fix(agent): take the workspace-map walk off the turn's critical path (M1)

crates/biorouter/src/agents/agent.rs

@@ -5447,11 +5447,17 @@ impl Agent {
     /// assistant messages). MOIM injection already re-normalized on the way
     /// through; this closes the same hole for sessions with no MOIM provider.
     /// `BIOROUTER_NORMALIZE_EACH_TURN=false` restores the old behaviour.
+    /// `cancel` is the turn's own token. It reaches this far down because the
+    /// workspace map's directory walk is the one piece of per-turn context
+    /// assembly that touches the filesystem, and a `Stop` has to be able to end
+    /// the wait for it — see `agents::workspace_summary` and finding M1 of the
+    /// 2026-09-10 test drive.
     async fn assemble_turn_context(
         &self,
         session_id: &str,
         conversation: &Conversation,
         working_dir: &std::path::Path,
+        cancel: Option<&CancellationToken>,
     ) -> Conversation {
         let _phase = super::phase_timing::Phase::start("agent.assemble_turn_context");
 
@@ -5462,6 +5468,7 @@ impl Agent {
             &self.extension_manager,
             working_dir,
             &self.normalizer,
+            cancel,
         )
         .await;
         drop(moim_phase);
@@ -9578,6 +9585,7 @@ impl Agent {
                             &session_config.id,
                             &conversation,
                             &working_dir,
+                            cancel_token.as_ref(),
                         )
                         .await
                     }

crates/biorouter/src/agents/extension_manager.rs

@@ -3152,10 +3152,14 @@ impl ExtensionManager {
             .map(|ext| ext.get_client())
     }
 
+    /// `cancel` is the turn's cancellation token, threaded down to the
+    /// workspace map so a `Stop` is honoured while its directory walk is still
+    /// outstanding. See `agents::workspace_summary`.
     pub async fn collect_moim(
         &self,
         session_id: &str,
         working_dir: &std::path::Path,
+        cancel: Option<&tokio_util::sync::CancellationToken>,
     ) -> Option<String> {
         // Use minute-level granularity to prevent conversation changes every second
         let timestamp = chrono::Local::now().format("%Y-%m-%d %H:%M:00").to_string();
@@ -3168,7 +3172,9 @@ impl ExtensionManager {
         // BR-1: give the model a bounded, gitignore-aware map of the workspace so
         // it doesn't rediscover project structure from scratch every session. The
         // map is cached and token-capped inside `workspace_summary`.
-        if let Some(map) = crate::agents::workspace_summary::workspace_summary(working_dir) {
+        if let Some(map) =
+            crate::agents::workspace_summary::workspace_summary(working_dir, cancel).await
+        {
             content.push('\n');
             content.push_str(&map);
             content.push('\n');
@@ -4280,7 +4286,7 @@ mod tests {
         let em = ExtensionManager::new_without_provider(temp_dir.path().to_path_buf());
         let working_dir = std::path::Path::new("/tmp");
 
-        if let Some(moim) = em.collect_moim("test-session-id", working_dir).await {
+        if let Some(moim) = em.collect_moim("test-session-id", working_dir, None).await {
             // Timestamp should end with :00 (seconds fixed to 00)
             assert!(
                 moim.contains(":00\n"),

crates/biorouter/src/agents/moim.rs

@@ -4,6 +4,7 @@ use crate::conversation::message::Message;
 use crate::conversation::{Conversation, SharedNormalizer};
 use rmcp::model::Role;
 use std::path::Path;
+use tokio_util::sync::CancellationToken;
 
 // Test-only utility. Do not use in production code. No `test` directive due to call outside crate.
 thread_local! {
@@ -71,13 +72,14 @@ pub async fn inject_moim(
     extension_manager: &ExtensionManager,
     working_dir: &Path,
     normalizer: &SharedNormalizer,
+    cancel: Option<&CancellationToken>,
 ) -> (Conversation, bool) {
     if SKIP.with(|f| f.get()) {
         return (conversation, false);
     }
 
     if let Some(moim) = extension_manager
-        .collect_moim(session_id, working_dir)
+        .collect_moim(session_id, working_dir, cancel)
         .await
     {
         let moim = cap_moim_block(moim, max_moim_tokens());
@@ -142,6 +144,7 @@ mod tests {
             &em,
             &working_dir,
             &SharedNormalizer::new(),
+            None,
         )
         .await;
         let msgs = result.messages();
@@ -180,6 +183,7 @@ mod tests {
             &em,
             &working_dir,
             &SharedNormalizer::new(),
+            None,
         )
         .await;
 
@@ -252,6 +256,7 @@ mod tests {
             &em,
             &working_dir,
             &SharedNormalizer::new(),
+            None,
         )
         .await;
         let msgs = result.messages();
@@ -379,6 +384,7 @@ mod tests {
             &em,
             &working_dir,
             &SharedNormalizer::new(),
+            None,
         )
         .await;