Add stacked chart primitives for account analytics (#45763)

## What changed Add daily stacked bar rendering in the TUI analytics module, staged for dashboard integration. - Plot three categories plus an Other remainder without renormalizing values, with separate positive and negative bands for signed credits. - Add readable numeric axes, calendar ticks, a selection cursor, and a callout showing the authoritative daily total. Distinguish missing days from zero usage. - Keep the selection visible in narrow viewports and omit labels that cannot fit without truncation. - Use terminal palette colors for series and adapt secondary text to terminal color support and background. ## Testing Add unit and snapshot coverage for axis scaling, signed bars on light and dark terminals, missing and zero values, narrow layouts, tiny segments, authoritative totals, and duplicate-date remainders. GitOrigin-RevId: 2ed58def17abd14e77929016a54fd20e91d45670
2026-09-17 12:23:33 +00:00 · 2026-09-15 18:44:58 +00:00
parent 1fc46a532b
commit af3bc6f796
18 changed files with 1671 additions and 2 deletions
--- a/codex-rs/tui/src/analytics.rs
+++ b/codex-rs/tui/src/analytics.rs
@@ -1,11 +1,13 @@
-//! Account analytics data preparation, staged for the dashboard integration.
+//! Account analytics data and chart primitives, staged for the dashboard integration.

 mod client;
 mod data;
 mod models;
 mod normalize;
+mod plot;
 mod render;
 mod report_data;
+mod styles;
 mod tokens;

 #[cfg(test)]
--- a/codex-rs/tui/src/analytics/plot.rs
+++ b/codex-rs/tui/src/analytics/plot.rs
@@ -0,0 +1,183 @@
+//! Daily stacked bars with fixed calendar ticks, a selection cursor, and an anchored value.
+//! Relative usage retains the server's scale; signed credits keep both bands.
+
+mod annotations;
+mod layout;
+mod painting;
+
+use self::layout::Layout;
+use self::painting::Band;
+use super::data;
+use super::render::parts;
+use crate::analytics::models::AccountAnalyticsDay;
+use crate::analytics::models::AccountAnalyticsUnit;
+use crate::analytics::models::AccountAnalyticsValue;
+use chrono::NaiveDate;
+use ratatui::buffer::Buffer;
+use ratatui::layout::Rect;
+use ratatui::text::Line;
+use ratatui::text::Span;
+use unicode_width::UnicodeWidthStr;
+
+/// Share the chart's scale with the selected-day summary, including signed values.
+pub(super) fn peak(
+    days: &[(NaiveDate, Option<&AccountAnalyticsDay>)],
+    categories: &[AccountAnalyticsValue],
+) -> f64 {
+    days.iter()
+        .filter_map(|(_, day)| *day)
+        .map(|day| {
+            parts(&day.values, categories)
+                .iter()
+                .map(|value| value.abs())
+                .sum::<f64>()
+                .max(day.total.abs())
+        })
+        .fold(/*init*/ 0.0, f64::max)
+}
+
+/// Two readable intervals cover the range; counts never use fractional ticks.
+pub(super) fn axis_max(peak: f64, unit: AccountAnalyticsUnit) -> f64 {
+    if peak == 0.0 {
+        return if matches!(
+            unit,
+            AccountAnalyticsUnit::Count | AccountAnalyticsUnit::Tokens
+        ) {
+            2.0
+        } else {
+            1.0
+        };
+    }
+    let step = if matches!(
+        unit,
+        AccountAnalyticsUnit::Count | AccountAnalyticsUnit::Tokens
+    ) {
+        (peak / 2.0).max(/*other*/ 1.0)
+    } else {
+        peak / 2.0
+    };
+    let magnitude = 10.0_f64.powf(step.log10().floor());
+    let normalized = step / magnitude;
+    let multiple = [1.0, 1.5, 2.0, 2.5, 3.0, 4.0, 5.0, 7.5, 10.0]
+        .into_iter()
+        .find(|multiple| {
+            *multiple >= normalized
+                && (!matches!(
+                    unit,
+                    AccountAnalyticsUnit::Count | AccountAnalyticsUnit::Tokens
+                ) || (multiple * magnitude).fract() == 0.0)
+        })
+        .unwrap_or(/*default*/ 10.0);
+    let ceiling = multiple * magnitude * 2.0;
+    if ceiling.is_finite() && ceiling >= peak {
+        ceiling
+    } else {
+        peak
+    }
+}
+
+/// Rendered chart geometry exposes its positive and optional negative value bands.
+#[derive(Default)]
+pub(super) struct Chart {
+    pub(super) lines: Vec<Line<'static>>,
+    pub(super) bands: usize,
+}
+
+/// Render a calendar selection; the cursor must index days and dimensions fit the terminal.
+pub(super) fn chart(
+    days: &[(NaiveDate, Option<&AccountAnalyticsDay>)],
+    categories: &[AccountAnalyticsValue],
+    cursor: usize,
+    width: usize,
+    height: usize,
+    unit: AccountAnalyticsUnit,
+) -> Chart {
+    if days.is_empty() || width == 0 {
+        return Chart::default();
+    }
+    let values = days
+        .iter()
+        .map(|(_, day)| {
+            day.map_or(
+                /*default*/ [0.0; 4],
+                |day| parts(&day.values, categories),
+            )
+        })
+        .collect::<Vec<_>>();
+    let bands = if values.iter().flatten().any(|value| *value < 0.0) {
+        &[Band::Positive, Band::Negative][..]
+    } else {
+        &[Band::Positive][..]
+    };
+    let peak = axis_max(peak(days, categories), unit);
+    let label_width =
+        tick(peak, unit).width().max(tick(peak / 2.0, unit).width()) + bands.len() - 1 + 2;
+    let layout = Layout::new(days.len(), cursor, width, height, label_width, bands);
+    let renderer = Renderer {
+        days,
+        values,
+        cursor,
+        peak,
+        unit,
+        bands,
+        layout,
+    };
+    let mut buf = Buffer::empty(Rect::new(
+        /*x*/ 0,
+        /*y*/ 0,
+        width as u16,
+        (layout.marker_row + 2) as u16,
+    ));
+    renderer.paint_bars(&mut buf);
+    renderer.annotate_missing(&mut buf);
+    renderer.paint_axis(&mut buf);
+    renderer.annotate_selection(&mut buf);
+    renderer.annotate_calendar(&mut buf);
+    let lines = buf
+        .content
+        .chunks(width)
+        .map(|row| {
+            Line::from(
+                row.iter()
+                    .map(|cell| Span::styled(cell.symbol().to_owned(), cell.style()))
+                    .collect::<Vec<_>>(),
+            )
+        })
+        .collect();
+    Chart {
+        lines,
+        bands: bands.len(),
+    }
+}
+
+/// Shared inputs for painting and annotations; all phases use the same calendar geometry.
+struct Renderer<'a> {
+    days: &'a [(NaiveDate, Option<&'a AccountAnalyticsDay>)],
+    values: Vec<[f64; 4]>,
+    cursor: usize,
+    peak: f64,
+    unit: AccountAnalyticsUnit,
+    bands: &'static [Band],
+    layout: Layout,
+}
+
+fn amount(value: f64, unit: AccountAnalyticsUnit) -> String {
+    match unit {
+        AccountAnalyticsUnit::RelativeUsage => data::amount(value),
+        AccountAnalyticsUnit::Count | AccountAnalyticsUnit::Tokens => data::amount(value.round()),
+        AccountAnalyticsUnit::Credits => data::credit_amount(value),
+    }
+}
+
+fn tick(value: f64, unit: AccountAnalyticsUnit) -> String {
+    match unit {
+        AccountAnalyticsUnit::Credits => data::amount(value),
+        AccountAnalyticsUnit::RelativeUsage
+        | AccountAnalyticsUnit::Count
+        | AccountAnalyticsUnit::Tokens => amount(value, unit),
+    }
+}
+
+#[cfg(test)]
+#[path = "plot_tests.rs"]
+mod tests;
--- a/codex-rs/tui/src/analytics/plot/annotations.rs
+++ b/codex-rs/tui/src/analytics/plot/annotations.rs
@@ -0,0 +1,183 @@
+//! Missing-day markers, selected-value callouts, and stable calendar labels.
+
+use super::Renderer;
+use super::amount;
+use super::layout::Layout;
+use super::painting::Band;
+use crate::analytics::styles::number;
+use crate::analytics::styles::secondary_style;
+use crate::style::accent_style;
+use ratatui::buffer::Buffer;
+use ratatui::style::Style;
+use ratatui::style::Styled;
+use ratatui::style::Stylize;
+use ratatui::text::Line;
+use unicode_width::UnicodeWidthStr;
+
+impl Renderer<'_> {
+    pub(super) fn annotate_missing(&self, buf: &mut Buffer) {
+        let Layout {
+            count,
+            height,
+            start,
+            ..
+        } = self.layout;
+        for (index, parts) in self.values[start..start + count].iter().enumerate() {
+            // The selected zero/missing value gets its own callout below; avoid repeating it.
+            if start + index != self.cursor {
+                let marker = match self.days[start + index].1 {
+                    None => Some('—'),
+                    Some(day) if day.total == 0.0 && parts.iter().all(|value| *value == 0.0) => {
+                        Some('0')
+                    }
+                    Some(_) => None,
+                };
+                if let Some(marker) = marker {
+                    buf[(self.layout.center(index) as u16, height as u16)]
+                        .set_char(marker)
+                        .set_style(Style::default().dim());
+                }
+            }
+        }
+    }
+
+    pub(super) fn annotate_selection(&self, buf: &mut Buffer) {
+        let Layout {
+            axis_width,
+            baseline,
+            height,
+            marker_row,
+            plot_width,
+            start,
+            width,
+            ..
+        } = self.layout;
+        let selected_total = self.days[self.cursor]
+            .1
+            .map_or(/*default*/ 0.0, |day| day.total);
+        let selected = self.days[self.cursor]
+            .1
+            .map_or_else(|| "—".into(), |_| amount(selected_total, self.unit));
+        // A partial number can mean a different amount; leave the cursor when the value cannot fit.
+        let selected = if selected.width() <= plot_width {
+            selected
+        } else {
+            String::new()
+        };
+        let x = self.layout.center(self.cursor - start);
+        let label_width = selected.width();
+        let label_x = x
+            .saturating_sub(label_width / 2)
+            .clamp(axis_width, width - label_width);
+        let below = selected_total < 0.0;
+        let band = if below {
+            Band::Negative
+        } else {
+            Band::Positive
+        };
+        let extent = self.values[self.cursor]
+            .iter()
+            .map(|value| band.amount(*value))
+            .sum::<f64>();
+        let rows = ((extent * height as f64 / self.peak).ceil() as usize).min(height);
+        let cap = if below {
+            baseline + rows
+        } else {
+            baseline - rows
+        };
+        let mut label_y = if below {
+            cap + 1
+        } else {
+            cap.saturating_sub(/*rhs*/ 1)
+        };
+        // Keep the callout close without painting over a neighboring bar. A guide connects any gap.
+        while (label_x..label_x + label_width)
+            .any(|col| buf[(col as u16, label_y as u16)].symbol() != " ")
+        {
+            if below {
+                label_y += 1;
+            } else if label_y > 0 {
+                label_y -= 1;
+            } else {
+                break;
+            }
+        }
+        let guide = if below {
+            cap + 1..label_y
+        } else {
+            label_y + 1..cap
+        };
+        for y in guide {
+            buf[(x as u16, y as u16)]
+                .set_char('┊')
+                .set_style(accent_style());
+        }
+        buf.set_line(
+            label_x as u16,
+            label_y as u16,
+            &Line::from(number(selected)),
+            label_width as u16,
+        );
+        buf[(x as u16, marker_row as u16)]
+            .set_char('▲')
+            .set_style(accent_style());
+    }
+
+    pub(super) fn annotate_calendar(&self, buf: &mut Buffer) {
+        let Layout {
+            axis_width,
+            count,
+            marker_row,
+            plot_width,
+            start,
+            width,
+            ..
+        } = self.layout;
+        // Calendar ticks depend only on the range/width, never on the current selection.
+        let mut occupied = vec![false; width];
+        // Give the two range endpoints priority over intermediate weekly ticks.
+        for index in std::iter::once(/*value*/ 0).chain((1..count).rev()) {
+            if self.days.len() > 7
+                && !(start + index).is_multiple_of(/*rhs*/ 7)
+                && index + 1 != count
+            {
+                continue;
+            }
+            let format = if self.days.len() <= 7 && plot_width / count < 7 {
+                "%-d"
+            } else {
+                "%b %-d"
+            };
+            let mut label = self.days[start + index].0.format(format).to_string();
+            if label.width() > plot_width {
+                label = self.days[start + index].0.format("%-d").to_string();
+            }
+            if label.width() > plot_width {
+                continue;
+            }
+            let offset = self
+                .layout
+                .center(index)
+                .saturating_sub(label.len() / 2)
+                .clamp(axis_width, width - label.len());
+            if occupied[offset.saturating_sub(/*rhs*/ 1)..(offset + label.len() + 1).min(width)]
+                .iter()
+                .any(|used| *used)
+            {
+                continue;
+            }
+            occupied[offset..offset + label.len()].fill(/*value*/ true);
+            let label = if start + index == self.cursor {
+                label.set_style(accent_style()).underlined()
+            } else {
+                label.set_style(secondary_style())
+            };
+            buf.set_line(
+                offset as u16,
+                (marker_row + 1) as u16,
+                &Line::from(label),
+                (width - offset) as u16,
+            );
+        }
+    }
+}
--- a/codex-rs/tui/src/analytics/plot/layout.rs
+++ b/codex-rs/tui/src/analytics/plot/layout.rs
@@ -0,0 +1,55 @@
+//! Calendar viewport and shared coordinates for bars, axes, and annotations.
+
+use super::painting::Band;
+
+#[derive(Clone, Copy)]
+pub(super) struct Layout {
+    pub(super) width: usize,
+    pub(super) height: usize,
+    pub(super) axis_width: usize,
+    pub(super) plot_width: usize,
+    pub(super) count: usize,
+    pub(super) start: usize,
+    pub(super) baseline: usize,
+    pub(super) marker_row: usize,
+}
+
+impl Layout {
+    pub(super) fn new(
+        day_count: usize,
+        cursor: usize,
+        width: usize,
+        height: usize,
+        label_width: usize,
+        bands: &[Band],
+    ) -> Self {
+        // Hide the axis when a complete label would crowd out the bars.
+        let axis_width = if width >= 30 && label_width <= width / 3 {
+            label_width
+        } else {
+            0
+        };
+        let plot_width = width - axis_width;
+        let count = day_count.min(plot_width);
+        let start = cursor.saturating_sub(count - 1).min(day_count - count);
+        let baseline = height + 1;
+        let marker_row = baseline + if bands.len() == 2 { height + 2 } else { 1 };
+        Self {
+            width,
+            height,
+            axis_width,
+            plot_width,
+            count,
+            start,
+            baseline,
+            marker_row,
+        }
+    }
+
+    pub(super) fn center(self, index: usize) -> usize {
+        self.axis_width
+            + (index * self.plot_width / self.count + (index + 1) * self.plot_width / self.count
+                - 1)
+                / 2
+    }
+}
--- a/codex-rs/tui/src/analytics/plot/painting.rs
+++ b/codex-rs/tui/src/analytics/plot/painting.rs
@@ -0,0 +1,132 @@
+//! Paint signed bar cells and numeric axes using the shared layout and scale.
+
+use super::Renderer;
+use super::layout::Layout;
+use super::tick;
+use crate::analytics::styles::secondary_style;
+use crate::analytics::styles::series_colors;
+use ratatui::buffer::Buffer;
+use ratatui::style::Style;
+use ratatui::style::Styled;
+use ratatui::text::Line;
+
+/// A signed stack grows away from the baseline; amounts are nonnegative within each band.
+#[derive(Clone, Copy)]
+pub(super) enum Band {
+    Positive,
+    Negative,
+}
+
+impl Band {
+    pub(super) fn amount(self, value: f64) -> f64 {
+        match self {
+            Self::Positive => value,
+            Self::Negative => -value,
+        }
+        .max(/*other*/ 0.0)
+    }
+
+    fn row_y(self, baseline: usize, row: usize) -> usize {
+        match self {
+            Self::Positive => baseline - row - 1,
+            Self::Negative => baseline + row + 1,
+        }
+    }
+
+    fn partial_glyph(self, level: usize) -> char {
+        // Reversing the complementary lower block paints a top-anchored partial refund.
+        let index = match self {
+            Self::Negative if level < 8 => 8 - level,
+            Self::Positive | Self::Negative => level,
+        };
+        [' ', '▁', '▂', '▃', '▄', '▅', '▆', '▇', '█'][index]
+    }
+}
+
+impl Renderer<'_> {
+    pub(super) fn paint_bars(&self, buf: &mut Buffer) {
+        let Layout {
+            axis_width,
+            baseline,
+            count,
+            height,
+            plot_width,
+            start,
+            ..
+        } = self.layout;
+        let colors = series_colors();
+        for (index, parts) in self.values[start..start + count].iter().enumerate() {
+            let left = axis_width + index * plot_width / count;
+            let step = (index + 1) * plot_width / count - index * plot_width / count;
+            let bar_width = (step * 2 / 3).clamp(/*min*/ 1, /*max*/ 12);
+            let x = left + (step - bar_width) / 2;
+            for band in self.bands {
+                let plotted = parts.iter().map(|value| band.amount(*value)).sum::<f64>();
+                let scaled = ((plotted * (height * 8) as f64 / self.peak) as usize)
+                    .max(usize::from(plotted > 0.0));
+                for row in 0..height {
+                    let level = scaled.saturating_sub(row * 8).min(/*other*/ 8);
+                    if level == 0 {
+                        continue;
+                    }
+                    let reverse = matches!(band, Band::Negative) && level < 8;
+                    let glyph = band.partial_glyph(level);
+                    let bottom = (row * 8) as f64 * self.peak / (height * 8) as f64;
+                    let top =
+                        ((row * 8 + level) as f64 * self.peak / (height * 8) as f64).min(plotted);
+                    let sample = bottom + (top - bottom) / 2.0;
+                    let mut cumulative = 0.0;
+                    let color = parts
+                        .iter()
+                        .position(|value| {
+                            cumulative += band.amount(*value);
+                            sample < cumulative
+                        })
+                        .unwrap_or(/*default*/ 3);
+                    let y = band.row_y(baseline, row);
+                    for col in x..x + bar_width {
+                        let cell = &mut buf[(col as u16, y as u16)];
+                        cell.set_char(glyph).set_fg(colors[color]);
+                        if reverse {
+                            cell.set_style(Style::default().reversed());
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    pub(super) fn paint_axis(&self, buf: &mut Buffer) {
+        let Layout {
+            axis_width,
+            baseline,
+            height,
+            width,
+            ..
+        } = self.layout;
+        for x in axis_width..width {
+            buf[(x as u16, baseline as u16)]
+                .set_char('─')
+                .set_style(Style::default().dim());
+        }
+        if axis_width > 0 {
+            let mut ticks = vec![(1, self.peak), (baseline, 0.0)];
+            if height >= 4 {
+                ticks.push((1 + height / 2, self.peak / 2.0));
+            }
+            if self.bands.len() == 2 {
+                ticks.push((baseline + height, -self.peak));
+            }
+            for (y, value) in ticks {
+                let label = tick(value, self.unit);
+                let x = axis_width.saturating_sub(label.len() + 1);
+                buf.set_line(
+                    x as u16,
+                    y as u16,
+                    &Line::from(label.set_style(secondary_style())),
+                    axis_width as u16,
+                );
+            }
+        }
+    }
+}
--- a/codex-rs/tui/src/analytics/plot_tests.rs
+++ b/codex-rs/tui/src/analytics/plot_tests.rs
@@ -0,0 +1,462 @@
+//! Chart scales, signed bands, missing days, narrow viewports, and terminal palettes.
+
+use super::*;
+use crate::analytics::models::AccountAnalyticsHistory;
+use crate::analytics::render::categories;
+use crate::analytics::styles::series_colors;
+use crate::terminal_palette::with_test_default_colors;
+use crate::terminal_probe::DefaultColors;
+use pretty_assertions::assert_eq;
+
+fn value(key: &str, value: f64) -> AccountAnalyticsValue {
+    AccountAnalyticsValue {
+        key: key.into(),
+        label: key.into(),
+        value,
+    }
+}
+
+fn display(chart: &Chart) -> String {
+    let text = chart
+        .lines
+        .iter()
+        .map(|line| line.to_string().trim_end().to_owned())
+        .collect::<Vec<_>>()
+        .join("\n");
+    let mut palette = Vec::new();
+    let mut rows = Vec::new();
+    for (row, line) in chart.lines.iter().enumerate() {
+        let mut previous = None;
+        let mut runs = Vec::new();
+        let mut column = 0;
+        for span in &line.spans {
+            let style = format!("{:?}", span.style);
+            let index = palette
+                .iter()
+                .position(|candidate| *candidate == style)
+                .unwrap_or_else(|| {
+                    palette.push(style);
+                    palette.len() - 1
+                });
+            if previous != Some(index) {
+                runs.push(format!("{column}:{index}"));
+                previous = Some(index);
+            }
+            column += span.width();
+        }
+        rows.push(format!("{row}: {}", runs.join(" ")));
+    }
+    let palette = palette
+        .iter()
+        .enumerate()
+        .map(|(index, style)| format!("{index}: {style}"))
+        .collect::<Vec<_>>()
+        .join("\n");
+    format!(
+        "{text}\n\nPalette:\n{palette}\nRows (column:palette):\n{}",
+        rows.join("\n")
+    )
+}
+
+#[test]
+fn numeric_axes_use_readable_intervals() {
+    use AccountAnalyticsUnit::Count;
+    use AccountAnalyticsUnit::Credits;
+    use AccountAnalyticsUnit::RelativeUsage;
+    use AccountAnalyticsUnit::Tokens;
+    let cases = [
+        (82.0, Count, 100.0),
+        (4_400.0, Credits, 5_000.0),
+        (4_999.0, Credits, 5_000.0),
+        (5_001.0, Credits, 6_000.0),
+        (49.0, Count, 50.0),
+        (1.0, Count, 2.0),
+        (3.0, Count, 4.0),
+        (1_337.0, Credits, 1_500.0),
+        (0.07, Credits, 0.08),
+        (0.000004, Credits, 0.000004),
+        (82.0, RelativeUsage, 100.0),
+        (1.0, Tokens, 2.0),
+    ];
+    assert_eq!(
+        cases.map(|(peak, unit, _)| axis_max(peak, unit)),
+        cases.map(|(_, _, expected)| expected)
+    );
+}
+
+#[test]
+fn stacked_parts_keep_the_remainder_and_full_denominator() {
+    let values = vec![
+        value("a", /*value*/ 4.0),
+        value("b", /*value*/ 2.0),
+        value("c", /*value*/ 1.0),
+        value("d", /*value*/ 6.0),
+        value("e", /*value*/ -1.0),
+    ];
+    let categories = vec![values[1].clone(), values[0].clone(), values[2].clone()];
+    assert_eq!(parts(&values, &categories), [2.0, 4.0, 1.0, 5.0]);
+    let day = AccountAnalyticsDay {
+        date: "2026-01-15".parse().unwrap(),
+        total: 20.0,
+        values,
+    };
+    let date = day.date;
+    assert_eq!(peak(&[(date, Some(&day))], &categories), 20.0);
+    let refund = AccountAnalyticsDay {
+        total: -1.0,
+        values: vec![value("a", /*value*/ 4.0), value("b", /*value*/ -5.0)],
+        ..day
+    };
+    assert_eq!(peak(&[(date, Some(&refund))], &categories), 9.0);
+}
+
+#[test]
+fn signed_chart_on_light_terminal() {
+    signed_chart(
+        "light",
+        DefaultColors {
+            fg: (0, 0, 0),
+            bg: (255, 255, 255),
+        },
+    );
+}
+
+#[test]
+fn signed_chart_on_dark_terminal() {
+    signed_chart(
+        "dark",
+        DefaultColors {
+            fg: (230, 230, 230),
+            bg: (16, 16, 16),
+        },
+    );
+}
+
+fn signed_chart(theme: &str, colors: DefaultColors) {
+    let history = AccountAnalyticsHistory {
+        unit: AccountAnalyticsUnit::Credits,
+        updated_at: None,
+        data: vec![
+            AccountAnalyticsDay {
+                date: "2026-01-13".parse().unwrap(),
+                total: 8.0,
+                values: vec![value("a", /*value*/ 10.0), value("b", /*value*/ -2.0)],
+            },
+            AccountAnalyticsDay {
+                date: "2026-01-14".parse().unwrap(),
+                total: -3.0,
+                values: vec![value("a", /*value*/ 1.0), value("b", /*value*/ -4.0)],
+            },
+            AccountAnalyticsDay {
+                date: "2026-01-15".parse().unwrap(),
+                total: 0.0,
+                values: vec![value("a", /*value*/ 3.0), value("b", /*value*/ -3.0)],
+            },
+        ],
+    };
+    let days = history
+        .data
+        .iter()
+        .map(|day| (day.date, Some(day)))
+        .collect::<Vec<_>>();
+    let categories = categories(&history);
+    with_test_default_colors(colors, || {
+        let rendered = chart(
+            &days,
+            &categories,
+            /*cursor*/ 1,
+            /*width*/ 44,
+            /*height*/ 4,
+            history.unit,
+        );
+        assert_eq!(rendered.bands, 2);
+        insta::assert_snapshot!(format!("signed_chart_{theme}"), display(&rendered));
+    });
+}
+
+#[test]
+fn missing_zero_and_narrow_charts_keep_the_selection_visible() {
+    let zero = AccountAnalyticsDay {
+        date: "2026-01-14".parse().unwrap(),
+        total: 0.0,
+        values: vec![value("a", /*value*/ 0.0)],
+    };
+    let used = AccountAnalyticsDay {
+        date: "2026-01-15".parse().unwrap(),
+        total: 5.0,
+        values: vec![value("a", /*value*/ 5.0)],
+    };
+    let days = [
+        ("2026-01-13".parse().unwrap(), None),
+        (zero.date, Some(&zero)),
+        (used.date, Some(&used)),
+    ];
+    with_test_default_colors(
+        DefaultColors {
+            fg: (230, 230, 230),
+            bg: (16, 16, 16),
+        },
+        || {
+            let mut snapshots = Vec::new();
+            for (width, cursor) in [(36, 0), (36, 1), (8, 2), (1, 2)] {
+                let rendered = chart(
+                    &days,
+                    &used.values,
+                    cursor,
+                    width,
+                    /*height*/ 3,
+                    AccountAnalyticsUnit::Count,
+                );
+                assert_eq!(rendered.bands, 1);
+                assert!(rendered.lines.iter().all(|line| line.width() <= width));
+                assert_eq!(
+                    rendered
+                        .lines
+                        .iter()
+                        .flat_map(|line| &line.spans)
+                        .filter(|span| span.content == "▲")
+                        .count(),
+                    1
+                );
+                if cursor == 0 {
+                    let dash = rendered
+                        .lines
+                        .iter()
+                        .find_map(|line| line.to_string().find('—'));
+                    let cursor = rendered
+                        .lines
+                        .iter()
+                        .find_map(|line| line.to_string().find('▲'));
+                    assert_eq!(dash, cursor);
+                }
+                snapshots.push(format!(
+                    "width={width}, cursor={cursor}\n{}",
+                    display(&rendered)
+                ));
+            }
+            insta::assert_snapshot!(snapshots.join("\n\n"));
+        },
+    );
+}
+
+#[test]
+fn zero_credit_history_uses_a_readable_scale() {
+    let history = crate::analytics::normalize::history(
+        serde_json::from_str(r#"{"data":[]}"#).unwrap(),
+        crate::analytics::models::AccountAnalyticsReport::Credits,
+        crate::analytics::models::AccountAnalyticsGrouping::Surface,
+        "2026-01-09".parse().unwrap(),
+        "2026-01-15".parse().unwrap(),
+    )
+    .unwrap()
+    .unwrap();
+    let days = history
+        .data
+        .iter()
+        .map(|day| (day.date, Some(day)))
+        .collect::<Vec<_>>();
+    let rendered = chart(
+        &days,
+        &[],
+        /*cursor*/ 6,
+        /*width*/ 44,
+        /*height*/ 4,
+        history.unit,
+    );
+    assert_eq!(axis_max(peak(&days, &[]), history.unit), 1.0);
+    insta::assert_snapshot!(display(&rendered));
+}
+
+#[test]
+fn partial_cells_use_the_midpoint_and_descend_from_the_baseline() {
+    let categories = vec![value("a", /*value*/ 0.8), value("b", /*value*/ 0.95)];
+    let mut snapshots = Vec::new();
+    for sign in [1.0, -1.0] {
+        let day = AccountAnalyticsDay {
+            date: "2026-01-14".parse().unwrap(),
+            total: 1.75 * sign,
+            values: categories
+                .iter()
+                .map(|value| AccountAnalyticsValue {
+                    value: value.value * sign,
+                    ..value.clone()
+                })
+                .collect(),
+        };
+        let days = [
+            (day.date, Some(&day)),
+            ("2026-01-15".parse().unwrap(), None),
+        ];
+        let rendered = chart(
+            &days,
+            &categories,
+            /*cursor*/ 1,
+            /*width*/ 12,
+            /*height*/ 1,
+            AccountAnalyticsUnit::Credits,
+        );
+        let cell = &rendered.lines[if sign > 0.0 { 1 } else { 3 }].spans[1];
+        assert_eq!(cell.style.fg, Some(series_colors()[1]));
+        assert_eq!(cell.content.as_ref(), if sign > 0.0 { "▇" } else { "▁" });
+        assert_eq!(
+            cell.style
+                .add_modifier
+                .contains(ratatui::style::Modifier::REVERSED),
+            sign < 0.0
+        );
+        snapshots.push(format!("sign={sign}\n{}", display(&rendered)));
+    }
+    insta::assert_snapshot!(snapshots.join("\n\n"));
+}
+
+#[test]
+fn oversized_axes_are_hidden_instead_of_truncated() {
+    let day = AccountAnalyticsDay {
+        date: "2026-01-15".parse().unwrap(),
+        total: 100_000_000.0,
+        values: vec![value("a", /*value*/ 100_000_000.0)],
+    };
+    let days = [(day.date, Some(&day))];
+    let mut snapshots = Vec::new();
+    for width in [8, 30, 35, 44] {
+        let rendered = chart(
+            &days,
+            &day.values,
+            /*cursor*/ 0,
+            width,
+            /*height*/ 4,
+            AccountAnalyticsUnit::Tokens,
+        );
+        let baseline = rendered.lines[5].to_string();
+        assert_eq!(baseline.starts_with('─'), width < 36);
+        if width == 8 {
+            assert!(rendered.lines[0].to_string().trim().is_empty());
+        }
+        snapshots.push(format!("width={width}\n{}", display(&rendered)));
+    }
+    insta::assert_snapshot!(snapshots.join("\n\n"));
+}
+
+#[test]
+fn selected_callout_keeps_the_authoritative_daily_total() {
+    let day = AccountAnalyticsDay {
+        date: "2026-01-15".parse().unwrap(),
+        total: 20.0,
+        values: vec![value("a", /*value*/ 8.0), value("b", /*value*/ 4.0)],
+    };
+    let days = [(day.date, Some(&day))];
+    let rendered = chart(
+        &days,
+        &day.values,
+        /*cursor*/ 0,
+        /*width*/ 44,
+        /*height*/ 4,
+        AccountAnalyticsUnit::Credits,
+    );
+    assert!(display(&rendered).contains("20.00"));
+    assert!(!display(&rendered).contains("12.00"));
+    insta::assert_snapshot!(display(&rendered));
+}
+
+#[test]
+fn narrow_long_range_charts_never_truncate_dates() {
+    let start: NaiveDate = "2026-01-01".parse().unwrap();
+    let history = start
+        .iter_days()
+        .take(/*n*/ 30)
+        .map(|date| AccountAnalyticsDay {
+            date,
+            total: 1.0,
+            values: vec![value("a", /*value*/ 1.0)],
+        })
+        .collect::<Vec<_>>();
+    let days = history
+        .iter()
+        .map(|day| (day.date, Some(day)))
+        .collect::<Vec<_>>();
+    let mut snapshots = Vec::new();
+    for (width, expected) in [(1, ""), (2, "15"), (5, "15"), (6, "Jan 15")] {
+        let rendered = chart(
+            &days,
+            &history[0].values,
+            /*cursor*/ 14,
+            width,
+            /*height*/ 3,
+            AccountAnalyticsUnit::Count,
+        );
+        assert_eq!(rendered.lines.last().unwrap().to_string().trim(), expected);
+        snapshots.push(format!("width={width}\n{}", display(&rendered)));
+    }
+    insta::assert_snapshot!(snapshots.join("\n\n"));
+}
+
+#[test]
+fn tiny_segments_keep_their_series_color_beside_a_large_day() {
+    let large = AccountAnalyticsDay {
+        date: "2026-01-14".parse().unwrap(),
+        total: 100.0,
+        values: vec![value("a", /*value*/ 100.0)],
+    };
+    let mut snapshots = Vec::new();
+    for sign in [1.0, -1.0] {
+        let tiny = AccountAnalyticsDay {
+            date: "2026-01-15".parse().unwrap(),
+            total: 0.01 * sign,
+            values: vec![value("a", 0.01 * sign)],
+        };
+        let days = [(large.date, Some(&large)), (tiny.date, Some(&tiny))];
+        let rendered = chart(
+            &days,
+            &large.values,
+            /*cursor*/ 0,
+            /*width*/ 44,
+            /*height*/ 4,
+            AccountAnalyticsUnit::Credits,
+        );
+        let glyph = if sign > 0.0 { "▁" } else { "▇" };
+        let cells = rendered
+            .lines
+            .iter()
+            .flat_map(|line| &line.spans)
+            .filter(|span| span.content == glyph)
+            .collect::<Vec<_>>();
+        assert!(!cells.is_empty());
+        assert!(
+            cells
+                .iter()
+                .all(|cell| cell.style.fg == Some(series_colors()[0]))
+        );
+        snapshots.push(format!("sign={sign}\n{}", display(&rendered)));
+    }
+    insta::assert_snapshot!(snapshots.join("\n\n"));
+}
+
+#[test]
+fn duplicate_message_dates_render_the_full_other_remainder() {
+    use crate::analytics::models::AccountAnalyticsGrouping;
+    use crate::analytics::models::AccountAnalyticsReport;
+    let date = "2026-01-15".parse().unwrap();
+    let response = serde_json::from_value(serde_json::json!({"data": [
+        {"date": "2026-01-15", "totals": {"turns": 10}, "clients": [{"client_id": "CODEX_CLI", "turns": 8}]},
+        {"date": "2026-01-15", "totals": {"turns": 10}, "clients": [{"client_id": "CODEX_CLI", "turns": 8}]}
+    ]})).unwrap();
+    let history = crate::analytics::normalize::history(
+        response,
+        AccountAnalyticsReport::Messages,
+        AccountAnalyticsGrouping::Surface,
+        date,
+        date,
+    )
+    .unwrap()
+    .unwrap();
+    let day = &history.data[0];
+    let rendered = chart(
+        &[(date, Some(day))],
+        &day.values,
+        /*cursor*/ 0,
+        /*width*/ 44,
+        /*height*/ 10,
+        AccountAnalyticsUnit::Count,
+    );
+    insta::assert_snapshot!(display(&rendered));
+}
--- a/codex-rs/tui/src/analytics/render.rs
+++ b/codex-rs/tui/src/analytics/render.rs
@@ -1,4 +1,4 @@
-//! Shared report category aggregation for token model filtering.
+//! Shared report category aggregation and stacked-chart partitioning.

 use super::models::AccountAnalyticsHistory;
 use super::models::AccountAnalyticsValue;
@@ -24,3 +24,20 @@ pub(super) fn categories(history: &AccountAnalyticsHistory) -> Vec<AccountAnalyt
    });
    values
 }
+
+/// The last plotted category collects all remaining values without renormalizing them.
+pub(super) fn parts(
+    values: &[AccountAnalyticsValue],
+    categories: &[AccountAnalyticsValue],
+) -> [f64; 4] {
+    let mut parts = [0.0; 4];
+    for value in values {
+        let index = categories
+            .iter()
+            .take(/*n*/ 3)
+            .position(|category| category.key == value.key)
+            .unwrap_or(/*default*/ 3);
+        parts[index] += value.value;
+    }
+    parts
+}
--- a/codex-rs/tui/src/analytics/snapshots/codex_tuianalyticsplottestsduplicate_message_dates_render_the_full_other_remainder.snap
+++ b/codex-rs/tui/src/analytics/snapshots/codex_tuianalyticsplottestsduplicate_message_dates_render_the_full_other_remainder.snap
@@ -0,0 +1,41 @@
+---
+source: tui/src/analytics/plot_tests.rs
+expression: display(&rendered)
+---
+                      20
+ 20               ████████████
+                  ████████████
+                  ████████████
+                  ████████████
+                  ████████████
+ 10               ████████████
+                  ████████████
+                  ████████████
+                  ████████████
+                  ████████████
+  0 ────────────────────────────────────────
+                       ▲
+                    Jan 15
+
+Palette:
+0: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset)
+1: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold()
+2: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset).dim()
+3: Style::new().magenta().bg(Color::Reset).underline_color(Color::Reset)
+4: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset)
+5: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold().underlined()
+Rows (column:palette):
+0: 0:0 22:1 24:0
+1: 0:0 1:2 3:0 18:3 30:0
+2: 0:0 18:3 30:0
+3: 0:0 18:4 30:0
+4: 0:0 18:4 30:0
+5: 0:0 18:4 30:0
+6: 0:0 1:2 3:0 18:4 30:0
+7: 0:0 18:4 30:0
+8: 0:0 18:4 30:0
+9: 0:0 18:4 30:0
+10: 0:0 18:4 30:0
+11: 0:0 2:2 3:0 4:2
+12: 0:0 23:1 24:0
+13: 0:0 20:5 26:0
--- a/codex-rs/tui/src/analytics/snapshots/codex_tuianalyticsplottestsmissing_zero_and_narrow_charts_keep_the_selection_visible.snap
+++ b/codex-rs/tui/src/analytics/snapshots/codex_tuianalyticsplottestsmissing_zero_and_narrow_charts_keep_the_selection_visible.snap
@@ -0,0 +1,101 @@
+---
+source: tui/src/analytics/plot_tests.rs
+expression: "snapshots.join(\"\\n\\n\")"
+---
+width=36, cursor=0
+
+ 6                         ▄▄▄▄▄▄▄
+                           ███████
+        —          0       ███████
+ 0 ─────────────────────────────────
+        ▲
+     Jan 13     Jan 14     Jan 15
+
+Palette:
+0: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset)
+1: Style::new().fg(Color::Rgb(165, 165, 165)).bg(Color::Reset).underline_color(Color::Reset)
+2: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset)
+3: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold()
+4: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset).dim()
+5: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold().underlined()
+Rows (column:palette):
+0: 0:0
+1: 0:0 1:1 2:0 27:2 34:0
+2: 0:0 27:2 34:0
+3: 0:0 8:3 9:0 19:4 20:0 27:2 34:0
+4: 0:0 1:1 2:0 3:4
+5: 0:0 8:3 9:0
+6: 0:0 5:5 11:0 16:1 22:0 27:1 33:0
+
+width=36, cursor=1
+
+ 6                         ▄▄▄▄▄▄▄
+                           ███████
+        —          0       ███████
+ 0 ─────────────────────────────────
+                   ▲
+     Jan 13     Jan 14     Jan 15
+
+Palette:
+0: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset)
+1: Style::new().fg(Color::Rgb(165, 165, 165)).bg(Color::Reset).underline_color(Color::Reset)
+2: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset)
+3: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset).dim()
+4: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold()
+5: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold().underlined()
+Rows (column:palette):
+0: 0:0
+1: 0:0 1:1 2:0 27:2 34:0
+2: 0:0 27:2 34:0
+3: 0:0 8:3 9:0 19:4 20:0 27:2 34:0
+4: 0:0 1:1 2:0 3:3
+5: 0:0 19:4 20:0
+6: 0:0 5:1 11:0 16:5 22:0 27:1 33:0
+
+width=8, cursor=2
+      5
+     ▄▄
+     ██
+—  0 ██
+────────
+      ▲
+13   15
+
+Palette:
+0: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset)
+1: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold()
+2: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset)
+3: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset).dim()
+4: Style::new().fg(Color::Rgb(165, 165, 165)).bg(Color::Reset).underline_color(Color::Reset)
+5: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold().underlined()
+Rows (column:palette):
+0: 0:0 6:1 7:0
+1: 0:0 5:2 7:0
+2: 0:0 5:2 7:0
+3: 0:3 1:0 3:3 4:0 5:2 7:0
+4: 0:3
+5: 0:0 6:1 7:0
+6: 0:4 2:0 5:5 7:0
+
+width=1, cursor=2
+5
+▄
+█
+█
+─
+▲
+
+
+Palette:
+0: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold()
+1: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset)
+2: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset).dim()
+3: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset)
+Rows (column:palette):
+0: 0:0
+1: 0:1
+2: 0:1
+3: 0:1
+4: 0:2
+5: 0:0
+6: 0:3
--- a/codex-rs/tui/src/analytics/snapshots/codex_tuianalyticsplottestsnarrow_long_range_charts_never_truncate_dates.snap
+++ b/codex-rs/tui/src/analytics/snapshots/codex_tuianalyticsplottestsnarrow_long_range_charts_never_truncate_dates.snap
@@ -0,0 +1,98 @@
+---
+source: tui/src/analytics/plot_tests.rs
+expression: "snapshots.join(\"\\n\\n\")"
+---
+width=1
+
+1
+▄
+█
+─
+▲
+
+
+Palette:
+0: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset)
+1: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold()
+2: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset)
+3: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset).dim()
+Rows (column:palette):
+0: 0:0
+1: 0:1
+2: 0:2
+3: 0:2
+4: 0:3
+5: 0:1
+6: 0:0
+
+width=2
+
+ 1
+▄▄
+██
+──
+ ▲
+15
+
+Palette:
+0: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset)
+1: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold()
+2: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset)
+3: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset).dim()
+4: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold().underlined()
+Rows (column:palette):
+0: 0:0
+1: 0:0 1:1
+2: 0:2
+3: 0:2
+4: 0:3
+5: 0:0 1:1
+6: 0:4
+
+width=5
+
+    1
+▄▄▄▄▄
+█████
+─────
+    ▲
+   15
+
+Palette:
+0: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset)
+1: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold()
+2: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset)
+3: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset).dim()
+4: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold().underlined()
+Rows (column:palette):
+0: 0:0
+1: 0:0 4:1
+2: 0:2
+3: 0:2
+4: 0:3
+5: 0:0 4:1
+6: 0:0 3:4
+
+width=6
+
+     1
+▄▄▄▄▄▄
+██████
+──────
+     ▲
+Jan 15
+
+Palette:
+0: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset)
+1: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold()
+2: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset)
+3: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset).dim()
+4: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold().underlined()
+Rows (column:palette):
+0: 0:0
+1: 0:0 5:1
+2: 0:2
+3: 0:2
+4: 0:3
+5: 0:0 5:1
+6: 0:4
--- a/codex-rs/tui/src/analytics/snapshots/codex_tuianalyticsplottestsoversized_axes_are_hidden_instead_of_truncated.snap
+++ b/codex-rs/tui/src/analytics/snapshots/codex_tuianalyticsplottestsoversized_axes_are_hidden_instead_of_truncated.snap
@@ -0,0 +1,107 @@
+---
+source: tui/src/analytics/plot_tests.rs
+expression: "snapshots.join(\"\\n\\n\")"
+---
+width=8
+
+ █████
+ █████
+ █████
+ █████
+────────
+   ▲
+Jan 15
+
+Palette:
+0: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset)
+1: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset)
+2: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset).dim()
+3: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold()
+4: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold().underlined()
+Rows (column:palette):
+0: 0:0
+1: 0:0 1:1 6:0
+2: 0:0 1:1 6:0
+3: 0:0 1:1 6:0
+4: 0:0 1:1 6:0
+5: 0:2
+6: 0:0 3:3 4:0
+7: 0:4 6:0
+
+width=30
+         100,000,000
+         ████████████
+         ████████████
+         ████████████
+         ████████████
+──────────────────────────────
+              ▲
+           Jan 15
+
+Palette:
+0: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset)
+1: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold()
+2: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset)
+3: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset).dim()
+4: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold().underlined()
+Rows (column:palette):
+0: 0:0 9:1 20:0
+1: 0:0 9:2 21:0
+2: 0:0 9:2 21:0
+3: 0:0 9:2 21:0
+4: 0:0 9:2 21:0
+5: 0:3
+6: 0:0 14:1 15:0
+7: 0:0 11:4 17:0
+
+width=35
+            100,000,000
+           ████████████
+           ████████████
+           ████████████
+           ████████████
+───────────────────────────────────
+                 ▲
+              Jan 15
+
+Palette:
+0: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset)
+1: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold()
+2: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset)
+3: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset).dim()
+4: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold().underlined()
+Rows (column:palette):
+0: 0:0 12:1 23:0
+1: 0:0 11:2 23:0
+2: 0:0 11:2 23:0
+3: 0:0 11:2 23:0
+4: 0:0 11:2 23:0
+5: 0:3
+6: 0:0 17:1 18:0
+7: 0:0 14:4 20:0
+
+width=44
+                       100,000,000
+ 100,000,000          ████████████
+                      ████████████
+  50,000,000          ████████████
+                      ████████████
+           0 ───────────────────────────────
+                            ▲
+                         Jan 15
+
+Palette:
+0: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset)
+1: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold()
+2: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset).dim()
+3: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset)
+4: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold().underlined()
+Rows (column:palette):
+0: 0:0 23:1 34:0
+1: 0:0 1:2 12:0 22:3 34:0
+2: 0:0 22:3 34:0
+3: 0:0 2:2 12:0 22:3 34:0
+4: 0:0 22:3 34:0
+5: 0:0 11:2 12:0 13:2
+6: 0:0 28:1 29:0
+7: 0:0 25:4 31:0
--- a/codex-rs/tui/src/analytics/snapshots/codex_tuianalyticsplottestspartial_cells_use_the_midpoint_and_descend_from_the_baseline.snap
+++ b/codex-rs/tui/src/analytics/snapshots/codex_tuianalyticsplottestspartial_cells_use_the_midpoint_and_descend_from_the_baseline.snap
@@ -0,0 +1,47 @@
+---
+source: tui/src/analytics/plot_tests.rs
+expression: "snapshots.join(\"\\n\\n\")"
+---
+sign=1
+
+ ▇▇▇▇   —
+────────────
+        ▲
+ 14    15
+
+Palette:
+0: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset)
+1: Style::new().magenta().bg(Color::Reset).underline_color(Color::Reset)
+2: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold()
+3: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset).dim()
+4: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold().underlined()
+Rows (column:palette):
+0: 0:0
+1: 0:0 1:1 5:0 8:2 9:0
+2: 0:3
+3: 0:0 8:2 9:0
+4: 0:0 1:3 3:0 7:4 9:0
+
+sign=-1
+
+        —
+────────────
+ ▁▁▁▁
+
+        ▲
+ 14    15
+
+Palette:
+0: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset)
+1: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold()
+2: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset).dim()
+3: Style::new().magenta().bg(Color::Reset).underline_color(Color::Reset).reversed()
+4: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold().underlined()
+Rows (column:palette):
+0: 0:0
+1: 0:0 8:1 9:0
+2: 0:2
+3: 0:0 1:3 5:0
+4: 0:0
+5: 0:0 8:1 9:0
+6: 0:0 1:2 3:0 7:4 9:0
--- a/codex-rs/tui/src/analytics/snapshots/codex_tuianalyticsplottestsselected_callout_keeps_the_authoritative_daily_total.snap
+++ b/codex-rs/tui/src/analytics/snapshots/codex_tuianalyticsplottestsselected_callout_keeps_the_authoritative_daily_total.snap
@@ -0,0 +1,29 @@
+---
+source: tui/src/analytics/plot_tests.rs
+expression: display(&rendered)
+---
+
+ 20                  20.00
+                  ▃▃▃▃▃▃▃▃▃▃▃▃
+ 10               ████████████
+                  ████████████
+  0 ────────────────────────────────────────
+                       ▲
+                    Jan 15
+
+Palette:
+0: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset)
+1: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset).dim()
+2: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold()
+3: Style::new().magenta().bg(Color::Reset).underline_color(Color::Reset)
+4: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset)
+5: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold().underlined()
+Rows (column:palette):
+0: 0:0
+1: 0:0 1:1 3:0 21:2 26:0
+2: 0:0 18:3 30:0
+3: 0:0 1:1 3:0 18:4 30:0
+4: 0:0 18:4 30:0
+5: 0:0 2:1 3:0 4:1
+6: 0:0 23:2 24:0
+7: 0:0 20:5 26:0
--- a/codex-rs/tui/src/analytics/snapshots/codex_tuianalyticsplottestssigned_chart_dark.snap
+++ b/codex-rs/tui/src/analytics/snapshots/codex_tuianalyticsplottestssigned_chart_dark.snap
@@ -0,0 +1,41 @@
+---
+source: tui/src/analytics/plot_tests.rs
+expression: display(&rendered)
+---
+
+   15
+        ▅▅▅▅▅▅▅▅
+  7.5   ████████
+        ████████    ▂▂▂▂▂▂▂▂     ▆▆▆▆▆▆▆▆
+    0 ──────────────────────────────────────
+        ▄▄▄▄▄▄▄▄    ████████     ▂▂▂▂▂▂▂▂
+
+                      -3.00
+  -15
+
+                        ▲
+        Jan 13       Jan 14       Jan 15
+
+Palette:
+0: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset)
+1: Style::new().fg(Color::Rgb(165, 165, 165)).bg(Color::Reset).underline_color(Color::Reset)
+2: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset)
+3: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset).dim()
+4: Style::new().magenta().bg(Color::Reset).underline_color(Color::Reset).reversed()
+5: Style::new().magenta().bg(Color::Reset).underline_color(Color::Reset)
+6: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold()
+7: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold().underlined()
+Rows (column:palette):
+0: 0:0
+1: 0:0 3:1 5:0
+2: 0:0 8:2 16:0
+3: 0:0 2:1 5:0 8:2 16:0
+4: 0:0 8:2 16:0 20:2 28:0 33:2 41:0
+5: 0:0 4:1 5:0 6:3
+6: 0:0 8:4 16:0 20:5 28:0 33:4 41:0
+7: 0:0
+8: 0:0 22:6 27:0
+9: 0:0 2:1 5:0
+10: 0:0
+11: 0:0 24:6 25:0
+12: 0:0 8:1 14:0 21:7 27:0 34:1 40:0
--- a/codex-rs/tui/src/analytics/snapshots/codex_tuianalyticsplottestssigned_chart_light.snap
+++ b/codex-rs/tui/src/analytics/snapshots/codex_tuianalyticsplottestssigned_chart_light.snap
@@ -0,0 +1,41 @@
+---
+source: tui/src/analytics/plot_tests.rs
+expression: display(&rendered)
+---
+
+   15
+        ▅▅▅▅▅▅▅▅
+  7.5   ████████
+        ████████    ▂▂▂▂▂▂▂▂     ▆▆▆▆▆▆▆▆
+    0 ──────────────────────────────────────
+        ▄▄▄▄▄▄▄▄    ████████     ▂▂▂▂▂▂▂▂
+
+                      -3.00
+  -15
+
+                        ▲
+        Jan 13       Jan 14       Jan 15
+
+Palette:
+0: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset)
+1: Style::new().fg(Color::Rgb(76, 76, 76)).bg(Color::Reset).underline_color(Color::Reset)
+2: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset)
+3: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset).dim()
+4: Style::new().magenta().bg(Color::Reset).underline_color(Color::Reset).reversed()
+5: Style::new().magenta().bg(Color::Reset).underline_color(Color::Reset)
+6: Style::new().fg(Color::Rgb(0, 95, 135)).bg(Color::Reset).underline_color(Color::Reset).bold()
+7: Style::new().fg(Color::Rgb(0, 95, 135)).bg(Color::Reset).underline_color(Color::Reset).bold().underlined()
+Rows (column:palette):
+0: 0:0
+1: 0:0 3:1 5:0
+2: 0:0 8:2 16:0
+3: 0:0 2:1 5:0 8:2 16:0
+4: 0:0 8:2 16:0 20:2 28:0 33:2 41:0
+5: 0:0 4:1 5:0 6:3
+6: 0:0 8:4 16:0 20:5 28:0 33:4 41:0
+7: 0:0
+8: 0:0 22:6 27:0
+9: 0:0 2:1 5:0
+10: 0:0
+11: 0:0 24:6 25:0
+12: 0:0 8:1 14:0 21:7 27:0 34:1 40:0
--- a/codex-rs/tui/src/analytics/snapshots/codex_tuianalyticsplotteststiny_segments_keep_their_series_color_beside_a_large_day.snap
+++ b/codex-rs/tui/src/analytics/snapshots/codex_tuianalyticsplotteststiny_segments_keep_their_series_color_beside_a_large_day.snap
@@ -0,0 +1,66 @@
+---
+source: tui/src/analytics/plot_tests.rs
+expression: "snapshots.join(\"\\n\\n\")"
+---
+sign=1
+           100.00
+ 100    ████████████
+        ████████████
+  50    ████████████
+        ████████████        ▁▁▁▁▁▁▁▁▁▁▁▁
+   0 ───────────────────────────────────────
+              ▲
+           Jan 14             Jan 15
+
+Palette:
+0: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset)
+1: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold()
+2: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset).dim()
+3: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset)
+4: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold().underlined()
+Rows (column:palette):
+0: 0:0 11:1 17:0
+1: 0:0 1:2 4:0 8:3 20:0
+2: 0:0 8:3 20:0
+3: 0:0 2:2 4:0 8:3 20:0
+4: 0:0 8:3 20:0 28:3 40:0
+5: 0:0 3:2 4:0 5:2
+6: 0:0 14:1 15:0
+7: 0:0 11:4 17:0 30:2 36:0
+
+sign=-1
+            100.00
+  100    ████████████
+         ████████████
+   50    ████████████
+         ████████████
+    0 ──────────────────────────────────────
+                            ▇▇▇▇▇▇▇▇▇▇▇▇
+
+
+ -100
+
+               ▲
+            Jan 14             Jan 15
+
+Palette:
+0: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset)
+1: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold()
+2: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset).dim()
+3: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset)
+4: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).reversed()
+5: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold().underlined()
+Rows (column:palette):
+0: 0:0 12:1 18:0
+1: 0:0 2:2 5:0 9:3 21:0
+2: 0:0 9:3 21:0
+3: 0:0 3:2 5:0 9:3 21:0
+4: 0:0 9:3 21:0
+5: 0:0 4:2 5:0 6:2
+6: 0:0 28:4 40:0
+7: 0:0
+8: 0:0
+9: 0:0 1:2 5:0
+10: 0:0
+11: 0:0 15:1 16:0
+12: 0:0 12:5 18:0 31:2 37:0
--- a/codex-rs/tui/src/analytics/snapshots/codex_tuianalyticsplottestszero_credit_history_uses_a_readable_scale.snap
+++ b/codex-rs/tui/src/analytics/snapshots/codex_tuianalyticsplottestszero_credit_history_uses_a_readable_scale.snap
@@ -0,0 +1,27 @@
+---
+source: tui/src/analytics/plot_tests.rs
+expression: display(&rendered)
+---
+
+   1
+
+ 0.5
+       0    0     0    0     0    0   0.00
+   0 ───────────────────────────────────────
+                                        ▲
+       9   10    11   12    13   14    15
+
+Palette:
+0: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset)
+1: Style::new().fg(Color::Reset).bg(Color::Reset).underline_color(Color::Reset).dim()
+2: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold()
+3: Style::new().cyan().bg(Color::Reset).underline_color(Color::Reset).bold().underlined()
+Rows (column:palette):
+0: 0:0
+1: 0:0 3:1 4:0
+2: 0:0
+3: 0:0 1:1 4:0
+4: 0:0 7:1 8:0 12:1 13:0 18:1 19:0 23:1 24:0 29:1 30:0 34:1 35:0 38:2 42:0
+5: 0:0 3:1 4:0 5:1
+6: 0:0 40:2 41:0
+7: 0:0 7:1 8:0 11:1 13:0 17:1 19:0 22:1 24:0 28:1 30:0 33:1 35:0 39:3 41:0
--- a/codex-rs/tui/src/analytics/styles.rs
+++ b/codex-rs/tui/src/analytics/styles.rs
@@ -0,0 +1,37 @@
+//! Charts and legends share the terminal's ANSI palette.
+//! Secondary text blends probed defaults only when the terminal supports that color depth.
+
+use crate::color::blend;
+use crate::style::accent_style;
+use crate::terminal_palette::StdoutColorLevel;
+use crate::terminal_palette::best_color;
+use crate::terminal_palette::default_bg;
+use crate::terminal_palette::default_fg;
+use crate::terminal_palette::effective_stdout_color_level;
+use ratatui::style::Color;
+use ratatui::style::Style;
+use ratatui::text::Span;
+
+pub(super) fn series_colors() -> [Color; 4] {
+    [Color::Cyan, Color::Magenta, Color::Green, Color::Reset]
+}
+
+pub(super) fn number(text: impl Into<String>) -> Span<'static> {
+    Span::styled(text.into(), accent_style())
+}
+
+/// Labels and instructions need more contrast than decorative rules or inactive values.
+pub(super) fn secondary_style() -> Style {
+    if !matches!(
+        effective_stdout_color_level(),
+        StdoutColorLevel::TrueColor | StdoutColorLevel::Ansi256
+    ) {
+        return Style::default().dim();
+    }
+    match (default_fg(), default_bg()) {
+        (Some(fg), Some(bg)) => {
+            Style::default().fg(best_color(blend(fg, bg, /*alpha*/ 0.70)))
+        }
+        _ => Style::default().dim(),
+    }
+}