subagent tool: add option to run in a different directory

hive-subagent-mcp/src/mcp.rs

@@ -37,6 +37,15 @@ struct StartArgs {
     /// belongs in `prompt_file`, not here.
     #[serde(default = "default_trigger")]
     trigger: String,
+    /// 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
+    /// derives its per-project session storage from this path, so
+    /// `continue`/`status` against this name must pass this exact same
+    /// `dir` again to find the session — see those tools' own docs.
+    #[serde(default)]
+    dir: Option<String>,
 }
 
 fn default_trigger() -> String {
@@ -53,12 +62,22 @@ 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
+    /// by directory, so a different (or omitted) `dir` here looks in the
+    /// wrong place and reports no session found under `name` even though
+    /// one exists.
+    #[serde(default)]
+    dir: Option<String>,
 }
 
 #[derive(Debug, Deserialize, JsonSchema)]
 struct StatusArgs {
     /// The subagent name to check.
     name: String,
+    /// The same `dir` given at `start`, if any — see `continue`'s `dir` doc
+    /// for why this has to match.
+    #[serde(default)]
+    dir: Option<String>,
 }
 
 #[derive(Debug, Deserialize, JsonSchema)]
@@ -95,6 +114,7 @@ impl SubagentMcp {
             args.model,
             &args.prompt_file,
             args.trigger,
+            args.dir.as_deref(),
         ) {
             Ok(msg) => msg,
             Err(e) => format!("start error: {e:#}"),
@@ -110,7 +130,13 @@ impl SubagentMcp {
             `start`. Refuses a name with no session on disk at all, or one already running."
     )]
     fn r#continue(&self, Parameters(args): Parameters<ContinueArgs>) -> String {
-        match session::continue_(&self.state, &args.name, args.prompt, args.model) {
+        match session::continue_(
+            &self.state,
+            &args.name,
+            args.prompt,
+            args.model,
+            args.dir.as_deref(),
+        ) {
             Ok(msg) => msg,
             Err(e) => format!("continue error: {e:#}"),
         }
@@ -138,7 +164,7 @@ impl SubagentMcp {
             `continue` to give it another turn), and no such session at all."
     )]
     fn status(&self, Parameters(args): Parameters<StatusArgs>) -> String {
-        match session::status(&self.state, &args.name) {
+        match session::status(&self.state, &args.name, args.dir.as_deref()) {
             Ok(msg) => msg,
             Err(e) => format!("status error: {e:#}"),
         }