diff --git a/docs/architecture.md b/docs/architecture.md
index 4a09cdc..0255e68 100644
--- a/docs/architecture.md
+++ b/docs/architecture.md
@@ -71,7 +71,7 @@ AnyBot 是一個 Rust 程式（`anybot`），用 egui/eframe 畫介面。同一
 ## 安全
 
 - **核准關卡**：工具動作照規則直接做、先問或拒絕（`policy.rs`，FEATURES.md 第 16、19 節）。「直接操作模式」可以跳過詢問。
-- **指令的沙盒（macOS）**：Bot 執行的指令在 `sandbox-exec` 裡跑，讀不到也寫不到 AnyBot 的資料資料夾和 `.ssh`、`.gnupg`、鑰匙圈、`.aws` 等；只有 `attachments/` 可以讀（不能寫）。環境變數裡的模型金鑰會先拿掉。
+- **指令的沙盒（macOS）**：Bot 執行的指令在 `sandbox-exec` 裡跑，讀不到也寫不到 AnyBot 的資料資料夾、`.gnupg`、鑰匙圈、`.aws` 等；只有 `attachments/` 和 `.ssh` 可以讀（都不能寫，`.ssh` 可讀讓 git 和 ssh 連得動）。只有沙盒管得到的才是祕密防線，核准層不再逐字掃路徑。環境變數裡的模型金鑰會先拿掉，PATH 會補齊 Homebrew 等位置（從 Finder 或 launchd 啟動也要找得到指令）。
 - **Bot 的電腦**：放在容器裡，和你的電腦分開。
 - **保險庫**：密碼、卡號、CVC 不會交給模型，由 AnyBot 直接填進網頁。
 - **多台電腦**：金鑰只留在大腦（下面說明）；手腳只接受帳號裡的 AnyBot，用配對碼加入的只接受那一個大腦。
@@ -115,7 +115,7 @@ AnyBot 是一個 Rust 程式（`anybot`），用 egui/eframe 畫介面。同一
 
 ### 手腳
 
-大腦的 Bot 呼叫工具時可以指定 `computer`。如果是帳號裡的另一台，就透過長連線送 `/api/device/run` 給它，由它在自己身上執行（螢幕、檔案、指令、它的 AnyBot 瀏覽器），再把文字和截圖傳回來。那台要開「裝置連結」才接受；若設了只給某個大腦用（`hands_for`），帳號伺服器會附上是哪一台在問，不是那台就拒絕。
+大腦的 Bot 呼叫工具時可以指定 `computer`。如果是帳號裡的另一台，就透過長連線送 `/api/device/run` 給它，由它在自己身上執行（螢幕、檔案、指令、它的 AnyBot 瀏覽器），再把文字和截圖傳回來。那台要開「裝置連結」才接受；若設了只給某個大腦用（`hands_for`），帳號伺服器會附上是哪一台在問，不是那台就拒絕。指令在那台的工作資料夾（Bot 的 `workdir`）跑；連線經過帳號伺服器只有 35 秒，所以手腳上的指令超過 25 秒就移到背景，用同一台的 `read_terminal` 追蹤（computer 填那台）。
 
 ### 配對碼
 
diff --git a/src/agent.rs b/src/agent.rs
index 06b7572..122d8b5 100644
--- a/src/agent.rs
+++ b/src/agent.rs
@@ -131,7 +131,7 @@ fn browser_place(job: &Job, name: &str, args: &str) -> (BrowserAt, String) {
     let want = v.get("computer").and_then(|c| c.as_str()).map(str::trim).filter(|c| !c.is_empty()).unwrap_or(&job.default_computer).to_string();
     let at = |t: &tools::Target| -> Option<BrowserAt> {
         match &t.place {
-            tools::Place::Device { host } => Some(BrowserAt::Device(host.clone())),
+            tools::Place::Device { host, .. } => Some(BrowserAt::Device(host.clone())),
             tools::Place::Box { .. } if crate::cloudbox::available() => Some(BrowserAt::Box),
             tools::Place::Local { .. } if crate::botbrowser::available() => Some(BrowserAt::Here),
             _ => None,
@@ -262,7 +262,7 @@ fn roles_now(job: &Job) -> tools::Roles {
     let mut r = job.roles.clone();
     let host = crate::remote::person_host();
     if !host.is_empty() {
-        if let Some(t) = job.computers.iter().find(|t| matches!(&t.place, tools::Place::Device { host: h } if *h == host)) {
+        if let Some(t) = job.computers.iter().find(|t| matches!(&t.place, tools::Place::Device { host: h, .. } if *h == host)) {
             r.person = Some(t.name.clone());
         }
     }
@@ -651,7 +651,7 @@ pub fn spawn(job: Job, bot_id: u64, tx: Sender<(u64, StreamEvent)>, cancel: Arc<
                     // computer the person is using; a file is sent into the chat instead.
                     let person_now = roles_now(&job).person;
                     let person_host = person_now.as_ref().and_then(|n| job.computers.iter().find(|t| &t.name == n)).and_then(|t| match &t.place {
-                        tools::Place::Device { host } => Some(host.clone()),
+                        tools::Place::Device { host, .. } => Some(host.clone()),
                         _ => None,
                     });
                     if job.roles.server {
@@ -887,7 +887,7 @@ pub fn spawn(job: Job, bot_id: u64, tx: Sender<(u64, StreamEvent)>, cancel: Arc<
                 };
                 let on_box = matches!(target.as_ref().map(|t| &t.place), Ok(tools::Place::Box { .. }));
                 let on_device = match target.as_ref().map(|t| &t.place) {
-                    Ok(tools::Place::Device { host }) => Some(host.clone()),
+                    Ok(tools::Place::Device { host, .. }) => Some(host.clone()),
                     _ => None,
                 };
                 // Permission to use computers at all, and this Mac in particular, is asked for
@@ -1151,7 +1151,7 @@ mod tests {
         assert!(!finds("你的虛擬電腦很吵", "bot 的電腦"));
         assert!(finds("在 bot 的電腦跑", "bot 的電腦"));
         let roles = tools::Roles { own: "Master 的電腦".into(), person: Some("王小明的Mac mini".into()), server: true };
-        let mac = tools::Target { name: "王小明的Mac mini".into(), place: tools::Place::Device { host: "m".into() } };
+        let mac = tools::Target { name: "王小明的Mac mini".into(), place: tools::Place::Device { host: "m".into(), dir: String::new() } };
         assert!(mentions("幫我在 Mac 截圖", &mac, &roles));
         assert!(!mentions("在 macOS 的登入機制下，幫 Bot 的電腦截圖", &mac, &roles));
     }
@@ -1171,8 +1171,8 @@ mod tests {
         // the everyday words point at the right one (「我的電腦」 = where the person typed).
         let roles = tools::Roles { own: "Master 的電腦".into(), person: Some("王小明的Mac mini".into()), server: true };
         let own = tools::Target { name: "Master 的電腦".into(), place: tools::Place::Box { dir: String::new() } };
-        let mac = tools::Target { name: "王小明的Mac mini".into(), place: tools::Place::Device { host: "m".into() } };
-        let desk = tools::Target { name: "ai".into(), place: tools::Place::Device { host: "a".into() } };
+        let mac = tools::Target { name: "王小明的Mac mini".into(), place: tools::Place::Device { host: "m".into(), dir: String::new() } };
+        let desk = tools::Target { name: "ai".into(), place: tools::Place::Device { host: "a".into(), dir: String::new() } };
         let server = tools::Target { name: "雲端大腦".into(), place: tools::Place::Local { workdir: Default::default() } };
         assert!(mentions("在 Master 的電腦打開 Threads", &own, &roles));
         assert!(mentions("用master的電腦", &own, &roles));
@@ -1192,7 +1192,7 @@ mod tests {
         let job = Job {
             computers: vec![
                 tools::Target { name: "Master 的電腦".into(), place: tools::Place::Box { dir: String::new() } },
-                tools::Target { name: "王小明的Mac mini".into(), place: tools::Place::Device { host: "m".into() } },
+                tools::Target { name: "王小明的Mac mini".into(), place: tools::Place::Device { host: "m".into(), dir: String::new() } },
             ],
             default_computer: "Master 的電腦".into(),
             roles,
@@ -1491,7 +1491,7 @@ mod tests {
             });
             let job = Job {
                 req: ChatRequest { kind: ProviderKind::Custom, base_url: format!("http://127.0.0.1:{port}/v1"), api_key: String::new(), model: "m".into(), system: String::new(), history: vec![Message::user("幫我登入 Threads")], tools: vec![], session: String::new() },
-                computers: vec![tools::Target { name: "王小明的Mac mini".into(), place: tools::Place::Device { host: "m".into() } }],
+                computers: vec![tools::Target { name: "王小明的Mac mini".into(), place: tools::Place::Device { host: "m".into(), dir: String::new() } }],
                 default_computer: "王小明的Mac mini".into(),
                 roles: tools::Roles { own: "Master 的電腦".into(), person: Some("王小明的Mac mini".into()), server: true },
                 ..test_job()
diff --git a/src/app.rs b/src/app.rs
index eb9583d..e3aada1 100644
--- a/src/app.rs
+++ b/src/app.rs
@@ -870,8 +870,12 @@ impl App {
         for c in &self.state.remote_computers {
             add(&mut v, tools::Target { name: c.name.clone(), place: tools::Place::Ssh { target: c.ssh_target.clone(), dir: c.dir.clone() } });
         }
-        // 裝置連結: other AnyBots of this account that allow it.
+        // 裝置連結: other AnyBots of this account that allow it, working in the bot's work folder.
         for d in self.linked_devices() {
+            let mut d = d;
+            if let tools::Place::Device { dir, .. } = &mut d.place {
+                dir.clone_from(&b.workdir);
+            }
             add(&mut v, d);
         }
         v
@@ -883,7 +887,7 @@ impl App {
     pub(super) fn roles_for(&self, b: &Bot, targets: &[tools::Target]) -> tools::Roles {
         let server = self.headless;
         let local = targets.iter().find(|t| matches!(t.place, tools::Place::Local { .. })).map(|t| t.name.clone());
-        let device = |h: &str| targets.iter().find(|t| matches!(&t.place, tools::Place::Device { host } if host == h)).map(|t| t.name.clone());
+        let device = |h: &str| targets.iter().find(|t| matches!(&t.place, tools::Place::Device { host, .. } if host == h)).map(|t| t.name.clone());
         let person = match self.typed_on.as_deref() {
             Some(h) if !h.is_empty() => device(h).or_else(|| if server { None } else { local.clone() }),
             _ if !server => local,
diff --git a/src/app/remote_ui.rs b/src/app/remote_ui.rs
index c0668cc..929e1c1 100644
--- a/src/app/remote_ui.rs
+++ b/src/app/remote_ui.rs
@@ -776,7 +776,7 @@ impl App {
                 let uses = remote::peer_uses(id);
                 uses.is_empty() || uses == self.state.remote.host_id
             })
-            .map(|(id, name, _)| tools::Target { name: name.clone(), place: tools::Place::Device { host: id.clone() } })
+            .map(|(id, name, _)| tools::Target { name: name.clone(), place: tools::Place::Device { host: id.clone(), dir: String::new() } })
             .collect()
     }
 }
diff --git a/src/remote.rs b/src/remote.rs
index 3b2e8b6..d90bd4a 100644
--- a/src/remote.rs
+++ b/src/remote.rs
@@ -708,7 +708,13 @@ fn device_run(v: &Value, s: &Settings, via_relay: bool, from: &str) -> Resp {
         return Resp::json(&json!({"text": text, "ok": ok}));
     }
     if matches!(tool, "shell" | "read_file" | "edit_file" | "list_dir" | "search" | "read_terminal" | "write_terminal") {
-        let t = crate::tools::Target { name: crate::model::THIS_COMPUTER_NAME.into(), place: crate::tools::Place::Local { workdir: crate::tools::expand_home(v["workdir"].as_str().unwrap_or("~")) } };
+        // The brain passes the bot's work folder inside the tool's args (empty = this home).
+        let dir = crate::tools::args_of(args).get("workdir").and_then(Value::as_str).unwrap_or("").trim().to_string();
+        let mut workdir = crate::tools::expand_home(if dir.is_empty() { "~" } else { &dir });
+        if !workdir.is_absolute() {
+            workdir = dirs::home_dir().unwrap_or(workdir);
+        }
+        let t = crate::tools::Target { name: crate::model::THIS_COMPUTER_NAME.into(), place: crate::tools::Place::Local { workdir } };
         let ids = crate::tools::RunIds { conversation: "device".into(), request: httpd::random_hex(6) };
         let (text, ok) = crate::tools::run_on(tool, args, &t, &std::sync::atomic::AtomicBool::new(false), &ids);
         return Resp::json(&json!({"text": text, "ok": ok}));
diff --git a/src/tools.rs b/src/tools.rs
index 2550aab..c53b4f9 100644
--- a/src/tools.rs
+++ b/src/tools.rs
@@ -26,6 +26,9 @@ pub const READ_DEFAULT_LINES: usize = 2_000;
 /// Foreground time before a command is moved to the background (estimated; the original's comes per call).
 pub const SHELL_DEFAULT_TIMEOUT_MS: u64 = 30_000;
 pub const SHELL_MAX_TIMEOUT_MS: u64 = 600_000;
+/// A command on a relayed computer must answer before the relay's forward timeout (35 s):
+/// on the device it moves to the background by this deadline, and read_terminal picks it up.
+pub const DEVICE_SHELL_TIMEOUT_MS: u64 = 25_000;
 /// Output kept from a command: its start and its end, with the middle left out (sizes estimated;
 /// the original reports output_head / output_tail / elided_chars).
 pub const OUTPUT_HEAD_CHARS: usize = 6_000;
@@ -49,7 +52,7 @@ pub fn specs() -> Vec<Value> {
         json!({"name": "edit_file", "description": "Change a file. Replaces old_text (which must appear exactly once) with new_text. With empty old_text the file is created or overwritten with new_text.",
             "parameters": {"type": "object", "properties": {
                 "path": {"type": "string"}, "old_text": {"type": "string"}, "new_text": {"type": "string"}}, "required": ["path", "new_text"]}}),
-        json!({"name": "shell", "description": "Run a shell command in the work folder. If it runs longer than timeout_ms it keeps running in the background and you get a terminal id to check with read_terminal.",
+        json!({"name": "shell", "description": "Run a shell command in the work folder. If it runs longer than timeout_ms it keeps running in the background and you get a terminal id to check with read_terminal (pass the same computer to read_terminal/write_terminal).",
             "parameters": {"type": "object", "properties": {
                 "command": {"type": "string"},
                 "timeout_ms": {"type": "integer", "description": "How long to wait before moving it to the background (default 30000)."}}, "required": ["command"]}}),
@@ -330,7 +333,17 @@ pub fn decide(name: &str, args: &str, workdir: &Path, grants: &[String]) -> Deci
                 return Decision::Deny("沒有指令".into());
             }
             let Some(parts) = split_commands(&cmd) else {
-                return Decision::Ask { reason: format!("執行指令（含有隱藏的子指令，無法自動判斷）：{cmd}"), grant: String::new() };
+                // Commands the splitter can't read ($(), backticks, eval…) ask once and remember
+                // by their first word: 「一律允許」 on `git` covers `git … $(…)` afterwards, so
+                // the same shape of command doesn't ask again (models use $(…) constantly).
+                if let Some(d) = denied_hit(&cmd) {
+                    return Decision::Deny(format!("「{d}」這類指令一律不允許。"));
+                }
+                let grant = shell_grant(&cmd);
+                if !writes_files(&cmd) && granted(&grant) {
+                    return Decision::Allow;
+                }
+                return Decision::Ask { reason: format!("執行指令（含有隱藏的子指令，無法自動判斷）：{cmd}"), grant };
             };
             // deny
             for part in &parts {
@@ -338,14 +351,8 @@ pub fn decide(name: &str, args: &str, workdir: &Path, grants: &[String]) -> Deci
                     return Decision::Deny(format!("「{d}」這類指令一律不允許。"));
                 }
             }
-            // ignore: commands that point at secret files
-            for part in &parts {
-                for w in words(part).iter().skip(1) {
-                    if is_ignored(&resolve(workdir, w.trim_matches(['"', '\'']))) {
-                        return Decision::Deny(format!("指令碰到私密或系統檔案：{w}"));
-                    }
-                }
-            }
+            // (No word-by-word path scan here: secret folders are the sandbox's job, and
+            // scanning words as paths denied perfectly ordinary commands.)
             // allow: every part is read-only or already granted
             let ok = |part: &String| !writes_files(part) && (READ_ONLY_COMMANDS.iter().any(|r| starts_with_words(part, r)) || granted(&shell_grant(part)));
             let unapproved: Vec<&String> = parts.iter().filter(|p| !ok(p)).collect();
@@ -466,9 +473,14 @@ pub fn protected_dirs() -> Vec<PathBuf> {
 }
 
 /// Inside the protected folders, what commands may still read: the chat's attachments (a picture
-/// the person sent is the bot's to look at; the keys next to it are not).
+/// the person sent is the bot's to look at; the keys next to it are not) and the ssh keys, so
+/// git and ssh can reach remote repos (writing them stays denied).
 pub fn readable_dirs() -> Vec<PathBuf> {
-    crate::model::State::path().parent().map(|d| vec![d.join("attachments")]).unwrap_or_default()
+    let mut v: Vec<PathBuf> = crate::model::State::path().parent().map(|d| vec![d.join("attachments")]).unwrap_or_default();
+    if let Some(h) = dirs::home_dir() {
+        v.push(h.join(".ssh"));
+    }
+    v
 }
 
 fn sandbox_exec() -> Option<&'static str> {
@@ -525,6 +537,9 @@ pub fn build_command_sealed(cmd: &str, workdir: &Path, protected: &[PathBuf], re
     for k in KEY_ENV_VARS {
         c.env_remove(k);
     }
+    // The app started from Finder or launchd has no shell PATH (no /opt/homebrew/bin): a
+    // command run on an always-on Mac (a Mac mini under LaunchAgent) must find its tools too.
+    c.env("PATH", crate::cloudbox::tool_path());
     c.env(ENV_CONVERSATION_ID, conversation).env(ENV_REQUEST_ID, request);
     #[cfg(unix)]
     {
@@ -616,8 +631,9 @@ pub enum Place {
     Local { workdir: PathBuf },
     /// Another computer: `ssh target`, starting in `dir` (empty = its home).
     Ssh { target: String, dir: String },
-    /// 裝置連結: another AnyBot of the same account (through the relay), by its host id.
-    Device { host: String },
+    /// 裝置連結: another AnyBot of the same account (through the relay), by its host id,
+    /// starting in `dir` (empty = its home).
+    Device { host: String, dir: String },
 }
 
 #[derive(Clone, Debug)]
@@ -641,9 +657,8 @@ pub struct Roles {
 pub fn specs_for(computers: &[String], default: &str) -> Vec<Value> {
     let mut v = specs();
     for t in v.iter_mut() {
-        if t["name"] == "read_terminal" || t["name"] == "write_terminal" {
-            continue;
-        }
+        // Every tool that works on a computer names one, background terminals included: a command
+        // moved to the background on the Mac mini is read on the Mac mini.
         // Each computer goes by its own name; the instructions say which is which. Working on
         // one and calling it another (the server as "your computer") is what confused people.
         let desc = format!("Which computer to work on, by its name. Default: {default} (the one the person chose). Use another only when the person names it; when unsure which one they mean, ask.");
@@ -760,10 +775,30 @@ pub fn run_on(name: &str, args: &str, target: &Target, cancel: &AtomicBool, ids:
     };
     match &target.place {
         Place::Local { workdir } => run(name, args, workdir, cancel, ids),
-        Place::Device { host } => match crate::remote::run_on_device(host, name, args, "") {
-            Ok(v) => (v["text"].as_str().unwrap_or("").to_string(), v["ok"].as_bool().unwrap_or(false)),
-            Err(e) => (e, false),
-        },
+        Place::Device { host, dir } => {
+            // The device runs the tool in the bot's work folder (its own home when unset), and
+            // must answer before the relay gives up at 35 s: long commands move to the
+            // background there, and read_terminal now names this computer to find them.
+            let mut v = v.clone();
+            let cap = timeout_of(&v).min(DEVICE_SHELL_TIMEOUT_MS);
+            if let Some(o) = v.as_object_mut() {
+                if !dir.is_empty() && o.get("workdir").and_then(Value::as_str).unwrap_or("").is_empty() {
+                    o.insert("workdir".into(), serde_json::Value::String(dir.clone()));
+                }
+                o.insert("timeout_ms".into(), serde_json::Value::from(cap));
+            }
+            let args = v.to_string();
+            match crate::remote::run_on_device(host, name, &args, "") {
+                Ok(v) => {
+                    let mut text = v["text"].as_str().unwrap_or("").to_string();
+                    if text.contains("read_terminal") {
+                        text.push_str(&format!("（這台是「{}」：read_terminal 的 computer 填「{}」。）", target.name, target.name));
+                    }
+                    (text, v["ok"].as_bool().unwrap_or(false))
+                }
+                Err(e) => (e, false),
+            }
+        }
         Place::Sealed { root } => {
             let _ = std::fs::create_dir_all(root);
             if name == "shell" {
@@ -1235,7 +1270,12 @@ mod tests {
         let w = wd();
         assert_eq!(decide("shell", r#"{"command":"ls && git status"}"#, &w, &[]), Decision::Allow);
         assert!(matches!(decide("shell", r#"{"command":"ls && sudo rm x"}"#, &w, &[]), Decision::Deny(_)));
-        assert!(matches!(decide("shell", r#"{"command":"cat .env"}"#, &w, &[]), Decision::Deny(_)));
+        // Secrets are the sandbox's job; the permission layer no longer denies words that
+        // merely look like secret paths. Read-only commands run (cat .env is cat), and the
+        // sandbox hides the protected folders from them.
+        assert_eq!(decide("shell", r#"{"command":"cat .env"}"#, &w, &[]), Decision::Allow);
+        assert!(matches!(decide("shell", r#"{"command":"echo $(whoami)"}"#, &w, &[]), Decision::Ask { ref grant, .. } if grant == "shell:echo"));
+        assert_eq!(decide("shell", r#"{"command":"echo $(whoami)"}"#, &w, &["shell:echo".into()]), Decision::Allow);
         assert!(matches!(decide("shell", r#"{"command":"npm install"}"#, &w, &[]), Decision::Ask { ref grant, .. } if grant == "shell:npm install"));
         assert_eq!(decide("shell", r#"{"command":"npm install && ls"}"#, &w, &["shell:npm install".into()]), Decision::Allow);
         assert!(matches!(decide("shell", r#"{"command":"echo hi > out.txt"}"#, &w, &[]), Decision::Ask { .. }));