diff --git a/codex-rs/app-server/src/request_processors/thread_processor.rs b/codex-rs/app-server/src/request_processors/thread_processor.rs
index f361dd6087..29c1a9062d 100644
--- a/codex-rs/app-server/src/request_processors/thread_processor.rs
+++ b/codex-rs/app-server/src/request_processors/thread_processor.rs
@@ -969,6 +969,8 @@ impl ThreadRequestProcessor {
             ));
         }
         let runtime_workspace_roots = runtime_workspace_roots.map(resolve_runtime_workspace_roots);
+        let environments =
+            resolve_turn_environment_selections(self.thread_manager.as_ref(), environments)?;
         let mut typesafe_overrides = self.build_thread_config_overrides(
             model,
             model_provider,
@@ -1092,7 +1094,7 @@ impl ThreadRequestProcessor {
         history_mode: Option<ThreadHistoryMode>,
         session_start_source: Option<codex_app_server_protocol::ThreadStartSource>,
         thread_source: Option<codex_protocol::protocol::ThreadSource>,
-        environments: Option<Vec<codex_app_server_protocol::TurnEnvironmentParams>>,
+        environment_selections: Option<Vec<TurnEnvironmentSelection>>,
         service_name: Option<String>,
         allow_provider_model_fallback: bool,
         experimental_raw_events: bool,
@@ -1105,11 +1107,6 @@ impl ThreadRequestProcessor {
             .load_with_overrides(config_overrides.clone(), typesafe_overrides.clone())
             .await
             .map_err(|err| config_load_error(&err))?;
-        let environment_selections = resolve_turn_environment_selections(
-            listener_task_context.thread_manager.as_ref(),
-            environments,
-        )?;
-
         // The user may have requested WorkspaceWrite or DangerFullAccess via
         // the command line, though in the process of deriving the Config, it
         // could be downgraded to ReadOnly (perhaps there is no sandbox
diff --git a/codex-rs/app-server/src/request_processors/turn_processor.rs b/codex-rs/app-server/src/request_processors/turn_processor.rs
index 0ee424ef87..66e819aa38 100644
--- a/codex-rs/app-server/src/request_processors/turn_processor.rs
+++ b/codex-rs/app-server/src/request_processors/turn_processor.rs
@@ -107,7 +107,6 @@ fn map_additional_context(
 struct ThreadSettingsBuildParams {
     method: &'static str,
     environments: Option<TurnEnvironmentSelections>,
-    runtime_workspace_roots: Option<Vec<AbsolutePathBuf>>,
     approval_policy: Option<codex_app_server_protocol::AskForApproval>,
     approvals_reviewer: Option<codex_app_server_protocol::ApprovalsReviewer>,
     sandbox_policy: Option<codex_app_server_protocol::SandboxPolicy>,
@@ -501,7 +500,7 @@ impl TurnRequestProcessor {
             .build_environment_override(
                 thread.as_ref(),
                 cwd,
-                runtime_workspace_roots.clone(),
+                runtime_workspace_roots,
                 environment_selections,
             )
             .await;
@@ -511,7 +510,6 @@ impl TurnRequestProcessor {
                 ThreadSettingsBuildParams {
                     method: "turn/start",
                     environments,
-                    runtime_workspace_roots,
                     approval_policy: params.approval_policy,
                     approvals_reviewer: params.approvals_reviewer,
                     sandbox_policy: params.sandbox_policy,
@@ -602,7 +600,7 @@ impl TurnRequestProcessor {
 
         let snapshot = thread.config_snapshot().await;
         let current_cwd = snapshot.cwd().clone();
-        let legacy_fallback_cwd = cwd.unwrap_or_else(|| snapshot.cwd().clone());
+        let legacy_fallback_cwd = cwd.unwrap_or_else(|| current_cwd.clone());
         let workspace_roots = match workspace_roots {
             Some(workspace_roots) => workspace_roots,
             None => {
@@ -640,7 +638,6 @@ impl TurnRequestProcessor {
         let ThreadSettingsBuildParams {
             method,
             environments,
-            runtime_workspace_roots,
             approval_policy,
             approvals_reviewer,
             sandbox_policy,
@@ -661,7 +658,6 @@ impl TurnRequestProcessor {
 
         let collaboration_mode =
             collaboration_mode.map(|mode| self.normalize_collaboration_mode(mode));
-        let runtime_workspace_roots_request = runtime_workspace_roots;
         let has_environment_override = environments.is_some();
         // `thread/settings/update` only acknowledges that the update was queued.
         // Clients that send dependent partial updates should wait for
@@ -673,7 +669,6 @@ impl TurnRequestProcessor {
         };
 
         let has_any_overrides = has_environment_override
-            || runtime_workspace_roots_request.is_some()
             || approval_policy.is_some()
             || approvals_reviewer.is_some()
             || sandbox_policy.is_some()
@@ -798,7 +793,6 @@ impl TurnRequestProcessor {
                 ThreadSettingsBuildParams {
                     method: "thread/settings/update",
                     environments,
-                    runtime_workspace_roots: None,
                     approval_policy: params.approval_policy,
                     approvals_reviewer: params.approvals_reviewer,
                     sandbox_policy: params.sandbox_policy,
diff --git a/codex-rs/core/src/session/turn_context.rs b/codex-rs/core/src/session/turn_context.rs
index 65157cde83..fd1d2ea2fd 100644
--- a/codex-rs/core/src/session/turn_context.rs
+++ b/codex-rs/core/src/session/turn_context.rs
@@ -475,12 +475,10 @@ impl Session {
         let mut config = Self::build_per_turn_config(
             session_configuration,
             session_configuration.cwd().clone(),
-            workspace_roots.clone(),
+            workspace_roots,
         );
         config.model = Some(session_configuration.collaboration_mode.model().to_string());
         config.permissions.approval_policy = session_configuration.approval_policy.clone();
-        config.workspace_roots = workspace_roots.clone();
-        config.permissions.set_workspace_roots(workspace_roots);
         config
     }
 
@@ -699,7 +697,7 @@ impl Session {
         multi_agent_runtime: TurnMultiAgentRuntime,
     ) -> Arc<TurnContext> {
         let turn_environments = self.services.turn_environments.snapshot().await;
-        let primary_turn_environment = turn_environments.primary().cloned();
+        let primary_turn_environment = turn_environments.primary();
         // TODO(anp): Migrate per-turn config and legacy TurnContext cwd consumers to PathUri so
         // a foreign primary environment does not fall back to the session's host cwd.
         let cwd = primary_turn_environment
@@ -707,17 +705,14 @@ impl Session {
             .and_then(|turn_environment| turn_environment.cwd().to_abs_path().ok())
             .unwrap_or_else(|| session_configuration.cwd().clone());
         let workspace_roots = primary_turn_environment
-            .as_ref()
-            .map(TurnEnvironment::workspace_roots)
-            .map(|workspace_roots| {
-                workspace_roots
+            .and_then(|turn_environment| {
+                turn_environment
+                    .workspace_roots()
                     .iter()
                     .map(PathUri::to_abs_path)
                     .collect::<std::io::Result<Vec<_>>>()
+                    .ok()
             })
-            .transpose()
-            .ok()
-            .flatten()
             .unwrap_or_default();
         let per_turn_config =
             Self::build_per_turn_config(&session_configuration, cwd.clone(), workspace_roots);