diff --git a/MODULE.bazel.lock b/MODULE.bazel.lock
index f541a2c7bf..4c0387e378 100644
--- a/MODULE.bazel.lock
+++ b/MODULE.bazel.lock
@@ -45,6 +45,7 @@
     "https://bcr.bazel.build/modules/bazel_features/1.34.0/MODULE.bazel": "e8475ad7c8965542e0c7aac8af68eb48c4af904be3d614b6aa6274c092c2ea1e",
     "https://bcr.bazel.build/modules/bazel_features/1.4.1/MODULE.bazel": "e45b6bb2350aff3e442ae1111c555e27eac1d915e77775f6fdc4b351b758b5d7",
     "https://bcr.bazel.build/modules/bazel_features/1.42.0/MODULE.bazel": "e8ca15cb2639c5f12183db6dcb678735555d0cdd739b32a0418b6532b5e565f8",
+    "https://bcr.bazel.build/modules/bazel_features/1.42.1/MODULE.bazel": "275a59b5406ff18c01739860aa70ad7ccb3cfb474579411decca11c93b951080",
     "https://bcr.bazel.build/modules/bazel_features/1.45.0/MODULE.bazel": "7daec6d87ab0703417486d4cb948af0b06f55d4d7c08cbb5978c80e79b538edf",
     "https://bcr.bazel.build/modules/bazel_features/1.45.0/source.json": "635e4536e09ff125b8972e0fa239c135fde5f18701f7d5115680560651dfb41d",
     "https://bcr.bazel.build/modules/bazel_features/1.9.0/MODULE.bazel": "885151d58d90d8d9c811eb75e3288c11f850e1d6b481a8c9f766adee4712358b",
@@ -67,8 +68,8 @@
     "https://bcr.bazel.build/modules/bazel_skylib/1.8.2/MODULE.bazel": "69ad6927098316848b34a9142bcc975e018ba27f08c4ff403f50c1b6e646ca67",
     "https://bcr.bazel.build/modules/bazel_skylib/1.9.0/MODULE.bazel": "72997b29dfd95c3fa0d0c48322d05590418edef451f8db8db5509c57875fb4b7",
     "https://bcr.bazel.build/modules/bazel_skylib/1.9.0/source.json": "7ad77c1e8c1b84222d9b3f3cae016a76639435744c19330b0b37c0a3c9da7dc0",
-    "https://bcr.bazel.build/modules/buildozer/8.2.1/MODULE.bazel": "61e9433c574c2bd9519cad7fa66b9c1d2b8e8d5f3ae5d6528a2c2d26e68d874d",
-    "https://bcr.bazel.build/modules/buildozer/8.2.1/source.json": "7c33f6a26ee0216f85544b4bca5e9044579e0219b6898dd653f5fb449cf2e484",
+    "https://bcr.bazel.build/modules/buildozer/8.5.1/MODULE.bazel": "a35d9561b3fc5b18797c330793e99e3b834a473d5fbd3d7d7634aafc9bdb6f8f",
+    "https://bcr.bazel.build/modules/buildozer/8.5.1/source.json": "e3386e6ff4529f2442800dee47ad28d3e6487f36a1f75ae39ae56c70f0cd2fbd",
     "https://bcr.bazel.build/modules/bzip2/1.0.8.bcr.3/MODULE.bazel": "29ecf4babfd3c762be00d7573c288c083672ab60e79c833ff7f49ee662e54471",
     "https://bcr.bazel.build/modules/bzip2/1.0.8.bcr.3/source.json": "8be4a3ef2599693f759e5c0990a4cc5a246ac08db4c900a38f852ba25b5c39be",
     "https://bcr.bazel.build/modules/gawk/5.3.2.bcr.3/MODULE.bazel": "f1b7bb2dd53e8f2ef984b39485ec8a44e9076dda5c4b8efd2fb4c6a6e856a31d",
@@ -141,9 +142,9 @@
     "https://bcr.bazel.build/modules/rules_cc/0.1.5/MODULE.bazel": "88dfc9361e8b5ae1008ac38f7cdfd45ad738e4fa676a3ad67d19204f045a1fd8",
     "https://bcr.bazel.build/modules/rules_cc/0.2.0/MODULE.bazel": "b5c17f90458caae90d2ccd114c81970062946f49f355610ed89bebf954f5783c",
     "https://bcr.bazel.build/modules/rules_cc/0.2.13/MODULE.bazel": "eecdd666eda6be16a8d9dc15e44b5c75133405e820f620a234acc4b1fdc5aa37",
-    "https://bcr.bazel.build/modules/rules_cc/0.2.14/MODULE.bazel": "353c99ed148887ee89c54a17d4100ae7e7e436593d104b668476019023b58df8",
     "https://bcr.bazel.build/modules/rules_cc/0.2.16/MODULE.bazel": "9242fa89f950c6ef7702801ab53922e99c69b02310c39fb6e62b2bd30df2a1d4",
-    "https://bcr.bazel.build/modules/rules_cc/0.2.16/source.json": "d03d5cde49376d87e14ec14b666c56075e5e3926930327fd5d0484a1ff2ac1cc",
+    "https://bcr.bazel.build/modules/rules_cc/0.2.17/MODULE.bazel": "1849602c86cb60da8613d2de887f9566a6d354a6df6d7009f9d04a14402f9a84",
+    "https://bcr.bazel.build/modules/rules_cc/0.2.17/source.json": "3832f45d145354049137c0090df04629d9c2b5493dc5c2bf46f1834040133a07",
     "https://bcr.bazel.build/modules/rules_cc/0.2.4/MODULE.bazel": "1ff1223dfd24f3ecf8f028446d4a27608aa43c3f41e346d22838a4223980b8cc",
     "https://bcr.bazel.build/modules/rules_cc/0.2.8/MODULE.bazel": "f1df20f0bf22c28192a794f29b501ee2018fa37a3862a1a2132ae2940a23a642",
     "https://bcr.bazel.build/modules/rules_foreign_cc/0.9.0/MODULE.bazel": "c9e8c682bf75b0e7c704166d79b599f93b72cfca5ad7477df596947891feeef6",
@@ -159,8 +160,8 @@
     "https://bcr.bazel.build/modules/rules_java/8.5.1/MODULE.bazel": "d8a9e38cc5228881f7055a6079f6f7821a073df3744d441978e7a43e20226939",
     "https://bcr.bazel.build/modules/rules_java/8.6.0/MODULE.bazel": "9c064c434606d75a086f15ade5edb514308cccd1544c2b2a89bbac4310e41c71",
     "https://bcr.bazel.build/modules/rules_java/8.6.1/MODULE.bazel": "f4808e2ab5b0197f094cabce9f4b006a27766beb6a9975931da07099560ca9c2",
-    "https://bcr.bazel.build/modules/rules_java/9.0.3/MODULE.bazel": "1f98ed015f7e744a745e0df6e898a7c5e83562d6b759dfd475c76456dda5ccea",
-    "https://bcr.bazel.build/modules/rules_java/9.0.3/source.json": "b038c0c07e12e658135bbc32cc1a2ded6e33785105c9d41958014c592de4593e",
+    "https://bcr.bazel.build/modules/rules_java/9.1.0/MODULE.bazel": "ee63f27e36a3fada80342869361182f120a9819c74320e8e65b1e04ba0cd7a9d",
+    "https://bcr.bazel.build/modules/rules_java/9.1.0/source.json": "da589573c1dee2c9ac4a568b301269a2e8191110ff0345c1a959fa7ea6c4dfd6",
     "https://bcr.bazel.build/modules/rules_jvm_external/4.4.2/MODULE.bazel": "a56b85e418c83eb1839819f0b515c431010160383306d13ec21959ac412d2fe7",
     "https://bcr.bazel.build/modules/rules_jvm_external/5.1/MODULE.bazel": "33f6f999e03183f7d088c9be518a63467dfd0be94a11d0055fe2d210f89aa909",
     "https://bcr.bazel.build/modules/rules_jvm_external/5.2/MODULE.bazel": "d9351ba35217ad0de03816ef3ed63f89d411349353077348a45348b096615036",
@@ -318,7 +319,7 @@
     },
     "@@pybind11_bazel+//:internal_configure.bzl%internal_configure_extension": {
       "general": {
-        "bzlTransitiveDigest": "06cynZ1bCvvy8zHPrrDlXq+Z68xmjctHpfFxi+zEpJY=",
+        "bzlTransitiveDigest": "b+RP7Sgl8KN0VHamrgTqzGLuYPcQ/Mo4ptNkkHUIIlA=",
         "usagesDigest": "D1r3lfzMuUBFxgG8V6o0bQTLMk3GkaGOaPzw53wrwyw=",
         "recordedInputs": [
           "REPO_MAPPING:pybind11_bazel+,bazel_tools bazel_tools",
@@ -340,7 +341,7 @@
     },
     "@@rules_kotlin+//src/main/starlark/core/repositories:bzlmod_setup.bzl%rules_kotlin_extensions": {
       "general": {
-        "bzlTransitiveDigest": "ABI1D/sbS1ovwaW/kHDoj8nnXjQ0oKU9fzmzEG4iT8o=",
+        "bzlTransitiveDigest": "Ga4z8lQy1YQ5rAMy+dOl0dqcCEBnYNCXku8x3YQmDZI=",
         "usagesDigest": "QI2z8ZUR+mqtbwsf2fLqYdJAkPOHdOV+tF2yVAUgRzw=",
         "recordedInputs": [
           "REPO_MAPPING:rules_kotlin+,bazel_tools bazel_tools"
@@ -397,7 +398,7 @@
     },
     "@@rules_python+//python/extensions:config.bzl%config": {
       "general": {
-        "bzlTransitiveDigest": "2hLgIvNVTLgxus0ZuXtleBe70intCfo0cHs8qvt6cdM=",
+        "bzlTransitiveDigest": "iibnRYgg8LpcfmH7EAnVwYePC3jsVaJ6Id8XxUjSZps=",
         "usagesDigest": "ZVSXMAGpD+xzVNPuvF1IoLBkty7TROO0+akMapt1pAg=",
         "recordedInputs": [
           "REPO_MAPPING:rules_python+,bazel_tools bazel_tools",
diff --git a/codex-rs/Cargo.lock b/codex-rs/Cargo.lock
index b899222384..411d191950 100644
--- a/codex-rs/Cargo.lock
+++ b/codex-rs/Cargo.lock
@@ -1916,6 +1916,7 @@ dependencies = [
  "codex-cloud-config",
  "codex-config",
  "codex-core",
+ "codex-core-api",
  "codex-core-plugins",
  "codex-exec-server",
  "codex-extension-api",
diff --git a/codex-rs/app-server/Cargo.toml b/codex-rs/app-server/Cargo.toml
index 37cdf219bf..fbbf92a5b2 100644
--- a/codex-rs/app-server/Cargo.toml
+++ b/codex-rs/app-server/Cargo.toml
@@ -35,6 +35,7 @@ codex-arg0 = { workspace = true }
 codex-cloud-config = { workspace = true }
 codex-config = { workspace = true }
 codex-core = { workspace = true }
+codex-core-api = { workspace = true }
 codex-core-plugins = { workspace = true }
 codex-exec-server = { workspace = true }
 codex-extension-api = { workspace = true }
diff --git a/codex-rs/app-server/src/request_processors/user_instructions.rs b/codex-rs/app-server/src/request_processors/user_instructions.rs
index ae9a4dce3c..8ef5492d38 100644
--- a/codex-rs/app-server/src/request_processors/user_instructions.rs
+++ b/codex-rs/app-server/src/request_processors/user_instructions.rs
@@ -1,7 +1,6 @@
-use codex_core::AgentsMdManager;
 use codex_core::ThreadManager;
 use codex_core::config::Config;
-use codex_protocol::error::CodexErr;
+use codex_core_api::load_thread_user_instructions as preload_thread_user_instructions;
 use codex_protocol::error::Result as CodexResult;
 use codex_protocol::protocol::TurnEnvironmentSelection;
 
@@ -12,24 +11,10 @@ pub(super) async fn load_thread_user_instructions(
     config: &mut Config,
     environments: &[TurnEnvironmentSelection],
 ) -> CodexResult<()> {
-    let Some(primary_selection) = environments.first() else {
-        config.user_instructions = None;
-        return Ok(());
-    };
-    let environment = thread_manager
-        .environment_manager()
-        .get_environment(&primary_selection.environment_id)
-        .ok_or_else(|| {
-            CodexErr::InvalidRequest(format!(
-                "unknown turn environment id `{}`",
-                primary_selection.environment_id
-            ))
-        })?;
-    let mut warnings = Vec::new();
-    let user_instructions = AgentsMdManager::new(config)
-        .load_user_instructions(environment.as_ref(), &mut warnings)
-        .await;
-    config.startup_warnings.extend(warnings);
-    config.user_instructions = user_instructions;
-    Ok(())
+    preload_thread_user_instructions(
+        config,
+        thread_manager.environment_manager().as_ref(),
+        environments,
+    )
+    .await
 }