src-tauri/src/commands/blueprint.rs

@@ -1323,6 +1323,15 @@ pub(crate) fn sync_blueprint_rules_with(
     root: &Path,
     sink: &dyn crate::WriteSink,
 ) -> Result<SyncResult, crate::WriteFailure> {
+    if crate::mcp_inject::files_managed_by_next(root) {
+        return Ok(SyncResult {
+            success: true,
+            conventions_written: false,
+            claude_md_action: "skipped".into(),
+            agents_md_action: "skipped".into(),
+            message: crate::mcp_inject::FILES_MANAGED_BY_NEXT_SKIP.into(),
+        });
+    }
     let bp_dir = root.join(".blueprint");
     let project_name = root
         .file_name()
@@ -2876,6 +2885,22 @@ pub fn archive_project_docs(project_path: String) -> Result<ArchiveResult, Strin
 #[cfg(test)]
 mod tests {
     use super::*;
+
+    // 共存期防回写：项目文件已由新炼境接管时，蓝图规则同步零写入
+    #[test]
+    fn sync_skips_projects_managed_by_next() {
+        let base = std::env::temp_dir().join(format!("lianjing_sync_guard_test_{}", std::process::id()));
+        let _ = std::fs::remove_dir_all(&base);
+        std::fs::create_dir_all(base.join(".lian-jing")).unwrap();
+        std::fs::create_dir_all(base.join(".blueprint")).unwrap();
+        std::fs::write(base.join(".lian-jing/context.json"), r#"{"project_id":"p1","files_managed_by":"lian-jing-next"}"#).unwrap();
+        let result = sync_blueprint_rules_with(&base, &crate::DiskSink).unwrap();
+        assert_eq!((result.agents_md_action.as_str(), result.claude_md_action.as_str()), ("skipped", "skipped"));
+        assert!(!result.conventions_written);
+        assert!(!base.join(".blueprint/CONVENTIONS.md").exists());
+        assert!(!base.join("AGENTS.md").exists() && !base.join("CLAUDE.md").exists());
+        let _ = std::fs::remove_dir_all(&base);
+    }
     use rusqlite::Connection;
     use std::fs;
 

src-tauri/src/commands/buff.rs

@@ -125,6 +125,10 @@ fn poll_all_buffs(app: &AppHandle) {
 
 fn check_project(app: &AppHandle, project_path: &str) -> Result<(), String> {
     let root = Path::new(project_path);
+    // 共存期防回写：项目文件已由新炼境接管，不再改写其任务卡
+    if crate::mcp_inject::files_managed_by_next(root) {
+        return Ok(());
+    }
 
     // 获取当前 HEAD commit
     let current_commit = match get_head_commit(root) {

src-tauri/src/commands/onboarding.rs

@@ -199,6 +199,14 @@ pub(crate) fn dispatch_templates_with(
     root: &Path,
     sink: &dyn crate::WriteSink,
 ) -> Vec<TemplateResult> {
+    if crate::mcp_inject::files_managed_by_next(root) {
+        return vec![TemplateResult {
+            name: ".lian-jing/context.json".into(),
+            action: "skipped".into(),
+            detail: crate::mcp_inject::FILES_MANAGED_BY_NEXT_SKIP.into(),
+            warning: None,
+        }];
+    }
     vec![
         dispatch_versioned(root, "AGENTS.md", TMPL_AGENTS, sink),
         dispatch_one(root, "lefthook.yml", TMPL_LEFTHOOK, sink),
@@ -1243,6 +1251,21 @@ pub fn silent_projects(conn: &rusqlite::Connection) -> Result<Vec<(String, i64)>
 
 #[cfg(test)]
 mod tests {
+    // 共存期防回写：项目文件已由新炼境接管时，接入包模板分发零写入
+    #[test]
+    fn dispatch_skips_projects_managed_by_next() {
+        let base = std::env::temp_dir().join(format!("lianjing_dispatch_guard_test_{}", std::process::id()));
+        let _ = std::fs::remove_dir_all(&base);
+        std::fs::create_dir_all(base.join(".lian-jing")).unwrap();
+        std::fs::create_dir_all(base.join(".blueprint")).unwrap();
+        std::fs::write(base.join(".lian-jing/context.json"), r#"{"project_id":"p1","files_managed_by":"lian-jing-next"}"#).unwrap();
+        let results = super::dispatch_templates(base.to_str().unwrap());
+        assert_eq!(results.len(), 1);
+        assert_eq!(results[0].action, "skipped");
+        assert!(!base.join("AGENTS.md").exists() && !base.join(".claude").exists() && !base.join("lefthook.yml").exists());
+        let _ = std::fs::remove_dir_all(&base);
+    }
+
     use super::*;
 
     #[test]

src-tauri/src/mcp_inject.rs

@@ -235,6 +235,20 @@ fn write_json_with(
         .map_err(|error| format!("写入 {label} 失败: {error}"))
 }
 
+/// 新炼境（lian-jing-next）接管项目文件后写入 `.lian-jing/context.json` 的 `files_managed_by` 取值。
+pub(crate) const FILES_MANAGED_BY_NEXT: &str = "lian-jing-next";
+
+/// 共存期防回写守卫：项目文件已由新炼境接管时，旧炼境的模板分发、蓝图规则同步与 buff 轮询一律跳过，
+/// 避免两边来回覆盖同一批托管文件。只读判断，文件缺失或不合法时视为未接管。
+pub(crate) fn files_managed_by_next(root: &std::path::Path) -> bool {
+    std::fs::read_to_string(root.join(".lian-jing").join("context.json"))
+        .ok()
+        .and_then(|text| serde_json::from_str::<Value>(&text).ok())
+        .is_some_and(|ctx| ctx.get("files_managed_by").and_then(Value::as_str) == Some(FILES_MANAGED_BY_NEXT))
+}
+
+pub(crate) const FILES_MANAGED_BY_NEXT_SKIP: &str = "项目文件已由新炼境接管（.lian-jing/context.json 的 files_managed_by），旧炼境不再分发";
+
 /// 写工具无关的项目身份锚点。项目根目录是边界，客户端项目 UI 或用户级配置均不是身份来源。
 /// 合并写入：保留未来字段与项目定制字段，只有炼境拥有的身份字段会被刷新。
 #[cfg(test)]
@@ -3623,6 +3637,26 @@ trust_level = "trusted"
         );
     }
 
+    #[test]
+    fn files_managed_by_next_guard_reads_context_and_survives_identity_rewrite() {
+        let base = std::env::temp_dir().join(format!("lianjing_files_guard_test_{}", std::process::id()));
+        let _ = std::fs::remove_dir_all(&base);
+        std::fs::create_dir_all(base.join(".lian-jing")).unwrap();
+        assert!(!files_managed_by_next(&base), "没有 context.json 视为未接管");
+        std::fs::write(
+            base.join(".lian-jing/context.json"),
+            r#"{"project_id":"p1","schema_version":1,"files_managed_by":"lian-jing-next"}"#,
+        )
+        .unwrap();
+        assert!(files_managed_by_next(&base));
+        // 旧炼境刷新身份时必须保留接管标记，否则守卫会被自己抹掉
+        write_canonical_context_at(&base, "p1").unwrap();
+        assert!(files_managed_by_next(&base), "身份合并写后接管标记仍在");
+        std::fs::write(base.join(".lian-jing/context.json"), r#"{"project_id":"p1","files_managed_by":"other"}"#).unwrap();
+        assert!(!files_managed_by_next(&base));
+        let _ = std::fs::remove_dir_all(&base);
+    }
+
     #[test]
     fn canonical_context_migrates_legacy_project_id_and_preserves_unknown_fields() {
         let base = std::env::temp_dir().join(format!(