diff --git a/apps/ai-game-creator-shell/src-tauri/src/agent/codex_app_server/execution.rs b/apps/ai-game-creator-shell/src-tauri/src/agent/codex_app_server/execution.rs
index 29806b1c9..cd6b98452 100644
--- a/apps/ai-game-creator-shell/src-tauri/src/agent/codex_app_server/execution.rs
+++ b/apps/ai-game-creator-shell/src-tauri/src/agent/codex_app_server/execution.rs
@@ -291,6 +291,26 @@ fn accepted(id: u64, method: &str) -> Value {
     }
 }
 
+/// app-server 交互回包未能送达的原因。
+///
+/// 两种失败共用同一条收束路径，但来源不同：写失败是 Codex 根本没收到 decision，回合绑定不一致
+/// 是回包已经产出、宿主无法确认执行作用域。留痕必须写真实原因，不能按函数名反推。
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub(super) enum ResponseDeliveryFailure {
+    /// stdin 写入 / flush 失败。
+    Write,
+    /// `bind_turn` 返回 false：回合绑定不一致。
+    TurnBindMismatch,
+}
+impl ResponseDeliveryFailure {
+    fn as_str(self) -> &'static str {
+        match self {
+            Self::Write => "response-write-failed",
+            Self::TurnBindMismatch => "turn-bind-mismatch",
+        }
+    }
+}
+
 impl ExecutionAdapter {
     pub(super) async fn for_turn(
         root: &Path,
@@ -789,15 +809,16 @@ impl ExecutionAdapter {
         .await;
     }
 
-    pub(super) fn response_write_failed(self: &Arc<Self>) {
-        // 回包写不出去时 Codex 侧等不到 decision，表现为「审批没有回应」；与主动 decline 分开留痕。
+    pub(super) fn response_delivery_failed(self: &Arc<Self>, cause: ResponseDeliveryFailure) {
+        // 回包没送达 Codex 时线上表现为「审批没有回应」；与主动 decline 分开留痕。
         // 同一回合内同一原因只留一行：这一步可能被重复触发。
         self.log_once(
-            "host-interaction\u{1}response-write-failed".to_string(),
+            format!("host-interaction\u{1}response-delivery:{}", cause.as_str()),
             |_| {
                 format!(
-                    "agent.direct_codex.approval.response_write_failed thread_id={}",
-                    self.thread_id
+                    "agent.direct_codex.approval.response_delivery_failed thread_id={} cause={}",
+                    self.thread_id,
+                    cause.as_str()
                 )
             },
         );
diff --git a/apps/ai-game-creator-shell/src-tauri/src/agent/codex_app_server/mod.rs b/apps/ai-game-creator-shell/src-tauri/src/agent/codex_app_server/mod.rs
index 3c00d1410..a9b0a3560 100644
--- a/apps/ai-game-creator-shell/src-tauri/src/agent/codex_app_server/mod.rs
+++ b/apps/ai-game-creator-shell/src-tauri/src/agent/codex_app_server/mod.rs
@@ -18,7 +18,7 @@ mod execution;
 mod model_catalog;
 pub(crate) use direct_project_identity::thread_id_for_project;
 use direct_project_identity::*;
-use execution::ExecutionAdapter;
+use execution::{ExecutionAdapter, ResponseDeliveryFailure};
 
 const GAME_CREATOR_CODEX_APP_SERVER_PROVIDER_ID: &str = "genarrative_agc";
 const GAME_CREATOR_CODEX_APP_SERVER_API_KEY_ENV: &str = "GENARRATIVE_AGC_CODEX_API_KEY";
@@ -4884,7 +4884,7 @@ async fn read_game_creator_codex_app_server_stdout(
                     };
                     if !sent {
                         if let Some(adapter) = adapter {
-                            adapter.response_write_failed();
+                            adapter.response_delivery_failed(ResponseDeliveryFailure::Write);
                         }
                     }
                 });
@@ -4916,7 +4916,9 @@ async fn read_game_creator_codex_app_server_stdout(
                         let adapter = inner.execution.lock().ok().and_then(|slot| slot.clone());
                         if let Some(adapter) = adapter {
                             if !adapter.bind_turn(turn_id) {
-                                adapter.response_write_failed();
+                                adapter.response_delivery_failed(
+                                    ResponseDeliveryFailure::TurnBindMismatch,
+                                );
                             }
                         }
                     }
diff --git a/docs/project-memory/shared-memory/decision-log.md b/docs/project-memory/shared-memory/decision-log.md
index d9c28492e..a00fa21cc 100644
--- a/docs/project-memory/shared-memory/decision-log.md
+++ b/docs/project-memory/shared-memory/decision-log.md
@@ -2,7 +2,7 @@
 
 ## 2026-10-01 DirectProject 审批拒绝原因留痕
 
-- 决策：宿主拒绝 app-server 的审批 / 交互请求时，原因必须落 AppData `RUST` 日志。稳定键 `agent.direct_codex.approval.denied`，字段为 `thread_id` / `method` / `reason` / `distinct_reasons`；未绑定宿主执行器时另记 `agent.direct_codex.interaction.no_adapter`（`method` / `outcome`，`outcome` 区分 `decline` / `empty-permissions` / `unsupported-method`），回包未送达另记 `agent.direct_codex.approval.response_write_failed`。
+- 决策：宿主拒绝 app-server 的审批 / 交互请求时，原因必须落 AppData `RUST` 日志。稳定键 `agent.direct_codex.approval.denied`，字段为 `thread_id` / `method` / `reason` / `distinct_reasons`；未绑定宿主执行器时另记 `agent.direct_codex.interaction.no_adapter`（`method` / `outcome`，`outcome` 区分 `decline` / `empty-permissions` / `unsupported-method`）；回包未送达另记 `agent.direct_codex.approval.response_delivery_failed`，`cause` 区分 `response-write-failed` 与 `turn-bind-mismatch`。
 - 原因：线上对审批只回 `{"decision":"decline"}`，模型与用户都看不到是哪一道闸门（合同缺失 / 预算耗尽 / 阶段已收束 / item 不在途 / 无适配器）拦下的，只能靠复现。
 - 边界：`reason` 只接受 `execution.rs` 内的静态分类或宿主自己的错误文本，不带请求参数、上游正文、路径或凭据；有界去重一律按 `MAX_DENIED_REASON_LOGS = 64` 条封顶——适配器路径按回合内 `(method, reason)`、未绑定执行器路径按进程级 `(method, outcome)`、回包未送达按回合内原因各只记一次。
 - 影响范围：`apps/ai-game-creator-shell/src-tauri/src/agent/codex_app_server/execution.rs`。