huskies: merge 543_story_resume_failed_coder_agents_with_resume_instead_of_starting_fresh_sessions

server/src/agents/pool/auto_assign/auto_assign.rs

@@ -262,7 +262,7 @@ impl AgentPool {
                             "[auto-assign] Assigning '{agent_name}' to '{story_id}' in {stage_dir}/"
                         );
                         if let Err(e) = self
-                            .start_agent(project_root, story_id, Some(&agent_name), None)
+                            .start_agent(project_root, story_id, Some(&agent_name), None, None)
                             .await
                         {
                             slog!(

server/src/agents/pool/pipeline/advance.rs

@@ -17,6 +17,7 @@ use super::super::{AgentPool, StoryAgent};
 impl AgentPool {
     /// Pipeline advancement: after an agent completes, move the story to
     /// the next pipeline stage and start the appropriate agent.
+    #[allow(clippy::too_many_arguments)]
     pub(super) async fn run_pipeline_advance(
         &self,
         story_id: &str,
@@ -25,6 +26,7 @@ impl AgentPool {
         project_root: Option<PathBuf>,
         worktree_path: Option<PathBuf>,
         merge_failure_reported: bool,
+        previous_session_id: Option<String>,
     ) {
         let project_root = match project_root {
             Some(p) => p,
@@ -81,7 +83,7 @@ impl AgentPool {
                             if let Err(e) = crate::agents::lifecycle::move_story_to_qa(&project_root, story_id) {
                                 slog_error!("[pipeline] Failed to move '{story_id}' to 3_qa/: {e}");
                             } else if let Err(e) = self
-                                .start_agent(&project_root, story_id, Some("qa"), None)
+                                .start_agent(&project_root, story_id, Some("qa"), None, None)
                                 .await
                             {
                                 slog_error!("[pipeline] Failed to start qa agent for '{story_id}': {e}");
@@ -118,7 +120,13 @@ impl AgentPool {
                             completion.gate_output
                         );
                         if let Err(e) = self
-                            .start_agent(&project_root, story_id, Some(agent_name), Some(&context))
+                            .start_agent(
+                                &project_root,
+                                story_id,
+                                Some(agent_name),
+                                Some(&context),
+                                previous_session_id,
+                            )
                             .await
                         {
                             slog_error!(
@@ -202,7 +210,7 @@ impl AgentPool {
                             coverage_output
                         );
                         if let Err(e) = self
-                            .start_agent(&project_root, story_id, Some("qa"), Some(&context))
+                            .start_agent(&project_root, story_id, Some("qa"), Some(&context), None)
                             .await
                         {
                             slog_error!("[pipeline] Failed to restart qa for '{story_id}': {e}");
@@ -223,7 +231,7 @@ impl AgentPool {
                         completion.gate_output
                     );
                     if let Err(e) = self
-                        .start_agent(&project_root, story_id, Some("qa"), Some(&context))
+                        .start_agent(&project_root, story_id, Some("qa"), Some(&context), None)
                         .await
                     {
                         slog_error!("[pipeline] Failed to restart qa for '{story_id}': {e}");
@@ -322,6 +330,7 @@ impl AgentPool {
                                 story_id,
                                 Some("mergemaster"),
                                 Some(&context),
+                                None,
                             )
                             .await
                         {
@@ -369,7 +378,7 @@ impl AgentPool {
             return;
         }
         if let Err(e) = self
-            .start_agent(project_root, story_id, Some("mergemaster"), None)
+            .start_agent(project_root, story_id, Some("mergemaster"), None, None)
             .await
         {
             slog_error!("[pipeline] Failed to start mergemaster for '{story_id}': {e}");
@@ -392,6 +401,7 @@ pub(super) fn spawn_pipeline_advance(
     worktree_path: Option<PathBuf>,
     watcher_tx: broadcast::Sender<WatcherEvent>,
     merge_failure_reported: bool,
+    previous_session_id: Option<String>,
 ) {
     let sid = story_id.to_string();
     let aname = agent_name.to_string();
@@ -410,6 +420,7 @@ pub(super) fn spawn_pipeline_advance(
             project_root,
             worktree_path,
             merge_failure_reported,
+            previous_session_id,
         )
         .await;
     });
@@ -524,6 +535,7 @@ mod tests {
             Some(root.to_path_buf()),
             None,
             false,
+            None,
         )
         .await;
 
@@ -565,6 +577,7 @@ mod tests {
             Some(root.to_path_buf()),
             None,
             false,
+            None,
         )
         .await;
 
@@ -606,6 +619,7 @@ mod tests {
             Some(root.to_path_buf()),
             None,
             false,
+            None,
         )
         .await;
 
@@ -639,6 +653,7 @@ mod tests {
             Some(root.to_path_buf()),
             None,
             false,
+            None,
         )
         .await;
 
@@ -706,6 +721,7 @@ stage = "qa"
             Some(root.to_path_buf()),
             None,
             false,
+            None,
         )
         .await;
 
@@ -777,6 +793,7 @@ stage = "qa"
             Some(root.to_path_buf()),
             None,
             false,
+            None,
         )
         .await;
 
@@ -883,6 +900,7 @@ stage = "qa"
             Some(root.to_path_buf()),
             None,
             false,
+            None,
         )
         .await;
 
@@ -950,6 +968,7 @@ stage = "qa"
             Some(root.to_path_buf()),
             None,
             false,
+            None,
         )
         .await;
 

server/src/agents/pool/pipeline/completion.rs

@@ -83,6 +83,7 @@ impl AgentPool {
             project_root_for_advance,
             wt_path_for_advance,
             merge_failure_reported_for_advance,
+            session_id_for_advance,
         ) = {
             let mut agents = self.agents.lock().map_err(|e| e.to_string())?;
             let agent = agents.get_mut(&key).ok_or_else(|| {
@@ -94,8 +95,9 @@ impl AgentPool {
             let pr = agent.project_root.clone();
             let wt = agent.worktree_info.as_ref().map(|w| w.path.clone());
             let mfr = agent.merge_failure_reported;
+            let sid_advance = agent.session_id.clone();
             agents.remove(&key);
-            (tx, sid, pr, wt, mfr)
+            (tx, sid, pr, wt, mfr, sid_advance)
         };
 
         // Emit Done so wait_for_agent unblocks.
@@ -128,6 +130,7 @@ impl AgentPool {
                     project_root_for_advance,
                     wt_path_for_advance,
                     merge_failure_reported_for_advance,
+                    session_id_for_advance,
                 )
                 .await;
         });
@@ -277,6 +280,8 @@ pub(in crate::agents::pool) async fn run_server_owned_completion(
         lock.remove(&key);
         (tx, pr, wt, mfr)
     };
+    // The completed session's ID is used to resume if gates fail.
+    let previous_session_id = session_id.clone();
 
     // Emit Done so wait_for_agent unblocks.
     let _ = tx.send(AgentEvent::Done {
@@ -299,6 +304,7 @@ pub(in crate::agents::pool) async fn run_server_owned_completion(
         wt_path_for_advance,
         watcher_tx,
         merge_failure_reported_for_advance,
+        previous_session_id,
     );
 }
 

server/src/agents/pool/start.rs

@@ -21,14 +21,22 @@ impl AgentPool {
     /// agent (story 190). If all coders are busy the call fails with an error
     /// indicating the story will be picked up when one becomes available.
     ///
-    /// If `resume_context` is provided, it is appended to the rendered prompt
+    /// If `resume_context` is provided and `session_id_to_resume` is `None`,
-    /// so the agent can pick up from a previous failed attempt.
+    /// the context is appended to the rendered prompt so the agent can pick up
+    /// from a previous failed attempt.
+    ///
+    /// If `session_id_to_resume` is provided, the agent is launched with
+    /// `--resume <session_id>` instead of `-p <full_prompt>`.  Only
+    /// `resume_context` (if any) is sent as the new message.  This lets
+    /// the agent re-enter the previous conversation without re-reading
+    /// CLAUDE.md and README, satisfying story 543.
     pub async fn start_agent(
         &self,
         project_root: &Path,
         story_id: &str,
         agent_name: Option<&str>,
         resume_context: Option<&str>,
+        session_id_to_resume: Option<String>,
     ) -> Result<AgentInfo, String> {
         let config = ProjectConfig::load(project_root)?;
 
@@ -310,6 +318,7 @@ impl AgentPool {
         let project_root_clone = project_root.to_path_buf();
         let config_clone = config.clone();
         let resume_context_owned = resume_context.map(str::to_string);
+        let session_id_to_resume_owned = session_id_to_resume;
         let sid = story_id.to_string();
         let aname = resolved_name.clone();
         let tx_clone = tx.clone();
@@ -397,10 +406,21 @@ impl AgentPool {
                 }
             };
 
-            // Append resume context if this is a restart with failure information.
+            // Build the effective prompt and determine resume session.
+            //
+            // When resuming a previous session, discard the full rendered prompt
+            // (which would re-read CLAUDE.md and README) and send only the gate
+            // failure context as a new message.  On a fresh start, append the
+            // failure context to the original prompt as before.
+            let effective_prompt = match &session_id_to_resume_owned {
+                Some(_) => resume_context_owned.unwrap_or_default(),
+                None => {
                     if let Some(ctx) = resume_context_owned {
                         prompt.push_str(&ctx);
                     }
+                    prompt
+                }
+            };
 
             // Step 3: transition to Running now that the worktree is ready.
             {
@@ -431,10 +451,11 @@ impl AgentPool {
                         agent_name: aname.clone(),
                         command,
                         args,
-                        prompt,
+                        prompt: effective_prompt,
                         cwd: wt_path_str,
                         inactivity_timeout_secs,
                         mcp_port: port_for_task,
+                        session_id_to_resume: session_id_to_resume_owned.clone(),
                     };
                     runtime
                         .start(ctx, tx_clone.clone(), log_clone.clone(), log_writer_clone)
@@ -447,10 +468,11 @@ impl AgentPool {
                         agent_name: aname.clone(),
                         command,
                         args,
-                        prompt,
+                        prompt: effective_prompt,
                         cwd: wt_path_str,
                         inactivity_timeout_secs,
                         mcp_port: port_for_task,
+                        session_id_to_resume: session_id_to_resume_owned.clone(),
                     };
                     runtime
                         .start(ctx, tx_clone.clone(), log_clone.clone(), log_writer_clone)
@@ -463,10 +485,11 @@ impl AgentPool {
                         agent_name: aname.clone(),
                         command,
                         args,
-                        prompt,
+                        prompt: effective_prompt,
                         cwd: wt_path_str,
                         inactivity_timeout_secs,
                         mcp_port: port_for_task,
+                        session_id_to_resume: session_id_to_resume_owned,
                     };
                     runtime
                         .start(ctx, tx_clone.clone(), log_clone.clone(), log_writer_clone)
@@ -646,7 +669,7 @@ stage = "coder"
         pool.inject_test_agent("other-story", "coder-1", AgentStatus::Running);
 
         let result = pool
-            .start_agent(tmp.path(), "42_my_story", None, None)
+            .start_agent(tmp.path(), "42_my_story", None, None, None)
             .await;
         match result {
             Ok(info) => {
@@ -688,7 +711,7 @@ stage = "coder"
         pool.inject_test_agent("story-1", "coder-1", AgentStatus::Running);
         pool.inject_test_agent("story-2", "coder-2", AgentStatus::Pending);
 
-        let result = pool.start_agent(tmp.path(), "story-3", None, None).await;
+        let result = pool.start_agent(tmp.path(), "story-3", None, None, None).await;
         assert!(result.is_err());
         let err = result.unwrap_err();
         assert!(
@@ -720,7 +743,7 @@ stage = "coder"
         let pool = AgentPool::new_test(3001);
         pool.inject_test_agent("story-1", "coder-1", AgentStatus::Running);
 
-        let result = pool.start_agent(tmp.path(), "story-3", None, None).await;
+        let result = pool.start_agent(tmp.path(), "story-3", None, None, None).await;
 
         assert!(result.is_err());
         let err = result.unwrap_err();
@@ -758,7 +781,7 @@ stage = "coder"
 
         let pool = AgentPool::new_test(3001);
 
-        let result = pool.start_agent(tmp.path(), "story-5", None, None).await;
+        let result = pool.start_agent(tmp.path(), "story-5", None, None, None).await;
         match result {
             Ok(_) => {}
             Err(e) => {
@@ -793,7 +816,7 @@ stage = "coder"
         pool.inject_test_agent("story-1", "coder-1", AgentStatus::Running);
 
         let result = pool
-            .start_agent(tmp.path(), "story-2", Some("coder-1"), None)
+            .start_agent(tmp.path(), "story-2", Some("coder-1"), None, None)
             .await;
         assert!(result.is_err());
         let err = result.unwrap_err();
@@ -819,7 +842,7 @@ stage = "coder"
         let pool = AgentPool::new_test(3001);
         pool.inject_test_agent("story-a", "qa", AgentStatus::Running);
 
-        let result = pool.start_agent(root, "story-b", Some("qa"), None).await;
+        let result = pool.start_agent(root, "story-b", Some("qa"), None, None).await;
 
         assert!(
             result.is_err(),
@@ -846,7 +869,7 @@ stage = "coder"
         let pool = AgentPool::new_test(3001);
         pool.inject_test_agent("story-a", "qa", AgentStatus::Completed);
 
-        let result = pool.start_agent(root, "story-b", Some("qa"), None).await;
+        let result = pool.start_agent(root, "story-b", Some("qa"), None, None).await;
 
         if let Err(ref e) = result {
             assert!(
@@ -880,7 +903,7 @@ stage = "coder"
         let pool = AgentPool::new_test(3099);
 
         let result = pool
-            .start_agent(root, "50_story_test", Some("coder-1"), None)
+            .start_agent(root, "50_story_test", Some("coder-1"), None, None)
             .await;
 
         assert!(
@@ -938,7 +961,7 @@ stage = "coder"
         let pool = AgentPool::new_test(3099);
         pool.inject_test_agent("story-x", "qa", AgentStatus::Running);
 
-        let result = pool.start_agent(root, "story-y", Some("qa"), None).await;
+        let result = pool.start_agent(root, "story-y", Some("qa"), None, None).await;
 
         assert!(result.is_err());
         let err = result.unwrap_err();
@@ -969,7 +992,7 @@ stage = "coder"
         pool.inject_test_agent("86_story_foo", "coder-1", AgentStatus::Pending);
 
         let result = pool
-            .start_agent(root, "130_story_bar", Some("coder-1"), None)
+            .start_agent(root, "130_story_bar", Some("coder-1"), None, None)
             .await;
 
         assert!(result.is_err(), "second start_agent must be rejected");
@@ -1012,7 +1035,7 @@ stage = "coder"
         let root1 = root.clone();
         let t1 = tokio::spawn(async move {
             pool1
-                .start_agent(&root1, "86_story_foo", Some("coder-1"), None)
+                .start_agent(&root1, "86_story_foo", Some("coder-1"), None, None)
                 .await
         });
 
@@ -1020,7 +1043,7 @@ stage = "coder"
         let root2 = root.clone();
         let t2 = tokio::spawn(async move {
             pool2
-                .start_agent(&root2, "130_story_bar", Some("coder-1"), None)
+                .start_agent(&root2, "130_story_bar", Some("coder-1"), None, None)
                 .await
         });
 
@@ -1065,7 +1088,7 @@ stage = "coder"
         pool.inject_test_agent("42_story_foo", "coder-1", AgentStatus::Running);
 
         let result = pool
-            .start_agent(root, "42_story_foo", Some("coder-2"), None)
+            .start_agent(root, "42_story_foo", Some("coder-2"), None, None)
             .await;
 
         assert!(
@@ -1103,7 +1126,7 @@ stage = "coder"
         pool.inject_test_agent("55_story_bar", "qa-1", AgentStatus::Running);
 
         let result = pool
-            .start_agent(root, "55_story_bar", Some("qa-2"), None)
+            .start_agent(root, "55_story_bar", Some("qa-2"), None, None)
             .await;
 
         assert!(result.is_err(), "second qa on same story must be rejected");
@@ -1141,7 +1164,7 @@ stage = "coder"
         let root1 = root.clone();
         let t1 = tokio::spawn(async move {
             pool1
-                .start_agent(&root1, "42_story_foo", Some("coder-1"), None)
+                .start_agent(&root1, "42_story_foo", Some("coder-1"), None, None)
                 .await
         });
 
@@ -1149,7 +1172,7 @@ stage = "coder"
         let root2 = root.clone();
         let t2 = tokio::spawn(async move {
             pool2
-                .start_agent(&root2, "42_story_foo", Some("coder-2"), None)
+                .start_agent(&root2, "42_story_foo", Some("coder-2"), None, None)
                 .await
         });
 
@@ -1193,7 +1216,7 @@ stage = "coder"
         pool.inject_test_agent("42_story_foo", "coder-1", AgentStatus::Running);
 
         let result = pool
-            .start_agent(root, "99_story_baz", Some("coder-2"), None)
+            .start_agent(root, "99_story_baz", Some("coder-2"), None, None)
             .await;
 
         if let Err(ref e) = result {
@@ -1231,7 +1254,7 @@ stage = "coder"
 
         let pool = AgentPool::new_test(3099);
         let result = pool
-            .start_agent(root, "310_story_foo", Some("mergemaster"), None)
+            .start_agent(root, "310_story_foo", Some("mergemaster"), None, None)
             .await;
 
         assert!(
@@ -1269,7 +1292,7 @@ stage = "coder"
 
         let pool = AgentPool::new_test(3099);
         let result = pool
-            .start_agent(root, "8842_story_qa_guard", Some("coder-1"), None)
+            .start_agent(root, "8842_story_qa_guard", Some("coder-1"), None, None)
             .await;
 
         assert!(
@@ -1307,7 +1330,7 @@ stage = "coder"
 
         let pool = AgentPool::new_test(3099);
         let result = pool
-            .start_agent(root, "55_story_baz", Some("qa"), None)
+            .start_agent(root, "55_story_baz", Some("qa"), None, None)
             .await;
 
         assert!(
@@ -1343,7 +1366,7 @@ stage = "coder"
 
         let pool = AgentPool::new_test(3099);
         let result = pool
-            .start_agent(root, "77_story_sup", Some("supervisor"), None)
+            .start_agent(root, "77_story_sup", Some("supervisor"), None, None)
             .await;
 
         match result {
@@ -1379,7 +1402,7 @@ stage = "coder"
 
         let pool = AgentPool::new_test(3099);
         let result = pool
-            .start_agent(root, "88_story_ok", Some("mergemaster"), None)
+            .start_agent(root, "88_story_ok", Some("mergemaster"), None, None)
             .await;
 
         match result {
@@ -1435,7 +1458,7 @@ stage = "coder"
 
         let pool = AgentPool::new_test(3098);
         let result = pool
-            .start_agent(root, "502_story_split_brain", Some("mergemaster"), None)
+            .start_agent(root, "502_story_split_brain", Some("mergemaster"), None, None)
             .await;
 
         // Stage check must not reject mergemaster.
@@ -1494,7 +1517,7 @@ stage = "coder"
         pool.inject_test_agent("other-story", "coder-sonnet", AgentStatus::Running);
 
         let result = pool
-            .start_agent(tmp.path(), "368_story_test", None, None)
+            .start_agent(tmp.path(), "368_story_test", None, None, None)
             .await;
         match result {
             Ok(info) => {
@@ -1557,7 +1580,7 @@ stage = "coder"
         pool.inject_test_agent("other-story", "coder-opus", AgentStatus::Running);
 
         let result = pool
-            .start_agent(tmp.path(), "368_story_test", None, None)
+            .start_agent(tmp.path(), "368_story_test", None, None, None)
             .await;
         assert!(result.is_err(), "expected error when preferred agent is busy");
         let err = result.unwrap_err();

server/src/agents/pty.rs

@@ -49,6 +49,7 @@ pub(in crate::agents) async fn run_agent_pty_streaming(
     inactivity_timeout_secs: u64,
     child_killers: Arc<Mutex<HashMap<String, Box<dyn ChildKiller + Send + Sync>>>>,
     watcher_tx: broadcast::Sender<WatcherEvent>,
+    session_id_to_resume: Option<&str>,
 ) -> Result<PtyResult, String> {
     let sid = story_id.to_string();
     let aname = agent_name.to_string();
@@ -58,6 +59,7 @@ pub(in crate::agents) async fn run_agent_pty_streaming(
     let cwd = cwd.to_string();
     let tx = tx.clone();
     let event_log = event_log.clone();
+    let resume_sid = session_id_to_resume.map(str::to_string);
 
     tokio::task::spawn_blocking(move || {
         run_agent_pty_blocking(
@@ -73,6 +75,7 @@ pub(in crate::agents) async fn run_agent_pty_streaming(
             inactivity_timeout_secs,
             &child_killers,
             &watcher_tx,
+            resume_sid.as_deref(),
         )
     })
     .await
@@ -166,6 +169,7 @@ fn run_agent_pty_blocking(
     inactivity_timeout_secs: u64,
     child_killers: &Arc<Mutex<HashMap<String, Box<dyn ChildKiller + Send + Sync>>>>,
     watcher_tx: &broadcast::Sender<WatcherEvent>,
+    session_id_to_resume: Option<&str>,
 ) -> Result<PtyResult, String> {
     let pty_system = native_pty_system();
 
@@ -180,9 +184,21 @@ fn run_agent_pty_blocking(
 
     let mut cmd = CommandBuilder::new(command);
 
-    // -p <prompt> must come first
+    // Launch mode: resume an existing session or start fresh.
+    if let Some(sid) = session_id_to_resume {
+        // Resume: --resume <session_id> restores previous conversation context.
+        // Only the failure context (prompt) is sent as a new message via -p.
+        cmd.arg("--resume");
+        cmd.arg(sid);
+        if !prompt.is_empty() {
             cmd.arg("-p");
             cmd.arg(prompt);
+        }
+    } else {
+        // Fresh session: deliver the full rendered prompt via -p.
+        cmd.arg("-p");
+        cmd.arg(prompt);
+    }
 
     // Add configured args (e.g., --directory /path/to/worktree, --model, etc.)
     for arg in args {
@@ -541,6 +557,7 @@ mod tests {
             0,
             child_killers,
             watcher_tx,
+            None,
         )
         .await;
 
@@ -594,6 +611,7 @@ mod tests {
             0,
             child_killers,
             watcher_tx,
+            None,
         )
         .await;
 
@@ -655,6 +673,7 @@ mod tests {
             0,
             child_killers,
             watcher_tx,
+            None,
         )
         .await;
         let after = chrono::Utc::now();

server/src/agents/runtime/claude_code.rs

@@ -52,6 +52,7 @@ impl AgentRuntime for ClaudeCodeRuntime {
             ctx.inactivity_timeout_secs,
             Arc::clone(&self.child_killers),
             self.watcher_tx.clone(),
+            ctx.session_id_to_resume.as_deref(),
         )
         .await?;
 

server/src/agents/runtime/gemini.rs

@@ -707,6 +707,7 @@ mod tests {
             cwd: "/tmp/wt".to_string(),
             inactivity_timeout_secs: 300,
             mcp_port: 3001,
+            session_id_to_resume: None,
         };
 
         let instruction = build_system_instruction(&ctx);
@@ -724,6 +725,7 @@ mod tests {
             cwd: "/tmp/wt".to_string(),
             inactivity_timeout_secs: 300,
             mcp_port: 3001,
+            session_id_to_resume: None,
         };
 
         let instruction = build_system_instruction(&ctx);
@@ -800,6 +802,7 @@ mod tests {
             cwd: "/tmp".to_string(),
             inactivity_timeout_secs: 300,
             mcp_port: 3001,
+            session_id_to_resume: None,
         };
 
         // The model extraction logic is inside start(), but we test the

server/src/agents/runtime/mod.rs

@@ -25,6 +25,12 @@ pub struct RuntimeContext {
     /// Port of the huskies MCP server, used by API-based runtimes (Gemini, OpenAI)
     /// to call back for tool execution.
     pub mcp_port: u16,
+    /// When set, resume a previous Claude Code session instead of starting fresh.
+    ///
+    /// The CLI is invoked as `claude --resume <session_id> [-p <prompt>]` rather
+    /// than `claude -p <full_prompt>`.  The agent re-enters the previous
+    /// conversation and receives the `prompt` (if non-empty) as a new message.
+    pub session_id_to_resume: Option<String>,
 }
 
 /// Result returned by a runtime after the agent session completes.
@@ -93,6 +99,7 @@ mod tests {
             cwd: "/tmp/wt".to_string(),
             inactivity_timeout_secs: 300,
             mcp_port: 3001,
+            session_id_to_resume: None,
         };
         assert_eq!(ctx.story_id, "42_story_foo");
         assert_eq!(ctx.agent_name, "coder-1");

server/src/agents/runtime/openai.rs

@@ -618,6 +618,7 @@ mod tests {
             cwd: "/tmp/wt".to_string(),
             inactivity_timeout_secs: 300,
             mcp_port: 3001,
+            session_id_to_resume: None,
         };
 
         assert_eq!(build_system_text(&ctx), "Custom system prompt");
@@ -634,6 +635,7 @@ mod tests {
             cwd: "/tmp/wt".to_string(),
             inactivity_timeout_secs: 300,
             mcp_port: 3001,
+            session_id_to_resume: None,
         };
 
         let text = build_system_text(&ctx);
@@ -683,6 +685,7 @@ mod tests {
             cwd: "/tmp".to_string(),
             inactivity_timeout_secs: 300,
             mcp_port: 3001,
+            session_id_to_resume: None,
         };
         assert!(ctx.command.starts_with("gpt"));
     }
@@ -698,6 +701,7 @@ mod tests {
             cwd: "/tmp".to_string(),
             inactivity_timeout_secs: 300,
             mcp_port: 3001,
+            session_id_to_resume: None,
         };
         assert!(ctx.command.starts_with("o"));
     }

server/src/chat/timer.rs

@@ -205,7 +205,7 @@ pub(crate) async fn tick_once(
         }
 
         match agents
-            .start_agent(project_root, &entry.story_id, None, None)
+            .start_agent(project_root, &entry.story_id, None, None, None)
             .await
         {
             Ok(info) => {

server/src/chat/transport/matrix/assign.rs

@@ -171,7 +171,7 @@ pub async fn handle_assign(
     );
 
     match agents
-        .start_agent(project_root, &story_id, Some(&agent_name), None)
+        .start_agent(project_root, &story_id, Some(&agent_name), None, None)
         .await
     {
         Ok(info) => {

server/src/chat/transport/matrix/start.rs

@@ -115,7 +115,7 @@ pub async fn handle_start(
     );
 
     match agents
-        .start_agent(project_root, &story_id, resolved_agent.as_deref(), None)
+        .start_agent(project_root, &story_id, resolved_agent.as_deref(), None, None)
         .await
     {
         Ok(info) => {

server/src/http/agents.rs

@@ -190,6 +190,7 @@ impl AgentsApi {
                 &payload.0.story_id,
                 payload.0.agent_name.as_deref(),
                 None,
+                None,
             )
             .await
             .map_err(bad_request)?;

server/src/http/mcp/agent_tools.rs

@@ -16,7 +16,7 @@ pub(super) async fn tool_start_agent(args: &Value, ctx: &AppContext) -> Result<S
     let project_root = ctx.agents.get_project_root(&ctx.state)?;
     let info = ctx
         .agents
-        .start_agent(&project_root, story_id, agent_name, None)
+        .start_agent(&project_root, story_id, agent_name, None, None)
         .await?;
 
     // Snapshot coverage baseline from the most recent coverage report (best-effort).

server/src/http/mcp/merge_tools.rs

@@ -144,7 +144,7 @@ pub(super) async fn tool_move_story_to_merge(args: &Value, ctx: &AppContext) ->
     // Start the mergemaster agent on the story worktree
     let info = ctx
         .agents
-        .start_agent(&project_root, story_id, Some(agent_name), None)
+        .start_agent(&project_root, story_id, Some(agent_name), None, None)
         .await?;
 
     serde_json::to_string_pretty(&json!({

server/src/http/mcp/qa_tools.rs

@@ -22,7 +22,7 @@ pub(super) async fn tool_request_qa(args: &Value, ctx: &AppContext) -> Result<St
     // Start the QA agent on the story worktree
     let info = ctx
         .agents
-        .start_agent(&project_root, story_id, Some(agent_name), None)
+        .start_agent(&project_root, story_id, Some(agent_name), None, None)
         .await?;
 
     serde_json::to_string_pretty(&json!({
@@ -60,7 +60,7 @@ pub(super) async fn tool_approve_qa(args: &Value, ctx: &AppContext) -> Result<St
     // Start the mergemaster agent
     let info = ctx
         .agents
-        .start_agent(&project_root, story_id, Some("mergemaster"), None)
+        .start_agent(&project_root, story_id, Some("mergemaster"), None, None)
         .await?;
 
     serde_json::to_string_pretty(&json!({
@@ -112,7 +112,7 @@ pub(super) async fn tool_reject_qa(args: &Value, ctx: &AppContext) -> Result<Str
     );
     if let Err(e) = ctx
         .agents
-        .start_agent(&project_root, story_id, Some(agent_name), Some(&context))
+        .start_agent(&project_root, story_id, Some(agent_name), Some(&context), None)
         .await
     {
         slog_warn!("[qa] Failed to restart coder for '{story_id}' after rejection: {e}");