diff --git a/codex-rs/app-server/tests/suite/v2/remote_thread_store.rs b/codex-rs/app-server/tests/suite/v2/remote_thread_store.rs
index 9787868f5..c4e8fb924 100644
--- a/codex-rs/app-server/tests/suite/v2/remote_thread_store.rs
+++ b/codex-rs/app-server/tests/suite/v2/remote_thread_store.rs
@@ -228,7 +228,6 @@ fn assert_no_local_persistence_artifacts(codex_home: &Path) -> Result<()> {
         BTreeSet::from([
             "config.toml".to_string(),
             "installation_id".to_string(),
-            "memories".to_string(),
             "skills".to_string(),
         ]),
         "non-local thread persistence should not create unexpected files in codex_home"
diff --git a/codex-rs/core/src/config/config_tests.rs b/codex-rs/core/src/config/config_tests.rs
index e8866aab3..950103562 100644
--- a/codex-rs/core/src/config/config_tests.rs
+++ b/codex-rs/core/src/config/config_tests.rs
@@ -1554,7 +1554,6 @@ async fn default_permissions_profile_populates_runtime_sandbox_policy() -> std::
     .await?;
 
     let cwd_root = cwd.path().abs();
-    let memories_root = codex_home.path().join("memories").abs();
     assert_eq!(
         config.permissions.file_system_sandbox_policy(),
         FileSystemSandboxPolicy::restricted(vec![
@@ -1576,18 +1575,12 @@ async fn default_permissions_profile_populates_runtime_sandbox_policy() -> std::
                 },
                 access: FileSystemAccessMode::Read,
             },
-            FileSystemSandboxEntry {
-                path: FileSystemPath::Path {
-                    path: memories_root.clone(),
-                },
-                access: FileSystemAccessMode::Write,
-            },
         ]),
     );
     assert_eq!(
         &config.legacy_sandbox_policy(),
         &SandboxPolicy::WorkspaceWrite {
-            writable_roots: vec![memories_root],
+            writable_roots: vec![],
             network_access: false,
             exclude_tmpdir_env_var: true,
             exclude_slash_tmp: true,
@@ -1816,7 +1809,7 @@ async fn managed_unrestricted_permission_profile_still_enables_network_requireme
 }
 
 #[tokio::test]
-async fn permission_profile_override_applies_runtime_roots_to_legacy_projection()
+async fn permission_profile_override_keeps_memories_root_out_of_legacy_projection()
 -> std::io::Result<()> {
     let codex_home = TempDir::new()?;
     let cwd = TempDir::new()?;
@@ -1851,7 +1844,7 @@ async fn permission_profile_override_applies_runtime_roots_to_legacy_projection(
 
     let memories_root = codex_home.path().join("memories").abs();
     assert!(
-        config
+        !config
             .permissions
             .file_system_sandbox_policy()
             .can_write_path_with_cwd(memories_root.as_path(), cwd.path())
@@ -1859,7 +1852,7 @@ async fn permission_profile_override_applies_runtime_roots_to_legacy_projection(
     assert_eq!(
         &config.legacy_sandbox_policy(),
         &SandboxPolicy::WorkspaceWrite {
-            writable_roots: vec![memories_root],
+            writable_roots: vec![],
             network_access: false,
             exclude_tmpdir_env_var: true,
             exclude_slash_tmp: true,
@@ -2757,9 +2750,6 @@ async fn permissions_profiles_allow_direct_write_roots_outside_workspace_root()
             description: Some("Workspace access.".to_string()),
         }]
     );
-    let memories_root = AbsolutePathBuf::from_absolute_path(std::fs::canonicalize(
-        codex_home.path().join("memories"),
-    )?)?;
     assert!(
         config
             .permissions
@@ -2769,7 +2759,7 @@ async fn permissions_profiles_allow_direct_write_roots_outside_workspace_root()
     assert_eq!(
         &config.legacy_sandbox_policy(),
         &SandboxPolicy::WorkspaceWrite {
-            writable_roots: vec![external_write_path, memories_root],
+            writable_roots: vec![external_write_path],
             network_access: false,
             exclude_tmpdir_env_var: true,
             exclude_slash_tmp: true,
@@ -4514,13 +4504,15 @@ async fn sqlite_home_defaults_to_codex_home_for_workspace_write() -> std::io::Re
 }
 
 #[tokio::test]
-async fn workspace_write_always_includes_memories_root_once() -> std::io::Result<()> {
+async fn workspace_write_includes_configured_writable_root_once_without_memories_root()
+-> std::io::Result<()> {
     let codex_home = TempDir::new()?;
     let memories_root = codex_home.path().join("memories");
+    let writable_root = codex_home.path().join("writable").abs();
     let config = Config::load_from_base_config_with_overrides(
         ConfigToml {
             sandbox_workspace_write: Some(SandboxWorkspaceWrite {
-                writable_roots: vec![memories_root.abs()],
+                writable_roots: vec![writable_root.clone(), writable_root.clone()],
                 ..Default::default()
             }),
             ..Default::default()
@@ -4540,21 +4532,22 @@ async fn workspace_write_always_includes_memories_root_once() -> std::io::Result
         }
     } else {
         assert!(
-            memories_root.is_dir(),
-            "expected memories root directory to exist at {}",
+            !memories_root.exists(),
+            "expected config load not to create memories root at {}",
             memories_root.display()
         );
         let expected_memories_root = memories_root.abs();
         match &config.legacy_sandbox_policy() {
             SandboxPolicy::WorkspaceWrite { writable_roots, .. } => {
+                assert!(!writable_roots.contains(&expected_memories_root));
                 assert_eq!(
                     writable_roots
                         .iter()
-                        .filter(|root| **root == expected_memories_root)
+                        .filter(|root| **root == writable_root)
                         .count(),
                     1,
                     "expected single writable root entry for {}",
-                    expected_memories_root.display()
+                    writable_root.display()
                 );
             }
             other => panic!("expected workspace-write policy, got {other:?}"),
@@ -4564,6 +4557,62 @@ async fn workspace_write_always_includes_memories_root_once() -> std::io::Result
     Ok(())
 }
 
+#[tokio::test]
+async fn memory_tool_makes_memories_root_readable_without_creating_or_widening_writes()
+-> std::io::Result<()> {
+    let codex_home = TempDir::new()?;
+    let cwd = TempDir::new()?;
+    let memories_root = codex_home.path().join("memories");
+    let memories_root_abs = memories_root.abs();
+
+    let config = Config::load_from_base_config_with_overrides(
+        ConfigToml {
+            features: Some(FeaturesToml::from(BTreeMap::from([(
+                "memories".to_string(),
+                true,
+            )]))),
+            sandbox_workspace_write: Some(SandboxWorkspaceWrite {
+                exclude_tmpdir_env_var: true,
+                exclude_slash_tmp: true,
+                ..Default::default()
+            }),
+            ..Default::default()
+        },
+        ConfigOverrides {
+            cwd: Some(cwd.path().to_path_buf()),
+            sandbox_mode: Some(SandboxMode::WorkspaceWrite),
+            ..Default::default()
+        },
+        codex_home.abs(),
+    )
+    .await?;
+
+    assert!(
+        !memories_root.exists(),
+        "expected config load not to create memories root at {}",
+        memories_root.display()
+    );
+    let file_system_policy = config.permissions.file_system_sandbox_policy();
+    assert!(file_system_policy.can_read_path_with_cwd(memories_root_abs.as_path(), cwd.path()));
+    assert!(!file_system_policy.can_write_path_with_cwd(memories_root_abs.as_path(), cwd.path()));
+
+    if cfg!(target_os = "windows") {
+        match &config.legacy_sandbox_policy() {
+            SandboxPolicy::ReadOnly { .. } => {}
+            other => panic!("expected read-only policy on Windows, got {other:?}"),
+        }
+    } else {
+        match &config.legacy_sandbox_policy() {
+            SandboxPolicy::WorkspaceWrite { writable_roots, .. } => {
+                assert!(!writable_roots.contains(&memories_root_abs));
+            }
+            other => panic!("expected workspace-write policy, got {other:?}"),
+        }
+    }
+
+    Ok(())
+}
+
 #[tokio::test]
 async fn config_defaults_to_file_cli_auth_store_mode() -> std::io::Result<()> {
     let codex_home = TempDir::new()?;
diff --git a/codex-rs/core/src/config/mod.rs b/codex-rs/core/src/config/mod.rs
index 3115921c2..618520b7b 100644
--- a/codex-rs/core/src/config/mod.rs
+++ b/codex-rs/core/src/config/mod.rs
@@ -2631,9 +2631,8 @@ impl Config {
             Some(WindowsSandboxModeToml::Unelevated) => WindowsSandboxLevel::RestrictedToken,
             None => WindowsSandboxLevel::from_features(&features),
         };
+        let memories_config: MemoriesConfig = cfg.memories.clone().unwrap_or_default().into();
         let memories_root = memory_root(&codex_home);
-        std::fs::create_dir_all(&memories_root)?;
-        let internal_writable_roots = vec![memories_root];
 
         let profiles_are_active = effective_permission_selection.profiles_are_active(
             default_permissions_override.as_deref(),
@@ -2701,8 +2700,8 @@ impl Config {
             file_system_sandbox_policy,
             mut active_permission_profile,
             mut profile_workspace_roots,
-        ) = if let Some(mut permission_profile) = permission_profile {
-            let (mut file_system_sandbox_policy, network_sandbox_policy) =
+        ) = if let Some(permission_profile) = permission_profile {
+            let (file_system_sandbox_policy, _network_sandbox_policy) =
                 permission_profile.to_runtime_permissions();
             let configured_network_proxy_config =
                 if profile_allows_configured_network_proxy(&permission_profile)
@@ -2726,30 +2725,6 @@ impl Config {
                 } else {
                     NetworkProxyConfig::default()
                 };
-            let materialized_file_system_sandbox_policy = file_system_sandbox_policy
-                .clone()
-                .materialize_project_roots_with_workspace_roots(&workspace_roots);
-            let materialized_permission_profile =
-                PermissionProfile::from_runtime_permissions_with_enforcement(
-                    permission_profile.enforcement(),
-                    &materialized_file_system_sandbox_policy,
-                    network_sandbox_policy,
-                );
-            let sandbox_policy = compatibility_sandbox_policy_for_permission_profile(
-                &materialized_permission_profile,
-                &materialized_file_system_sandbox_policy,
-                network_sandbox_policy,
-                resolved_cwd.as_path(),
-            );
-            if matches!(sandbox_policy, SandboxPolicy::WorkspaceWrite { .. }) {
-                file_system_sandbox_policy = file_system_sandbox_policy
-                    .with_additional_legacy_workspace_writable_roots(&internal_writable_roots);
-                permission_profile = PermissionProfile::from_runtime_permissions_with_enforcement(
-                    permission_profile.enforcement(),
-                    &file_system_sandbox_policy,
-                    network_sandbox_policy,
-                );
-            }
             (
                 configured_network_proxy_config,
                 permission_profile,
@@ -2794,7 +2769,7 @@ impl Config {
             dedupe_absolute_paths(&mut configured_workspace_roots);
             file_system_sandbox_policy = file_system_sandbox_policy
                 .with_materialized_project_roots_for_workspace_roots(&configured_workspace_roots);
-            let mut permission_profile = if let Some(permission_profile) =
+            let permission_profile = if let Some(permission_profile) =
                 builtin_permission_profile(default_permissions, builtin_workspace_write_settings)
             {
                 permission_profile
@@ -2804,30 +2779,6 @@ impl Config {
                     network_sandbox_policy,
                 )
             };
-            let materialized_file_system_sandbox_policy = file_system_sandbox_policy
-                .clone()
-                .materialize_project_roots_with_workspace_roots(&workspace_roots);
-            let materialized_permission_profile =
-                PermissionProfile::from_runtime_permissions_with_enforcement(
-                    permission_profile.enforcement(),
-                    &materialized_file_system_sandbox_policy,
-                    network_sandbox_policy,
-                );
-            let sandbox_policy = compatibility_sandbox_policy_for_permission_profile(
-                &materialized_permission_profile,
-                &materialized_file_system_sandbox_policy,
-                network_sandbox_policy,
-                resolved_cwd.as_path(),
-            );
-            if matches!(sandbox_policy, SandboxPolicy::WorkspaceWrite { .. }) {
-                file_system_sandbox_policy = file_system_sandbox_policy
-                    .with_additional_legacy_workspace_writable_roots(&internal_writable_roots);
-                permission_profile = PermissionProfile::from_runtime_permissions_with_enforcement(
-                    permission_profile.enforcement(),
-                    &file_system_sandbox_policy,
-                    network_sandbox_policy,
-                );
-            }
             let active_permission_profile = if using_implicit_builtin_profile
                 && default_permissions == BUILT_IN_WORKSPACE_PROFILE
                 && cfg.sandbox_workspace_write.is_some()
@@ -2885,29 +2836,8 @@ impl Config {
                 );
                 permission_profile = PermissionProfile::read_only();
             }
-            let (mut file_system_sandbox_policy, network_sandbox_policy) =
+            let (file_system_sandbox_policy, _network_sandbox_policy) =
                 permission_profile.to_runtime_permissions();
-            let materialized_file_system_sandbox_policy = permission_profile
-                .clone()
-                .materialize_project_roots_with_workspace_roots(&workspace_roots)
-                .file_system_sandbox_policy();
-            if matches!(permission_profile.enforcement(), SandboxEnforcement::Managed)
-                && materialized_file_system_sandbox_policy.can_write_path_with_cwd(
-                    resolved_cwd.as_path(),
-                    resolved_cwd.as_path(),
-                )
-                && !materialized_file_system_sandbox_policy.has_full_disk_write_access()
-            {
-                // Keep Codex runtime write access while storing the runtime
-                // workspace roots separately on the thread.
-                file_system_sandbox_policy = file_system_sandbox_policy
-                    .with_additional_legacy_workspace_writable_roots(&internal_writable_roots);
-                permission_profile = PermissionProfile::from_runtime_permissions_with_enforcement(
-                    permission_profile.enforcement(),
-                    &file_system_sandbox_policy,
-                    network_sandbox_policy,
-                );
-            }
             (
                 configured_network_proxy_config,
                 permission_profile,
@@ -3324,11 +3254,14 @@ impl Config {
             network_requirements,
             &network_permission_profile,
         )?;
-        let helper_readable_roots = get_readable_roots_required_for_codex_runtime(
+        let mut helper_readable_roots = get_readable_roots_required_for_codex_runtime(
             &codex_home,
             zsh_path.as_ref(),
             main_execve_wrapper_exe.as_ref(),
         );
+        if features.enabled(Feature::MemoryTool) && memories_config.use_memories {
+            helper_readable_roots.push(memories_root);
+        }
         let effective_permission_profile = constrained_permission_profile.value.get().clone();
         let (mut effective_file_system_sandbox_policy, effective_network_sandbox_policy) =
             effective_permission_profile.to_runtime_permissions();
@@ -3438,7 +3371,7 @@ impl Config {
             agent_max_threads,
             agent_max_depth,
             agent_roles,
-            memories: cfg.memories.unwrap_or_default().into(),
+            memories: memories_config,
             agent_job_max_runtime_seconds,
             agent_interrupt_message_enabled,
             codex_home,
diff --git a/codex-rs/memories/write/src/start.rs b/codex-rs/memories/write/src/start.rs
index 007f5f8bb..809bf775b 100644
--- a/codex-rs/memories/write/src/start.rs
+++ b/codex-rs/memories/write/src/start.rs
@@ -50,6 +50,10 @@ pub fn start_memories_startup_task(
 
     tokio::spawn(async move {
         let root = memory_root(&config.codex_home);
+        if let Err(err) = tokio::fs::create_dir_all(&root).await {
+            warn!("failed creating memories root: {err}");
+            return;
+        }
         if let Err(err) = seed_extension_instructions(&root).await {
             warn!("failed seeding memory extension instructions: {err}");
         }
diff --git a/codex-rs/memories/write/src/startup_tests.rs b/codex-rs/memories/write/src/startup_tests.rs
index 1a735b366..bd0a9904e 100644
--- a/codex-rs/memories/write/src/startup_tests.rs
+++ b/codex-rs/memories/write/src/startup_tests.rs
@@ -26,6 +26,21 @@ use tempfile::TempDir;
 use tokio::time::Duration;
 use tokio::time::Instant;
 
+#[tokio::test]
+async fn memories_startup_creates_memory_root() -> anyhow::Result<()> {
+    let server = start_mock_server().await;
+    let home = Arc::new(TempDir::new()?);
+    let memory_root = home.path().join("memories");
+    let test = build_test_codex(&server, home).await?;
+
+    assert!(!memory_root.exists());
+    trigger_memories_startup(&test).await;
+    wait_for_dir(&memory_root).await?;
+
+    shutdown_test_codex(&test).await?;
+    Ok(())
+}
+
 #[tokio::test]
 async fn memories_startup_phase2_tracks_workspace_diff_across_runs() -> anyhow::Result<()> {
     let server = start_mock_server().await;
@@ -408,6 +423,21 @@ async fn wait_for_file_removed(path: &Path) -> anyhow::Result<()> {
     }
 }
 
+async fn wait_for_dir(path: &Path) -> anyhow::Result<()> {
+    let deadline = Instant::now() + Duration::from_secs(10);
+    loop {
+        if tokio::fs::try_exists(path).await? && path.is_dir() {
+            return Ok(());
+        }
+        assert!(
+            Instant::now() < deadline,
+            "timed out waiting for {} to be created",
+            path.display()
+        );
+        tokio::time::sleep(Duration::from_millis(50)).await;
+    }
+}
+
 async fn wait_for_request(mock: &ResponseMock, expected_count: usize) -> Vec<ResponsesRequest> {
     let deadline = Instant::now() + Duration::from_secs(10);
     loop {