@@ -123,7 +123,8 @@ mark is refused. Use the panel or search for Claude agents.
 - **What agents cost** (pi): the menu's top line totals what pi agents
   spent today, this week, and this month (`$8.86 today · $457 this week ·
   $8.86 this month`); each agent's line adds what its session spent today
-  (menu, panel, search), and `dingger status` shows both. Periods start at
+  (at the right edge in the panel and search, after the place in the
+  menu), and `dingger status` shows both. Periods start at
   00:00 UTC (a week on Monday, a month on its 1st). The daemon reads pi's
   session files (`~/.pi/agent/sessions`, and those of running agents
   elsewhere) in a thread of its own every 15 seconds, only what was
@@ -133,6 +134,15 @@ own file, and summing every file would count them again (in one month
   here, $1,024 of $2,991). The totals include agents since closed or
   started over. Amounts are what pi prices each reply at (its model
   configuration); Claude Code records no prices, so it is not counted.
+- **Context use** (pi): how full each agent's context window is, the
+  number pi's own footer shows. The panel and search draw it as a small
+  meter at the right edge, after the cost (gray; yellow above 70% and red
+  above 90%, as in pi; the number on hover); the menu adds it as text
+  (`$0.70 · 10%`), and `dingger status` has a CTX column. The extension
+  reports it after each message, compaction, model change, and turn; right
+  after compacting pi does not know it until the next reply, and neither
+  does dingger (no meter). Agents on an older extension show none until
+  they reload.
 - **Forgotten drafts** (pi): an agent with text left in its input box shows
   `✎` before its name wherever you are not looking at it (where you look,
   you may be typing it). Idle agents with one come first among idle agents;
@@ -162,7 +172,7 @@
 All per-pane state lives in tmux pane options (`@agent_state`,
 `@dingger_since`, `@dingger_hook`, `@dingger_importance`,
 `@dingger_extension`, `@dingger_control`, `@dingger_draft`,
-`@dingger_cost`), so restarting dingger loses nothing.
+`@dingger_cost`, `@dingger_context`), so restarting dingger loses nothing.
 
 ### Keeping pi agents on the current extension
 
@@ -197,7 +207,7 @@ ## Usage
 
 ```bash
 dingger watch                 # the daemon (run by launchd, see below)
-dingger status                # agents in priority order, with what they spent
+dingger status                # agents in priority order, with cost and context use
 dingger focus [--pane ID]     # jump to an agent (default: the top waiter)
 dingger importance [LEVEL]    # an agent's importance: high, normal, low
 dingger unread [--pane ID]    # mark an idle agent unread (done again)
@@ -271,7 +281,8 @@ `/reload`, an extension's blocked event, screen detection without the
 extension, restore, reloading an agent on an old extension (and refusing
 while busy or with a draft), drafts (reported, cleared, kept across a
 crash and put back by restore), cost (priced replies, counted once across
-a real `pi --fork`), and exit. To try a release without installing it:
+a real `pi --fork`), context use (pi's footer's number, through a
+compaction), and exit. To try a release without installing it:
 `npm install --prefix /tmp/pi-next @earendil-works/pi-coding-agent@<version>`
 (through `sfw`), then `tests/pi-live.sh /tmp/pi-next/node_modules/.bin/pi`.
 

@@ -116,6 +116,9 @@ // left behind. Each session's draft is also kept in a file of its own, so
 // it comes back when the session does after a crash, a restart, or
 // `pi --session`.
 let draft = "";
+// How full the context window is, in percent, as pi's footer shows it;
+// "" when unknown (right after compacting, before the next reply).
+let context = "";
 const draftDir = path.join(path.dirname(socketPath), "drafts");
 // Enough to find the agent by it; the file keeps all of it.
 const reportedDraftChars = 500;
@@ -178,6 +181,7 @@ importance,
       extension: extensionVersion,
       ...(controlListening ? { control: controlPath } : {}),
       draft: draft.slice(0, reportedDraftChars),
+      context,
       seq: Date.now() * 1000,
       ...(sessionFile ? { agent_session_path: sessionFile } : {}),
     },
@@ -342,6 +346,26 @@ saveDraft(text);
     void report(undefined);
   }
 
+  /** Report how full the context window is, when that changed. */
+  function checkContext(ctx: any, quiet = false): void {
+    let next = "";
+    try {
+      const percent = ctx?.getContextUsage?.()?.percent;
+      if (typeof percent === "number" && Number.isFinite(percent)) {
+        next = percent.toFixed(1);
+      }
+    } catch {
+      return;
+    }
+    if (next === context) {
+      return;
+    }
+    context = next;
+    if (!quiet) {
+      void report(undefined);
+    }
+  }
+
   function checkDraftSoon(): void {
     if (draftTimer) {
       clearTimeout(draftTimer);
@@ -469,6 +493,8 @@ });
     // Each session has its own: /new starts at normal, /resume brings its own back.
     importance = savedImportance(ctx);
     announceImportance();
+    // The report below carries it.
+    checkContext(ctx, true);
     publishState(true);
   });
 
@@ -481,6 +507,15 @@ // The prompt left the input box.
     checkDraftSoon();
   });
 
+  // Each message fills the context (a prompt by pi's estimate, a reply by
+  // its usage); compacting empties it; another model or branch changes it.
+  for (const event of ["message_end", "session_compact", "model_select", "session_tree"]) {
+    pi.on(event, (_event, ctx) => {
+      latestCtx = ctx;
+      checkContext(ctx);
+    });
+  }
+
   pi.on("agent_settled", (_event, ctx) => {
     latestCtx = ctx;
     if (ctx?.isIdle?.() !== true) {
@@ -488,6 +523,8 @@ return;
     }
 
     agentActive = false;
+    // The last reply's usage: message_end comes before pi counts it.
+    checkContext(ctx);
     publishState();
     // Escape puts queued messages back into the input box.
     checkDraftSoon();

@@ -28,7 +28,9 @@ //! `{"method":"agents.reload_outdated"}`, and the watcher reloads each agent
 //! on an old extension once it is idle and off screen.
 //!
 //! It also carries the `draft` in the agent's input box ("" for none), for
-//! marking a draft you left behind; never logged.
+//! marking a draft you left behind; never logged. And `context`: how full
+//! the agent's context window is, in percent, as pi's footer shows it (""
+//! when unknown, as right after compacting).
 //!
 //! Each line is answered with `{"ok":true}`.
 //!
@@ -74,6 +76,8 @@ extension: Option<String>,
     control: Option<String>,
     /// The draft in the agent's input box, as one line ("" for none).
     draft: Option<String>,
+    /// How full its context window is: whole percent ("" when unknown).
+    context: Option<String>,
     /// When the last report arrived.
     at: Option<Instant>,
 }
@@ -172,6 +176,8 @@ #[serde(default)]
     control: Option<String>,
     #[serde(default)]
     draft: Option<String>,
+    #[serde(default)]
+    context: Option<String>,
 }
 
 fn handle_stream(stream: UnixStream) {
@@ -239,6 +245,7 @@ importance,
             extension: params.extension,
             control: params.control,
             draft: params.draft,
+            context: params.context,
         };
         record(params.pane_id, state, reported);
         wake();
@@ -253,6 +260,7 @@ importance: Option<Importance>,
     extension: Option<String>,
     control: Option<String>,
     draft: Option<String>,
+    context: Option<String>,
 }
 
 /// The longest draft kept: enough to find an agent by it.
@@ -297,9 +305,27 @@ pane.control = Some(control);
     }
     if let Some(draft) = reported.draft {
         pane.draft = Some(draft_line(&draft));
+    }
+    if let Some(context) = reported.context {
+        pane.context = Some(context_percent(&context));
+    }
+}
+
+/// A reported context use as whole percent ("12.6" is "13"); "" for
+/// unknown, or anything not a percentage.
+fn context_percent(value: &str) -> String {
+    match value.trim().parse::<f64>() {
+        Ok(percent) if percent.is_finite() && percent >= 0.0 => format!("{:.0}", percent.min(999.0)),
+        _ => String::new(),
     }
 }
 
+/// How full the pane's agent's context window is ("" when unknown), if its
+/// extension reports it.
+pub fn context(pane_id: &str) -> Option<String> {
+    reports().get(pane_id).and_then(|pane| pane.context.clone())
+}
+
 /// Start listening; reports accumulate for the watcher to consume.
 pub fn spawn_listener() -> Result<(), String> {
     let path = socket_path();
@@ -438,6 +464,21 @@ record("%t4".into(), None, Reported { importance: Some(Importance::Low), ..Default::default() });
         assert_eq!(extension("%t4"), (Some("v1".into()), Some("/s/pi-1.sock".into())));
         record("%t4".into(), None, Reported { extension: Some("v2".into()), ..Default::default() });
         assert_eq!(extension("%t4").0.as_deref(), Some("v2"));
+    }
+
+    #[test]
+    fn context_use_is_kept_as_whole_percent_until_reported_again() {
+        let context = |text: &str| Reported { context: Some(text.into()), ..Default::default() };
+        assert_eq!(super::context("%t6"), None, "an extension that does not report it");
+        record("%t6".into(), None, context("12.6"));
+        assert_eq!(super::context("%t6").as_deref(), Some("13"));
+        record("%t6".into(), None, Reported::default());
+        assert_eq!(super::context("%t6").as_deref(), Some("13"), "kept by a report without one");
+        record("%t6".into(), None, context(""));
+        assert_eq!(super::context("%t6").as_deref(), Some(""), "unknown, after compacting");
+        for (value, want) in [("0", "0"), ("0.4", "0"), ("97.5", "98"), ("1e9", "999"), ("-3", ""), ("NaN", ""), ("x", "")] {
+            assert_eq!(context_percent(value), want, "{value}");
+        }
     }
 
     #[test]

@@ -448,7 +448,8 @@ }
 
 /// Every agent pane in herdr's priority order (blocked, done, working,
 /// idle), oldest-waiting first within a status. ✎ marks a draft left in
-/// the agent's input box. COST is what a pi agent spent today (UTC); the
+/// the agent's input box. CTX is how full a pi agent's context window is.
+/// COST is what a pi agent spent today (UTC); the
 /// last line totals today, this week, and this month, closed agents included.
 fn status() -> Result<(), String> {
     let mut panes: Vec<_> = tmux::list_panes()?
@@ -467,7 +468,7 @@ (watcher::list_order(status, watcher::forgotten_draft(pane), importance, since), pane.display_target.clone())
     });
     let place = |pane: &tmux::Pane| pane.display_target.replacen(':', " · ", 1);
     let width = panes.iter().map(|pane| place(pane).chars().count()).max().unwrap_or(5).max(5);
-    println!("{:<8} {:<width$}  {:<7} {:>8}  NAME", "STATUS", "WHERE", "AGENT", "COST");
+    println!("{:<8} {:<width$}  {:<7} {:>8} {:>4}  NAME", "STATUS", "WHERE", "AGENT", "COST", "CTX");
     for pane in &panes {
         let state = if pane.written_state.is_empty() { "-" } else { &pane.written_state };
         let agent = pane.agent.map(detect_core::agent_label).unwrap_or("-");
@@ -478,7 +479,8 @@ importance::Importance::Low => format!("{} (low)", pane.written_name),
             importance::Importance::Normal => pane.written_name.clone(),
         };
         let cost = if pane.written_cost.is_empty() { String::new() } else { format!("${}", pane.written_cost) };
-        println!("{state:<8} {:<width$}  {agent:<7} {cost:>8}  {draft}{}", place(pane), name.trim());
+        let context = if pane.written_context.is_empty() { String::new() } else { format!("{}%", pane.written_context) };
+        println!("{state:<8} {:<width$}  {agent:<7} {cost:>8} {context:>4}  {draft}{}", place(pane), name.trim());
     }
     let global = |name: &str| tmux::show_global(name).unwrap_or_default();
     let spent = [("today", "@dingger_cost_today"), ("this week", "@dingger_cost_week"), ("this month", "@dingger_cost_month")]

@@ -36,6 +36,8 @@ /// The draft in the agent's input box, as one line.
     pub written_draft: String,
     /// What the agent's session spent today (UTC), in dollars.
     pub written_cost: String,
+    /// How full the agent's context window is, in whole percent.
+    pub written_context: String,
 }
 
 
@@ -121,14 +123,15 @@ "#{@dingger_importance}\t",
         "#{@dingger_extension}\t",
         "#{@dingger_control}\t",
         "#{@dingger_draft}\t",
-        "#{@dingger_cost}",
+        "#{@dingger_cost}\t",
+        "#{@dingger_context}",
     );
     let out = run_tmux(&["list-panes", "-a", "-F", format])?;
     let mut panes: Vec<Pane> = Vec::new();
     let mut process_tree = None;
     for line in out.lines() {
         let fields: Vec<&str> = line.split('\t').collect();
-        if fields.len() < 24 {
+        if fields.len() < 25 {
             continue;
         }
         let attended = fields[4] == "1" && fields[5] != "0";
@@ -175,6 +178,7 @@ written_extension: fields[20].to_string(),
             written_control: fields[21].to_string(),
             written_draft: fields[22].to_string(),
             written_cost: fields[23].to_string(),
+            written_context: fields[24].to_string(),
         });
     }
     Ok(panes)

@@ -28,6 +28,7 @@ //! - `@dingger_extension`, `@dingger_control` the version of pi's extension
 //!   and its control socket, for reloading agents on an old one
 //! - `@dingger_draft` the draft in the agent's input box, as one line
 //! - `@dingger_cost`  what the agent's session spent today (see `cost`)
+//! - `@dingger_context` how full its context window is, in whole percent
 
 use std::collections::HashMap;
 
@@ -525,6 +526,12 @@ // The draft goes with the agent too.
         match (pane.agent, hooks::draft(&pane.pane_id)) {
             (Some(_), Some(draft)) => change("@dingger_draft", &pane.written_draft, draft),
             (None, _) => change("@dingger_draft", &pane.written_draft, String::new()),
+            _ => {}
+        }
+        // And how full its context window is.
+        match (pane.agent, hooks::context(&pane.pane_id)) {
+            (Some(_), Some(context)) => change("@dingger_context", &pane.written_context, context),
+            (None, _) => change("@dingger_context", &pane.written_context, String::new()),
             _ => {}
         }
         if let Err(err) = tmux::set_pane_options(&pane.pane_id, &changes) {

@@ -30,6 +30,9 @@ let mochaText = mocha(205, 214, 244)
 let mochaSubtext = mocha(166, 173, 200)
 let mochaOverlay = mocha(108, 112, 134)
 let mochaBlue = mocha(137, 180, 250)
+let mochaRed = mocha(243, 139, 168)
+let mochaYellow = mocha(249, 226, 175)
+let mochaSurface = mocha(69, 71, 90)
 
 // MARK: herdr's status vocabulary
 
@@ -99,6 +102,9 @@ /// The user looks at this pane: its window is active in an attached session.
     var attended: Bool = false
     /// What its session spent today (UTC), in dollars (`@dingger_cost`).
     var cost: Double = 0
+    /// How full its context window is, in percent (`@dingger_context`), as
+    /// pi's footer shows it; nil when unknown.
+    var context: Double? = nil
 
     var location: String { "\(session) · \(window)" }
     /// A draft left behind: where the user looks, they may be typing it.
@@ -117,17 +123,41 @@ /// The title's text as plain text: `! ` marks a high agent, `✎ ` a
     /// forgotten draft.
     var markedLabel: String { (importance == .high ? "! " : "") + (forgottenDraft ? "✎ " : "") + label }
 
-    /// Dim second line: where it runs, which harness, whether it is low,
-    /// what it spent today, and how long it waits.
+    /// The menu's dim second line: where it runs, which harness, whether
+    /// it is low, how long it waits, what it spent today, and how full its
+    /// context is.
     var subtitle: String {
+        var parts = [place]
+        if cost >= 0.005 { parts.append(dollars(cost)) }
+        if let context { parts.append(contextText(context)) }
+        return parts.joined(separator: " · ")
+    }
+
+    /// The panel's second line, before its cost and context columns.
+    var place: String {
         var parts = [location, agent]
         if importance == .low { parts.append("low") }
-        if cost >= 0.005 { parts.append(dollars(cost)) }
         if waiting, since != Int.max {
             parts.append("\(status.rawValue) \(elapsed(sinceMs: since))")
         }
         return parts.joined(separator: " · ")
     }
+
+    /// The panel's row as text: its columns, then cost and context.
+    var panelText: String {
+        let right = [cost >= 0.005 ? dollars(cost) : nil, context.map(contextText)].compactMap { $0 }
+        return "\(status.symbol) \(status.rawValue)\t\(markedLabel)\t\(place)"
+            + (right.isEmpty ? "" : "\t" + right.joined(separator: " "))
+    }
+}
+
+/// "10%".
+func contextText(_ value: Double) -> String { "\(Int(value.rounded()))%" }
+
+/// The context meter's color: as pi's footer, yellow above 70% and red
+/// above 90%; nil below.
+func contextWarning(_ value: Double) -> NSColor? {
+    value > 90 ? mochaRed : value > 70 ? mochaYellow : nil
 }
 
 /// "$0.42", "$19.85"; whole dollars from $100: "$1,967".
@@ -326,19 +356,19 @@ func fetchRows() -> [Row] {
     let format = [
         "#{pane_id}", "#{@agent}", "#{@agent_state}", "#{@dingger_since}", "#{@agent_name}",
         "#{session_name}", "#{window_name}", "#{window_panes}", "#{pane_index}", "#{pane_current_path}",
-        "#{@dingger_importance}", "#{window_active}", "#{session_attached}", "#{@dingger_draft}", "#{@dingger_cost}",
+        "#{@dingger_importance}", "#{window_active}", "#{session_attached}", "#{@dingger_draft}", "#{@dingger_cost}", "#{@dingger_context}",
     ].joined(separator: "\t")
     guard let out = tmux(["list-panes", "-a", "-F", format]) else { return [] }
     let lines = out.split(separator: "\n").map {
         $0.split(separator: "\t", omittingEmptySubsequences: false).map(String.init)
     }
     // Looked at in any of its sessions, as the daemon counts it.
-    let attended = Set(lines.filter { $0.count >= 15 && $0[11] == "1" && $0[12] != "0" }.map { $0[0] })
+    let attended = Set(lines.filter { $0.count >= 16 && $0[11] == "1" && $0[12] != "0" }.map { $0[0] })
     // A pane in several sessions (a session group, a linked window) is
     // listed once, under its first session, as the daemon counts it.
     var listed = Set<String>()
     let rows: [Row] = lines.compactMap { f in
-        guard f.count >= 15, !f[1].isEmpty, listed.insert(f[0]).inserted else { return nil }
+        guard f.count >= 16, !f[1].isEmpty, listed.insert(f[0]).inserted else { return nil }
         let status = Status(rawValue: f[2]) ?? .unknown
         guard status != .unknown else { return nil }
         let window = (Int(f[7]) ?? 1) > 1 ? "\(f[6]).\(f[8])" : f[6]
@@ -346,7 +376,7 @@ return Row(paneId: f[0], agent: f[1], name: f[4], status: status,
                    session: f[5], window: window, since: Int(f[3]) ?? Int.max,
                    path: f[9].hasPrefix(home) ? "~" + f[9].dropFirst(home.count) : f[9],
                    importance: Importance(option: f[10]), draft: f[13], attended: attended.contains(f[0]),
-                   cost: Double(f[14]) ?? 0)
+                   cost: Double(f[14]) ?? 0, context: Double(f[15]))
     }
     return rows.sorted(by: listedBefore)
 }

@@ -163,7 +163,7 @@ lines.append("↺ \(offerTitle)\t\(offer.detail)" + (restoring ? "" : "\t[Not now]"))
         }
         for (index, row) in rows.enumerated() {
             if index == separatorBefore { lines.append("---") }
-            lines.append("\(row.status.symbol) \(row.status.rawValue)\t\(row.markedLabel)\t\(row.subtitle)")
+            lines.append(row.panelText)
         }
         if overflow > 0 { lines.append("+\(overflow) more waiting") }
         if showsSummary {
@@ -291,8 +291,10 @@
     @objc private func run() { handler() }
 }
 
-/// One agent row: colored symbol and name, then a dim subtitle. Right-click
-/// offers "Mark as unread" for an idle agent.
+/// One agent row: colored symbol and name, then a dim line with where it
+/// runs, and at its right edge today's cost and a context meter, each in a
+/// fixed column so they line up down the list. Right-click offers "Mark as
+/// unread" for an idle agent.
 final class PanelRowView: ClickView {
     private let selected: Bool
     private let contextMenu: NSMenu?
@@ -311,10 +313,35 @@ super.init(frame: .zero)
         self.onClick = { onClick(row.paneId) }
         let title = singleLine(NSTextField(
             labelWithAttributedString: titleText ?? rowTitle(row, primary: mochaText, secondary: mochaSubtext)))
-        let subtitleLabel = NSTextField(labelWithString: row.subtitle)
-        subtitleLabel.font = .systemFont(ofSize: 11)
-        subtitleLabel.textColor = mochaSubtext
-        let subtitle = singleLine(subtitleLabel)
+        let placeLabel = NSTextField(labelWithString: row.place)
+        placeLabel.font = .systemFont(ofSize: 11)
+        placeLabel.textColor = mochaSubtext
+        let place = singleLine(placeLabel)
+        let cost = NSTextField(labelWithString: row.cost >= 0.005 ? dollars(row.cost) : "")
+        cost.font = .monospacedDigitSystemFont(ofSize: 11, weight: .regular)
+        cost.textColor = mochaSubtext
+        cost.alignment = .right
+        let meter = ContextMeter(percent: row.context)
+        // The meter at the right edge, the cost before it; the place takes
+        // what is left and truncates.
+        let subtitle = NSView()
+        for view in [place, cost, meter] {
+            view.translatesAutoresizingMaskIntoConstraints = false
+            subtitle.addSubview(view)
+        }
+        NSLayoutConstraint.activate([
+            meter.trailingAnchor.constraint(equalTo: subtitle.trailingAnchor),
+            meter.centerYAnchor.constraint(equalTo: subtitle.centerYAnchor),
+            meter.widthAnchor.constraint(equalToConstant: ContextMeter.size.width),
+            meter.heightAnchor.constraint(equalToConstant: ContextMeter.size.height),
+            cost.trailingAnchor.constraint(equalTo: meter.leadingAnchor, constant: -6),
+            cost.widthAnchor.constraint(equalToConstant: 52),
+            cost.firstBaselineAnchor.constraint(equalTo: place.firstBaselineAnchor),
+            place.leadingAnchor.constraint(equalTo: subtitle.leadingAnchor),
+            place.trailingAnchor.constraint(lessThanOrEqualTo: cost.leadingAnchor, constant: -6),
+            place.topAnchor.constraint(equalTo: subtitle.topAnchor),
+            place.bottomAnchor.constraint(equalTo: subtitle.bottomAnchor),
+        ])
         let stack = NSStackView(views: [title, subtitle])
         stack.orientation = .vertical
         stack.alignment = .leading
@@ -327,7 +354,7 @@ stack.trailingAnchor.constraint(equalTo: trailingAnchor, constant: -8),
             stack.topAnchor.constraint(equalTo: topAnchor, constant: 5),
             stack.bottomAnchor.constraint(equalTo: bottomAnchor, constant: -5),
             title.widthAnchor.constraint(lessThanOrEqualTo: stack.widthAnchor),
-            subtitle.widthAnchor.constraint(lessThanOrEqualTo: stack.widthAnchor),
+            subtitle.widthAnchor.constraint(equalTo: stack.widthAnchor),
         ])
         toolTip = row.name.isEmpty ? nil : row.name
     }
@@ -340,6 +367,38 @@ override func draw(_ dirtyRect: NSRect) {
         guard hovered || selected else { return }
         NSColor.white.withAlphaComponent(selected ? 0.14 : 0.08).setFill()
         NSBezierPath(roundedRect: bounds, xRadius: 6, yRadius: 6).fill()
+    }
+}
+
+/// How full an agent's context window is: a small bar, gray, then yellow
+/// above 70% and red above 90% (as pi's footer); nothing when unknown.
+final class ContextMeter: NSView {
+    static let size = NSSize(width: 44, height: 5)
+    let percent: Double?
+
+    init(percent: Double?) {
+        self.percent = percent
+        super.init(frame: NSRect(origin: .zero, size: Self.size))
+        translatesAutoresizingMaskIntoConstraints = false
+        toolTip = percent.map { "\(contextText($0)) of context" }
+    }
+
+    required init?(coder: NSCoder) { fatalError("not used") }
+
+    /// The filled part: at least a dot, at most the whole bar.
+    static func fill(_ percent: Double, width: CGFloat) -> CGFloat {
+        max(size.height, min(width, width * CGFloat(percent) / 100))
+    }
+
+    override func draw(_ dirtyRect: NSRect) {
+        guard let percent else { return }
+        let radius = bounds.height / 2
+        mochaSurface.setFill()
+        NSBezierPath(roundedRect: bounds, xRadius: radius, yRadius: radius).fill()
+        (contextWarning(percent) ?? mochaOverlay.blended(withFraction: 0.35, of: mochaSubtext) ?? mochaOverlay).setFill()
+        var filled = bounds
+        filled.size.width = Self.fill(percent, width: bounds.width)
+        NSBezierPath(roundedRect: filled, xRadius: radius, yRadius: radius).fill()
     }
 }
 
@@ -718,12 +777,28 @@ "full: no separator without waiting agents")
     check(full.plainText.hasSuffix("[Show less ▴]") && !compact.plainText.contains("Show"),
           "toggle offered only when allowed, labelled by layout")
 
+    // Context use.
+    var filling = row("f", .idle)
+    filling.cost = 3.12
+    filling.context = 78.4
+    check(filling.subtitle == "s · f · pi · $3.12 · 78%", "context: the menu's text, after the cost")
+    check(filling.place == "s · f · pi" && filling.panelText.hasSuffix("\ts · f · pi\t$3.12 78%"),
+          "context: the panel's columns")
+    check(contextWarning(70) == nil && contextWarning(70.5) == mochaYellow && contextWarning(90.5) == mochaRed,
+          "context: pi's colors, above 70% and 90%")
+    check(ContextMeter.fill(0, width: 44) == 5 && ContextMeter.fill(50, width: 44) == 22
+          && ContextMeter.fill(150, width: 44) == 44, "context: the bar's fill")
+    filling.context = nil
+    filling.cost = 0
+    check(filling.subtitle == "s · f · pi" && !filling.panelText.contains("%"), "context: unknown, nothing")
+
     // Spend.
     check(dollars(0.42) == "$0.42" && dollars(19.849) == "$19.85" && dollars(99.994) == "$99.99"
           && dollars(99.996) == "$100" && dollars(1967.14) == "$1,967", "spend: cents below $100, then whole dollars")
     var spender = row("s", .done)
     spender.cost = 19.85
-    check(spender.subtitle.hasPrefix("s · s · pi · $19.85 · done "), "spend: today's in the subtitle, before the wait")
+    check(spender.subtitle.hasPrefix("s · s · pi · done ") && spender.subtitle.hasSuffix(" · $19.85"),
+          "spend: today's in the menu's subtitle, after the wait")
     spender.cost = 0.004
     check(!spender.subtitle.contains("$"), "spend: nothing spent, nothing shown")
     check(Spend(today: 8.86, week: 456.87, month: 8.86).line == "$8.86 today · $457 this week · $8.86 this month"

@@ -180,7 +180,7 @@ }
         for match in visible {
             let row = match.row
             let marker = row.paneId == selected ? "›" : " "
-            lines.append("\(marker) \(row.status.symbol) \(row.status.rawValue)\t\(row.markedLabel)\t\(row.subtitle)")
+            lines.append("\(marker) \(row.panelText)")
         }
         lines.append(footer)
         return lines.joined(separator: "\n")

@@ -1144,6 +1144,40 @@ expect "in the total too" "gopt @dingger_cost_today" 2.75
 t kill-session -t cost
 expect "closed agents still count" "gopt @dingger_cost_today" 2.75 10
 
+# --- 26. how full each agent's context is --------------------------------------
+echo "26. context use"
+context_report() { # pane context
+  python3 - "$HOOK" "$1" "$2" <<'PY'
+import json, socket, sys
+params = {"pane_id": sys.argv[2], "agent": "pi", "state": "idle", "context": sys.argv[3]}
+s = socket.socket(socket.AF_UNIX)
+s.connect(sys.argv[1])
+s.sendall((json.dumps({"method": "pane.report_agent", "params": params}) + "\n").encode())
+s.close()
+PY
+}
+# A process named pi (found by name, so it can also exit), started in a
+# shell that stays.
+t new-session -d -s ctx -n x1 -c "$DIR" "/bin/sh"
+X1=$(t display -p -t ctx:x1 '#{pane_id}')
+t send-keys -t "$X1" "$DIR/rbin/real/pi 100000" Enter
+# The daemon polls slowly here; a poke has it look now.
+expect "a pi agent" "$DINGGER poke; opt $X1 @agent" pi 80
+context_report "$X1" 78.4
+expect "kept in whole percent" "opt $X1 @dingger_context" 78 50
+expect "the menu: its percentage" "mb --print | grep -F 'ctx · x1' | cut -f3" "ctx · x1 · pi · 78%"
+expect "the panel: in its own column" "mb --print-panel --full | grep -F 'ctx · x1' | cut -f3,4" "ctx · x1 · pi	78%"
+expect "dingger status: CTX" "$DINGGER status | grep -F 'ctx · x1' | grep -c ' 78%  '" 1
+context_report "$X1" ""
+expect "unknown (compacted): none" "opt $X1 @dingger_context" "" 50
+expect "nor in the menu" "mb --print | grep -F 'ctx · x1' | cut -f3" "ctx · x1 · pi"
+context_report "$X1" 12
+expect "known again" "opt $X1 @dingger_context" 12 50
+t send-keys -t "$X1" C-c
+expect "the agent exits" "$DINGGER poke; opt $X1 @agent" "" 80
+expect "its context goes with it" "opt $X1 @dingger_context" "" 50
+t kill-session -t ctx
+
 # Every daemon this run started must stop with it.
 kill "$DAEMON_PID" "$DAEMON2_PID" 2>/dev/null
 expect "the test daemons stop" "ps -o pid= -p $DAEMON_PID,$DAEMON2_PID | wc -l | tr -d ' '" 0

@@ -16,6 +16,7 @@ PI_BIN=$(cd "$(dirname "$1")" && pwd)/$(basename "$1")
 ROOT=$(cd "$(dirname "$0")/.." && pwd)
 DINGGER="${2:-$ROOT/target/release/dingger}"
 case "$DINGGER" in /*) ;; *) DINGGER="$PWD/$DINGGER" ;; esac
+MENU="$ROOT/target/dingger-menu"
 D=$(mktemp -d /tmp/dingger-pi-live.XXXXXX)
 R="dingger-pi-live-$$"
 PASSES=0; FAILS=0
@@ -50,9 +51,11 @@ # that blocks the way extensions do), one without (screen detection).
 for agent in agent agent-plain; do
   mkdir -p "$D/$agent/extensions"
   cat >"$D/$agent/models.json" <<EOF
-{"providers": {"fake": {"baseUrl": "http://127.0.0.1:$PORT/v1", "api": "openai-completions", "apiKey": "fake", "models": [{"id": "fake-model", "cost": {"input": 100000, "output": 1000000, "cacheRead": 0, "cacheWrite": 0}}]}}}
+{"providers": {"fake": {"baseUrl": "http://127.0.0.1:$PORT/v1", "api": "openai-completions", "apiKey": "fake", "models": [{"id": "fake-model", "contextWindow": 400, "cost": {"input": 100000, "output": 1000000, "cacheRead": 0, "cacheWrite": 0}}]}}}
 EOF
-  echo '{"defaultProvider": "fake", "defaultModel": "fake-model"}' >"$D/$agent/settings.json"
+  # A small window, so a few replies fill it measurably; nothing compacts
+  # on its own, and /compact keeps almost nothing.
+  echo '{"defaultProvider": "fake", "defaultModel": "fake-model", "compaction": {"enabled": false, "keepRecentTokens": 1}}' >"$D/$agent/settings.json"
 done
 PI_CODING_AGENT_DIR="$D/agent" "$DINGGER" install pi >/dev/null
 cat >"$D/agent/extensions/test-blocked.ts" <<'EOF'
@@ -217,6 +220,36 @@ [ "$FORK" != "$SESSION_FILE" ] && [ "$(replies "$FORK")" -eq $((N + 1)) ] \
   && pass "pi --fork: a new file with the $N replies copied and its own" || fail "fork: $FORK ($(replies "$FORK") replies)"
 expect "the fork adds only its own reply" "t show -gv @dingger_cost_today 2>/dev/null" "$(python3 -c "print(f'{4*($N+1):.2f}')")" 30
 expect "the agent's own spend is unchanged" "t show -pv -t main:agent @dingger_cost 2>/dev/null" "$WANT"
+# How full its context is: the number pi's footer shows ("3.3%/400"), in
+# an agent of its own (compacting would hide this one's conversation from
+# the restore below).
+mkdir -p "$D/work3"
+t new-window -d -t main: -n ctx -c "$D/work3"
+t send-keys -t main:ctx "pi $NO_MCP" Enter
+expect "context: an agent of its own" "st ctx" idle 150
+footer() { t capture-pane -p -t main:ctx | grep -oE '(\?|[0-9.]+%)/400' | tail -1 | sed 's|/400||'; }
+as_footer() { python3 -c "import sys; f=sys.argv[1]; print('' if f in ('?', '') else round(float(f.rstrip('%'))))" "$(footer)"; }
+ctx() { t show -pv -t main:ctx @dingger_context 2>/dev/null; }
+same_as_footer() { [ "$(ctx)" = "$(as_footer)" ] && echo same || echo "dingger [$(ctx)] footer [$(footer)]"; }
+expect "context: none yet" "footer; ctx" "0.0%
+0" 30
+for msg in "slow 1 one" "slow 1 two"; do
+  t send-keys -t main:ctx -l "$msg" && t send-keys -t main:ctx Enter
+  expect "and done" "st ctx" done 60
+done
+expect "context: after replies, pi's footer" "footer" "3.3%" 30
+expect "context: dingger has pi's number" same_as_footer same 30
+t send-keys -t main:ctx -l "/compact" && t send-keys -t main:ctx Enter
+expect "context: after compacting, pi does not know" "footer" "?" 60
+expect "context: nor does dingger" same_as_footer same 30
+expect "the menu shows no percentage" "\"$MENU\" --print | grep -F 'main · ctx' | grep -c '%'" 0
+t send-keys -t main:ctx -l "slow 1 after compacting" && t send-keys -t main:ctx Enter
+expect "and done" "st ctx" done 60
+expect "context: known again after a reply" "ctx | grep -cE '^[0-9]+$'" 1 30
+expect "context: pi's number again" same_as_footer same 30
+expect "the menu: the percentage last" "\"$MENU\" --print | grep -F 'main · ctx' | cut -f3 | grep -oE ' [0-9]+%$'" " $(ctx)%"
+expect "the panel: cost, then context" "\"$MENU\" --print-panel --full | grep -F 'main · ctx' | cut -f4 | grep -oE '^\\\$[0-9.]+ [0-9]+%$' | grep -c ' $(ctx)%'" 1
+t kill-window -t main:ctx
 
 echo "2. screen detection (pi without the extension)"
 t send-keys -t main:plain "PI_CODING_AGENT_DIR=$D/agent-plain pi $NO_MCP" Enter