diff --git a/apps/ai-game-creator-shell/src-tauri/src/plugin_host.rs b/apps/ai-game-creator-shell/src-tauri/src/plugin_host.rs
index fcaa5b22d..5c505e70d 100644
--- a/apps/ai-game-creator-shell/src-tauri/src/plugin_host.rs
+++ b/apps/ai-game-creator-shell/src-tauri/src/plugin_host.rs
@@ -7,7 +7,7 @@
 
 use std::collections::{BTreeMap, BTreeSet};
 use std::fs;
-use std::io::{BufRead, BufReader, Write};
+use std::io::{BufRead, BufReader, Read, Write};
 use std::path::{Component, Path, PathBuf};
 use std::process::{Child, ChildStdin, Command, Stdio};
 use std::sync::atomic::{AtomicBool, AtomicU8, Ordering};
@@ -43,6 +43,7 @@ const RPC_TIMEOUT: Duration = Duration::from_secs(10);
 const EDITOR_RPC_TIMEOUT: Duration = Duration::from_secs(90);
 const MAX_MANIFEST_BYTES: u64 = 1024 * 1024;
 const MAX_RPC_BYTES: usize = 2 * 1024 * 1024;
+const MAX_PLUGIN_STDERR_BYTES: usize = 64 * 1024;
 
 const KNOWN_PERMISSIONS: &[&str] = &[
     "events.subscribe",
@@ -163,6 +164,7 @@ struct RunningPlugin {
     lines: Option<Receiver<Result<String, String>>>,
     pending: PendingRpc,
     registrations: Arc<Mutex<PluginRegistrations>>,
+    stderr_summary: Arc<Mutex<String>>,
     next_request_id: u64,
     editor_context: Option<ProjectContext>,
     active: Arc<AtomicBool>,
@@ -578,7 +580,7 @@ fn spawn_plugin(manifest: &PluginManifest, root: &Path) -> Result<RunningPlugin,
         .env("AGC_PLUGIN_API_VERSION", &manifest.api_version)
         .stdin(Stdio::piped())
         .stdout(Stdio::piped())
-        .stderr(Stdio::null());
+        .stderr(Stdio::piped());
     for variable in [
         "PATH",
         "SystemRoot",
@@ -606,6 +608,35 @@ fn spawn_plugin(manifest: &PluginManifest, root: &Path) -> Result<RunningPlugin,
     let mut child = command
         .spawn()
         .map_err(|error| format!("启动插件失败：{error}"))?;
+    let stderr = match child.stderr.take() {
+        Some(stderr) => stderr,
+        None => {
+            let _ = child.kill();
+            let _ = child.wait();
+            return Err("插件 stderr 不可用".to_string());
+        }
+    };
+    let stderr_summary = Arc::new(Mutex::new(String::new()));
+    let stderr_summary_writer = Arc::clone(&stderr_summary);
+    thread::spawn(move || {
+        let mut bytes = Vec::new();
+        let result = stderr
+            .take((MAX_PLUGIN_STDERR_BYTES + 1) as u64)
+            .read_to_end(&mut bytes);
+        let summary = match result {
+            Ok(_) if bytes.len() > MAX_PLUGIN_STDERR_BYTES => {
+                "插件 stderr 超过大小上限".to_string()
+            }
+            Ok(_) => crate::sanitize_diagnostic_message(&String::from_utf8_lossy(&bytes), None)
+                .chars()
+                .take(1200)
+                .collect(),
+            Err(error) => format!("读取插件 stderr 失败：{error}"),
+        };
+        if let Ok(mut stored) = stderr_summary_writer.lock() {
+            *stored = summary;
+        }
+    });
     #[cfg(windows)]
     let job = match crate::process_session::WindowsProcessJob::assign_std(&child) {
         Ok(job) => job,
@@ -651,6 +682,7 @@ fn spawn_plugin(manifest: &PluginManifest, root: &Path) -> Result<RunningPlugin,
         lines: Some(receiver),
         pending: Arc::new(Mutex::new(BTreeMap::new())),
         registrations: Arc::new(Mutex::new(PluginRegistrations::default())),
+        stderr_summary,
         next_request_id: 1,
         editor_context: None,
         active: Arc::new(AtomicBool::new(true)),
@@ -982,9 +1014,27 @@ impl PluginHost {
                             .as_mut()
                             .and_then(|running| match running.child.try_wait() {
                                 Ok(Some(status)) => Some(if let Some(code) = status.code() {
-                                    format!("插件进程已退出：exitCode={code}")
+                                    format!(
+                                        "插件进程已退出：exitCode={code}{}",
+                                        running
+                                            .stderr_summary
+                                            .lock()
+                                            .ok()
+                                            .filter(|summary| !summary.is_empty())
+                                            .map(|summary| format!("；stderr={summary}"))
+                                            .unwrap_or_default()
+                                    )
                                 } else {
-                                    "插件进程已被信号终止".to_string()
+                                    format!(
+                                        "插件进程已被信号终止{}",
+                                        running
+                                            .stderr_summary
+                                            .lock()
+                                            .ok()
+                                            .filter(|summary| !summary.is_empty())
+                                            .map(|summary| format!("；stderr={summary}"))
+                                            .unwrap_or_default()
+                                    )
                                 }),
                                 Ok(None) => None,
                                 Err(error) => Some(format!("读取插件进程状态失败：{error}")),
diff --git a/docs/project-memory/plans/【里程碑】AGC错误具体文本展示-2026-10-04.md b/docs/project-memory/plans/【里程碑】AGC错误具体文本展示-2026-10-04.md
index 7e91b6880..833ecec18 100644
--- a/docs/project-memory/plans/【里程碑】AGC错误具体文本展示-2026-10-04.md
+++ b/docs/project-memory/plans/【里程碑】AGC错误具体文本展示-2026-10-04.md
@@ -100,3 +100,4 @@ DirectProject 回合失败在确认不是客户端内部不可归类故障时，
 - 发布构建预检原先把 `package.json` 元数据/读取/解析错误当成“没有 build”，把 `package-lock.json` 读取/解析错误当成“没有锁定版本”；现分别区分 NotFound 与真实读盘/JSON 错误，保留相对工作区路径和底层正文。
 - 发布尝试账本和工作区偏好文件原先把损坏、权限、类型和 JSON 解析失败当成空账本/默认偏好；现只有文件不存在才使用默认，其他读取错误沿发布幂等和建项目录命令返回具体正文。
 - 插件主机扫描工作区、读取进程状态、停止插件和禁用插件时原先吞掉目录项/`try_wait`/kill/wait 错误；现保留插件状态错误并阻止“停止失败却显示已禁用”，正常主动 kill 的非零退出码不再误报。
+- 插件进程 stderr 原先使用 `Stdio::null()`，即使进程退出也只能显示退出码；现以有界脱敏 sidecar 保留插件 stderr，并在退出状态中附带正文。