viewer: click to copy values, amounts, and identifiers

Company details (EIN, state number, address, every profile value), an
entry's number and amount, an account's code and balance, a document's
file name and SHA-256 copy on click: a pointer and copy icon on hover,
a check for a moment after. Amounts copy as their exact plain decimal
(fmt::plain: no "$", commas, or parentheses; "-" for negatives); where a
click already drills down (report cells, register and transaction rows,
general ledger lines), a right-click menu copies the amounts, the entry
number, or the description. The sidebar's chain check copies the
journal head and data folder.

tests/copy.rs: every display style copies back to the exact value
(property), and clicking the EIN, an entry's amount, and its number puts
exactly that on the clipboard.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GWVo7x3UHw5kwCUaWxiejX

crates/ledger-gui/src/app.rs

@@ -675,12 +675,23 @@ fn live_status(ui: &mut Ui, b: &Books, since_update: f64, live: bool) {
                 } else {
                     (icon::WARNING_CIRCLE, p.negative)
                 };
-                ui.label(
+                let r = ui
-                    RichText::new(format!("{glyph} {text}"))
+                    .label(
-                        .font(theme::regular(11.5))
+                        RichText::new(format!("{glyph} {text}"))
-                        .color(color),
+                            .font(theme::regular(11.5))
-                )
+                            .color(color),
-                .on_hover_text(tip);
+                    )
+                    .on_hover_text(tip);
+                if text == "Journal chain verified" {
+                    r.context_menu(|ui| {
+                        crate::widgets::copy_item(ui, "Copy journal head", &b.head);
+                        crate::widgets::copy_item(
+                            ui,
+                            "Copy data folder",
+                            &b.data_dir.display().to_string(),
+                        );
+                    });
+                }
             }
         });
 }

crates/ledger-gui/src/fmt.rs

@@ -87,6 +87,31 @@ fn group(d: Decimal) -> String {
     format!("{out}.{frac}")
 }
 
+/// The plain decimal behind a displayed amount, for the clipboard:
+/// `$1,234.56` → `1234.56`, `(207.68)` and `−12.00` → `-207.68`, `-12.00`.
+/// Exact (the display never rounds). None when the text isn't an amount.
+pub fn plain(display: &str) -> Option<String> {
+    let t = display.trim();
+    let (neg, t) = match t.strip_prefix('(').and_then(|x| x.strip_suffix(')')) {
+        Some(inner) => (true, inner),
+        None => (false, t),
+    };
+    let (neg, t) = match t.strip_prefix('\u{2212}').or_else(|| t.strip_prefix('-')) {
+        Some(rest) => (!neg, rest),
+        None => (neg, t.strip_prefix('+').unwrap_or(t)),
+    };
+    let digits: String = t.chars().filter(|c| !matches!(c, '$' | ',')).collect();
+    let d: Decimal = digits.parse().ok()?;
+    if digits.is_empty() || !digits.chars().all(|c| c.is_ascii_digit() || c == '.') {
+        return None;
+    }
+    Some(if neg && !d.is_zero() {
+        format!("-{digits}")
+    } else {
+        digits
+    })
+}
+
 /// A percent change from `prev` to `now`, if `prev` isn't zero.
 pub fn pct_change(prev: Decimal, now: Decimal) -> Option<f64> {
     if prev.is_zero() {
@@ -213,5 +238,12 @@ mod tests {
         assert_eq!(label("ein"), "EIN");
         assert_eq!(label("irs_name_control"), "IRS name control");
         assert_eq!(words("PrepaidExpense"), "Prepaid expense");
+        assert_eq!(plain("$1,234.56").as_deref(), Some("1234.56"));
+        assert_eq!(plain("(207.68)").as_deref(), Some("-207.68"));
+        assert_eq!(plain("\u{2212}$12.00").as_deref(), Some("-12.00"));
+        assert_eq!(plain("+1,000.005").as_deref(), Some("1000.005"));
+        assert_eq!(plain("0.00").as_deref(), Some("0.00"));
+        assert_eq!(plain("Debit"), None);
+        assert_eq!(plain(""), None);
     }
 }

crates/ledger-gui/src/pages/accounts.rs

@@ -168,18 +168,22 @@ pub fn show_account(ui: &mut Ui, b: &Books, id: u64, shell: &mut Shell<'_>) {
         .range
         .unwrap_or((first.min(b.today), b.today));
     page(ui, "account", |ui| {
-        ui.label(
+        widgets::copyable(
+            ui,
             RichText::new(format!("{:?} account · {}", a.account_type, a.code))
                 .font(theme::regular(13.0))
                 .color(p.muted),
+            &a.code,
         );
         ui.label(RichText::new(&a.name).font(theme::bold(26.0)));
         ui.add_space(4.0);
         let bal = b.balance_on(id, b.today);
-        ui.label(
+        widgets::copyable(
+            ui,
             RichText::new(format!("Balance today {}", fmt::dollars(bal)))
                 .font(theme::regular(15.0))
                 .color(p.muted),
+            &fmt::plain(&fmt::dollars(bal)).unwrap_or_default(),
         );
         ui.add_space(14.0);
         let hist = balance_history(&b.ledger, &[id]);
@@ -274,6 +278,25 @@ pub fn show_account(ui: &mut Ui, b: &Books, id: u64, shell: &mut Shell<'_>) {
                         vec2(w, if sub.is_empty() { 30.0 } else { 42.0 }),
                         Sense::click(),
                     );
+                    resp.context_menu(|ui| {
+                        for (label, v) in [("Copy debit", d), ("Copy credit", c)] {
+                            if !v.is_zero() {
+                                widgets::copy_item(
+                                    ui,
+                                    label,
+                                    &fmt::plain(&fmt::money(v)).unwrap_or_default(),
+                                );
+                            }
+                        }
+                        widgets::copy_item(
+                            ui,
+                            "Copy balance",
+                            &fmt::plain(&fmt::money(bal)).unwrap_or_default(),
+                        );
+                        if let Some(id) = sub.strip_prefix('#').and_then(|t| t.split(' ').next()) {
+                            widgets::copy_item(ui, "Copy entry number", &format!("#{id}"));
+                        }
+                    });
                     if resp.hovered() && !strong {
                         ui.painter().rect_filled(r, CornerRadius::same(6), p.hover);
                     }

crates/ledger-gui/src/pages/company.rs

@@ -20,7 +20,7 @@ fn kv(ui: &mut Ui, k: &str, v: &str) {
     // Narrow, the label goes above its value.
     if ui.available_width() < 360.0 {
         ui.label(RichText::new(k).font(theme::regular(12.0)).color(p.muted));
-        ui.add(egui::Label::new(RichText::new(v).font(theme::regular(13.0))).wrap());
+        widgets::copyable(ui, RichText::new(v).font(theme::regular(13.0)), v);
         ui.add_space(4.0);
         return;
     }
@@ -34,7 +34,7 @@ fn kv(ui: &mut Ui, k: &str, v: &str) {
             theme::regular(13.0),
             p.muted,
         );
-        ui.add(egui::Label::new(RichText::new(v).font(theme::regular(13.0))).wrap());
+        widgets::copyable(ui, RichText::new(v).font(theme::regular(13.0)), v);
     });
 }
 

crates/ledger-gui/src/pages/documents.rs

@@ -246,7 +246,11 @@ fn detail(ui: &mut Ui, b: &Books, a: &Attachment, shell: &mut Shell<'_>) {
                     }
                 });
             });
-            ui.label(RichText::new(&a.file_name).font(theme::bold(20.0)));
+            widgets::copyable(
+                ui,
+                RichText::new(&a.file_name).font(theme::bold(20.0)),
+                &a.file_name,
+            );
             ui.add_space(8.0);
             egui::Grid::new(("docfacts", a.id))
                 .num_columns(2)
@@ -265,8 +269,10 @@ fn detail(ui: &mut Ui, b: &Books, a: &Attachment, shell: &mut Shell<'_>) {
                     ui.label(fmt::timestamp(&a.created_at));
                     ui.end_row();
                     k(ui, "SHA-256");
-                    ui.add(
+                    widgets::copyable(
-                        egui::Label::new(RichText::new(&a.blob_sha).monospace().size(11.5)).wrap(),
+                        ui,
+                        RichText::new(&a.blob_sha).monospace().size(11.5),
+                        &a.blob_sha,
                     );
                     ui.end_row();
                     if let Some(e) = a.entry_id {

crates/ledger-gui/src/pages/entry.rs

@@ -24,10 +24,12 @@ pub fn detail(ui: &mut Ui, b: &Books, e: &EntryInfo, shell: &mut Shell<'_>) {
         .auto_shrink(false)
         .show(ui, |ui| {
             ui.horizontal(|ui| {
-                ui.label(
+                widgets::copyable(
+                    ui,
                     RichText::new(format!("Entry #{}", e.id))
                         .font(theme::regular(12.5))
                         .color(p.muted),
+                    &format!("#{}", e.id),
                 );
                 ui.with_layout(egui::Layout::right_to_left(egui::Align::Center), |ui| {
                     if ui
@@ -106,7 +108,11 @@ pub fn detail(ui: &mut Ui, b: &Books, e: &EntryInfo, shell: &mut Shell<'_>) {
                     ui.label(fmt::date(e.date));
                     ui.end_row();
                     k(ui, "Amount");
-                    ui.label(RichText::new(fmt::dollars(e.amount)).font(theme::semibold(14.0)));
+                    widgets::copyable(
+                        ui,
+                        RichText::new(fmt::dollars(e.amount)).font(theme::semibold(14.0)),
+                        &fmt::plain(&fmt::dollars(e.amount)).unwrap_or_default(),
+                    );
                     ui.end_row();
                     if let Some(c) = &created {
                         k(ui, "Recorded");

crates/ledger-gui/src/pages/reports.rs

@@ -1540,15 +1540,37 @@ fn render(ui: &mut Ui, t: &Table, pdf: &PdfInfo, shell: &mut Shell<'_>) {
                             egui::pos2(x1 - col_w + 8.0, rr.top()),
                             egui::pos2(x1, rr.bottom()),
                         );
+                        let copy = fmt::plain(&text);
                         let cresp = ui.interact(
                             cell,
                             ui.id().with(("cell", ri, i)),
-                            if c.drill.is_some() {
+                            if c.drill.is_some() || copy.is_some() {
                                 Sense::click()
                             } else {
                                 Sense::hover()
                             },
                         );
+                        // An amount copies as its plain decimal: a click
+                        // where the cell doesn't drill down, the right-click
+                        // menu where it does.
+                        if let Some(v) = &copy {
+                            if c.drill.is_some() {
+                                cresp.context_menu(|ui| widgets::copy_item(ui, "Copy amount", v));
+                            } else {
+                                if cresp.hovered() {
+                                    ui.ctx().set_cursor_icon(egui::CursorIcon::PointingHand);
+                                }
+                                if cresp.clicked() {
+                                    widgets::copy_now(ui, cresp.id, v);
+                                }
+                                let note = if widgets::recently_copied(ui, cresp.id) {
+                                    "Copied"
+                                } else {
+                                    "Click to copy"
+                                };
+                                cresp.clone().on_hover_text(note);
+                            }
+                        }
                         let hovered = c.drill.is_some() && cresp.hovered();
                         let vcolor = if hovered { p.accent } else { color };
                         let vfont = if matches!(r.kind, Kind::Line) {
@@ -1677,6 +1699,15 @@ fn gl(ui: &mut Ui, b: &Books, s: NaiveDate, e: NaiveDate, shell: &mut Shell<'_>)
                            color: egui::Color32|
                  -> egui::Response {
                     let (r, resp) = ui.allocate_exact_size(vec2(w, 24.0), Sense::click());
+                    resp.context_menu(|ui| {
+                        for v in &vals {
+                            if let Some(id) = v.strip_prefix('#') {
+                                widgets::copy_item(ui, "Copy entry number", &format!("#{id}"));
+                            } else if let Some(a) = fmt::plain(v) {
+                                widgets::copy_item(ui, &format!("Copy {v}"), &a);
+                            }
+                        }
+                    });
                     if resp.hovered() && !strong {
                         ui.painter().rect_filled(r, CornerRadius::same(4), p.hover);
                     }

crates/ledger-gui/src/pages/transactions.rs

@@ -134,6 +134,22 @@ fn list(ui: &mut Ui, b: &Books, selected: Option<u64>, shell: &mut Shell<'_>) {
 fn row(ui: &mut Ui, b: &Books, e: &EntryInfo, on: bool, since_update: f64) -> egui::Response {
     let p = pal(ui.ctx());
     let (rect, resp) = ui.allocate_exact_size(vec2(ui.available_width(), 50.0), Sense::click());
+    resp.context_menu(|ui| {
+        widgets::copy_item(
+            ui,
+            "Copy amount",
+            &fmt::plain(&fmt::money(e.amount)).unwrap_or_default(),
+        );
+        if !e.cash_effect.is_zero() {
+            widgets::copy_item(
+                ui,
+                "Copy cash effect",
+                &fmt::plain(&fmt::money(e.cash_effect)).unwrap_or_default(),
+            );
+        }
+        widgets::copy_item(ui, "Copy entry number", &format!("#{}", e.id));
+        widgets::copy_item(ui, "Copy description", &e.description);
+    });
     let fresh = b.fresh.contains(&e.id) && since_update < 8.0;
     if on {
         ui.painter()

crates/ledger-gui/src/widgets.rs

@@ -114,15 +114,35 @@ pub fn amount_cell(
     } else {
         theme::regular(14.0)
     };
+    // An amount copies as its plain decimal: a click when the cell doesn't
+    // drill down, the right-click menu when it does.
+    let copy = crate::fmt::plain(text);
     let (rect, resp) = ui.allocate_exact_size(
         vec2(width, 22.0),
-        if drill {
+        if drill || copy.is_some() {
             Sense::click()
         } else {
             Sense::hover()
         },
     );
     let p = pal(ui.ctx());
+    let copy_id = resp.id.with("copy");
+    if let Some(v) = &copy {
+        if drill {
+            resp.context_menu(|ui| copy_item(ui, "Copy amount", v));
+        } else if resp.clicked() {
+            copy_now(ui, copy_id, v);
+        }
+    }
+    let copied = copy.is_some() && !drill && recently_copied(ui, copy_id);
+    if copy.is_some() && !drill && resp.hovered() {
+        ui.ctx().set_cursor_icon(egui::CursorIcon::PointingHand);
+    }
+    let resp = if copy.is_some() && !drill {
+        resp.on_hover_text(if copied { "Copied" } else { "Click to copy" })
+    } else {
+        resp
+    };
     let hovered = drill && resp.hovered();
     let galley = ui.painter().layout_no_wrap(
         text.to_string(),
@@ -143,6 +163,15 @@ pub fn amount_cell(
             Stroke::new(1.0, p.accent),
         );
     }
+    if copied {
+        ui.painter().text(
+            egui::pos2(pos.x - 4.0, rect.center().y),
+            egui::Align2::RIGHT_CENTER,
+            egui_phosphor::regular::CHECK,
+            egui::FontId::proportional(12.0),
+            p.positive,
+        );
+    }
     ui.painter().galley(pos, galley, color);
     resp
 }
@@ -223,6 +252,73 @@ pub fn empty(ui: &mut Ui, icon: &str, title: &str, text: &str) {
     });
 }
 
+/// Put `value` on the clipboard, remembering when under `id` (for the
+/// brief "Copied" check).
+pub fn copy_now(ui: &Ui, id: egui::Id, value: &str) {
+    ui.ctx().copy_text(value.to_string());
+    let now = ui.input(|i| i.time);
+    ui.ctx().data_mut(|d| d.insert_temp(id, now));
+}
+
+/// Whether `id` was copied in the last moment; keeps repainting until the
+/// check fades.
+pub fn recently_copied(ui: &Ui, id: egui::Id) -> bool {
+    let at: Option<f64> = ui.ctx().data(|d| d.get_temp(id));
+    let now = ui.input(|i| i.time);
+    let recent = at.is_some_and(|t| now - t < 1.2);
+    if recent {
+        ui.ctx()
+            .request_repaint_after(std::time::Duration::from_millis(200));
+    }
+    recent
+}
+
+/// A value that copies itself when clicked: a pointer and a copy icon on
+/// hover, a check for a moment after.
+pub fn copyable(ui: &mut Ui, text: RichText, value: &str) -> Response {
+    let id = ui.id().with(("copy", value));
+    let p = pal(ui.ctx());
+    ui.horizontal(|ui| {
+        ui.spacing_mut().item_spacing.x = 4.0;
+        let r = ui.add(egui::Label::new(text).sense(Sense::click()));
+        let recent = recently_copied(ui, id);
+        let (slot, _) = ui.allocate_exact_size(vec2(14.0, 14.0), Sense::hover());
+        if r.hovered() || recent {
+            ui.painter().text(
+                slot.center(),
+                egui::Align2::CENTER_CENTER,
+                if recent {
+                    egui_phosphor::regular::CHECK
+                } else {
+                    egui_phosphor::regular::COPY
+                },
+                egui::FontId::proportional(12.0),
+                if recent { p.positive } else { p.muted },
+            );
+        }
+        if r.hovered() {
+            ui.ctx().set_cursor_icon(egui::CursorIcon::PointingHand);
+        }
+        let r = r.on_hover_text(if recent { "Copied" } else { "Click to copy" });
+        if r.clicked() {
+            copy_now(ui, id, value);
+        }
+        r
+    })
+    .inner
+}
+
+/// A "Copy …" item for a right-click menu.
+pub fn copy_item(ui: &mut Ui, label: &str, value: &str) {
+    if ui
+        .button(format!("{} {label}", egui_phosphor::regular::COPY))
+        .clicked()
+    {
+        ui.ctx().copy_text(value.to_string());
+        ui.close();
+    }
+}
+
 /// "Copy prompt": puts an agent prompt on the clipboard.
 pub fn copy_prompt(ui: &mut Ui, prompt: &str) {
     let p = pal(ui.ctx());

crates/ledger-gui/tests/copy.rs

@@ -0,0 +1,106 @@
+//! Click to copy: values leave the viewer exactly.
+//!
+//! ```text
+//! GOAL: what people retype into forms (the EIN, an amount, an entry
+//!       number) can be copied instead, and copies exactly.
+//! SOURCE: DECISION (Stephen, 2026-10-14: click-to-copy on the company
+//!         page, amounts, and identifiers).
+//! INVARIANTS:
+//!   1. An amount copies as its plain decimal: fmt::plain of money,
+//!      accounting, or dollars text is the exact value, with "-" for a
+//!      negative and no "$", commas, or parentheses.
+//!   2. Clicking a company value or an entry's amount puts exactly that
+//!      value on the clipboard.
+//! ```
+
+use egui::OutputCommand;
+use egui_kittest::Harness;
+use egui_kittest::kittest::Queryable;
+use ledger_gui::nav::Route;
+use ledger_gui::{App, Source, data, fmt};
+use proptest::prelude::*;
+use rust_decimal::Decimal;
+
+proptest! {
+    /// INVARIANT 1: every display style copies back to the same value.
+    #[test]
+    fn an_amount_copies_as_its_exact_value(
+        mantissa in -10i128.pow(16)..10i128.pow(16),
+        scale in 0u32..8,
+    ) {
+        let d = Decimal::from_i128_with_scale(mantissa, scale);
+        for shown in [fmt::money(d), fmt::accounting(d), fmt::dollars(d)] {
+            let plain = fmt::plain(&shown).expect("an amount");
+            prop_assert!(!plain.contains(['$', ',', '(', ')', '\u{2212}']), "{}", plain);
+            prop_assert_eq!(plain.parse::<Decimal>().unwrap(), d, "{} copied as {}", shown, plain);
+        }
+    }
+}
+
+fn copied(h: &Harness<'_, App>) -> Vec<String> {
+    h.output()
+        .platform_output
+        .commands
+        .iter()
+        .filter_map(|c| match c {
+            OutputCommand::CopyText(t) => Some(t.clone()),
+            _ => None,
+        })
+        .collect()
+}
+
+/// INVARIANT 2, on the demo books.
+#[test]
+fn clicking_a_value_copies_it() {
+    let dir = std::env::temp_dir().join(format!("ledger-gui-copy-{}", std::process::id()));
+    let _ = std::fs::remove_dir_all(&dir);
+    let today = chrono::NaiveDate::from_ymd_opt(2026, 10, 12).unwrap();
+    ledger_gui::demo::build(&dir, today).unwrap();
+    let source = Source {
+        data_dir: dir.join("books-data"),
+        books_toml: Some(dir.join("wanderbooks.toml")),
+        today: Some(today),
+    };
+    let open = |route: Route| {
+        let books = data::load_once(&source).unwrap();
+        let mut h = Harness::builder()
+            .with_size(egui::vec2(1280.0, 900.0))
+            .build_eframe(|cc| App::with_books(&cc.egui_ctx, books, false, route));
+        h.run_steps(3);
+        h
+    };
+
+    // The company's EIN, as written in wanderbooks.toml.
+    let ein = data::load_once(&source)
+        .unwrap()
+        .settings
+        .company
+        .profile
+        .iter()
+        .find(|(k, _)| k == "ein")
+        .map(|(_, v)| v.clone())
+        .expect("the demo has an EIN");
+    let mut h = open(Route::Company);
+    h.get_by_label(&ein).click();
+    h.step();
+    assert_eq!(copied(&h), [ein]);
+
+    // An entry's amount, as a plain decimal.
+    let books = data::load_once(&source).unwrap();
+    let e = books.entries.iter().find(|e| !e.amount.is_zero()).unwrap();
+    let (id, amount) = (e.id, e.amount);
+    drop(books);
+    let mut h = open(Route::Entry(id));
+    let shown = fmt::dollars(amount);
+    h.get_by_label(&shown).click();
+    h.step();
+    assert_eq!(copied(&h), [fmt::plain(&shown).unwrap()]);
+    assert_eq!(copied(&h)[0].parse::<Decimal>().unwrap(), amount);
+
+    // The entry number.
+    let mut h = open(Route::Entry(id));
+    h.get_by_label(&format!("Entry #{id}")).click();
+    h.step();
+    assert_eq!(copied(&h), [format!("#{id}")]);
+    let _ = std::fs::remove_dir_all(&dir);
+}