From d04bc4b6bd503aee2932d20aaa6144dba5cb6b27 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jaroslav=20Bene=C5=A1?= <houmeres@houmeres.sk>
Date: Mon, 9 Nov 2026 10:50:46 +0000
Subject: [PATCH] The activity panel, and continuing an agent chat in a
 terminal

The activity panel beside a chat, from /api/v2's activity routes: Context
(used share, tokens against the window, a segmented bar and a row per
category), Outputs (the files written, lines added and removed, each opening
in the viewer), Background tasks (a team's members as a tree, helpers and
commands: state, elapsed time counting on between reads, model, latest step,
what it is writing, its whole conversation read-only, Stop -- a member after
a confirmation, as it takes those under it), the team's room (who to whom,
reports marked, the words through the page's own markdown) and the plan.

The chat follows GET /chats/{chat}/activity/events while it is open: the strip
above the message box sums the agents up and opens the panel; a new version
reads the panel again while it is open, the costly context part on opening,
after a reply and at most every 15 s. The stream is reopened when the server
closes it, and more slowly while it fails. Beside the chat on a wide window
(the viewer then goes over the chat), over it below --bp-wide, a full-height
sheet at --bp-narrow. The header's Activity button, the palette and Escape
open and close it.

An agent chat with a device session (device_session_id) can be continued in a
terminal: the chat's menu and a header button show 'cd <folder> && lembas -s
<id>' to copy, with lembas the CLI as it starts here (on PATH, else the app's
own copy by its path). Shown rather than run: no terminal opens the same way
on every desktop.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 src-tauri/src/cli.rs |  51 ++++
 src-tauri/src/lib.rs |   8 +
 ui/app.css           | 203 ++++++++++++-
 ui/index.html        |  10 +
 ui/js/activity.js    | 667 +++++++++++++++++++++++++++++++++++++++++++
 ui/js/chat.js        |  78 ++++-
 ui/js/dom.js         |   4 +
 ui/js/explorer.js    |  41 +--
 ui/js/main.js        |   8 +
 ui/js/popup.js       |  42 +++
 10 files changed, 1072 insertions(+), 40 deletions(-)
 create mode 100644 ui/js/activity.js

diff --git a/src-tauri/src/cli.rs b/src-tauri/src/cli.rs
index 4979653..d6aed76 100644
--- a/src-tauri/src/cli.rs
+++ b/src-tauri/src/cli.rs
@@ -42,6 +42,37 @@ pub fn binary() -> PathBuf {
         .unwrap_or_else(|| PathBuf::from(exe_name()))
 }
 
+/// How a person starts the CLI in a terminal on this computer: `lembas` where one is on PATH
+/// (installed by hand: it shares the app's sessions, the directories are the same), else the
+/// bundled one by its full path, quoted for a POSIX shell. The bundled copy is never on PATH.
+pub fn terminal_word() -> String {
+    let path = std::env::var_os("PATH").unwrap_or_default();
+    on_path(&path, exe_name()).map_or_else(
+        || shell_quote(&binary().to_string_lossy()),
+        |_| exe_name().to_string(),
+    )
+}
+
+fn on_path(path: &std::ffi::OsStr, name: &str) -> Option<PathBuf> {
+    std::env::split_paths(path)
+        .map(|dir| dir.join(name))
+        .find(|p| p.is_file())
+}
+
+/// A word for a POSIX shell: as it is when it is plainly safe, else in single quotes.
+pub fn shell_quote(word: &str) -> String {
+    let plain = !word.is_empty()
+        && word.chars().all(|c| {
+            c.is_ascii_alphanumeric()
+                || matches!(c, '/' | '.' | '-' | '_' | '+' | ':' | '@' | '%' | '=')
+        });
+    if plain {
+        word.to_string()
+    } else {
+        format!("'{}'", word.replace('\'', "'\\''"))
+    }
+}
+
 fn home() -> PathBuf {
     std::env::var_os("HOME")
         .or_else(|| std::env::var_os("USERPROFILE"))
@@ -179,6 +210,26 @@ mod tests {
         d
     }
 
+    #[test]
+    fn a_word_for_the_shell_is_quoted_only_when_it_must_be() {
+        assert_eq!(
+            shell_quote("/usr/lib/llembas-desktop/lembas"),
+            "/usr/lib/llembas-desktop/lembas"
+        );
+        assert_eq!(shell_quote("/home/a b/lembas"), "'/home/a b/lembas'");
+        assert_eq!(shell_quote("it's"), "'it'\\''s'");
+        assert_eq!(shell_quote(""), "''");
+    }
+
+    #[test]
+    fn the_cli_on_path_is_found_by_name() {
+        let d = scratch("path");
+        assert_eq!(on_path(d.as_os_str(), "lembas"), None);
+        fs::write(d.join("lembas"), b"").unwrap();
+        assert_eq!(on_path(d.as_os_str(), "lembas"), Some(d.join("lembas")));
+        fs::remove_dir_all(&d).unwrap();
+    }
+
     #[test]
     fn linked_reads_the_logins_the_cli_wrote() {
         let d = scratch("linked");
diff --git a/src-tauri/src/lib.rs b/src-tauri/src/lib.rs
index dff47df..5e74037 100644
--- a/src-tauri/src/lib.rs
+++ b/src-tauri/src/lib.rs
@@ -437,6 +437,13 @@ async fn model_image(handle: AppHandle, path: String) -> Result<String, ApiError
         .map_err(|e| ApiError::new(0, e.to_string()))?
 }
 
+/// How the CLI is started in a terminal here (`lembas`, or the bundled one by its path): the
+/// first word of "continue in a terminal" for an agent chat on this computer.
+#[tauri::command]
+fn terminal_word() -> String {
+    cli::terminal_word()
+}
+
 /// A frame of a reply being written, as the page hears it.
 #[derive(Clone, Serialize)]
 struct Frame {
@@ -1436,6 +1443,7 @@ pub fn run() {
             api,
             api_text,
             model_image,
+            terminal_word,
             stream_open,
             stream_close,
             local_list,
diff --git a/ui/app.css b/ui/app.css
index 7fb6525..47c899a 100644
--- a/ui/app.css
+++ b/ui/app.css
@@ -1,6 +1,7 @@
 /* LLeMbas Desktop's page. Every colour, size, space and font is a token from tokens.css (the
    server's, copied by scripts/fetch-tokens.sh and pinned); the only values of this page's own are
-   the title bar's height and the setup card's width, named below. Media queries cannot read a
+   the title bar's height, the setup card's width and the activity panel's number columns, named
+   below. Media queries cannot read a
    custom property, so the two breakpoints are written out and named after the tokens they are:
    48rem is --bp-narrow (the sidebar becomes a drawer), 64rem is --bp-wide (the viewer goes over
    the chat instead of beside it).
@@ -18,6 +19,10 @@
   --card-max: 40rem;
   /* The sidebar toggle's track in the title bar: none until the sidebar is a drawer. */
   --side-btn-w: 0px;
+  /* The activity panel's number columns: a token count or a share ("180k", "63.0%"), and an
+     elapsed time ("2h 03m"), in the panel's monospaced figures. */
+  --num-col: 4.5em;
+  --time-col: 5.5em;
 }
 
 html, body { margin: 0; height: 100%; overflow: hidden; }
@@ -376,7 +381,7 @@ label, .label { font: var(--text-sm) / var(--leading-tight) var(--font-ui); colo
 
 /* --- The chat ------------------------------------------------------------------------------ */
 
-.main, .settings { grid-area: main; min-width: 0; min-height: 0; display: grid; grid-template-rows: auto minmax(0, 1fr) auto auto; }
+.main, .settings { grid-area: main; min-width: 0; min-height: 0; display: grid; grid-template-rows: auto minmax(0, 1fr) auto auto auto; }
 .settings { grid-template-rows: auto minmax(0, 1fr); }
 
 .head {
@@ -495,23 +500,20 @@ label, .label { font: var(--text-sm) / var(--leading-tight) var(--font-ui); colo
    its word before them -- fixed tracks, so nothing moves when a number grows a digit. */
 .agents {
   display: inline-grid;
-  grid-template-columns: repeat(2, minmax(0, 1fr));
-  grid-template-areas: "min max";
+  grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr);
   gap: var(--sp-2);
   align-items: center;
   width: 100%;
   height: var(--control-h);
 }
-.agents__dash { display: none; }
+.agents__dash { color: var(--ink-muted); }
 .agents__input { width: 100%; min-width: 0; height: var(--control-h); padding: 0 var(--control-px-sm); }
 .agents--compact {
   grid-template-columns: auto calc(var(--w-field-xs) / 2) auto calc(var(--w-field-xs) / 2);
-  grid-template-areas: none;
   width: auto;
   height: var(--control-h-sm);
   font: var(--text-sm) var(--font-ui);
 }
-.agents--compact .agents__dash { display: inline; color: var(--ink-muted); }
 .agents--compact .agents__input { height: var(--control-h-sm); }
 .agents__label { color: var(--ink-muted); white-space: nowrap; }
 /* The model picker: a button the height of a control, avatar · name · chevron. */
@@ -783,6 +785,173 @@ label, .label { font: var(--text-sm) / var(--leading-tight) var(--font-ui); colo
 .viewer__note { padding: var(--sp-4); font-size: var(--text-sm); color: var(--ink-muted); }
 .viewer__note.is-error { color: var(--warning); }
 
+/* --- The activity panel -------------------------------------------------------------------------
+   Beside the chat, the inspector's width; while the viewer is open too, the viewer goes over the
+   chat (it was opened from here, and three columns of text beside the sidebar do not fit). Over
+   the chat from --bp-wide down, as the viewer is; at --bp-narrow that is a full-height sheet. */
+
+.shell[data-activity="true"],
+.shell[data-activity="true"][data-viewer="true"] {
+  grid-template-columns: var(--sidebar-width) minmax(0, 1fr) var(--inspector-width);
+  grid-template-areas: "side main activity";
+}
+.shell[data-activity="true"] .viewer { grid-area: main; z-index: var(--z-panel); border-left: 0; }
+.activity {
+  grid-area: activity;
+  min-width: 0;
+  min-height: 0;
+  display: grid;
+  grid-template-rows: auto minmax(0, 1fr);
+  border-left: var(--border-w) solid var(--border);
+  background: var(--bg);
+}
+/* Title and close on two known tracks; with an agent's conversation open, Back before them. */
+.activity__head { grid-template-columns: minmax(0, 1fr) var(--control-h-sm); }
+.activity[data-view="agent"] .activity__head { grid-template-columns: var(--control-h-sm) minmax(0, 1fr) var(--control-h-sm); }
+.activity__body { overflow: auto; min-height: 0; display: grid; align-content: start; font-size: var(--text-sm); }
+.activity__section { padding: var(--sp-3); border-bottom: var(--border-w) solid var(--border); min-width: 0; }
+.activity__section:last-child { border-bottom: 0; }
+.activity__heading, .activity__subheading {
+  display: grid;
+  grid-template-columns: minmax(0, 1fr) auto;
+  gap: var(--sp-2);
+  align-items: center;
+  margin: 0;
+  font: 600 var(--text-sm) / var(--leading-tight) var(--font-ui);
+  color: var(--ink);
+  cursor: pointer;
+}
+.activity__heading::-webkit-details-marker { display: none; }
+.activity__section[open] > .activity__heading { margin-bottom: var(--sp-3); }
+.activity__subheading { margin: var(--sp-4) 0 var(--sp-2); cursor: default; }
+.activity__count { font: var(--text-xs) var(--font-mono); color: var(--ink-muted); }
+.activity__empty { margin: 0; padding: var(--sp-1) 0; color: var(--ink-faint); font-size: var(--text-sm); }
+.activity__empty.is-error { color: var(--warning); padding: var(--sp-3); }
+.activity__plan { min-width: 0; }
+
+/* Context: the line, the bar, then one row per category on four fixed tracks -- swatch, the name
+   that gives, and two number columns -- so the numbers stand in columns in any language. The
+   categories' colours are tokens, one each. */
+.ctx { display: grid; gap: var(--sp-2); }
+.ctx__used { display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: var(--sp-2); margin: 0; color: var(--ink); }
+.ctx__of { font-family: var(--font-mono); color: var(--ink-muted); }
+.ctx__bar { display: flex; height: var(--sp-2); overflow: hidden; background: var(--surface-active); border-radius: var(--radius-full); }
+.ctx__seg { flex: none; width: var(--share, 0); background: var(--ctx, var(--ink-faint)); }
+.ctx__rows { display: grid; margin: 0; padding: 0; list-style: none; }
+.ctx__row {
+  display: grid;
+  grid-template-columns: var(--sp-3) minmax(0, 1fr) var(--num-col) var(--num-col);
+  gap: var(--sp-2);
+  align-items: center;
+  min-height: var(--row-h);
+}
+.ctx__key { width: var(--sp-3); height: var(--sp-3); border-radius: var(--radius-sm); background: var(--ctx, var(--ink-faint)); }
+.ctx--free.ctx__key { background: transparent; border: var(--border-w) solid var(--border-strong); }
+.ctx__name { overflow: hidden; white-space: nowrap; text-overflow: ellipsis; color: var(--ink-muted); }
+.ctx__num { font: var(--text-xs) var(--font-mono); text-align: right; color: var(--ink-muted); }
+.ctx__note { margin: 0; font-size: var(--text-xs); color: var(--ink-faint); }
+.ctx--messages { --ctx: var(--accent); }
+.ctx--system { --ctx: var(--ink-muted); }
+.ctx--memory { --ctx: var(--warning); }
+.ctx--instructions { --ctx: var(--success); }
+.ctx--tools { --ctx: var(--ink); }
+.ctx--mcp_tools { --ctx: var(--danger); }
+.ctx--since { --ctx: var(--ink-faint); }
+.ctx--buffer { --ctx: var(--border-strong); }
+.ctx--free { --ctx: transparent; }
+
+/* Outputs: icon, the name (cut, never wrapped), the lines added and removed. */
+.outs { display: grid; margin: 0; padding: 0; list-style: none; }
+.outs__row { display: grid; grid-template-columns: var(--sp-4) minmax(0, 1fr) auto; gap: var(--sp-2); align-items: center; min-height: var(--row-h); color: var(--ink-muted); }
+.outs__name { overflow: hidden; white-space: nowrap; text-overflow: ellipsis; padding: 0; font: var(--text-sm) var(--font-ui); color: var(--ink); text-align: left; background: none; border: 0; cursor: pointer; }
+.outs__name:hover { color: var(--accent); text-decoration: underline; }
+.outs__diff { display: grid; grid-auto-flow: column; gap: var(--sp-2); font: var(--text-xs) var(--font-mono); }
+.outs__add { color: var(--success); }
+.outs__del { color: var(--danger); }
+
+/* Background tasks. An agent's row is one grid of known tracks: state dot, what it is (the one
+   track that gives, cut), elapsed time in a column of its own width, the stop button at its size
+   (an empty box where there is none) -- so rows line up whatever each says. */
+.tasks { display: grid; gap: var(--sp-2); min-width: 0; }
+.tasks__summary, .tasks__team { margin: 0; color: var(--ink-muted); }
+.tasks__goal { margin: 0; color: var(--ink); }
+.tasks__list { display: grid; gap: var(--sp-1); }
+.tasks__more > summary { cursor: pointer; padding: var(--sp-1) 0; color: var(--ink-muted); }
+.tasks__more[open] > summary { margin-bottom: var(--sp-1); }
+.agent { margin-left: calc(var(--depth, 0) * var(--sp-4)); background: var(--surface); border: var(--border-w) solid var(--border); border-radius: var(--radius); min-width: 0; }
+.agent__row {
+  display: grid;
+  grid-template-columns: var(--dot-size) minmax(0, 1fr) var(--time-col) var(--control-h-sm);
+  gap: var(--sp-2);
+  align-items: center;
+  min-height: var(--control-h);
+  padding: 0 var(--sp-1) 0 var(--sp-3);
+  cursor: pointer;
+  list-style: none;
+}
+.agent__row::-webkit-details-marker { display: none; }
+.agent__dot { width: var(--dot-size); height: var(--dot-size); border-radius: var(--radius-full); background: var(--ink-faint); }
+.agent.is-working .agent__dot { background: var(--accent); }
+.agent.is-queued .agent__dot, .agent.is-waiting .agent__dot { background: var(--warning); }
+.agent.is-done .agent__dot { background: var(--leaf); }
+.agent.is-error .agent__dot { background: var(--danger); }
+.agent__what { display: grid; min-width: 0; }
+.agent__name, .agent__role { overflow: hidden; white-space: nowrap; text-overflow: ellipsis; }
+.agent__name { color: var(--ink); }
+.agent__role { font-size: var(--text-xs); color: var(--ink-muted); }
+.agent__time { font: var(--text-xs) var(--font-mono); text-align: right; color: var(--ink-muted); }
+.agent__stop { width: var(--control-h-sm); height: var(--control-h-sm); }
+.agent__body { display: grid; gap: var(--sp-2); padding: var(--sp-2) var(--sp-3) var(--sp-3); border-top: var(--border-w) solid var(--border); min-width: 0; }
+.agent__body > .btn { justify-self: start; }
+.agent__facts { display: flex; flex-wrap: wrap; gap: var(--sp-1) var(--sp-3); margin: 0; font-size: var(--text-xs); color: var(--ink-muted); }
+.agent__state { color: var(--ink); }
+.agent__model { font-family: var(--font-mono); overflow-wrap: anywhere; }
+.agent__brief { margin: 0; white-space: pre-wrap; overflow-wrap: anywhere; color: var(--ink); }
+.agent__step { display: grid; grid-template-columns: var(--dot-size) auto minmax(0, 1fr); gap: var(--sp-2); align-items: center; margin: 0; }
+.agent__verb { color: var(--ink); white-space: nowrap; }
+.agent__title { overflow: hidden; white-space: nowrap; text-overflow: ellipsis; font: var(--text-xs) var(--font-mono); color: var(--ink-muted); }
+.agent__text { margin: 0; max-height: calc(6 * var(--row-h)); overflow: auto; white-space: pre-wrap; overflow-wrap: anywhere; font-size: var(--text-xs); color: var(--ink-muted); }
+
+/* The team's room: who to whom, a report marked, the words as markdown. */
+.room { display: grid; gap: var(--sp-2); margin: 0; padding: 0; list-style: none; }
+.room__entry { display: grid; gap: var(--sp-1); padding: var(--sp-2) var(--sp-3); background: var(--surface); border: var(--border-w) solid var(--border); border-radius: var(--radius); min-width: 0; }
+.room__entry.is-report { border-left: var(--border-w-thick) solid var(--leaf); }
+.room__meta { display: grid; grid-template-columns: auto minmax(0, 1fr) auto; gap: var(--sp-2); align-items: center; font-size: var(--text-xs); color: var(--ink-muted); }
+.room__n { font-family: var(--font-mono); }
+.room__route { overflow: hidden; white-space: nowrap; text-overflow: ellipsis; }
+.room__badge { color: var(--leaf); border-color: var(--leaf); }
+
+/* One agent's conversation, read-only. */
+.convo__head { display: grid; gap: var(--sp-2); padding: var(--sp-3); border-bottom: var(--border-w) solid var(--border); }
+.convo__head > .btn { justify-self: start; }
+.convo { display: grid; gap: var(--sp-3); padding: var(--sp-3); min-width: 0; }
+.convo__turn { font-size: var(--text-sm); }
+.convo__tools { display: grid; gap: var(--sp-1); margin: var(--sp-2) 0 0; padding: 0; list-style: none; }
+.convo__tool { display: grid; grid-template-columns: var(--dot-size) auto minmax(0, 1fr); gap: var(--sp-2); align-items: center; font-size: var(--text-xs); }
+
+/* The strip above the message box: what the agents are doing, one line, and the way into the panel. */
+.strip { padding: var(--sp-2) var(--sp-4) 0; }
+.strip__btn {
+  display: grid;
+  grid-template-columns: var(--dot-size) minmax(0, 1fr) auto;
+  gap: var(--sp-2);
+  align-items: center;
+  width: 100%;
+  max-width: var(--thread-max-width);
+  min-height: var(--control-h);
+  margin: 0 auto;
+  padding: 0 var(--control-px-sm);
+  font: var(--text-sm) var(--font-ui);
+  color: var(--ink-muted);
+  text-align: left;
+  background: var(--surface);
+  border: var(--border-w) solid var(--border);
+  border-radius: var(--radius);
+  cursor: pointer;
+}
+.strip__btn:hover { color: var(--ink); background: var(--surface-hover); }
+.strip__text { overflow: hidden; white-space: nowrap; text-overflow: ellipsis; }
+
 /* --- Menus, dialogs and the palette ----------------------------------------------------------- */
 
 .menu {
@@ -836,6 +1005,19 @@ label, .label { font: var(--text-sm) / var(--leading-tight) var(--font-ui); colo
 .dialog::backdrop { background: var(--scrim); }
 .dialog__body { display: grid; gap: var(--sp-3); padding: var(--sp-4); }
 .dialog__title { font: 600 var(--text-md) / var(--leading-tight) var(--font-ui); }
+/* A line to copy: as it is, on one line that scrolls on its own rather than the dialog. */
+.dialog__code {
+  margin: 0;
+  padding: var(--sp-2) var(--sp-3);
+  overflow-x: auto;
+  white-space: pre;
+  font: var(--text-sm) var(--font-mono);
+  color: var(--ink);
+  background: var(--code-bg);
+  border: var(--border-w) solid var(--code-border);
+  border-radius: var(--radius);
+  user-select: all;
+}
 .dialog__input { width: 100%; }
 .dialog__actions { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: var(--sp-2); }
 
@@ -866,6 +1048,9 @@ label, .label { font: var(--text-sm) / var(--leading-tight) var(--font-ui); colo
 @media (max-width: 64rem) {
   .shell[data-viewer="true"] { grid-template-columns: var(--sidebar-width) minmax(0, 1fr); grid-template-areas: "side main"; }
   .viewer { grid-area: main; z-index: var(--z-panel); border-left: 0; }
+  .shell[data-activity="true"],
+  .shell[data-activity="true"][data-viewer="true"] { grid-template-columns: var(--sidebar-width) minmax(0, 1fr); grid-template-areas: "side main"; }
+  .activity { grid-area: main; z-index: var(--z-panel); border-left: 0; }
 }
 
 /* 48rem (--bp-narrow): the sidebar is a drawer, opened from the title bar. */
@@ -873,7 +1058,8 @@ label, .label { font: var(--text-sm) / var(--leading-tight) var(--font-ui); colo
   :root { --side-btn-w: var(--titlebar-h); }
   .bar__side { visibility: visible; }
   .bar__host { display: none; }
-  .shell, .shell[data-viewer="true"] { grid-template-columns: minmax(0, 1fr); grid-template-areas: "main"; }
+  .shell, .shell[data-viewer="true"],
+  .shell[data-activity="true"], .shell[data-activity="true"][data-viewer="true"] { grid-template-columns: minmax(0, 1fr); grid-template-areas: "main"; }
   .side {
     position: absolute;
     inset: 0 auto 0 0;
@@ -893,6 +1079,7 @@ label, .label { font: var(--text-sm) / var(--leading-tight) var(--font-ui); colo
   .head__tools:empty { display: none; }
   .thread { padding: var(--sp-3); }
   .composer { padding: var(--sp-2) var(--sp-3) var(--sp-3); }
+  .strip { padding: var(--sp-2) var(--sp-3) 0; }
   .cards { padding: var(--sp-2) var(--sp-3) 0; }
   .card { padding: var(--sp-4); gap: var(--sp-4); }
   .msg--user { max-width: 100%; }
diff --git a/ui/index.html b/ui/index.html
index b375e67..8104b61 100644
--- a/ui/index.html
+++ b/ui/index.html
@@ -87,6 +87,7 @@
         <div class="messages" id="messages"></div>
       </div>
       <div class="cards" id="cards" hidden></div>
+      <div class="strip" id="activity-strip" hidden aria-live="polite"></div>
       <form class="composer" id="composer" hidden data-running="false" data-drag="false">
         <ul class="composer__files" id="composer-files" hidden></ul>
         <button type="button" class="btn composer__attach" id="attach" aria-label="Attach files" title="Attach files" data-i18n-aria-label data-i18n-title></button>
@@ -108,6 +109,15 @@
       <div class="settings__body" id="settings-body"></div>
     </section>
 
+    <aside class="activity" id="activity" hidden aria-labelledby="activity-title">
+      <header class="viewer__head activity__head">
+        <button type="button" class="pane__btn" id="activity-back" hidden aria-label="Back" title="Back" data-i18n-aria-label data-i18n-title></button>
+        <h2 class="viewer__name" id="activity-title"></h2>
+        <button type="button" class="pane__btn" id="activity-close" aria-label="Close the activity panel" title="Close the activity panel" data-i18n-aria-label data-i18n-title></button>
+      </header>
+      <div class="activity__body" id="activity-body"></div>
+    </aside>
+
     <aside class="viewer" id="viewer" hidden aria-labelledby="viewer-name">
       <header class="viewer__head">
         <div class="viewer__id">
diff --git a/ui/js/activity.js b/ui/js/activity.js
new file mode 100644
index 0000000..1846f9c
--- /dev/null
+++ b/ui/js/activity.js
@@ -0,0 +1,667 @@
+// The chat's activity panel, beside it: what is in its context, by category, against the model's
+// window; the files the chat and its agents wrote; every background agent -- a team's members as
+// a tree, helpers and commands -- with its state, how long it has run, its model, its latest step
+// and what it is writing, its whole conversation read-only and a button to stop it; the team's
+// room; and the plan. The strip above the message box sums the agents up and opens it. The same
+// facts as the server's own panel (`services/activity.py`), from /api/v2:
+//
+//   GET  /chats/{chat}/activity?since=&context=   everything, with a `version`
+//   GET  /chats/{chat}/activity/events            `activity` {version, summary} on each change
+//   GET  /chats/{chat}/agents/{kind}/{id}         one agent and its conversation
+//   POST /chats/{chat}/agents/{kind}/{id}/stop
+//
+// The events stream is followed for as long as a chat is open: it keeps the strip current, and
+// while the panel is open a new `version` reads the panel again. The context is the costly part
+// of a read; it is asked for when the panel opens, after a reply and at most every so often.
+//
+// Every name, role, brief, step, room message and conversation here is a model's words: set as
+// text, and a room message or a reply through the page's own markdown (markdown.js), which
+// builds elements and never parses HTML.
+
+import { $, h, clear, icon, ICONS } from "./dom.js"
+import { get, post, follow, why } from "./bridge.js"
+import { markdown } from "./markdown.js"
+import { ask } from "./popup.js"
+import { openServerFile } from "./explorer.js"
+
+const ACTIVE = ["queued", "working", "waiting"]
+// How many live agents show before "Show N more", as on the server's panel.
+const SHOWN = 6
+// The context is read again on a change at most this often (ms); always on opening and after a reply.
+const CONTEXT_EVERY = 15000
+
+let layout = () => {} // (on) -> the shell makes room for the panel
+let chat = null // the open chat: { id, kind, … }
+let stream = null // the events stream's handle
+let retry = 0 // the reconnect timer
+let failures = 0
+let summary = null
+let version = ""
+let data = null // the last `activity`
+let room = [] // the room so far: each read asks only for what came after `cursor`
+let cursor = 0
+let readAt = 0 // when `data` was read: the elapsed times count on from there
+let contextAt = 0
+let reading = null // the read in flight
+let readAgain = "" // "", "plain" or "context": what to read again once the read in flight is done
+let view = null // null: the panel; { kind, id, name }: one agent's conversation
+const openRows = new Set() // agents unfolded, by kind:id; sections folded, by name
+let ticker = 0
+
+// --- Words ----------------------------------------------------------------------------------------
+
+/** A duration as both harnesses write one: 5s, 1m 05s, 2h 03m. */
+export function duration(seconds) {
+  const total = Math.max(0, Math.round(Number(seconds) || 0))
+  if (total < 60) return `${total}s`
+  const minutes = Math.floor(total / 60)
+  if (minutes < 60) return `${minutes}m ${String(total % 60).padStart(2, "0")}s`
+  return `${Math.floor(minutes / 60)}h ${String(minutes % 60).padStart(2, "0")}m`
+}
+
+/** A token count at a glance: 950, 14.2k, 180k, 1.54M (the server's `compact_tokens`). */
+export function compact(value) {
+  const n = Math.trunc(Number(value) || 0)
+  const trim = (x, digits) => x.toFixed(digits).replace(/\.?0+$/, "")
+  if (n < 1000) return String(n)
+  if (n < 100000) return `${trim(n / 1000, 1)}k`
+  if (n < 1000000) return `${Math.round(n / 1000)}k`
+  return `${trim(n / 1000000, 2)}M`
+}
+
+/** "3 agents working · 1 queued · 2 finished", or "" for none (the server's `summary_text`). */
+export function summaryText(counts) {
+  if (!counts) return ""
+  const parts = []
+  if (counts.working === 1) parts.push(t("1 agent working"))
+  else if (counts.working) parts.push(t("%(n)s agents working", { n: counts.working }))
+  if (counts.queued) parts.push(t("%(n)s queued", { n: counts.queued }))
+  if (counts.waiting) parts.push(t("%(n)s waiting", { n: counts.waiting }))
+  if (counts.finished) parts.push(t("%(n)s finished", { n: counts.finished }))
+  return parts.join(" · ")
+}
+
+function stateWord(state) {
+  return { queued: t("queued"), working: t("working"), waiting: t("waiting"), done: t("done"), stopped: t("stopped"), error: t("failed") }[state] || String(state || "")
+}
+
+function contextWord(key) {
+  return (
+    {
+      messages: t("Messages"),
+      system: t("System prompt"),
+      memory: t("Memory and personal"),
+      instructions: t("Instruction files"),
+      tools: t("Tools"),
+      mcp_tools: t("MCP tools"),
+      since: t("Since the last reply"),
+      buffer: t("Compaction buffer"),
+      free: t("Free space"),
+    }[key] || String(key)
+  )
+}
+
+/** A percentage through a sentence written the server's way (`%%` is a percent sign). */
+function percentSentence(text, fields) {
+  return t(text, fields).replace(/%%/g, "%")
+}
+
+/** A plan's phases and their tasks, done ones struck through: the panel's and the cards'. */
+export function planList(plan) {
+  return h(
+    "ol",
+    { class: "plan" },
+    (plan.phases || []).map((p) =>
+      h("li", null, h("span", { class: "plan__phase", text: p.title }), h("ul", null, (p.tasks || []).map((task) => h("li", { class: `plan__task is-${task.status}`, text: task.text })))),
+    ),
+  )
+}
+
+// --- Following a chat -----------------------------------------------------------------------------
+
+const enc = encodeURIComponent
+
+export function panelOpen() {
+  return !$("activity").hidden
+}
+
+/** The chat whose activity is followed: the one open, or null for none (a new chat, the settings). */
+export function watchActivity(next) {
+  const id = next?.id || null
+  if (id && chat?.id === id) {
+    chat = next
+    return
+  }
+  stop()
+  chat = id ? next : null
+  summary = null
+  version = ""
+  data = null
+  room = []
+  cursor = 0
+  readAt = contextAt = 0
+  view = null
+  openRows.clear()
+  renderStrip()
+  $("activity-open")?.setAttribute("aria-expanded", String(panelOpen()))
+  if (!chat) {
+    if (panelOpen()) showPanel(false)
+    return
+  }
+  listenTo(chat.id)
+  if (panelOpen()) {
+    render()
+    read(true)
+  }
+}
+
+/** A reply has ended, or the chat's settings changed: the context and the outputs move with it. */
+export function activityChanged() {
+  if (chat && panelOpen()) read(true)
+}
+
+function stop() {
+  clearTimeout(retry)
+  retry = 0
+  failures = 0
+  stream?.close()
+  stream = null
+}
+
+async function listenTo(id) {
+  try {
+    const handle = await follow(`/chats/${enc(id)}/activity/events`, {
+      onFrame: (event, frame) => {
+        if (chat?.id !== id || event !== "activity" || !frame || typeof frame !== "object") return
+        failures = 0
+        heard(frame)
+      },
+      // The server closes the stream after a while (`close`): it is opened again at once. A broken
+      // one is opened again later, more slowly each time -- polling, in effect, while it fails.
+      onEnd: (err) => {
+        if (chat?.id !== id) return
+        stream = null
+        failures = err ? failures + 1 : 0
+        retry = setTimeout(() => {
+          if (chat?.id === id && !stream) {
+            if (err && panelOpen()) read(false)
+            listenTo(id)
+          }
+        }, err ? Math.min(60000, 5000 * failures) : 500)
+      },
+    })
+    if (chat?.id !== id) handle.close()
+    else stream = handle
+  } catch {
+    if (chat?.id !== id) return
+    failures += 1
+    retry = setTimeout(() => chat?.id === id && listenTo(id), Math.min(60000, 5000 * failures))
+  }
+}
+
+function heard(frame) {
+  summary = frame.summary || summary
+  renderStrip()
+  if (frame.version && frame.version !== version) {
+    version = frame.version
+    if (panelOpen()) read(Date.now() - contextAt > CONTEXT_EVERY)
+  }
+}
+
+/** Read the panel's facts; one read at a time, and one more after it if asked for meanwhile. */
+async function read(withContext) {
+  if (!chat) return
+  if (reading) {
+    readAgain = withContext ? "context" : readAgain || "plain"
+    return reading
+  }
+  const id = chat.id
+  reading = (async () => {
+    try {
+      const a = (await get(`/chats/${enc(id)}/activity?since=${cursor}&context=${withContext ? "true" : "false"}`)).activity
+      if (chat?.id !== id || !a) return
+      if (!withContext) a.context = data?.context ?? null
+      else contextAt = Date.now()
+      if (a.team) {
+        // A cursor lower than ours is a room begun again (a new team): read from the start.
+        if (a.team.cursor < cursor) {
+          room = []
+          cursor = 0
+          readAgain = readAgain || "plain"
+        }
+        for (const m of a.team.room || []) if (m.n > cursor) room.push(m)
+        cursor = Math.max(cursor, a.team.cursor || 0)
+      } else {
+        room = []
+        cursor = 0
+      }
+      data = a
+      version = a.version || version
+      summary = a.summary || summary
+      readAt = Date.now()
+      renderStrip()
+      if (view) await readAgent()
+      else render()
+    } catch (err) {
+      if (chat?.id === id && !data) renderError(why(err))
+    }
+  })()
+  await reading
+  reading = null
+  if (readAgain) {
+    const ctxToo = readAgain === "context"
+    readAgain = ""
+    read(ctxToo)
+  }
+}
+
+// --- The strip above the message box ---------------------------------------------------------------
+
+function renderStrip() {
+  const strip = $("activity-strip")
+  const text = chat && summary?.total ? summaryText(summary) : ""
+  strip.hidden = !text
+  if (!text) return clear(strip)
+  const busy = summary.active > 0
+  strip.replaceChildren(
+    h(
+      "button",
+      { type: "button", class: "strip__btn", "aria-label": `${text} — ${t("Open the activity panel")}`, onclick: () => showPanel(true) },
+      h("span", { class: `dot${busy ? " is-busy" : " is-ok"}`, "aria-hidden": "true" }),
+      h("span", { class: "strip__text", text }),
+      icon(ICONS.chevron),
+    ),
+  )
+}
+
+// --- The panel ------------------------------------------------------------------------------------------
+
+/** Open or close the panel (the header's Activity button, the strip, Escape). */
+export function showPanel(on) {
+  if (on && !chat) return
+  $("activity").hidden = !on
+  layout(on)
+  $("activity-open")?.setAttribute("aria-expanded", String(on))
+  clearInterval(ticker)
+  ticker = 0
+  if (!on) {
+    view = null
+    return
+  }
+  ticker = setInterval(tick, 1000)
+  render()
+  read(true)
+  $("activity-close").focus()
+}
+
+export function togglePanel() {
+  showPanel(!panelOpen())
+}
+
+/** The elapsed times of agents still at work count on between reads. */
+function tick() {
+  if (document.visibilityState !== "visible") return
+  const extra = (Date.now() - readAt) / 1000
+  for (const el of document.querySelectorAll("#activity .agent__time[data-active]")) {
+    el.textContent = duration(Number(el.dataset.seconds) + extra)
+  }
+}
+
+function renderError(text) {
+  clear($("activity-body")).append(h("p", { class: "activity__empty is-error", text }))
+}
+
+function section(name, title, count, ...body) {
+  const el = h(
+    "details",
+    { class: "activity__section", open: !openRows.has(`section:${name}`) },
+    h("summary", { class: "activity__heading" }, h("span", { text: title }), count ? h("span", { class: "activity__count", text: String(count) }) : null),
+    ...body,
+  )
+  el.addEventListener("toggle", () => (el.open ? openRows.delete(`section:${name}`) : openRows.add(`section:${name}`)))
+  return el
+}
+
+function render() {
+  $("activity").dataset.view = "panel"
+  const head = $("activity-title")
+  $("activity-back").hidden = true
+  head.textContent = t("Activity")
+  const body = $("activity-body")
+  if (!data) {
+    clear(body).append(h("p", { class: "activity__empty", text: t("Loading…") }))
+    return
+  }
+  // Kept where the reader was: the panel is drawn again on every change.
+  const scroll = body.scrollTop
+  body.replaceChildren(
+    section("context", t("Context"), 0, contextPart(data.context)),
+    section("outputs", t("Outputs"), (data.outputs || []).length, outputsPart(data.outputs || [])),
+    section("tasks", t("Background tasks"), 0, tasksPart()),
+    data.plan ? section("plan", t("Plan"), 0, h("div", { class: "activity__plan" }, planList(data.plan))) : null,
+  )
+  body.scrollTop = scroll
+}
+
+function contextPart(c) {
+  if (!c) return h("p", { class: "activity__empty", text: t("Not measured.") })
+  const known = c.percent !== null && c.percent !== undefined
+  const used = h(
+    "p",
+    { class: "ctx__used" },
+    h("span", { text: known ? percentSentence("%(percent)s%% used", { percent: c.percent }) : t("%(tokens)s tokens", { tokens: compact(c.used) }) }),
+    h("span", { class: "ctx__of", text: known ? `${compact(c.used)} / ${compact(c.limit)}` : t("window unknown") }),
+  )
+  const cats = c.categories || []
+  const bar = c.limit
+    ? h(
+        "div",
+        { class: "ctx__bar", role: "img", "aria-label": percentSentence("%(percent)s%% of the context window used", { percent: c.percent ?? 0 }) },
+        cats
+          .filter((r) => r.key !== "free" && r.tokens)
+          .map((r) => {
+            const seg = h("span", { class: `ctx__seg ctx--${safeKey(r.key)}` })
+            seg.style.setProperty("--share", `${Math.max(0, Math.min(100, Number(r.percent) || 0))}%`)
+            return seg
+          }),
+      )
+    : null
+  const rows = h(
+    "ul",
+    { class: "ctx__rows" },
+    cats.map((r) =>
+      h(
+        "li",
+        { class: "ctx__row" },
+        h("span", { class: `ctx__key ctx--${safeKey(r.key)}`, "aria-hidden": "true" }),
+        h("span", { class: "ctx__name", text: contextWord(r.key) }),
+        h("span", { class: "ctx__num", text: compact(r.tokens) }),
+        h("span", { class: "ctx__num", text: r.percent === null || r.percent === undefined ? "—" : `${r.percent}%` }),
+      ),
+    ),
+  )
+  const note = h(
+    "p",
+    { class: "ctx__note" },
+    `${c.measured ? t("Counted by the model at the last reply; the categories are estimated.") : t("Estimated: no reply has been counted yet.")} ${t("%(n)s tools offered.", { n: c.tools_count ?? 0 })}`,
+  )
+  return h("div", { class: "ctx" }, used, bar, rows, note)
+}
+
+/** A category's key as a class name: the server's words, kept to letters and underscores. */
+function safeKey(key) {
+  return String(key).replace(/[^a-z_]/gi, "") || "other"
+}
+
+function outputsPart(outputs) {
+  if (!outputs.length) return h("p", { class: "activity__empty", text: t("No files written in this chat yet.") })
+  return h(
+    "ul",
+    { class: "outs" },
+    outputs.map((o) =>
+      h(
+        "li",
+        { class: "outs__row" },
+        icon(ICONS.file),
+        h("button", { type: "button", class: "outs__name", title: `${o.path} — ${t("Open in the viewer")}`, onclick: () => openServerFile(o.path, o.name) }, h("bdi", { text: o.name || o.path })),
+        h(
+          "span",
+          { class: "outs__diff" },
+          o.added === null || o.added === undefined ? null : [h("span", { class: "outs__add", text: `+${o.added}` }), h("span", { class: "outs__del", text: `−${o.removed ?? 0}` })],
+        ),
+      ),
+    ),
+  )
+}
+
+function tasksPart() {
+  const entries = data.agents || []
+  const team = data.team
+  const box = h("div", { class: "tasks", "aria-live": "polite" })
+  if (!entries.length && !team) {
+    box.append(h("p", { class: "activity__empty", text: t("Nothing runs in the background. Helpers, commands and a team's members show here while they work.") }))
+    return box
+  }
+  box.append(h("p", { class: "tasks__summary", text: summaryText(data.summary) || t("Nothing running.") }))
+  if (team) {
+    box.append(h("p", { class: "tasks__team", text: t("Team: %(size)s of %(max)s agents", { size: team.size, max: team.max }) }))
+    if (team.goal) box.append(h("p", { class: "tasks__goal", text: team.goal }))
+  }
+  const live = entries.filter((e) => ACTIVE.includes(e.state))
+  const ended = entries.filter((e) => !ACTIVE.includes(e.state))
+  if (live.length) {
+    box.append(h("div", { class: "tasks__list" }, live.slice(0, SHOWN).map(agentRows)))
+    if (live.length > SHOWN) box.append(fold("more", t("Show %(n)s more", { n: live.length - SHOWN }), live.slice(SHOWN)))
+  }
+  if (ended.length) box.append(fold("finished", t("%(n)s finished", { n: ended.length }), ended))
+  if (team) {
+    box.append(h("h3", { class: "activity__subheading", text: t("Room") }))
+    box.append(
+      room.length
+        ? h(
+            "ol",
+            { class: "room" },
+            room.map((m) =>
+              h(
+                "li",
+                { class: `room__entry${m.report ? " is-report" : ""}` },
+                h(
+                  "div",
+                  { class: "room__meta" },
+                  h("span", { class: "room__n", text: `#${m.n}` }),
+                  h("span", { class: "room__route", text: `${m.from} → ${(m.to || []).join(", ")}` }),
+                  m.report ? h("span", { class: "chip room__badge", text: t("report") }) : null,
+                ),
+                h("div", { class: "room__text md" }, markdown(String(m.text || ""))),
+              ),
+            ),
+          )
+        : h("p", { class: "activity__empty", text: t("Nothing has been said in the room yet.") }),
+    )
+  }
+  return box
+}
+
+/** A folded list of agents ("Show 3 more", "12 finished"), remembered open across redraws. */
+function fold(name, label, list) {
+  const el = h("details", { class: "tasks__more", open: openRows.has(`fold:${name}`) }, h("summary", { text: label }), h("div", { class: "tasks__list" }, list.map(agentRows)))
+  el.addEventListener("toggle", () => (el.open ? openRows.add(`fold:${name}`) : openRows.delete(`fold:${name}`)))
+  return el
+}
+
+/** An agent and, under it, the agents it leads or started. */
+function agentRows(a) {
+  return [agentRow(a), ...(a.children || []).map(agentRows)]
+}
+
+function agentRow(a) {
+  const key = `${a.kind}:${a.id}`
+  const active = ACTIVE.includes(a.state)
+  const time = h("span", { class: "agent__time", title: stateWord(a.state), text: duration(a.seconds) })
+  if (active) {
+    time.dataset.active = ""
+    time.dataset.seconds = String(Number(a.seconds) || 0)
+  }
+  const stopBtn = a.stoppable
+    ? h(
+        "button",
+        {
+          type: "button",
+          class: "pane__btn agent__stop",
+          "aria-label": t("Stop %(name)s", { name: a.name }),
+          title: t("Stop %(name)s", { name: a.name }),
+          onclick: (e) => {
+            e.preventDefault()
+            e.stopPropagation()
+            stopAgent(a)
+          },
+        },
+        icon(ICONS.stop),
+      )
+    : h("span", { class: "agent__stop", "aria-hidden": "true" })
+  const facts = h(
+    "p",
+    { class: "agent__facts" },
+    h("span", { class: "agent__state", text: stateWord(a.state) }),
+    a.agent ? h("span", { text: a.agent }) : null,
+    a.model ? h("span", { class: "agent__model", text: a.model }) : null,
+    a.steps ? h("span", { text: t("%(steps)s steps, %(tools)s tools", { steps: a.steps, tools: a.tools }) }) : null,
+  )
+  const step = a.step
+    ? h(
+        "p",
+        { class: `agent__step${a.step.error ? " is-error" : ""}` },
+        h("span", { class: `dot${a.step.error ? " is-error" : a.step.running ? " is-busy" : " is-ok"}`, "aria-hidden": "true" }),
+        h("span", { class: "agent__verb", text: a.step.label || a.step.tool || "" }),
+        a.step.title ? h("code", { class: "agent__title", text: a.step.title }) : null,
+      )
+    : null
+  const el = h(
+    "details",
+    { class: `agent is-${safeKey(a.state)}`, open: openRows.has(key) },
+    h(
+      "summary",
+      { class: "agent__row" },
+      h("span", { class: "agent__dot", "aria-hidden": "true" }),
+      h("span", { class: "agent__what" }, h("span", { class: "agent__name", text: a.name || a.id }), a.role ? h("span", { class: "agent__role", text: a.role }) : null),
+      time,
+      stopBtn,
+    ),
+    h(
+      "div",
+      { class: "agent__body" },
+      facts,
+      a.brief ? h("p", { class: "agent__brief", text: a.brief }) : null,
+      step,
+      a.text ? h("p", { class: "agent__text", text: a.text }) : null,
+      a.transcript
+        ? h("button", { type: "button", class: "btn btn--sm", text: t("Open its conversation"), onclick: () => openAgent(a) })
+        : null,
+    ),
+  )
+  el.style.setProperty("--depth", String(Math.max(0, Math.min(6, Number(a.depth) || 0))))
+  el.addEventListener("toggle", () => (el.open ? openRows.add(key) : openRows.delete(key)))
+  return el
+}
+
+async function stopAgent(a) {
+  if (!chat) return
+  if (a.kind === "member") {
+    const yes = await ask({
+      title: t("Stop %(name)s", { name: a.name }),
+      text: t("Stop %(name)s and the members under it? They leave the team.", { name: a.name }),
+      ok: t("Stop"),
+      cancel: t("Cancel"),
+      danger: true,
+    })
+    if (!yes) return
+  }
+  try {
+    await post(`/chats/${enc(chat.id)}/agents/${enc(a.kind)}/${enc(a.id)}/stop`)
+  } catch (err) {
+    // 409: it had finished meanwhile; the read below shows that.
+    if (err?.status !== 409) renderError(why(err))
+  }
+  read(false)
+}
+
+// --- One agent's conversation, read-only ------------------------------------------------------------
+
+function openAgent(a) {
+  view = { kind: a.kind, id: a.id, name: a.name || a.id }
+  $("activity").dataset.view = "agent"
+  $("activity-title").textContent = view.name
+  $("activity-back").hidden = false
+  clear($("activity-body")).append(h("p", { class: "activity__empty", text: t("Loading…") }))
+  readAgent()
+}
+
+function closeAgent() {
+  view = null
+  render()
+  $("activity-close").focus()
+}
+
+async function readAgent() {
+  if (!chat || !view) return
+  const { kind, id } = view
+  let r
+  try {
+    r = await get(`/chats/${enc(chat.id)}/agents/${enc(kind)}/${enc(id)}`)
+  } catch (err) {
+    if (view?.id === id) clear($("activity-body")).append(h("p", { class: "activity__empty is-error", text: why(err) }))
+    return
+  }
+  if (view?.kind !== kind || view?.id !== id) return
+  const a = r.agent || {}
+  const body = $("activity-body")
+  const atEnd = body.scrollHeight - body.scrollTop - body.clientHeight < 40
+  const head = h(
+    "div",
+    { class: "convo__head" },
+    h(
+      "p",
+      { class: "agent__facts" },
+      h("span", { class: "agent__state", text: stateWord(a.state) }),
+      h("span", { text: duration(a.seconds) }),
+      a.model ? h("span", { class: "agent__model", text: a.model }) : null,
+    ),
+    a.role ? h("p", { class: "agent__role", text: a.role }) : null,
+    a.stoppable ? h("button", { type: "button", class: "btn btn--sm", text: t("Stop %(name)s", { name: a.name || id }), onclick: () => stopAgent(a) }) : null,
+  )
+  const turns = (r.transcript || []).map((turn) => {
+    if (turn.role === "user") {
+      return h("article", { class: `msg msg--user convo__turn${turn.machine ? " is-machine" : ""}` }, h("div", { class: "msg__text", text: String(turn.text || "") }))
+    }
+    return h(
+      "article",
+      { class: "msg msg--assistant convo__turn" },
+      turn.text ? h("div", { class: "md" }, markdown(String(turn.text))) : null,
+      turn.tools?.length
+        ? h(
+            "ul",
+            { class: "convo__tools" },
+            turn.tools.map((c) =>
+              h(
+                "li",
+                { class: "convo__tool" },
+                h("span", { class: `dot${c.isError ? " is-error" : " is-ok"}`, "aria-hidden": "true" }),
+                h("span", { class: "agent__verb", text: String(c.name || "") }),
+                c.title ? h("code", { class: "agent__title", text: String(c.title) }) : null,
+              ),
+            ),
+          )
+        : null,
+      turn.error ? h("p", { class: "msg__note is-error", text: String(turn.error) }) : null,
+      turn.running ? h("p", { class: "msg__status muted", text: t("Writing…") }) : null,
+    )
+  })
+  body.replaceChildren(head, h("div", { class: "convo" }, turns.length ? turns : h("p", { class: "activity__empty", text: t("Nothing yet.") })))
+  if (atEnd) body.scrollTop = body.scrollHeight
+}
+
+// --- Start ------------------------------------------------------------------------------------------
+
+export function initActivity({ onLayout }) {
+  layout = onLayout || layout
+  $("activity-close").replaceChildren(icon(ICONS.close))
+  $("activity-close").addEventListener("click", () => showPanel(false))
+  $("activity-back").replaceChildren(icon(ICONS.back))
+  $("activity-back").addEventListener("click", closeAgent)
+  // Before the viewer's own Escape (capture): while the viewer is open, it closes first and the
+  // panel stays; one Escape closes one thing.
+  document.addEventListener(
+    "keydown",
+    (e) => {
+      if (e.key !== "Escape" || !panelOpen() || e.defaultPrevented || document.querySelector("dialog[open], .menu")) return
+      if (!$("viewer").hidden) return
+      e.preventDefault()
+      if (view) closeAgent()
+      else showPanel(false)
+    },
+    true,
+  )
+  document.addEventListener("visibilitychange", () => {
+    if (document.visibilityState === "visible" && chat && panelOpen()) read(false)
+  })
+}
diff --git a/ui/js/chat.js b/ui/js/chat.js
index 79fc7f9..f711aa6 100644
--- a/ui/js/chat.js
+++ b/ui/js/chat.js
@@ -11,9 +11,10 @@ import { api, get, getText, post, patch, del, follow, why, invoke, openLink } fr
 import { markdown } from "./markdown.js"
 import { openViewer, showKind } from "./viewer.js"
 import { readLocal } from "./explorer.js"
-import { menu, ask } from "./popup.js"
+import { menu, ask, showLine } from "./popup.js"
 import { avatar, modelPicker, effortControl, agentsControl, teamPossible, levelsOf } from "./models.js"
 import { readyIds, sending, sent, discard } from "./attach.js"
+import { watchActivity, activityChanged, togglePanel, panelOpen, planList } from "./activity.js"
 
 const MODES = ["manual", "edit", "auto", "plan"]
 
@@ -369,7 +370,10 @@ class Live {
       this.status.textContent = t("The connection to the reply was lost: %(why)s", { why: why(err) })
       this.status.classList.add("is-error")
       this.el.append(h("button", { type: "button", class: "btn btn--sm", text: t("Read again"), onclick: reload }))
-    } else reload()
+    } else {
+      reload()
+      activityChanged()
+    }
   }
 }
 
@@ -493,16 +497,6 @@ function cardOf(chat, card) {
   return el
 }
 
-function planList(plan) {
-  return h(
-    "ol",
-    { class: "plan" },
-    (plan.phases || []).map((p) =>
-      h("li", null, h("span", { class: "plan__phase", text: p.title }), h("ul", null, (p.tasks || []).map((task) => h("li", { class: `plan__task is-${task.status}`, text: task.text })))),
-    ),
-  )
-}
-
 // --- Opening a chat --------------------------------------------------------------------------------
 
 function setTitle(title) {
@@ -526,13 +520,38 @@ function renderHead(chat) {
       MODES.map((m) => h("option", { value: m, text: modeName(m), selected: chat.mode === m })),
     )
     tools.append(mode)
+    if (chat.device_session_id) {
+      tools.append(
+        h(
+          "button",
+          { type: "button", class: "pane__btn", "aria-label": t("Continue in a terminal"), title: t("Continue in a terminal"), onclick: () => continueInTerminal(open?.chat || chat) },
+          icon(ICONS.terminal),
+        ),
+      )
+    }
   }
   const slot = h("span", { class: "head__model" })
   tools.append(slot)
   chatModels(chat).then((models) => {
     if (open?.chat?.id === chat.id) headModel(slot, chat, models)
   })
-  tools.append(h("button", { type: "button", class: "pane__btn", "aria-label": t("More"), title: t("More"), onclick: (e) => chatMenu(e.currentTarget, open?.chat || chat) }, icon(ICONS.more)))
+  tools.append(
+    h(
+      "button",
+      {
+        type: "button",
+        class: "pane__btn",
+        id: "activity-open",
+        "aria-label": t("Activity"),
+        title: t("Activity"),
+        "aria-controls": "activity",
+        "aria-expanded": String(panelOpen()),
+        onclick: togglePanel,
+      },
+      icon(ICONS.bolt),
+    ),
+    h("button", { type: "button", class: "pane__btn", "aria-label": t("More"), title: t("More"), onclick: (e) => chatMenu(e.currentTarget, open?.chat || chat) }, icon(ICONS.more)),
+  )
 }
 
 /** The models this chat may switch to (its data group's), or the account's when that fails. */
@@ -574,6 +593,7 @@ async function headModel(slot, chat, models) {
             if (open?.chat?.id === chat.id) {
               open.chat = r.chat
               headModel(slot, r.chat, models)
+              activityChanged()
             }
           } catch (err) {
             alertIn(why(err))
@@ -624,12 +644,41 @@ export function chatMenu(anchor, chat) {
   const base = ctx.status()?.server
   const mayDelete = ctx.me()?.permissions?.["chat.delete"] !== false
   const items = [{ label: t("Rename…"), run: () => renameChat(chat) }]
+  if (chat.kind === "agent" && chat.device_session_id) items.push({ label: t("Continue in a terminal…"), run: () => continueInTerminal(chat) })
   if (base) items.push({ label: t("Open in the web interface"), run: () => openLink(`${base}/chat/${encodeURIComponent(chat.id)}`) })
   items.push(null, { label: t("Archive chat"), run: () => archiveChat(chat) })
   if (mayDelete) items.push({ label: t("Delete chat"), danger: true, run: () => deleteChat(chat) })
   menu(anchor, items)
 }
 
+/**
+ * Continue an agent chat in a terminal: the CLI's own session on the device it works on
+ * (`device_session_id`), opened with `lembas -s <id>` in the chat's folder. Shown to copy rather
+ * than run: a terminal is not something every desktop opens the same way, and the command is the
+ * person's to run where they want it. On this computer the first word is the CLI as it is
+ * started here (`lembas` on PATH, else the app's own copy by its path).
+ */
+export async function continueInTerminal(chat) {
+  const session = String(chat.device_session_id || "")
+  if (!/^[A-Za-z0-9_-]+$/.test(session)) return
+  const here = onThisComputer(chat)
+  let word = "lembas"
+  if (here) word = await invoke("terminal_word").catch(() => "lembas")
+  const dir = chat.device?.directory || ""
+  const quoted = /^[A-Za-z0-9/._+:@%=-]+$/.test(dir) ? dir : `'${dir.replace(/'/g, "'\\''")}'`
+  const code = `${dir ? `cd ${quoted} && ` : ""}${word} -s ${session}`
+  await showLine({
+    title: t("Continue in a terminal"),
+    text: here
+      ? t("Run this in a terminal: the agent's session goes on there, in this chat's folder, and the chat keeps it.")
+      : t("Run this in a terminal on the computer this chat works on: the agent's session goes on there, and the chat keeps it."),
+    code,
+    copy: t("Copy"),
+    copied: t("Copied"),
+    close: t("Close"),
+  })
+}
+
 async function renameChat(chat) {
   const title = await ask({ title: t("Rename chat"), value: chat.title || "", ok: t("Rename"), cancel: t("Cancel") })
   if (!title || title === chat.title) return
@@ -704,6 +753,7 @@ export async function openChat(id) {
   if (open?.chat?.id !== id) return
   open.chat = r.chat
   open.more = r.more
+  watchActivity(r.chat)
   renderHead(r.chat)
   clear(list)
   if (r.more) list.append(earlier())
@@ -751,6 +801,7 @@ function reload() {
 export function closeChat() {
   if (open?.live) open.live.stop()
   open = null
+  watchActivity(null)
   invoke("set_open_chat", { chat: null })
 }
 
@@ -869,6 +920,7 @@ async function createChat(text, attachments) {
   $("new-chat").hidden = true
   open = { chat: r.chat, live: null, more: false }
   invoke("set_open_chat", { chat: r.chat.id })
+  watchActivity(r.chat)
   renderHead(r.chat)
   clear($("messages"))
   if (r.message) $("messages").append(userMessage(r.message))
diff --git a/ui/js/dom.js b/ui/js/dom.js
index a3beb35..90cb3d6 100644
--- a/ui/js/dom.js
+++ b/ui/js/dom.js
@@ -79,6 +79,10 @@ export const ICONS = {
   edit: "M10.75 1.75l3.5 3.5-8.5 8.5h-3.5v-3.5zM3.75 10.87v1.38h1.38l6.62-6.62-1.38-1.38z",
   copy: "M5 1.5h8.5V11H5zM6.5 3v6.5H12V3zM2.5 5H4v8.5h6.5V15h-8z",
   attach: "M7.25 2.5h1.5v4.75h4.75v1.5H8.75v4.75h-1.5V8.75H2.5v-1.5h4.75z",
+  bolt: "M9.5 1L3 9.25h4.25L6.5 15 13 6.75H8.75z",
+  stop: "M4.5 4.5h7v7h-7z",
+  back: "M10 3.5L5.5 8 10 12.5 11.1 11.4 7.7 8 11.1 4.6z",
+  terminal: "M1.5 2.5h13v11h-13zM3 4v8h10V4zM4.2 5.4l2.6 2.6-2.6 2.6-1-1L4.8 8 3.2 6.4zM7.5 10h4v1.5h-4z",
   search: "M7 2a5 5 0 013.95 8.07l3.24 3.24-1.06 1.06-3.24-3.24A5 5 0 117 2zm0 1.5a3.5 3.5 0 100 7 3.5 3.5 0 000-7z",
 }
 
diff --git a/ui/js/explorer.js b/ui/js/explorer.js
index 525b82f..73f9bc4 100644
--- a/ui/js/explorer.js
+++ b/ui/js/explorer.js
@@ -130,28 +130,31 @@ export function renderServer() {
   tree(box, {
     rootPath: "/",
     list: async (path) => (await get(SERVER_FILES.list(path))).entries || [],
-    open: async (e) => {
-      const where = t("Server")
-      try {
-        const f = await readServer(e.path)
-        openViewer({
-          name: f.name || e.name,
-          path: f.path || e.path,
-          where,
-          text: f.text,
-          // The server's own kind and language: its table and the viewer's are the same one.
-          kind: ["markdown", "code", "text", "html"].includes(f.kind) ? f.kind : undefined,
-          language: f.language || undefined,
-          withheld: f.withheld,
-          size: f.size,
-        })
-      } catch (err) {
-        openViewer({ name: e.name, path: e.path, where, error: why(err) })
-      }
-    },
+    open: (e) => openServerFile(e.path, e.name),
   })
 }
 
+/** A file in the server's tree, in the viewer: from the explorer and from a chat's outputs. */
+export async function openServerFile(path, name) {
+  const where = t("Server")
+  try {
+    const f = await readServer(path)
+    openViewer({
+      name: f.name || name,
+      path: f.path || path,
+      where,
+      text: f.text,
+      // The server's own kind and language: its table and the viewer's are the same one.
+      kind: ["markdown", "code", "text", "html"].includes(f.kind) ? f.kind : undefined,
+      language: f.language || undefined,
+      withheld: f.withheld,
+      size: f.size,
+    })
+  } catch (err) {
+    openViewer({ name, path, where, error: why(err) })
+  }
+}
+
 export function initExplorer() {
   for (const pane of document.querySelectorAll(".pane")) {
     const toggle = pane.querySelector(".pane__toggle")
diff --git a/ui/js/main.js b/ui/js/main.js
index b0f9a9d..44cca28 100644
--- a/ui/js/main.js
+++ b/ui/js/main.js
@@ -14,6 +14,7 @@ import { initList, refreshList, markCurrent } from "./list.js"
 import { initChat, openChat, newChat, closeChat, openChatId, chatMenu } from "./chat.js"
 import { initAttach, allowAttach } from "./attach.js"
 import { initPalette, openPalette } from "./palette.js"
+import { initActivity, showPanel, togglePanel, panelOpen } from "./activity.js"
 
 let status = null
 let view = "" // "setup" | "app"
@@ -171,6 +172,7 @@ function commands() {
     { label: t("New chat"), run: () => startNew("chat") },
     { label: t("Settings"), run: () => showSettings(true) },
   ]
+  if (openChatId()) out.push({ label: panelOpen() ? t("Close the activity panel") : t("Open the activity panel"), run: togglePanel })
   if (status?.linked) out.push({ label: status.agent_wanted ? t("Stop the agent") : t("Start the agent"), run: () => invoke("set_agent", { on: !status.agent_wanted }) })
   out.push(
     { label: status?.linked ? t("Link again") : t("Link this computer"), run: () => invoke("link_computer").catch(() => showSettings(true)) },
@@ -191,6 +193,7 @@ function sideOpen(on) {
 // --- Settings -----------------------------------------------------------------------------------
 
 function showSettings(on) {
+  if (on) showPanel(false)
   $("settings").hidden = !on
   $("main").hidden = on
   if (on) {
@@ -241,6 +244,11 @@ async function boot() {
   onViewer((on) => {
     $("shell").dataset.viewer = String(on)
   })
+  initActivity({
+    onLayout: (on) => {
+      $("shell").dataset.activity = String(on)
+    },
+  })
 
   for (const b of document.querySelectorAll(".switch button")) b.addEventListener("click", () => setKind(b.dataset.kind))
   $("new-chat-btn").prepend(icon(ICONS.plus))
diff --git a/ui/js/popup.js b/ui/js/popup.js
index 10e9d9d..d5bb560 100644
--- a/ui/js/popup.js
+++ b/ui/js/popup.js
@@ -124,3 +124,45 @@ export function ask({ title, text, value, ok, cancel, danger }) {
     } else okBtn.focus()
   })
 }
+
+/**
+ * A modal dialog that shows a line to copy: `title`, `text`, the line itself (`code`, shown as
+ * it is and selectable), and Copy beside Close. Resolves when it is closed.
+ */
+export function showLine({ title, text, code, copy, copied, close }) {
+  return new Promise((resolve) => {
+    const line = h("pre", { class: "dialog__code", tabindex: "0", text: code })
+    const copyBtn = h("button", { type: "button", class: "btn btn--primary", text: copy })
+    const closeBtn = h("button", { type: "button", class: "btn", text: close })
+    const dlg = h(
+      "dialog",
+      { class: "dialog" },
+      h("div", { class: "dialog__body" }, h("h2", { class: "dialog__title", text: title }), text ? h("p", { class: "muted", text }) : null, line, h("div", { class: "dialog__actions" }, closeBtn, copyBtn)),
+    )
+    const done = () => {
+      dlg.close()
+      dlg.remove()
+      resolve()
+    }
+    copyBtn.addEventListener("click", () => {
+      navigator.clipboard
+        ?.writeText(code)
+        .then(() => (copyBtn.textContent = copied))
+        .catch(() => {
+          // No clipboard: the line is selected, for Ctrl+C.
+          const range = document.createRange()
+          range.selectNodeContents(line)
+          getSelection()?.removeAllRanges()
+          getSelection()?.addRange(range)
+        })
+    })
+    closeBtn.addEventListener("click", done)
+    dlg.addEventListener("cancel", (e) => {
+      e.preventDefault()
+      done()
+    })
+    document.body.append(dlg)
+    dlg.showModal()
+    copyBtn.focus()
+  })
+}