = repo.path().join("worktrees").join("feat").join("pushed");
+
+    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/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 SessionError::KillGuarded(breakdown) = err else {
+        panic!("expected KillGuarded, got {err:?}");
+    };
+    assert_eq!(breakdown.uncommitted_files, 0);
+    assert_eq!(breakdown.untracked_files, 0);
+    assert!(breakdown.unpushed_commits >= 1);
+
+    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("pushed branch kills");
+    assert!(!wt_path.exists());
+    assert!(!fx.manager.has(s.id).await);
+}
+
+/// Ignored files NEVER block (#79): build output like `target/` exists in
+/// every Rust checkout, and an ignored-only worktree stays killable.
+#[tokio::test]
+async fn killing_an_ignored_only_worktree_succeeds() {
+    let fx = DaemonFixture::new();
+    let repo = TempDir::new().unwrap();
+    init_repo(repo.path());
+    // .gitignore must be committed before the worktree branches off, or it
+    // would itself read as an untracked file.
+    std::fs::write(repo.path().join(".gitignore"), b"/target\n").unwrap();
+    run_git_in(repo.path(), &["add", ".gitignore"]);
+    run_git_in(repo.path(), &["commit", "-q", "-m", "ignore target"]);
+    let origin = TempDir::new().unwrap();
+    init_bare_repo(origin.path());
+
+    let wt_path = repo.path().join("worktrees").join("feat").join("rusty");
+    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/rusty".into(),
+                cleanup_on_kill: true,
+                create_branch: true,
+            }),
+        })
+        .await
+        .expect("create");
+    std::fs::create_dir_all(wt_path.join("target")).unwrap();
+    std::fs::write(wt_path.join("target").join("app.o"), b"binary\n").unwrap();
+
+    // Branch pushed; the only dirt is ignored output.
+    push_all_to_origin(repo.path(), origin.path());
+
+    fx.manager
+        .kill(s.id)
+        .await
+        .expect("ignored files never block");
+    assert!(!wt_path.exists());
+    assert!(!fx.manager.has(s.id).await);
+}
+
+fn run_git_in(dir: &std::path::Path, args: &[&str]) {
+    let out = Command::new("git")
+        .arg("-C")
+        .arg(dir)
+        .args(args)
+        .output()
+        .expect("git spawn");
+    assert!(
+        out.status.success(),
+        "git {args:?} failed: {}",
+        String::from_utf8_lossy(&out.stderr)
     );
-    assert!(fx.manager.snapshot().await.is_empty());
 }
 
 #[tokio::test]

crates/maestro-daemon/tests/worktree.rs

@@ -6,8 +6,9 @@ mod common;
 use std::path::PathBuf;
 use std::process::Command;
 
-use common::init_repo;
+use common::{init_bare_repo, init_repo, push_all_to_origin};
 use maestro_daemon::worktree::WorktreeManager;
+use maestro_daemon::worktree_probe::in_the_way;
 use tempfile::TempDir;
 
 fn worktree_branches(repo: &PathBuf) -> Vec<String> {
@@ -134,6 +135,123 @@ fn add_twice_generates_distinct_paths() {
     assert!(p2.exists());
 }
 
+/// The unsaved-work probe (#79) counts uncommitted tracked changes.
+#[test]
+fn the_probe_counts_uncommitted_tracked_changes() {
+    let repo_dir = TempDir::new().unwrap();
+    let repo = repo_dir.path().to_path_buf();
+    init_repo(&repo);
+
+    let mgr = WorktreeManager::new(None);
+    let path = mgr.add_new(&repo, "feat/dirty").expect("add");
+    std::fs::write(path.join("README"), b"unsaved edits\n").unwrap();
+
+    let w = in_the_way(&path).expect("probe");
+    assert_eq!(w.uncommitted_files, 1);
+    assert_eq!(w.untracked_files, 0);
+}
+
+/// Untracked sources count; a staged new file is also unsaved tracked work.
+#[test]
+fn the_probe_counts_untracked_files() {
+    let repo_dir = TempDir::new().unwrap();
+    let repo = repo_dir.path().to_path_buf();
+    init_repo(&repo);
+
+    let mgr = WorktreeManager::new(None);
+    let path = mgr.add_new(&repo, "feat/untracked").expect("add");
+    std::fs::write(path.join("notes.txt"), b"wip\n").unwrap();
+    std::fs::write(path.join("more.txt"), b"also wip\n").unwrap();
+
+    let w = in_the_way(&path).expect("probe");
+    assert_eq!(w.untracked_files, 2);
+    assert_eq!(w.uncommitted_files, 0);
+
+    run_git(&path, &["add", "notes.txt"]);
+    let w = in_the_way(&path).expect("probe");
+    assert_eq!(w.uncommitted_files, 1, "staged counts as uncommitted");
+    assert_eq!(w.untracked_files, 1);
+}
+
+/// Ignored files NEVER block: every Rust checkout has a `target/`, and
+/// counting ignored output would leave no session killable (#79).
+#[test]
+fn the_probe_ignores_ignored_files() {
+    let repo_dir = TempDir::new().unwrap();
+    let repo = repo_dir.path().to_path_buf();
+    init_repo(&repo);
+
+    // .gitignore must be committed, or it would itself read as untracked.
+    std::fs::write(repo.join(".gitignore"), b"/target\n").unwrap();
+    run_git(&repo, &["add", ".gitignore"]);
+    run_git(&repo, &["commit", "-q", "-m", "ignore target"]);
+
+    let mgr = WorktreeManager::new(None);
+    let path = mgr.add_new(&repo, "feat/builds").expect("add");
+    std::fs::create_dir_all(path.join("target")).unwrap();
+    std::fs::write(path.join("target").join("app.o"), b"binary\n").unwrap();
+
+    let w = in_the_way(&path).expect("probe");
+    assert_eq!(w.uncommitted_files, 0);
+    assert_eq!(w.untracked_files, 0);
+
+    // With the branch pushed too, an ignored-only tree reads fully clean.
+    let origin_dir = TempDir::new().unwrap();
+    init_bare_repo(origin_dir.path());
+    push_all_to_origin(&repo, origin_dir.path());
+    let w = in_the_way(&path).expect("probe after push");
+    assert!(w.is_clear(), "ignored-only worktree must read clean: {w:?}");
+}
+
+/// Commits reachable from no remote-tracking ref block; pushing the branch
+/// clears them. With no remote at all every commit is unreachable from one,
+/// which is exactly why feature branches almost always refuse (#79).
+#[test]
+fn the_probe_counts_unpushed_commits_until_the_branch_is_pushed() {
+    let repo_dir = TempDir::new().unwrap();
+    let repo = repo_dir.path().to_path_buf();
+    init_repo(&repo);
+
+    let mgr = WorktreeManager::new(None);
+    let path = mgr.add_new(&repo, "feat/branch").expect("add");
+
+    let w = in_the_way(&path).expect("probe");
+    assert!(
+        w.unpushed_commits >= 1,
+        "a fresh branch has no remote-tracking ref: {w:?}"
+    );
+
+    let origin_dir = TempDir::new().unwrap();
+    init_bare_repo(origin_dir.path());
+    push_all_to_origin(&repo, origin_dir.path());
+
+    let w = in_the_way(&path).expect("probe after push");
+    assert_eq!(w.unpushed_commits, 0, "{w:?}");
+    assert!(w.is_clear(), "pushed and clean must be empty: {w:?}");
+}
+
+/// The full breakdown names each blocker with its count.
+#[test]
+fn the_probe_reports_every_blocker_at_once() {
+    let repo_dir = TempDir::new().unwrap();
+    let repo = repo_dir.path().to_path_buf();
+    init_repo(&repo);
+
+    let mgr = WorktreeManager::new(None);
+    let path = mgr.add_new(&repo, "feat/mixed").expect("add");
+    std::fs::write(path.join("README"), b"edited\n").unwrap();
+    std::fs::write(path.join("scratch.txt"), b"untracked\n").unwrap();
+
+    let w = in_the_way(&path).expect("probe");
+    assert_eq!(w.uncommitted_files, 1);
+    assert_eq!(w.untracked_files, 1);
+    assert!(w.unpushed_commits >= 1);
+    let summary = w.to_string();
+    assert!(summary.contains("1 uncommitted file"), "{summary}");
+    assert!(summary.contains("1 untracked file"), "{summary}");
+    assert!(summary.contains("unpushed commit"), "{summary}");
+}
+
 #[test]
 fn remove_prunes_worktree() {
     let repo_dir = TempDir::new().unwrap();
@@ -211,8 +329,14 @@ fn add_existing_checks_out_branch_without_creating_it() {
     );
 }
 
+/// Removal is guarded upstream now (#79): the kill refuses unsaved work
+/// before anything is torn down, so by the time `remove` runs the tree is
+/// clean. Git still refuses a dirty tree on its own — this asserts that last
+/// line of defense — and committed-but-unpushed work does not block removal,
+/// because `worktree remove` keeps `refs/heads/<branch>` and the commits stay
+/// reachable.
 #[test]
-fn remove_refuses_worktree_with_uncommitted_changes() {
+fn remove_still_relies_on_git_refusing_a_dirty_tree() {
     let repo_dir = TempDir::new().unwrap();
     let repo = repo_dir.path().to_path_buf();
     init_repo(&repo);
@@ -225,10 +349,6 @@ fn remove_refuses_worktree_with_uncommitted_changes() {
         .expect_err("dirty worktree must be refused");
     assert!(path.exists(), "guarded worktree must stay on disk");
 
-    // Committing it makes removal safe: `worktree remove` keeps
-    // `refs/heads/feat/dirty`, so the work is still reachable. Refusing here
-    // instead would make every unpushed branch a one-shot, since the path is
-    // deterministic and the leftover tree blocks the next spawn (#56 review).
     run_git(&path, &["add", "."]);
     run_git(&path, &["commit", "-q", "-m", "saved"]);
 
@@ -410,7 +530,8 @@ fn a_guarded_leftover_is_never_adopted() {
     let first = mgr.add_new(&repo, "feat/resume").expect("add");
     std::fs::write(first.join("notes.txt"), b"unsaved\n").unwrap();
 
-    // The guard refuses, leaving it on disk.
+    // Removal is refused — git itself refuses a dirty tree — leaving it on
+    // disk; the daemon-side guard lives on the kill (#79).
     mgr.remove(&repo, &first)
         .expect_err("dirty tree is guarded");
 

crates/maestro-e2e/tests/e2e.rs

@@ -160,6 +160,7 @@ async fn kill_removes_clean_worktree() {
         "expected a worktree for feature/e2e under <repo>/worktrees, got: {worktrees:?}"
     );
 
+    push_to_throwaway_origin(base.path());
     client.kill_session(s.id).await.expect("kill");
 
     // Give the daemon a moment to remove the worktree, then verify.
@@ -177,11 +178,12 @@ async fn kill_removes_clean_worktree() {
     );
 }
 
-/// The guard (#56): killing a session whose worktree holds uncommitted
-/// changes must leave the tree on disk — cleanup is unconditional, so this
-/// guard is what keeps a stray kill from destroying work.
+/// The kill guard (#79): killing a session whose worktree holds uncommitted
+/// changes is refused outright. Nothing happens — the session keeps running
+/// as the operator's handle on their unfinished work, the tree stays on disk,
+/// and the refusal names what blocked it and how much.
 #[tokio::test(flavor = "multi_thread")]
-async fn kill_spares_worktree_with_uncommitted_changes() {
+async fn kill_refuses_worktree_with_uncommitted_changes() {
     let (_daemon, client) = bring_up().await;
 
     let base = TempDir::new().unwrap();
@@ -209,17 +211,25 @@ async fn kill_spares_worktree_with_uncommitted_changes() {
     assert!(wt_path.exists());
     std::fs::write(wt_path.join("README"), b"unsaved edits\n").unwrap();
 
-    client.kill_session(s.id).await.expect("kill");
-
-    // The session is gone but the dirty worktree stays findable on disk.
-    let deadline = Instant::now() + Duration::from_secs(5);
-    while Instant::now() < deadline {
-        let sessions = client.list_sessions().await.unwrap_or_default();
-        if sessions.is_empty() {
-            break;
+    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);
         }
-        tokio::time::sleep(Duration::from_millis(100)).await;
+        other => panic!("expected a kill_guarded refusal, got {other:?}"),
     }
+
+    // The session survives and the dirty worktree stays findable on disk.
+    let sessions = client.list_sessions().await.unwrap_or_default();
+    assert!(
+        sessions.iter().any(|x| x.id == s.id),
+        "a refused kill must keep the session alive"
+    );
     assert!(
         wt_path.exists(),
         "guarded worktree must be left on disk after kill"
@@ -270,6 +280,7 @@ 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());
     client.kill_session(s.id).await.expect("kill");
 }
 
@@ -317,6 +328,7 @@ async fn spawn_new_branch_creates_worktree_and_runs_in_it() {
     )
     .await;
 
+    push_to_throwaway_origin(base.path());
     client.kill_session(s.id).await.expect("kill");
 }
 
@@ -364,6 +376,7 @@ async fn second_spawn_on_same_branch_is_rejected() {
         "original worktree must be untouched"
     );
 
+    push_to_throwaway_origin(base.path());
     client.kill_session(first.id).await.expect("kill");
 }
 
@@ -406,6 +419,7 @@ async fn spawn_from_linked_worktree_places_in_main_checkout() {
         "worktrees must never nest inside another worktree"
     );
 
+    push_to_throwaway_origin(base.path());
     client.kill_session(s.id).await.expect("kill");
 }
 
@@ -774,6 +788,24 @@ 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) {
+    let origin = tempfile::TempDir::new().unwrap();
+    run_git(
+        &["init", "-q", "--bare", origin.path().to_str().unwrap()],
+        repo,
+    );
+    let _ = Command::new("git")
+        .arg("-C")
+        .arg(repo)
+        .args(["remote", "add", "origin", origin.path().to_str().unwrap()])
+        .output()
+        .expect("git remote add");
+    run_git(&["push", "-q", "--all", "origin"], repo);
+}
+
 #[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, Session,
+    Project, RecentDirs, RetainedWorktree, Session,
 };
 
 /// Time budget for establishing a TCP connection to the daemon.
@@ -148,6 +148,23 @@ impl DaemonClient {
             .await
     }
 
+    /// `GET /api/worktrees` (#80): every retained worktree with its in-the-way
+    /// breakdown as of this read.
+    pub async fn list_worktrees(&self) -> Result<Vec<RetainedWorktree>, ClientError> {
+        self.get(routes::WORKTREES, &[]).await
+    }
+
+    /// `DELETE /api/worktrees/:id` (#86): reclaim one retained worktree. The
+    /// daemon removes the directory and drops the store entry; the branch is
+    /// never deleted.
+    pub async fn reclaim_worktree(&self, id: Uuid) -> Result<(), ClientError> {
+        let resp = self
+            .send(Method::DELETE, &routes::worktree(id), &[], None::<&()>)
+            .await?;
+        check(resp).await?;
+        Ok(())
+    }
+
     // -- plumbing -----------------------------------------------------------
 
     async fn get<T: DeserializeOwned>(

crates/maestro-protocol/src/lib.rs

@@ -195,6 +195,35 @@ pub struct RetainedWorktree {
     pub in_the_way: InTheWay,
 }
 
+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
+    /// uses for both the kill refusal and the retained list, so the two
+    /// cannot describe the same tree differently.
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        let parts = [
+            (self.uncommitted_files, "uncommitted file"),
+            (self.untracked_files, "untracked file"),
+            (self.unpushed_commits, "unpushed commit"),
+        ];
+        let said: Vec<String> = parts
+            .into_iter()
+            .filter(|(n, _)| *n > 0)
+            .map(|(n, unit)| {
+                if n == 1 {
+                    format!("1 {unit}")
+                } else {
+                    format!("{n} {unit}s")
+                }
+            })
+            .collect();
+        if said.is_empty() {
+            return write!(f, "no unsaved work");
+        }
+        write!(f, "{}", said.join(", "))
+    }
+}
+
 /// HTTP `POST /api/sessions` body.
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
 pub struct CreateSessionRequest {
@@ -300,6 +329,10 @@ pub struct BranchInfo {
 pub struct ErrorInfo {
     pub code: String,
     pub message: String,
+    /// Set only by the kill guard (#79): the unsaved work that blocked
+    /// `DELETE /api/sessions/:id`, so a client can render counts directly.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub unsaved_work: Option<InTheWay>,
 }
 
 /// The envelope every `/api/*` failure is wrapped in: `{"error": {…}}`.
@@ -320,6 +353,7 @@ impl ApiError {
             error: ErrorInfo {
                 code: code.into(),
                 message: message.into(),
+                unsaved_work: None,
             },
         }
     }
@@ -684,6 +718,7 @@ mod tests {
             ClientControl::Error(ErrorInfo {
                 code: "bad_frame".into(),
                 message: "decode failed".into(),
+                unsaved_work: None,
             }),
             resize,
         ] {