diff --git a/src/agent/environment.rs b/src/agent/environment.rs
index a301894..cd09b48 100644
--- a/src/agent/environment.rs
+++ b/src/agent/environment.rs
@@ -99,7 +99,10 @@ impl SandboxStatus {
 
     /// Memory in use and its limit, in bytes.
     pub fn memory(mut self, used: u64, limit: u64) -> Self {
-        assert!(limit > 0 && used <= limit, "memory {used} of {limit}");
+        assert!(limit > 0, "memory {used} of no limit");
+        if used > limit {
+            log::error!("environment: memory {used} past its limit {limit}; the meter fills");
+        }
         self.memory = Some((used, limit));
         self
     }
@@ -173,7 +176,7 @@ impl RenderOnce for SandboxStatus {
                 Meter::new(
                     (self.id.clone(), "memory"),
                     "Memory",
-                    used as f32 / limit as f32,
+                    used.min(limit) as f32 / limit as f32,
                 )
                 .detail(format!(
                     "{} of {}",
diff --git a/src/agent/memory.rs b/src/agent/memory.rs
index 457dfc3..fae4bb9 100644
--- a/src/agent/memory.rs
+++ b/src/agent/memory.rs
@@ -166,7 +166,7 @@ pub struct Checkpoint {
 pub struct CheckpointList {
     id: ElementId,
     checkpoints: Vec<Checkpoint>,
-    current: usize,
+    current: Option<usize>,
     on_rewind: Option<Pick>,
 }
 
@@ -178,15 +178,17 @@ impl CheckpointList {
         current: usize,
     ) -> Self {
         let checkpoints: Vec<Checkpoint> = checkpoints.into_iter().collect();
-        assert!(
-            current < checkpoints.len(),
-            "checkpoint {current} of {}",
-            checkpoints.len()
-        );
+        let held = current < checkpoints.len();
+        if !held {
+            log::error!(
+                "checkpoints: checkpoint {current} of {}; none current",
+                checkpoints.len()
+            );
+        }
         Self {
             id: id.into(),
             checkpoints,
-            current,
+            current: held.then_some(current),
             on_rewind: None,
         }
     }
@@ -210,7 +212,7 @@ impl RenderOnce for CheckpointList {
                 let rewind = self
                     .on_rewind
                     .clone()
-                    .filter(|_| ix != current)
+                    .filter(|_| current != Some(ix))
                     .map(|rewind| {
                         Button::new((self.id.clone(), format!("rewind-{ix}")), "Rewind to here")
                             .variant(ButtonVariant::Ghost)
@@ -233,12 +235,12 @@ impl RenderOnce for CheckpointList {
                             .items_center()
                             .gap_x_2()
                             .child(plural(point.files as u64, "file", "files"))
-                            .when(ix == current, |meta| {
+                            .when(current == Some(ix), |meta| {
                                 meta.child(div().text_color(colors.accent).child("Here now"))
                             })
                             .children(rewind),
                     );
-                timeline.item(if ix == current {
+                timeline.item(if current == Some(ix) {
                     item.tone(Tone::Accent)
                 } else {
                     item
diff --git a/src/agent/previews.rs b/src/agent/previews.rs
index c100de3..fb9324c 100644
--- a/src/agent/previews.rs
+++ b/src/agent/previews.rs
@@ -71,7 +71,7 @@ pub struct BrowserPreview {
     id: ElementId,
     url: SharedString,
     frames: Vec<SharedString>,
-    shown: usize,
+    shown: Option<usize>,
     ratio: f32,
     loading: bool,
     on_show: Option<Pick>,
@@ -86,12 +86,18 @@ impl BrowserPreview {
         shown: usize,
     ) -> Self {
         let frames: Vec<SharedString> = frames.into_iter().map(Into::into).collect();
-        assert!(shown < frames.len(), "frame {shown} of {}", frames.len());
+        let held = shown < frames.len();
+        if !held {
+            log::error!(
+                "browser preview: frame {shown} of {}; none shown",
+                frames.len()
+            );
+        }
         Self {
             id: id.into(),
             url: url.into(),
             frames,
-            shown,
+            shown: held.then_some(shown),
             ratio: FRAME,
             loading: false,
             on_show: None,
@@ -170,7 +176,7 @@ impl RenderOnce for BrowserPreview {
                         .h(thumb)
                         .rounded(theme.radius(Radius::Sm))
                         .border_1()
-                        .border_color(if ix == shown {
+                        .border_color(if shown == Some(ix) {
                             colors.accent
                         } else {
                             colors.border
@@ -205,7 +211,7 @@ impl RenderOnce for BrowserPreview {
                     .when(strip.is_none(), |frame| {
                         frame.rounded_b(theme.radius(Radius::Lg))
                     })
-                    .child({
+                    .children(shown.map(|shown| {
                         let image =
                             Image::new((self.id.clone(), "frame"), source(&self.frames[shown]))
                                 .size_full();
@@ -214,7 +220,7 @@ impl RenderOnce for BrowserPreview {
                         } else {
                             image
                         }
-                    }),
+                    })),
             )
             .children(strip)
     }
diff --git a/src/agent/progress.rs b/src/agent/progress.rs
index e5cf462..f07e231 100644
--- a/src/agent/progress.rs
+++ b/src/agent/progress.rs
@@ -262,7 +262,10 @@ impl AgentProgress {
         done: usize,
         total: usize,
     ) -> Self {
-        assert!(total > 0 && done <= total, "progress of {done} in {total}");
+        assert!(total > 0, "progress of {done} in none");
+        if done > total {
+            log::error!("agent progress: {done} done of {total}; the bar fills");
+        }
         Self {
             id: id.into(),
             current: current.into(),
@@ -308,7 +311,10 @@ impl RenderOnce for AgentProgress {
                     })),
             )
             .child({
-                let bar = ProgressBar::new((self.id, "bar"), self.done as f32 / self.total as f32);
+                let bar = ProgressBar::new(
+                    (self.id, "bar"),
+                    self.done.min(self.total) as f32 / self.total as f32,
+                );
                 if self.total >= 2 {
                     bar.segments(self.total)
                 } else {
diff --git a/src/agent/tests/environment.rs b/src/agent/tests/environment.rs
index cce5e42..7c803bd 100644
--- a/src/agent/tests/environment.rs
+++ b/src/agent/tests/environment.rs
@@ -163,10 +163,29 @@ fn every_checkpoint_but_the_current_rewinds(cx: &mut TestAppContext) {
     );
 }
 
-#[test]
-#[should_panic(expected = "memory 5 of 4")]
-fn memory_past_its_limit_fails_loud() {
-    let _ = SandboxStatus::new("box", "python", SandboxState::Ready).memory(5, 4);
+/// A sandbox past its memory limit and checkpoints whose current one left.
+struct Overrun;
+
+impl Render for Overrun {
+    fn render(&mut self, _: &mut Window, _: &mut Context<Self>) -> impl IntoElement {
+        let point = Checkpoint {
+            key: "one".into(),
+            label: "One".into(),
+            at: Timestamp::UNIX_EPOCH,
+            files: 1,
+        };
+        div()
+            .w(px(360.0))
+            .child(SandboxStatus::new("box", "python", SandboxState::Ready).memory(5, 4))
+            .child(CheckpointList::new("points", [point], 4))
+    }
+}
+
+#[gpui::test]
+fn memory_past_its_limit_and_a_gone_checkpoint_draw(cx: &mut TestAppContext) {
+    setup(cx);
+    let (_, cx) = cx.add_window_view(|_, _| Overrun);
+    settle(cx);
 }
 
 #[test]
diff --git a/src/agent/tests/mod.rs b/src/agent/tests/mod.rs
index 4fb859d..5d19385 100644
--- a/src/agent/tests/mod.rs
+++ b/src/agent/tests/mod.rs
@@ -129,13 +129,7 @@ fn the_prompt_walks_deny_always_then_once(cx: &mut TestAppContext) {
     );
 }
 
-#[test]
-#[should_panic(expected = "progress of 6 in 5")]
-fn progress_past_its_total_fails_loud() {
-    let _ = AgentProgress::new("progress", "Writing", 6, 5);
-}
-
-/// A progress bar for a task of one step, `done` or not.
+/// A progress bar for a task of one step, `done` or not; live counts may run past it.
 struct Single {
     done: usize,
 }
@@ -148,6 +142,13 @@ impl Render for Single {
     }
 }
 
+#[gpui::test]
+fn progress_past_its_total_fills_the_bar(cx: &mut TestAppContext) {
+    cx.update(Theme::init);
+    let (_, cx) = cx.add_window_view(|_, _| Single { done: 6 });
+    settle(cx);
+}
+
 #[gpui::test]
 fn a_task_of_one_step_draws_before_and_after(cx: &mut TestAppContext) {
     cx.update(Theme::init);
diff --git a/src/agent/tests/previews.rs b/src/agent/tests/previews.rs
index f7c0c1a..936e49c 100644
--- a/src/agent/tests/previews.rs
+++ b/src/agent/tests/previews.rs
@@ -52,10 +52,25 @@ fn a_frame_shows_from_the_keyboard(cx: &mut TestAppContext) {
     );
 }
 
-#[test]
-#[should_panic(expected = "frame 3 of 3")]
-fn a_frame_past_the_last_fails_loud() {
-    let _ = BrowserPreview::new("browser", "localhost", ["a.png", "b.png", "c.png"], 3);
+/// A browser asked to show a frame it no longer holds.
+struct Past;
+
+impl Render for Past {
+    fn render(&mut self, _: &mut Window, _: &mut Context<Self>) -> impl IntoElement {
+        div().w(px(480.0)).child(BrowserPreview::new(
+            "browser",
+            "localhost",
+            ["a.png", "b.png", "c.png"],
+            3,
+        ))
+    }
+}
+
+#[gpui::test]
+fn a_frame_past_the_last_shows_none(cx: &mut TestAppContext) {
+    setup(cx);
+    let (_, cx) = cx.add_window_view(|_, _| Past);
+    settle(cx);
 }
 
 #[test]
diff --git a/tasks/panics.md b/tasks/panics.md
index 4a7999b..cf8ddae 100644
--- a/tasks/panics.md
+++ b/tasks/panics.md
@@ -38,7 +38,7 @@ Each item reads every site in its folders, fixes what the rules name, updates ca
 - [x] P21 Documents — `src/documents`
 - [x] P22 Collaboration — `src/collab`
 - [x] P23 AI Chat — `src/chat`
-- [ ] P24 Agent — `src/agent`
+- [x] P24 Agent — `src/agent`
 - [ ] P25 Generative — `src/generative`
 - [ ] P26 Media — `src/media`
 - [ ] P27 Files — `src/files`
@@ -89,3 +89,4 @@ One line per item: what changed, what stayed and why, review rounds.
 - P21: block editor listeners painted for a block, field, cell or kind since gone log and change nothing, a dropped picture drag leaves undo alone; a visual block press or edit over text the owner replaced is dropped; nested images parse; a version or find hit past its list selects none. Review: 4 rounds.
 - P22: annotations and suggestions outside their text log and stay out, picks and decisions keeping the owner's index; `accept` returns `Option`; a gone pick, active thread or followed peer logs; yours at no count comes off; a masked field clamps a stale offset, so remote cursors and selections draw. Kept: a thread's comments, presence max, one list's order, empty marks, constant role and mode tables. Review: 3 rounds.
 - P23: a branch version past its total logs and shows a dash, its arrows off; a parameter outside its range logs and pegs; a passage's matches outside it log and stay out. Kept: one-value contracts (progress, scores, shapes, peaks, levels, limits, prices, capacity, format, hour), the composer's trigger rows and stream reveal by construction; `places` skips zero, so `decimals` meets no zero step. Review: 2 rounds.
+- P24: a checkpoint or browser frame past its list logs and marks none; progress past its total and memory past its limit log and fill their bars, the text keeping the real counts; three `should_panic` tests became render tests. Kept: the artifact's preview-or-source builder check, one-value contracts (cost, cpu, pointer, totals and limits above zero), registry lookups over a constant table. Review: 1 round.