diff --git a/apps/ai-game-creator-shell/src-tauri/src/agent/runtime_driver/task_start.rs b/apps/ai-game-creator-shell/src-tauri/src/agent/runtime_driver/task_start.rs
index 9db5f7eac..3ff8e559a 100644
--- a/apps/ai-game-creator-shell/src-tauri/src/agent/runtime_driver/task_start.rs
+++ b/apps/ai-game-creator-shell/src-tauri/src/agent/runtime_driver/task_start.rs
@@ -519,7 +519,7 @@ fn start_game_creator_agent_background_task_with_link_in_session_lane_with_proje
             let error = redact_agent_runtime_project_paths(root, &error, 500);
             let failed_task = AgentRuntimeTaskRecord {
                 status: "failed".to_string(),
-                phase: "planning-session-projection-failed".to_string(),
+                phase: AGENT_RUNTIME_TASK_PHASE_PLANNING_SESSION_PROJECTION_FAILED.to_string(),
                 current_action: "Fast GDD session 未能安全绑定，后台任务未执行".to_string(),
                 terminal_detail: Some(error.clone()),
                 error: Some(error.clone()),
diff --git a/apps/ai-game-creator-shell/src-tauri/src/agent/runtime_state.rs b/apps/ai-game-creator-shell/src-tauri/src/agent/runtime_state.rs
index 2eaccbcbd..f0b760e52 100644
--- a/apps/ai-game-creator-shell/src-tauri/src/agent/runtime_state.rs
+++ b/apps/ai-game-creator-shell/src-tauri/src/agent/runtime_state.rs
@@ -4,6 +4,12 @@ static AGENT_RUNTIME_EVENT_ID_SEQUENCE: std::sync::atomic::AtomicU64 =
     std::sync::atomic::AtomicU64::new(1);
 
 pub(crate) const AGENT_RUNTIME_PUBLIC_STATUS_MESSAGE_ID_PREFIX: &str = "runtime-public-status-";
+/// task journal 只在**读**的时候校验 phase 白名单，写侧不校验。所以一个没登记的
+/// phase 落盘之后，整份 journal 从那一行起再也读不出来：`agent.run_status` 对该
+/// Agent 永久失败，父 run 只能瞎转到 needs-reconciliation。实测就是这么炸的。
+/// 让写方和白名单引用同一个常量，两边不可能再漂移。
+pub(crate) const AGENT_RUNTIME_TASK_PHASE_PLANNING_SESSION_PROJECTION_FAILED: &str =
+    "planning-session-projection-failed";
 
 fn game_creator_agent_runtime_public_status_message_id(
     agent_id: &str,
@@ -4089,6 +4095,7 @@ fn validate_game_creator_agent_runtime_task_status_phase(
             | "completion-contract-failed"
             | "conversation-write-failed"
             | "public-status-write-failed"
+            | AGENT_RUNTIME_TASK_PHASE_PLANNING_SESSION_PROJECTION_FAILED
             | "parent-terminal"
             | "parent-link-missing"
     ) {
diff --git a/apps/ai-game-creator-shell/src-tauri/src/tests/runtime_state.rs b/apps/ai-game-creator-shell/src-tauri/src/tests/runtime_state.rs
index 1e3b140d1..b77477437 100644
--- a/apps/ai-game-creator-shell/src-tauri/src/tests/runtime_state.rs
+++ b/apps/ai-game-creator-shell/src-tauri/src/tests/runtime_state.rs
@@ -235,19 +235,33 @@ fn runtime_task_reader_accepts_rare_persisted_phases() {
         "failed",
         "public-status-write-failed",
     );
+    // 写侧不校验 phase，只有读侧校验：白名单漏登记一个 phase，落盘之后整份 journal
+    // 从那一行起再也读不出来，`agent.run_status` 对该 Agent 永久失败。这里用写方
+    // 引用的同一个常量，漏登记会在这条用例上先红。
+    let planning_session_projection_failed = runtime_task_json_line(
+        "planning-session-projection-failed-run",
+        "failed",
+        AGENT_RUNTIME_TASK_PHASE_PLANNING_SESSION_PROJECTION_FAILED,
+    );
     fs::write(
         &path,
-        format!("{brief}\n{parent_link_missing}\n{public_status_write_failed}\n"),
+        format!(
+            "{brief}\n{parent_link_missing}\n{public_status_write_failed}\n{planning_session_projection_failed}\n"
+        ),
     )
     .expect("write rare persisted task phases");
 
     let records = read_all_game_creator_agent_runtime_tasks(&path)
         .expect("known persisted task phases must remain readable");
 
-    assert_eq!(records.len(), 3);
+    assert_eq!(records.len(), 4);
     assert_eq!(records[0].phase, "brief");
     assert_eq!(records[1].phase, "parent-link-missing");
     assert_eq!(records[2].phase, "public-status-write-failed");
+    assert_eq!(
+        records[3].phase,
+        AGENT_RUNTIME_TASK_PHASE_PLANNING_SESSION_PROJECTION_FAILED
+    );
     fs::remove_dir_all(root).ok();
 }