subagent tool: remember dir per session name so continue/status don't need to repeat it

hive-subagent-mcp/src/mcp.rs

@@ -40,10 +40,12 @@ struct StartArgs {
     /// Working directory for the subagent's session — e.g. a git worktree
     /// you've already prepared for it, so a parallel batch of subagents
     /// never race on the same working tree. Must exist. Omit to inherit
-    /// this daemon's own working directory (today's default). Claude
+    /// this daemon's own working directory (today's default). The daemon
-    /// derives its per-project session storage from this path, so
+    /// remembers whichever `dir` you give here against `name`, so a later
-    /// `continue`/`status` against this name must pass this exact same
+    /// `continue`/`status` for the same name doesn't need to repeat it —
-    /// `dir` again to find the session — see those tools' own docs.
+    /// only pass it there again if you want to point at a *different*
+    /// directory. Forgotten on a daemon restart, same as everything else
+    /// this daemon tracks in memory.
     #[serde(default)]
     dir: Option<String>,
 }
@@ -62,10 +64,9 @@ struct ContinueArgs {
     /// default — this does not have to match whatever model `start` used.
     #[serde(default)]
     model: Option<String>,
-    /// The same `dir` given at `start`, if any — sessions are stored keyed
+    /// Omit to reuse whatever `dir` `start` (or a prior `continue`) used for
-    /// by directory, so a different (or omitted) `dir` here looks in the
+    /// this name — the daemon remembers it. Only pass this to point the
-    /// wrong place and reports no session found under `name` even though
+    /// session at a *different* directory than last time.
-    /// one exists.
     #[serde(default)]
     dir: Option<String>,
 }
@@ -74,8 +75,11 @@ struct ContinueArgs {
 struct StatusArgs {
     /// The subagent name to check.
     name: String,
-    /// The same `dir` given at `start`, if any — see `continue`'s `dir` doc
+    /// Omit to use whatever `dir` was last remembered for this name (see
-    /// for why this has to match.
+    /// `start`'s `dir` doc) — you only need this if nothing's running or
+    /// reserved for `name` right now (the common "is it running" case never
+    /// even looks at it) *and* you want to check a different directory's
+    /// session than the one last remembered.
     #[serde(default)]
     dir: Option<String>,
 }

hive-subagent-mcp/src/session.rs

@@ -3,13 +3,17 @@
 //!
 //! **No task files, no restart recovery.** The daemon's only state is an
 //! in-memory `name -> Option<Cancel>` map (see `State`'s own doc for what
-//! the `None`/`Some` split is for), live for exactly as long as the process
+//! the `None`/`Some` split is for) plus a `name -> dir` memory so `start`'s
+//! `dir` doesn't have to be repeated on every later `continue`/`status`
+//! (`State::resolve_dir`) — both live for exactly as long as the process
 //! is — a daemon restart means whatever was running gets killed with it
-//! (`tokio`'s own child-process drop semantics), not adopted. The durable
+//! (`tokio`'s own child-process drop semantics), not adopted, and the
+//! remembered `dir` is gone too. The durable
 //! record of a subagent's existence is `hive_claude::SessionStore` — claude's
 //! own on-disk session, found again by name. `continue` is how a caller
 //! reattaches to it, whether that's "give it a new turn" or "the daemon
-//! restarted and I want to pick this back up."
+//! restarted and I want to pick this back up" — after a restart, re-supply
+//! `dir` once if the session isn't in the daemon's own default directory.
 //!
 //! **No mid-turn compaction.** Building on `hive_claude::Claude::spawn` +
 //! `RunningClaude::wait` directly (not `InfiniteSession::run`) is what makes
@@ -43,6 +47,7 @@ use hive_claude::{Attach, Cancel, Claude, Config, NoopSink, SessionStore};
 /// unless the check *is* the reservation — see `reserve`.
 pub struct State {
     running: Mutex<HashMap<String, Option<Cancel>>>,
+    dirs: Mutex<HashMap<String, String>>,
     socket: PathBuf,
 }
 
@@ -51,6 +56,7 @@ impl State {
     pub fn new(socket: PathBuf) -> Self {
         Self {
             running: Mutex::new(HashMap::new()),
+            dirs: Mutex::new(HashMap::new()),
             socket,
         }
     }
@@ -92,6 +98,28 @@ impl State {
             running.remove(name);
         }
     }
+
+    /// An explicit `dir` is remembered against `name` and returned as-is; an
+    /// omitted one (`None`) falls back to whatever was last remembered for
+    /// `name`, so a `start` that gave a `dir` doesn't force every later
+    /// `continue`/`status` against the same name to repeat it. Explicit
+    /// always wins and updates the memory — there's no way to say "forget
+    /// it, use the default" once something's been remembered short of
+    /// giving a genuinely different `dir`, a deliberate simplicity trade,
+    /// not an oversight. In-memory only, same durability envelope as
+    /// `running`: a daemon restart forgets it same as it forgets everything
+    /// else here — the caller re-supplies `dir` once, same as it always
+    /// could.
+    fn resolve_dir(&self, name: &str, dir: Option<&str>) -> Option<String> {
+        let mut dirs = self.dirs.lock().unwrap_or_else(PoisonError::into_inner);
+        match dir {
+            Some(d) => {
+                dirs.insert(name.to_owned(), d.to_owned());
+                Some(d.to_owned())
+            }
+            None => dirs.get(name).cloned(),
+        }
+    }
 }
 
 /// A caller-chosen name, validated the same way `hive-bash-mcp`'s task ids
@@ -179,10 +207,11 @@ pub fn start(
     dir: Option<&str>,
 ) -> anyhow::Result<String> {
     validate_name(name)?;
+    let dir = state.resolve_dir(name, dir);
     if !state.reserve(name) {
         anyhow::bail!("subagent `{name}` is already running — use `continue` or `interrupt`");
     }
-    let result = start_reserved(state, name, model, prompt_file, trigger, dir);
+    let result = start_reserved(state, name, model, prompt_file, trigger, dir.as_deref());
     if result.is_err() {
         state.release_reservation(name);
     }
@@ -239,12 +268,13 @@ pub fn continue_(
     dir: Option<&str>,
 ) -> anyhow::Result<String> {
     validate_name(name)?;
+    let dir = state.resolve_dir(name, dir);
     if !state.reserve(name) {
         anyhow::bail!(
             "subagent `{name}` is already running — use `interrupt` first if you meant to redirect it"
         );
     }
-    let result = continue_reserved(state, name, prompt, model, dir);
+    let result = continue_reserved(state, name, prompt, model, dir.as_deref());
     if result.is_err() {
         state.release_reservation(name);
     }
@@ -336,6 +366,7 @@ fn spawn_and_track(
 /// An invalid name, or no session — running or on disk — under `name`.
 pub fn status(state: &State, name: &str, dir: Option<&str>) -> anyhow::Result<String> {
     validate_name(name)?;
+    let dir = state.resolve_dir(name, dir);
     match state.occupancy(name) {
         Some(true) => return Ok(format!("subagent `{name}` is running")),
         Some(false) => {
@@ -345,7 +376,7 @@ pub fn status(state: &State, name: &str, dir: Option<&str>) -> anyhow::Result<St
         }
         None => {}
     }
-    let config = build_config(name, None, None, dir);
+    let config = build_config(name, None, None, dir.as_deref());
     let store = build_store(&config)?;
     if store.find_by_title(name).is_some() {
         Ok(format!(
@@ -500,6 +531,47 @@ mod tests {
         );
     }
 
+    #[test]
+    fn resolve_dir_remembers_an_explicit_dir_and_falls_back_to_it_when_omitted() {
+        let state = State::new(PathBuf::from("/dev/null"));
+        assert_eq!(
+            state.resolve_dir("n", None),
+            None,
+            "nothing remembered yet — omitted dir has nothing to fall back to"
+        );
+        assert_eq!(
+            state.resolve_dir("n", Some("/tmp/worktree")),
+            Some("/tmp/worktree".to_owned()),
+            "an explicit dir is returned as-is"
+        );
+        assert_eq!(
+            state.resolve_dir("n", None),
+            Some("/tmp/worktree".to_owned()),
+            "a later omitted dir falls back to what was just remembered"
+        );
+        assert_eq!(
+            state.resolve_dir("n", Some("/tmp/other")),
+            Some("/tmp/other".to_owned()),
+            "a later explicit dir overrides the memory, not just reads it"
+        );
+        assert_eq!(
+            state.resolve_dir("n", None),
+            Some("/tmp/other".to_owned()),
+            "the fallback now reflects the override"
+        );
+    }
+
+    #[test]
+    fn resolve_dir_does_not_cross_names() {
+        let state = State::new(PathBuf::from("/dev/null"));
+        state.resolve_dir("a", Some("/tmp/a"));
+        assert_eq!(
+            state.resolve_dir("b", None),
+            None,
+            "an unrelated name's memory must stay empty"
+        );
+    }
+
     #[test]
     fn build_config_sets_cwd_only_when_a_dir_is_given() {
         let with = build_config("n", None, None, Some("/tmp/some-worktree"));