diff --git a/src/hooks/useBufferedValue.ts b/src/hooks/useBufferedValue.ts
index ed605d2..0f13e2d 100644
--- a/src/hooks/useBufferedValue.ts
+++ b/src/hooks/useBufferedValue.ts
@@ -1,28 +1,35 @@
 /*
- * SPDX-FileCopyrightText: 2020 Stalwart Labs LLC <hello@stalw.art>
+ * SPDX-FileCopyrightText: 2026 Coffey Labs LLC
  *
- * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-SEL
+ * SPDX-License-Identifier: AGPL-3.0-only
  */
 
 import { useState, type Dispatch, type SetStateAction } from 'react';
 
+/**
+ * A local copy of `value` that a field edits freely (half-typed text, say),
+ * replaced whenever `value` itself changes. `transform` turns the value into
+ * what the field edits. The copy is replaced during render, not in an
+ * effect, so the field never shows the old value for a frame.
+ */
 export function useBufferedValue<T, S = T>(
   value: T,
   transform: (v: T) => S = (v) => v as unknown as S,
 ): [S, Dispatch<SetStateAction<S>>] {
-  const [prev, setPrev] = useState(value);
-  const [local, setLocal] = useState<S>(() => transform(value));
-  if (!Object.is(value, prev)) {
-    setPrev(value);
-    setLocal(transform(value));
+  const [source, setSource] = useState(value);
+  const [draft, setDraft] = useState<S>(() => transform(value));
+  if (!Object.is(source, value)) {
+    setSource(value);
+    setDraft(transform(value));
   }
-  return [local, setLocal];
+  return [draft, setDraft];
 }
 
+/** Calls `reset` during render whenever `key` changes, to drop state tied to the old key. */
 export function useResetOnChange<K>(key: K, reset: () => void): void {
-  const [prev, setPrev] = useState(key);
-  if (!Object.is(key, prev)) {
-    setPrev(key);
+  const [seen, setSeen] = useState(key);
+  if (!Object.is(seen, key)) {
+    setSeen(key);
     reset();
   }
 }
diff --git a/src/hooks/useDocumentTitle.ts b/src/hooks/useDocumentTitle.ts
index e7643c9..2199932 100644
--- a/src/hooks/useDocumentTitle.ts
+++ b/src/hooks/useDocumentTitle.ts
@@ -1,21 +1,19 @@
 /*
- * SPDX-FileCopyrightText: 2020 Stalwart Labs LLC <hello@stalw.art>
  * SPDX-FileCopyrightText: 2026 Coffey Labs LLC
  *
- * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-SEL
- *
- * Modified by Coffey Labs in 2026 for INBUXA.
+ * SPDX-License-Identifier: AGPL-3.0-only
  */
 
 import { useEffect } from 'react';
 
-const APP_NAME = 'inbuxa Admin';
+const APP = 'inbuxa Admin';
 
-export function useDocumentTitle(title?: string | null) {
+/** Titles the browser tab "Page · inbuxa Admin" while the page is shown. */
+export function useDocumentTitle(title?: string | null): void {
   useEffect(() => {
-    document.title = title ? `${title} · ${APP_NAME}` : APP_NAME;
+    document.title = title ? `${title} · ${APP}` : APP;
     return () => {
-      document.title = APP_NAME;
+      document.title = APP;
     };
   }, [title]);
 }
diff --git a/src/lib/basePath.ts b/src/lib/basePath.ts
index 7cfcef1..87f7157 100644
--- a/src/lib/basePath.ts
+++ b/src/lib/basePath.ts
@@ -1,15 +1,16 @@
 /*
- * SPDX-FileCopyrightText: 2020 Stalwart Labs LLC <hello@stalw.art>
+ * SPDX-FileCopyrightText: 2026 Coffey Labs LLC
  *
- * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-SEL
+ * SPDX-License-Identifier: AGPL-3.0-only
  */
 
-let cached: string | undefined;
+let basePath: string | undefined;
 
+/**
+ * Where the console is served, from the page's `<base href>`, without the
+ * trailing slash: '' at the root, '/admin' under a path. Read once.
+ */
 export function getBasePath(): string {
-  if (cached !== undefined) return cached;
-
-  const base = document.querySelector('base')?.getAttribute('href') ?? '/';
-  cached = base.replace(/\/+$/, '');
-  return cached;
+  basePath ??= (document.querySelector('base')?.getAttribute('href') ?? '/').replace(/\/+$/, '');
+  return basePath;
 }
diff --git a/src/lib/debug.test.ts b/src/lib/debug.test.ts
new file mode 100644
index 0000000..7523bf2
--- /dev/null
+++ b/src/lib/debug.test.ts
@@ -0,0 +1,44 @@
+/*
+ * SPDX-FileCopyrightText: 2026 Coffey Labs LLC
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import { describe, expect, it } from 'vitest';
+
+import { describeInvocations, flagOn } from './debug';
+
+describe('flagOn', () => {
+  it('turns on for any value but empty, 0 or false, in development only', () => {
+    expect(flagOn('1', true)).toBe(true);
+    expect(flagOn('yes', true)).toBe(true);
+    expect(flagOn('FALSE', true)).toBe(false);
+    expect(flagOn('0', true)).toBe(false);
+    expect(flagOn('', true)).toBe(false);
+    expect(flagOn(undefined, true)).toBe(false);
+    expect(flagOn('1', false)).toBe(false);
+  });
+});
+
+describe('describeInvocations', () => {
+  it('sums up calls and responses', () => {
+    expect(
+      describeInvocations([
+        ['x:Domain/get', { accountId: 'a', ids: null }, 'c0'],
+        ['x:Domain/set', { update: { d1: {}, d2: {} }, destroy: ['d3'] }, 'c1'],
+        ['x:Domain/query', { ids: ['a', 'b'], total: 2 }, 'c2'],
+        ['error', { type: 'forbidden' }, 'c3'],
+      ]),
+    ).toEqual([
+      { method: 'x:Domain/get', callId: 'c0', ids: 'all' },
+      { method: 'x:Domain/set', callId: 'c1', update: 2, destroy: 1 },
+      { method: 'x:Domain/query', callId: 'c2', ids: 2, total: 2 },
+      { method: 'error', callId: 'c3', error: 'forbidden' },
+    ]);
+  });
+
+  it('copes with anything that is not a list of invocations', () => {
+    expect(describeInvocations(undefined)).toEqual([]);
+    expect(describeInvocations(['oops'])).toEqual([{ method: '?', callId: '?' }]);
+  });
+});
diff --git a/src/lib/debug.ts b/src/lib/debug.ts
index 9519788..b450478 100644
--- a/src/lib/debug.ts
+++ b/src/lib/debug.ts
@@ -1,108 +1,80 @@
 /*
- * SPDX-FileCopyrightText: 2020 Stalwart Labs LLC <hello@stalw.art>
+ * SPDX-FileCopyrightText: 2026 Coffey Labs LLC
  *
- * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-SEL
+ * SPDX-License-Identifier: AGPL-3.0-only
  */
 
-const isDev = import.meta.env.DEV;
+/**
+ * Console logging for development builds, switched on in `.env.local`:
+ *
+ *   VITE_DEBUG_JMAP=1    every JMAP request and its responses
+ *   VITE_DEBUG_FORMS=1   every form change, as the data that would be saved
+ *
+ * Production builds never log, whatever the variables say.
+ */
 
-function isEnabled(envVar: string | undefined): boolean {
-  if (!isDev || !envVar) return false;
-  const v = envVar.toLowerCase();
-  return v !== '' && v !== 'false' && v !== '0';
+/** Whether a debug variable turns logging on: set, and not "0" or "false". */
+export function flagOn(value: string | undefined, dev = import.meta.env.DEV): boolean {
+  return dev && !!value && !['0', 'false'].includes(value.toLowerCase());
 }
 
-export const debugJmap = isEnabled(import.meta.env.VITE_DEBUG_JMAP);
-export const debugForms = isEnabled(import.meta.env.VITE_DEBUG_FORMS);
+export const debugJmap = flagOn(import.meta.env.VITE_DEBUG_JMAP);
+export const debugForms = flagOn(import.meta.env.VITE_DEBUG_FORMS);
 
-type JmapCall = [string, Record<string, unknown>, string];
+const count = (v: unknown) => (Array.isArray(v) ? v.length : v && typeof v === 'object' ? Object.keys(v).length : 0);
 
-function summarizeArgs(args: Record<string, unknown>): string {
-  const parts: string[] = [];
-  if (typeof args.accountId === 'string') {
-    parts.push(`account=${truncate(args.accountId, 12)}`);
-  }
-  if (Array.isArray(args.ids)) {
-    parts.push(`ids=${args.ids.length}`);
-  } else if (args.ids === null) {
-    parts.push('ids=all');
-  }
-  if (args.create && typeof args.create === 'object') {
-    parts.push(`create=${Object.keys(args.create).length}`);
-  }
-  if (args.update && typeof args.update === 'object') {
-    parts.push(`update=${Object.keys(args.update).length}`);
-  }
-  if (Array.isArray(args.destroy)) {
-    parts.push(`destroy=${args.destroy.length}`);
-  }
-  if (Array.isArray(args.list)) {
-    parts.push(`list=${args.list.length}`);
-  }
-  if (typeof args.total === 'number') {
-    parts.push(`total=${args.total}`);
-  }
-  return parts.join(' ');
-}
-
-function truncate(s: string, max: number): string {
-  return s.length > max ? s.slice(0, max - 1) + '…' : s;
-}
-
-function buildSummaryRows(calls: unknown): Array<Record<string, string>> {
-  if (!Array.isArray(calls)) return [];
-  return calls.map((call, idx) => {
-    if (!Array.isArray(call) || call.length < 3) {
-      return { '#': String(idx), method: '?', callId: '?', summary: '' };
+/** One row per method call or response: what it is and how much it touches. */
+export function describeInvocations(invocations: unknown): Record<string, string | number>[] {
+  if (!Array.isArray(invocations)) return [];
+  return invocations.map((inv) => {
+    const [name, args, callId] = Array.isArray(inv) ? inv : [];
+    const a: Record<string, unknown> = args && typeof args === 'object' ? args : {};
+    const row: Record<string, string | number> = { method: String(name ?? '?'), callId: String(callId ?? '?') };
+    if (a.ids === null) row.ids = 'all';
+    else if (Array.isArray(a.ids)) row.ids = a.ids.length;
+    for (const key of [
+      'create',
+      'update',
+      'destroy',
+      'list',
+      'created',
+      'updated',
+      'destroyed',
+      'notCreated',
+      'notUpdated',
+      'notDestroyed',
+    ]) {
+      if (a[key] != null && count(a[key])) row[key] = count(a[key]);
     }
-    const [method, args, callId] = call as JmapCall;
-    return {
-      '#': String(idx),
-      method,
-      callId,
-      summary: args && typeof args === 'object' ? summarizeArgs(args) : '',
-    };
+    if (typeof a.total === 'number') row.total = a.total;
+    if (name === 'error' && typeof a.type === 'string') row.error = a.type;
+    return row;
   });
 }
 
 export function logJmapExchange(methodCalls: unknown, methodResponses: unknown, durationMs?: number): void {
   if (!debugJmap) return;
-
-  const hasError = Array.isArray(methodResponses) && methodResponses.some((r) => Array.isArray(r) && r[0] === 'error');
-
-  const methodNames = Array.isArray(methodCalls)
-    ? methodCalls.map((c) => (Array.isArray(c) && typeof c[0] === 'string' ? c[0] : '?')).join(' · ')
-    : '?';
-
-  const durationLabel = typeof durationMs === 'number' ? ` (${Math.round(durationMs)}ms)` : '';
-
-  const headerColor = hasError ? '#dc2626' : '#2563eb';
-
+  const responses = describeInvocations(methodResponses);
+  const failed = responses.some((r) => r.method === 'error');
+  const names = describeInvocations(methodCalls)
+    .map((r) => r.method)
+    .join(', ');
+  const took = durationMs === undefined ? '' : ` ${Math.round(durationMs)} ms`;
   console.groupCollapsed(
-    `%c[JMAP]%c ${methodNames}${durationLabel}${hasError ? ' (with errors)' : ''}`,
-    `color: ${headerColor}; font-weight: bold`,
-    'color: inherit',
+    `%cJMAP%c ${names}${took}${failed ? ' — error' : ''}`,
+    `color:${failed ? '#dc2626' : '#0d9488'};font-weight:600`,
+    '',
   );
-
-  console.groupCollapsed('%c→ request', 'color: #2563eb; font-weight: bold');
-  console.table(buildSummaryRows(methodCalls));
-  console.log(JSON.stringify(methodCalls, null, 2));
-  console.groupEnd();
-
-  console.groupCollapsed(
-    `%c← response${hasError ? ' (with errors)' : ''}`,
-    `color: ${hasError ? '#dc2626' : '#16a34a'}; font-weight: bold`,
-  );
-  console.table(buildSummaryRows(methodResponses));
-  console.log(JSON.stringify(methodResponses, null, 2));
-  console.groupEnd();
-
+  console.table(describeInvocations(methodCalls));
+  console.table(responses);
+  console.debug('request', methodCalls);
+  console.debug('responses', methodResponses);
   console.groupEnd();
 }
 
 export function logFormChange(label: string, data: unknown): void {
   if (!debugForms) return;
-  console.groupCollapsed(`%c[Form]%c ${label}`, 'color: #9333ea; font-weight: bold', 'color: inherit');
-  console.log(JSON.stringify(data, null, 2));
+  console.groupCollapsed(`%cForm%c ${label}`, 'color:#7c3aed;font-weight:600', '');
+  console.debug(data);
   console.groupEnd();
 }
diff --git a/src/lib/durationFormat.test.ts b/src/lib/durationFormat.test.ts
index 50c7373..0d0af6e 100644
--- a/src/lib/durationFormat.test.ts
+++ b/src/lib/durationFormat.test.ts
@@ -1,229 +1,99 @@
 /*
- * SPDX-FileCopyrightText: 2020 Stalwart Labs LLC <hello@stalw.art>
+ * SPDX-FileCopyrightText: 2026 Coffey Labs LLC
  *
- * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-SEL
+ * SPDX-License-Identifier: AGPL-3.0-only
  */
 
-import { describe, it, expect } from 'vitest';
+import { describe, expect, it } from 'vitest';
+
 import {
-  bytesToHuman,
-  humanToBytes,
-  formatSize,
-  msToHuman,
-  humanToMs,
-  formatDuration,
-  SIZE_UNITS,
   DURATION_UNITS,
+  SIZE_UNITS,
+  bytesToHuman,
+  formatDuration,
+  formatSize,
+  humanToBytes,
+  humanToMs,
+  msToHuman,
 } from './durationFormat';
 
-describe('SIZE_UNITS', () => {
-  it('should contain the expected units in order', () => {
+describe('sizes', () => {
+  it('lists the units a size field offers, smallest first', () => {
     expect(SIZE_UNITS).toEqual(['B', 'KB', 'MB', 'GB', 'TB']);
   });
+
+  it.each([
+    [0, 0, 'B'],
+    [1, 1, 'B'],
+    [1023, 1023, 'B'],
+    [1024, 1, 'KB'],
+    [1500, 1.46, 'KB'],
+    [1536, 1.5, 'KB'],
+    [5 * 1024 ** 2, 5, 'MB'],
+    [1024 ** 3 + 1, 1, 'GB'],
+    [3 * 1024 ** 4, 3, 'TB'],
+    [2048 * 1024 ** 4, 2048, 'TB'],
+  ])('shows %d bytes as %d %s', (bytes, value, unit) => {
+    expect(bytesToHuman(bytes)).toEqual({ value, unit });
+  });
+
+  it('leaves values under one byte as bytes', () => {
+    expect(bytesToHuman(0.5)).toEqual({ value: 0.5, unit: 'B' });
+    expect(bytesToHuman(-10)).toEqual({ value: -10, unit: 'B' });
+  });
+
+  it('turns a value and unit back into whole bytes', () => {
+    expect(humanToBytes(1.5, 'KB')).toBe(1536);
+    expect(humanToBytes(1.46, 'KB')).toBe(1495);
+    expect(humanToBytes(2, 'GB')).toBe(2 * 1024 ** 3);
+    expect(humanToBytes(7, 'B')).toBe(7);
+  });
+
+  it('passes the value through for a unit it does not know', () => {
+    expect(humanToBytes(12, 'PB')).toBe(12);
+  });
+
+  it('formats as "value unit"', () => {
+    expect(formatSize(0)).toBe('0 B');
+    expect(formatSize(1536)).toBe('1.5 KB');
+    expect(formatSize(50 * 1024 ** 2)).toBe('50 MB');
+  });
 });
 
-describe('DURATION_UNITS', () => {
-  it('should contain the expected units in order', () => {
+describe('durations', () => {
+  it('lists the units a duration field offers, smallest first', () => {
     expect(DURATION_UNITS).toEqual(['ms', 's', 'min', 'h', 'd']);
   });
-});
 
-describe('bytesToHuman', () => {
-  it('should return 0 B for 0 bytes', () => {
-    expect(bytesToHuman(0)).toEqual({ value: 0, unit: 'B' });
+  it.each([
+    [0, 0, 'ms'],
+    [999, 999, 'ms'],
+    [1000, 1, 's'],
+    [1500, 1.5, 's'],
+    [90_000, 1.5, 'min'],
+    [3_600_000, 1, 'h'],
+    [5_400_000, 1.5, 'h'],
+    [86_400_000, 1, 'd'],
+    [30 * 86_400_000, 30, 'd'],
+    [100_000, 1.67, 'min'],
+  ])('shows %d ms as %d %s', (ms, value, unit) => {
+    expect(msToHuman(ms)).toEqual({ value, unit });
   });
 
-  it('should keep small values in bytes', () => {
-    expect(bytesToHuman(500)).toEqual({ value: 500, unit: 'B' });
+  it('turns a value and unit back into whole milliseconds', () => {
+    expect(humanToMs(1.5, 's')).toBe(1500);
+    expect(humanToMs(2, 'min')).toBe(120_000);
+    expect(humanToMs(1, 'd')).toBe(86_400_000);
+    expect(humanToMs(1.67, 'min')).toBe(100_200);
+    expect(humanToMs(9, 'weeks')).toBe(9);
   });
 
-  it('should keep 512 bytes as B', () => {
-    expect(bytesToHuman(512)).toEqual({ value: 512, unit: 'B' });
-  });
-
-  it('should convert 1024 bytes to 1 KB', () => {
-    expect(bytesToHuman(1024)).toEqual({ value: 1, unit: 'KB' });
-  });
-
-  it('should convert 1536 bytes to 1.5 KB', () => {
-    expect(bytesToHuman(1536)).toEqual({ value: 1.5, unit: 'KB' });
-  });
-
-  it('should convert 1500 bytes to 1.46 KB', () => {
-    expect(bytesToHuman(1500)).toEqual({ value: 1.46, unit: 'KB' });
-  });
-
-  it('should convert 1048576 bytes to 1 MB', () => {
-    expect(bytesToHuman(1048576)).toEqual({ value: 1, unit: 'MB' });
-  });
-
-  it('should convert 10485760 bytes to 10 MB', () => {
-    expect(bytesToHuman(10485760)).toEqual({ value: 10, unit: 'MB' });
-  });
-
-  it('should convert 1073741824 bytes to 1 GB', () => {
-    expect(bytesToHuman(1073741824)).toEqual({ value: 1, unit: 'GB' });
-  });
-
-  it('should convert 1099511627776 bytes to 1 TB', () => {
-    expect(bytesToHuman(1099511627776)).toEqual({ value: 1, unit: 'TB' });
-  });
-});
-
-describe('humanToBytes', () => {
-  it('should convert 1 KB to 1024 bytes', () => {
-    expect(humanToBytes(1, 'KB')).toBe(1024);
-  });
-
-  it('should convert 10 MB to 10485760 bytes', () => {
-    expect(humanToBytes(10, 'MB')).toBe(10485760);
-  });
-
-  it('should convert 1.5 GB to 1610612736 bytes', () => {
-    expect(humanToBytes(1.5, 'GB')).toBe(1610612736);
-  });
-
-  it('should convert 0 B to 0', () => {
-    expect(humanToBytes(0, 'B')).toBe(0);
-  });
-
-  it('should return the raw value for an unknown unit', () => {
-    expect(humanToBytes(42, 'XYZ')).toBe(42);
-  });
-});
-
-describe('formatSize', () => {
-  it('should format 0 bytes as "0 B"', () => {
-    expect(formatSize(0)).toBe('0 B');
-  });
-
-  it('should format 1024 bytes as "1 KB"', () => {
-    expect(formatSize(1024)).toBe('1 KB');
-  });
-
-  it('should format 1572864 bytes as "1.5 MB"', () => {
-    expect(formatSize(1572864)).toBe('1.5 MB');
-  });
-
-  it('should format large values in TB', () => {
-    expect(formatSize(1099511627776)).toBe('1 TB');
-  });
-});
-
-describe('msToHuman', () => {
-  it('should return 0 ms for 0', () => {
-    expect(msToHuman(0)).toEqual({ value: 0, unit: 'ms' });
-  });
-
-  it('should keep 500 as ms', () => {
-    expect(msToHuman(500)).toEqual({ value: 500, unit: 'ms' });
-  });
-
-  it('should convert 1000 ms to 1 s', () => {
-    expect(msToHuman(1000)).toEqual({ value: 1, unit: 's' });
-  });
-
-  it('should convert 1500 ms to 1.5 s', () => {
-    expect(msToHuman(1500)).toEqual({ value: 1.5, unit: 's' });
-  });
-
-  it('should convert 60000 ms to 1 min', () => {
-    expect(msToHuman(60000)).toEqual({ value: 1, unit: 'min' });
-  });
-
-  it('should convert 300000 ms to 5 min', () => {
-    expect(msToHuman(300000)).toEqual({ value: 5, unit: 'min' });
-  });
-
-  it('should convert 90000 ms to 1.5 min', () => {
-    expect(msToHuman(90000)).toEqual({ value: 1.5, unit: 'min' });
-  });
-
-  it('should convert 3600000 ms to 1 h', () => {
-    expect(msToHuman(3600000)).toEqual({ value: 1, unit: 'h' });
-  });
-
-  it('should convert 86400000 ms to 1 d', () => {
-    expect(msToHuman(86400000)).toEqual({ value: 1, unit: 'd' });
-  });
-});
-
-describe('humanToMs', () => {
-  it('should convert 5 s to 5000 ms', () => {
-    expect(humanToMs(5, 's')).toBe(5000);
-  });
-
-  it('should convert 1 min to 60000 ms', () => {
-    expect(humanToMs(1, 'min')).toBe(60000);
-  });
-
-  it('should convert 2 h to 7200000 ms', () => {
-    expect(humanToMs(2, 'h')).toBe(7200000);
-  });
-
-  it('should convert 1 d to 86400000 ms', () => {
-    expect(humanToMs(1, 'd')).toBe(86400000);
-  });
-
-  it('should return the raw value for an unknown unit', () => {
-    expect(humanToMs(99, 'eons')).toBe(99);
-  });
-});
-
-describe('formatDuration', () => {
-  it('should format 0 as "0ms"', () => {
+  it('spells a duration out by its parts', () => {
     expect(formatDuration(0)).toBe('0ms');
-  });
-
-  it('should format 500 ms as "500ms"', () => {
-    expect(formatDuration(500)).toBe('500ms');
-  });
-
-  it('should format 5000 ms as "5s"', () => {
-    expect(formatDuration(5000)).toBe('5s');
-  });
-
-  it('should format 65000 ms as "1m 5s"', () => {
-    expect(formatDuration(65000)).toBe('1m 5s');
-  });
-
-  it('should format 3661000 ms as "1h 1m 1s"', () => {
-    expect(formatDuration(3661000)).toBe('1h 1m 1s');
-  });
-
-  it('should format 86400000 ms as "1d"', () => {
-    expect(formatDuration(86400000)).toBe('1d');
-  });
-
-  it('should format 90061500 ms as "1d 1h 1m 1s 500ms"', () => {
-    expect(formatDuration(90061500)).toBe('1d 1h 1m 1s 500ms');
-  });
-});
-
-describe('round-trip: bytes', () => {
-  it.each([1024, 1048576, 1073741824, 1099511627776])('bytesToHuman -> humanToBytes should recover %d', (original) => {
-    const { value, unit } = bytesToHuman(original);
-    expect(humanToBytes(value, unit)).toBe(original);
-  });
-
-  it('should be close for non-exact values', () => {
-    const original = 123456789;
-    const { value, unit } = bytesToHuman(original);
-    const recovered = humanToBytes(value, unit);
-    expect(Math.abs(recovered - original) / original).toBeLessThan(0.01);
-  });
-});
-
-describe('round-trip: duration', () => {
-  it.each([1000, 60000, 3600000, 86400000])('msToHuman -> humanToMs should recover %d', (original) => {
-    const { value, unit } = msToHuman(original);
-    expect(humanToMs(value, unit)).toBe(original);
-  });
-
-  it('should be close for non-exact values', () => {
-    const original = 123456;
-    const { value, unit } = msToHuman(original);
-    const recovered = humanToMs(value, unit);
-    expect(Math.abs(recovered - original) / original).toBeLessThan(0.01);
+    expect(formatDuration(250)).toBe('250ms');
+    expect(formatDuration(61_000)).toBe('1m 1s');
+    expect(formatDuration(3_600_000)).toBe('1h');
+    expect(formatDuration(90_061_001)).toBe('1d 1h 1m 1s 1ms');
+    expect(formatDuration(2 * 86_400_000 + 30_000)).toBe('2d 30s');
   });
 });
diff --git a/src/lib/durationFormat.ts b/src/lib/durationFormat.ts
index 1c540a7..a45bcc0 100644
--- a/src/lib/durationFormat.ts
+++ b/src/lib/durationFormat.ts
@@ -1,96 +1,64 @@
 /*
- * SPDX-FileCopyrightText: 2020 Stalwart Labs LLC <hello@stalw.art>
+ * SPDX-FileCopyrightText: 2026 Coffey Labs LLC
  *
- * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-SEL
+ * SPDX-License-Identifier: AGPL-3.0-only
  */
 
+/**
+ * Sizes and durations as people read them: the field widgets show a number
+ * and a unit, and store bytes or milliseconds.
+ */
+
+type Scale = Record<string, number>;
+
+const SIZE_SCALE = { B: 1, KB: 1024, MB: 1024 ** 2, GB: 1024 ** 3, TB: 1024 ** 4 } satisfies Scale;
+const DURATION_SCALE = { ms: 1, s: 1000, min: 60_000, h: 3_600_000, d: 86_400_000 } satisfies Scale;
+
 export const SIZE_UNITS = ['B', 'KB', 'MB', 'GB', 'TB'] as const;
+export const DURATION_UNITS = ['ms', 's', 'min', 'h', 'd'] as const;
 
-const SIZE_FACTORS: Record<string, number> = {
-  B: 1,
-  KB: 1024,
-  MB: 1024 ** 2,
-  GB: 1024 ** 3,
-  TB: 1024 ** 4,
-};
-
-export function bytesToHuman(bytes: number): { value: number; unit: string } {
-  if (bytes === 0) return { value: 0, unit: 'B' };
-
-  for (let i = SIZE_UNITS.length - 1; i >= 0; i--) {
-    const unit = SIZE_UNITS[i];
-    const factor = SIZE_FACTORS[unit];
-    const v = bytes / factor;
-    if (v >= 1) {
-      const rounded = Math.round(v * 100) / 100;
-      return { value: rounded, unit };
-    }
-  }
-
-  return { value: bytes, unit: 'B' };
+/** The largest unit that keeps the number at 1 or more, to two decimals. */
+function largestUnit(amount: number, scale: Scale, units: readonly string[]) {
+  const unit = [...units].reverse().find((u) => amount / scale[u] >= 1);
+  if (!unit) return { value: amount, unit: units[0] };
+  return { value: Math.round((amount / scale[unit]) * 100) / 100, unit };
 }
 
-export function humanToBytes(value: number, unit: string): number {
-  const factor = SIZE_FACTORS[unit];
-  if (factor === undefined) return value;
-  return Math.round(value * factor);
+/** A number in a unit back to the base amount; an unknown unit leaves it as is. */
+function fromUnit(value: number, unit: string, scale: Scale) {
+  const factor = scale[unit];
+  return factor === undefined ? value : Math.round(value * factor);
 }
 
+export const bytesToHuman = (bytes: number) => largestUnit(bytes, SIZE_SCALE, SIZE_UNITS);
+export const humanToBytes = (value: number, unit: string) => fromUnit(value, unit, SIZE_SCALE);
+
+/** "1.5 KB". */
 export function formatSize(bytes: number): string {
   const { value, unit } = bytesToHuman(bytes);
   return `${value} ${unit}`;
 }
 
-export const DURATION_UNITS = ['ms', 's', 'min', 'h', 'd'] as const;
+export const msToHuman = (ms: number) => largestUnit(ms, DURATION_SCALE, DURATION_UNITS);
+export const humanToMs = (value: number, unit: string) => fromUnit(value, unit, DURATION_SCALE);
 
-const DURATION_FACTORS: Record<string, number> = {
-  ms: 1,
-  s: 1_000,
-  min: 60_000,
-  h: 3_600_000,
-  d: 86_400_000,
-};
-
-export function msToHuman(ms: number): { value: number; unit: string } {
-  if (ms === 0) return { value: 0, unit: 'ms' };
-
-  for (let i = DURATION_UNITS.length - 1; i >= 0; i--) {
-    const unit = DURATION_UNITS[i];
-    const factor = DURATION_FACTORS[unit];
-    const v = ms / factor;
-    if (v >= 1) {
-      const rounded = Math.round(v * 100) / 100;
-      return { value: rounded, unit };
-    }
-  }
-
-  return { value: ms, unit: 'ms' };
-}
-
-export function humanToMs(value: number, unit: string): number {
-  const factor = DURATION_FACTORS[unit];
-  if (factor === undefined) return value;
-  return Math.round(value * factor);
-}
+const PARTS: [string, number][] = [
+  ['d', DURATION_SCALE.d],
+  ['h', DURATION_SCALE.h],
+  ['m', DURATION_SCALE.min],
+  ['s', DURATION_SCALE.s],
+  ['ms', 1],
+];
 
+/** "1d 2h 3m", leaving out the parts that are zero; "0ms" for nothing. */
 export function formatDuration(ms: number): string {
   if (ms === 0) return '0ms';
-
-  const d = Math.floor(ms / 86_400_000);
-  ms %= 86_400_000;
-  const h = Math.floor(ms / 3_600_000);
-  ms %= 3_600_000;
-  const m = Math.floor(ms / 60_000);
-  ms %= 60_000;
-  const s = Math.floor(ms / 1_000);
-  ms %= 1_000;
-
-  const parts: string[] = [];
-  if (d > 0) parts.push(`${d}d`);
-  if (h > 0) parts.push(`${h}h`);
-  if (m > 0) parts.push(`${m}m`);
-  if (s > 0) parts.push(`${s}s`);
-  if (ms > 0) parts.push(`${ms}ms`);
-
-  return parts.join(' ');
+  let rest = ms;
+  const out: string[] = [];
+  for (const [label, size] of PARTS) {
+    const n = size === 1 ? rest : Math.floor(rest / size);
+    rest -= size === 1 ? n : n * size;
+    if (n > 0) out.push(`${n}${label}`);
+  }
+  return out.join(' ');
 }
diff --git a/src/lib/jmapErrors.test.ts b/src/lib/jmapErrors.test.ts
new file mode 100644
index 0000000..bccffe2
--- /dev/null
+++ b/src/lib/jmapErrors.test.ts
@@ -0,0 +1,45 @@
+/*
+ * SPDX-FileCopyrightText: 2026 Coffey Labs LLC
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import { describe, expect, it } from 'vitest';
+
+import { friendlySetError, validationErrorMessage } from './jmapErrors';
+
+describe('validationErrorMessage', () => {
+  it('says what the field needs', () => {
+    expect(validationErrorMessage({ type: 'Required', property: 'name' })).toBe('This field is required.');
+    expect(validationErrorMessage({ type: 'MaxLength', property: 'name', required: 64 })).toBe('Maximum length is 64.');
+    expect(validationErrorMessage({ type: 'MinValue', property: 'port', required: 1 })).toBe('Minimum value is 1.');
+  });
+
+  it("gives the server's reason for an invalid value, when there is one", () => {
+    expect(validationErrorMessage({ type: 'Invalid', property: 'host', value: 'Not a hostname' })).toBe(
+      'Not a hostname',
+    );
+    expect(validationErrorMessage({ type: 'Invalid', property: 'host', value: '' })).toBe('Invalid value.');
+    expect(validationErrorMessage({ type: 'Invalid', property: 'host' })).toBe('Invalid value.');
+  });
+});
+
+describe('friendlySetError', () => {
+  it("prefers the server's own description", () => {
+    expect(friendlySetError({ type: 'forbidden', description: 'Only tenant admins may do this.' })).toBe(
+      'Only tenant admins may do this.',
+    );
+  });
+
+  it('explains the known error types', () => {
+    expect(friendlySetError({ type: 'objectIsLinked' })).toBe(
+      'This item is referenced by other items and cannot be deleted.',
+    );
+    expect(friendlySetError({ type: 'singleton' })).toBe('This item is a singleton and cannot be deleted.');
+  });
+
+  it('names a type it does not know, including ones that look like object keys', () => {
+    expect(friendlySetError({ type: 'somethingNew' })).toBe('Unexpected error (somethingNew).');
+    expect(friendlySetError({ type: 'toString' })).toBe('Unexpected error (toString).');
+  });
+});
diff --git a/src/lib/jmapErrors.ts b/src/lib/jmapErrors.ts
index 9b483f2..0ae53aa 100644
--- a/src/lib/jmapErrors.ts
+++ b/src/lib/jmapErrors.ts
@@ -1,66 +1,49 @@
 /*
- * SPDX-FileCopyrightText: 2020 Stalwart Labs LLC <hello@stalw.art>
+ * SPDX-FileCopyrightText: 2026 Coffey Labs LLC
  *
- * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-SEL
+ * SPDX-License-Identifier: AGPL-3.0-only
  */
 
-import type { JmapSetError, ValidationError } from '@/types/jmap';
+/** The server's JMAP errors in words an admin can act on. */
 import i18n from '@/i18n';
+import type { JmapSetError, ValidationError } from '@/types/jmap';
 
-export function validationErrorMessage(ve: ValidationError): string {
-  switch (ve.type) {
-    case 'Required':
-      return i18n.t('form.required', 'This field is required.');
-    case 'MaxLength':
-      return i18n.t('form.maxLengthIs', 'Maximum length is {{max}}.', { max: ve.required });
-    case 'MinLength':
-      return i18n.t('form.minLengthIs', 'Minimum length is {{min}}.', { min: ve.required });
-    case 'MaxValue':
-      return i18n.t('form.maxValueIs', 'Maximum value is {{max}}.', { max: ve.required });
-    case 'MinValue':
-      return i18n.t('form.minValueIs', 'Minimum value is {{min}}.', { min: ve.required });
-    default:
-      if (ve.value && ve.value.length > 0) return ve.value;
-      return i18n.t('form.invalidValue', 'Invalid value.');
-  }
+const t = i18n.t.bind(i18n);
+
+/** The message under a field the server refused. */
+export function validationErrorMessage({ type, required, value }: ValidationError): string {
+  if (type === 'Required') return t('form.required', 'This field is required.');
+  if (type === 'MaxLength') return t('form.maxLengthIs', 'Maximum length is {{max}}.', { max: required });
+  if (type === 'MinLength') return t('form.minLengthIs', 'Minimum length is {{min}}.', { min: required });
+  if (type === 'MaxValue') return t('form.maxValueIs', 'Maximum value is {{max}}.', { max: required });
+  if (type === 'MinValue') return t('form.minValueIs', 'Minimum value is {{min}}.', { min: required });
+  // 'Invalid': the server's own reason, when it gave one.
+  return value || t('form.invalidValue', 'Invalid value.');
 }
 
+const SET_ERRORS: Record<string, () => string> = {
+  forbidden: () => t('jmapErrors.forbidden', 'You do not have permission to perform this action.'),
+  notFound: () => t('jmapErrors.notFound', 'The item was not found. It may have been already deleted.'),
+  objectIsLinked: () => t('jmapErrors.objectIsLinked', 'This item is referenced by other items and cannot be deleted.'),
+  invalidForeignKey: () => t('jmapErrors.invalidForeignKey', 'This item references another item that does not exist.'),
+  primaryKeyViolation: () => t('jmapErrors.primaryKeyViolation', 'An item with the same key already exists.'),
+  alreadyExists: () => t('jmapErrors.alreadyExists', 'An item with the same identifier already exists.'),
+  overQuota: () => t('jmapErrors.overQuota', 'The operation exceeds your storage quota.'),
+  tooLarge: () => t('jmapErrors.tooLarge', 'The item is too large.'),
+  rateLimit: () => t('jmapErrors.rateLimit', 'Too many requests. Please try again later.'),
+  singleton: () => t('jmapErrors.singleton', 'This item is a singleton and cannot be deleted.'),
+  mailboxHasChild: () => t('jmapErrors.mailboxHasChild', 'This mailbox has child mailboxes. Delete them first.'),
+  mailboxHasEmail: () => t('jmapErrors.mailboxHasEmail', 'This mailbox contains messages. Remove them first.'),
+  calendarHasEvent: () => t('jmapErrors.calendarHasEvent', 'This calendar contains events. Remove them first.'),
+  addressBookHasContents: () =>
+    t('jmapErrors.addressBookHasContents', 'This address book has contacts. Remove them first.'),
+  nodeHasChildren: () => t('jmapErrors.nodeHasChildren', 'This item has children. Delete them first.'),
+  validationFailed: () => t('jmapErrors.validationFailed', 'The data did not pass validation.'),
+};
+
+/** Why a create, update or delete failed: the server's description if it sent one, else ours for the type. */
 export function friendlySetError(err: JmapSetError): string {
   if (err.description) return err.description;
-  switch (err.type) {
-    case 'forbidden':
-      return i18n.t('jmapErrors.forbidden', 'You do not have permission to perform this action.');
-    case 'notFound':
-      return i18n.t('jmapErrors.notFound', 'The item was not found. It may have been already deleted.');
-    case 'objectIsLinked':
-      return i18n.t('jmapErrors.objectIsLinked', 'This item is referenced by other items and cannot be deleted.');
-    case 'invalidForeignKey':
-      return i18n.t('jmapErrors.invalidForeignKey', 'This item references another item that does not exist.');
-    case 'primaryKeyViolation':
-      return i18n.t('jmapErrors.primaryKeyViolation', 'An item with the same key already exists.');
-    case 'alreadyExists':
-      return i18n.t('jmapErrors.alreadyExists', 'An item with the same identifier already exists.');
-    case 'overQuota':
-      return i18n.t('jmapErrors.overQuota', 'The operation exceeds your storage quota.');
-    case 'tooLarge':
-      return i18n.t('jmapErrors.tooLarge', 'The item is too large.');
-    case 'rateLimit':
-      return i18n.t('jmapErrors.rateLimit', 'Too many requests. Please try again later.');
-    case 'singleton':
-      return i18n.t('jmapErrors.singleton', 'This item is a singleton and cannot be deleted.');
-    case 'mailboxHasChild':
-      return i18n.t('jmapErrors.mailboxHasChild', 'This mailbox has child mailboxes. Delete them first.');
-    case 'mailboxHasEmail':
-      return i18n.t('jmapErrors.mailboxHasEmail', 'This mailbox contains messages. Remove them first.');
-    case 'calendarHasEvent':
-      return i18n.t('jmapErrors.calendarHasEvent', 'This calendar contains events. Remove them first.');
-    case 'addressBookHasContents':
-      return i18n.t('jmapErrors.addressBookHasContents', 'This address book has contacts. Remove them first.');
-    case 'nodeHasChildren':
-      return i18n.t('jmapErrors.nodeHasChildren', 'This item has children. Delete them first.');
-    case 'validationFailed':
-      return i18n.t('jmapErrors.validationFailed', 'The data did not pass validation.');
-    default:
-      return i18n.t('jmapErrors.unexpected', 'Unexpected error ({{type}}).', { type: err.type });
-  }
+  const known = Object.hasOwn(SET_ERRORS, err.type) ? SET_ERRORS[err.type] : undefined;
+  return known ? known() : t('jmapErrors.unexpected', 'Unexpected error ({{type}}).', { type: err.type });
 }
diff --git a/src/lib/jmapUtils.test.ts b/src/lib/jmapUtils.test.ts
new file mode 100644
index 0000000..d714379
--- /dev/null
+++ b/src/lib/jmapUtils.test.ts
@@ -0,0 +1,26 @@
+/*
+ * SPDX-FileCopyrightText: 2026 Coffey Labs LLC
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import { describe, expect, it } from 'vitest';
+
+import { jmapMapToArray } from './jmapUtils';
+
+describe('jmapMapToArray', () => {
+  it('keeps an array', () => {
+    const list = ['a', 'b'];
+    expect(jmapMapToArray(list)).toBe(list);
+  });
+
+  it('orders an object by its numeric keys', () => {
+    expect(jmapMapToArray({ '10': 'k', '2': 'c', '0': 'a', '1': 'b' })).toEqual(['a', 'b', 'c', 'k']);
+  });
+
+  it('reads anything else as an empty list', () => {
+    expect(jmapMapToArray(null)).toEqual([]);
+    expect(jmapMapToArray(undefined)).toEqual([]);
+    expect(jmapMapToArray('abc')).toEqual([]);
+  });
+});
diff --git a/src/lib/jmapUtils.ts b/src/lib/jmapUtils.ts
index f184b10..eed84df 100644
--- a/src/lib/jmapUtils.ts
+++ b/src/lib/jmapUtils.ts
@@ -1,17 +1,20 @@
 /*
- * SPDX-FileCopyrightText: 2020 Stalwart Labs LLC <hello@stalw.art>
+ * SPDX-FileCopyrightText: 2026 Coffey Labs LLC
  *
- * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-SEL
+ * SPDX-License-Identifier: AGPL-3.0-only
  */
 
+/** What the server sends in place of a secret's value. */
 export const SECRET_MASK = '****';
 
-export function jmapMapToArray<T>(val: unknown): T[] {
-  if (Array.isArray(val)) return val as T[];
-  if (val && typeof val === 'object') {
-    return Object.entries(val as Record<string, T>)
-      .sort(([a], [b]) => Number(a) - Number(b))
-      .map(([, v]) => v);
-  }
-  return [];
+/**
+ * A list the server may send as an array or as an object keyed by position
+ * ("0", "1", …), as an array in that order. Anything else is an empty list.
+ */
+export function jmapMapToArray<T>(value: unknown): T[] {
+  if (Array.isArray(value)) return value as T[];
+  if (value === null || typeof value !== 'object') return [];
+  const byIndex = Object.entries(value as Record<string, T>);
+  byIndex.sort((a, b) => Number(a[0]) - Number(b[0]));
+  return byIndex.map((entry) => entry[1]);
 }
diff --git a/src/lib/lastVisited.test.ts b/src/lib/lastVisited.test.ts
new file mode 100644
index 0000000..6961e92
--- /dev/null
+++ b/src/lib/lastVisited.test.ts
@@ -0,0 +1,74 @@
+/*
+ * SPDX-FileCopyrightText: 2026 Coffey Labs LLC
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import { beforeAll, beforeEach, describe, expect, it, vi } from 'vitest';
+
+import type { Layout, Schema } from '@/types/schema';
+
+const layoutMock = vi.hoisted(() => ({
+  accessible: new Set<string>(),
+  firstAccessible: null as string | null,
+  firstVisible: null as string | null,
+}));
+vi.mock('@/lib/layout', () => ({
+  isLinkAccessible: (_s: unknown, view: string) => layoutMock.accessible.has(view),
+  findFirstAccessibleLinkInLayout: () => layoutMock.firstAccessible,
+  findFirstVisibleLinkInLayout: () => layoutMock.firstVisible,
+}));
+
+import { rememberLastVisited, sectionLandingLink } from './lastVisited';
+
+const schema = {} as Schema;
+const settings = { name: 'Settings' } as Layout;
+const land = () => sectionLandingLink(schema, settings, 'community', () => true);
+
+describe('last visited page per section', () => {
+  // In memory: Node's own `localStorage` global, empty without a storage file, hides happy-dom's.
+  beforeAll(() => {
+    const store = new Map<string, string>();
+    vi.stubGlobal('localStorage', {
+      getItem: (k: string) => store.get(k) ?? null,
+      setItem: (k: string, v: string) => void store.set(k, v),
+      clear: () => store.clear(),
+    });
+  });
+
+  beforeEach(() => {
+    localStorage.clear();
+    layoutMock.accessible = new Set(['x:Domain', 'x:Account']);
+    layoutMock.firstAccessible = 'x:Overview';
+    layoutMock.firstVisible = 'x:Locked';
+  });
+
+  it('opens a section on the page last used there', () => {
+    rememberLastVisited('Settings', 'x:Domain');
+    rememberLastVisited('Management', 'x:Account');
+    expect(land()).toBe('x:Domain');
+    expect(JSON.parse(localStorage.getItem('inbuxa-last-visited')!)).toEqual({
+      Settings: 'x:Domain',
+      Management: 'x:Account',
+    });
+  });
+
+  it('skips a remembered page the admin can no longer open', () => {
+    rememberLastVisited('Settings', 'x:Gone');
+    expect(land()).toBe('x:Overview');
+  });
+
+  it('falls back to the first page shown when none may be opened', () => {
+    layoutMock.firstAccessible = null;
+    expect(land()).toBe('x:Locked');
+  });
+
+  it('ignores garbled storage', () => {
+    localStorage.setItem('inbuxa-last-visited', '["x:Domain"]');
+    expect(land()).toBe('x:Overview');
+    localStorage.setItem('inbuxa-last-visited', '{not json');
+    expect(land()).toBe('x:Overview');
+    rememberLastVisited('Settings', 'x:Domain');
+    expect(land()).toBe('x:Domain');
+  });
+});
diff --git a/src/lib/lastVisited.ts b/src/lib/lastVisited.ts
index 9101e98..fa928f7 100644
--- a/src/lib/lastVisited.ts
+++ b/src/lib/lastVisited.ts
@@ -1,12 +1,14 @@
 /*
- * SPDX-FileCopyrightText: 2020 Stalwart Labs LLC <hello@stalw.art>
  * SPDX-FileCopyrightText: 2026 Coffey Labs LLC
  *
- * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-SEL
- *
- * Modified by Coffey Labs in 2026 for INBUXA.
+ * SPDX-License-Identifier: AGPL-3.0-only
  */
 
+/**
+ * Each section (Management, Settings, Account) opens on the page the admin
+ * last used in it, kept in this browser. A remembered page the admin can no
+ * longer open is skipped.
+ */
 import {
   findFirstAccessibleLinkInLayout,
   findFirstVisibleLinkInLayout,
@@ -16,28 +18,29 @@ import {
 } from '@/lib/layout';
 import type { Layout, Schema } from '@/types/schema';
 
-const STORAGE_KEY = 'inbuxa-last-visited';
+const KEY = 'inbuxa-last-visited';
 
-function readAll(): Record<string, unknown> {
+/** Section name → view name; empty when storage is missing, blocked or garbled. */
+function remembered(): Record<string, unknown> {
   try {
-    const raw = localStorage.getItem(STORAGE_KEY);
-    const parsed: unknown = raw ? JSON.parse(raw) : null;
-    return parsed && typeof parsed === 'object' && !Array.isArray(parsed) ? (parsed as Record<string, unknown>) : {};
+    const value: unknown = JSON.parse(localStorage.getItem(KEY) ?? '{}');
+    return value !== null && typeof value === 'object' && !Array.isArray(value) ? { ...value } : {};
   } catch {
     return {};
   }
 }
 
 export function rememberLastVisited(section: string, viewName: string): void {
+  const all = remembered();
+  if (all[section] === viewName) return;
   try {
-    const all = readAll();
-    if (all[section] === viewName) return;
-    localStorage.setItem(STORAGE_KEY, JSON.stringify({ ...all, [section]: viewName }));
+    localStorage.setItem(KEY, JSON.stringify({ ...all, [section]: viewName }));
   } catch {
-    return;
+    // Storage full or blocked: the section opens on its first page instead.
   }
 }
 
+/** Where a section opens: the page last used there, else its first page the admin may open, else its first page. */
 export function sectionLandingLink(
   schema: Schema,
   layout: Layout,
@@ -45,10 +48,8 @@ export function sectionLandingLink(
   canGet: CanGet,
   hasPerm?: HasPermission,
 ): string | null {
-  const last = readAll()[layout.name];
-  if (typeof last === 'string' && isLinkAccessible(schema, last, edition, canGet, hasPerm)) {
-    return last;
-  }
+  const last = remembered()[layout.name];
+  if (typeof last === 'string' && isLinkAccessible(schema, last, edition, canGet, hasPerm)) return last;
   return (
     findFirstAccessibleLinkInLayout(schema, layout, edition, canGet, hasPerm) ??
     findFirstVisibleLinkInLayout(schema, layout, edition, canGet, hasPerm)
diff --git a/src/lib/listFilter.test.ts b/src/lib/listFilter.test.ts
index b06a48f..b0ed6e3 100644
--- a/src/lib/listFilter.test.ts
+++ b/src/lib/listFilter.test.ts
@@ -1,155 +1,86 @@
 /*
- * SPDX-FileCopyrightText: 2020 Stalwart Labs LLC <hello@stalw.art>
+ * SPDX-FileCopyrightText: 2026 Coffey Labs LLC
  *
- * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-SEL
+ * SPDX-License-Identifier: AGPL-3.0-only
  */
 
-import { describe, it, expect } from 'vitest';
-import { buildJmapFilter } from './listFilter';
-import type { Filter } from '@/types/schema';
+import { describe, expect, it } from 'vitest';
 
-const dateFilter: Filter = { type: 'date', field: 'timestamp', label: 'Date' };
-const textFilter: Filter = { type: 'text', field: 'text', label: 'Text' };
-const intFilter: Filter = { type: 'integer', field: 'size', label: 'Size' };
+import type { Filter } from '@/types/schema';
+import { buildJmapFilter } from './listFilter';
+
+const dateFilter = [{ field: 'created', type: 'date' }] as Filter[];
+const x = (appliedFilters: Record<string, string>) =>
+  buildJmapFilter({ appliedFilters, filters: dateFilter, isXPrefixed: true });
 
 describe('buildJmapFilter', () => {
-  it('returns an empty object when nothing is applied', () => {
-    expect(buildJmapFilter({ appliedFilters: {}, isXPrefixed: true })).toEqual({});
+  it('starts from the static filters and adds what the reader picked', () => {
+    expect(
+      buildJmapFilter({ appliedFilters: { name: 'ann' }, filtersStatic: { kind: 'user' }, isXPrefixed: true }),
+    ).toEqual({ kind: 'user', name: 'ann' });
+    expect(buildJmapFilter({ appliedFilters: {}, isXPrefixed: false })).toEqual({});
   });
 
-  it('merges filtersStatic', () => {
-    const filter = buildJmapFilter({
-      appliedFilters: {},
-      filtersStatic: { hasErrors: true },
-      isXPrefixed: true,
-    });
-    expect(filter).toEqual({ hasErrors: true });
+  it('leaves out empty values, and operators on their own', () => {
+    expect(
+      buildJmapFilter({ appliedFilters: { name: '', size: '5', sizeOp: 'gt', quotaOp: 'lt' }, isXPrefixed: true }),
+    ).toEqual({ sizeIsGreaterThan: '5' });
   });
 
-  it('skips empty and Op-only keys', () => {
-    const filter = buildJmapFilter({
-      appliedFilters: { text: '', textOp: 'eq' },
-      filters: [textFilter],
-      isXPrefixed: true,
-    });
-    expect(filter).toEqual({});
-  });
-
-  it('passes text filters through verbatim', () => {
-    const filter = buildJmapFilter({
-      appliedFilters: { text: 'hello' },
-      filters: [textFilter],
-      isXPrefixed: true,
-    });
-    expect(filter).toEqual({ text: 'hello' });
-  });
-
-  it('applies the operator suffix for integer filters', () => {
-    const filter = buildJmapFilter({
-      appliedFilters: { size: '1024', sizeOp: 'gt' },
-      filters: [intFilter],
-      isXPrefixed: true,
-    });
-    expect(filter).toEqual({ sizeIsGreaterThan: '1024' });
-  });
-
-  describe('date filters (x-prefixed, with operator UI)', () => {
-    it('expands a default date-only equality into a full-day range', () => {
-      const filter = buildJmapFilter({
-        appliedFilters: { timestamp: '2026-06-17' },
-        filters: [dateFilter],
-        isXPrefixed: true,
-      });
-      expect(filter).toEqual({
-        timestampIsGreaterThanOrEqual: '2026-06-17T00:00:00Z',
-        timestampIsLessThan: '2026-06-18T00:00:00Z',
-      });
-    });
-
-    it('treats an explicit eq operator the same as the default', () => {
-      const filter = buildJmapFilter({
-        appliedFilters: { timestamp: '2026-06-17', timestampOp: 'eq' },
-        filters: [dateFilter],
-        isXPrefixed: true,
-      });
-      expect(filter).toEqual({
-        timestampIsGreaterThanOrEqual: '2026-06-17T00:00:00Z',
-        timestampIsLessThan: '2026-06-18T00:00:00Z',
-      });
-    });
-
-    it('appends midnight UTC for the After (gt) operator', () => {
-      const filter = buildJmapFilter({
-        appliedFilters: { timestamp: '2026-06-17', timestampOp: 'gt' },
-        filters: [dateFilter],
-        isXPrefixed: true,
-      });
-      expect(filter).toEqual({ timestampIsGreaterThan: '2026-06-17T00:00:00Z' });
-    });
-
-    it('appends midnight UTC for the Before (lt) operator', () => {
-      const filter = buildJmapFilter({
-        appliedFilters: { timestamp: '2026-06-17', timestampOp: 'lt' },
-        filters: [dateFilter],
-        isXPrefixed: true,
-      });
-      expect(filter).toEqual({ timestampIsLessThan: '2026-06-17T00:00:00Z' });
-    });
-
-    it('rolls over month boundaries', () => {
-      const filter = buildJmapFilter({
-        appliedFilters: { timestamp: '2026-06-30' },
-        filters: [dateFilter],
-        isXPrefixed: true,
-      });
-      expect(filter).toEqual({
-        timestampIsGreaterThanOrEqual: '2026-06-30T00:00:00Z',
-        timestampIsLessThan: '2026-07-01T00:00:00Z',
-      });
-    });
-
-    it('rolls over year boundaries', () => {
-      const filter = buildJmapFilter({
-        appliedFilters: { timestamp: '2026-12-31' },
-        filters: [dateFilter],
-        isXPrefixed: true,
-      });
-      expect(filter).toEqual({
-        timestampIsGreaterThanOrEqual: '2026-12-31T00:00:00Z',
-        timestampIsLessThan: '2027-01-01T00:00:00Z',
-      });
-    });
-
-    it('handles leap-year February', () => {
-      const filter = buildJmapFilter({
-        appliedFilters: { timestamp: '2028-02-28' },
-        filters: [dateFilter],
-        isXPrefixed: true,
-      });
-      expect(filter).toEqual({
-        timestampIsGreaterThanOrEqual: '2028-02-28T00:00:00Z',
-        timestampIsLessThan: '2028-02-29T00:00:00Z',
-      });
-    });
-
-    it('passes a full datetime through with only the operator suffix applied', () => {
-      const filter = buildJmapFilter({
-        appliedFilters: { timestamp: '2026-06-17T08:30:00Z', timestampOp: 'gt' },
-        filters: [dateFilter],
-        isXPrefixed: true,
-      });
-      expect(filter).toEqual({ timestampIsGreaterThan: '2026-06-17T08:30:00Z' });
+  it.each([
+    ['eq', 'size'],
+    ['gt', 'sizeIsGreaterThan'],
+    ['gte', 'sizeIsGreaterThanOrEqual'],
+    ['lt', 'sizeIsLessThan'],
+    ['lte', 'sizeIsLessThanOrEqual'],
+  ])('names the property for the %s operator: %s', (op, key) => {
+    expect(buildJmapFilter({ appliedFilters: { size: '10', sizeOp: op }, isXPrefixed: true })).toEqual({
+      [key]: '10',
     });
   });
 
-  describe('date filters (non-x-prefixed, no operator UI)', () => {
-    it('appends midnight UTC as an exact match without range expansion', () => {
-      const filter = buildJmapFilter({
-        appliedFilters: { timestamp: '2026-06-17' },
-        filters: [dateFilter],
-        isXPrefixed: false,
+  describe('a date on an x: object', () => {
+    it('covers the whole UTC day when no operator, or eq, is picked', () => {
+      const day = {
+        createdIsGreaterThanOrEqual: '2026-03-14T00:00:00Z',
+        createdIsLessThan: '2026-03-15T00:00:00Z',
+      };
+      expect(x({ created: '2026-03-14' })).toEqual(day);
+      expect(x({ created: '2026-03-14', createdOp: 'eq' })).toEqual(day);
+    });
+
+    it('runs the day over into the next month, year and leap day', () => {
+      expect(x({ created: '2026-01-31' }).createdIsLessThan).toBe('2026-02-01T00:00:00Z');
+      expect(x({ created: '2025-12-31' }).createdIsLessThan).toBe('2026-01-01T00:00:00Z');
+      expect(x({ created: '2028-02-28' }).createdIsLessThan).toBe('2028-02-29T00:00:00Z');
+      expect(x({ created: '2027-02-28' }).createdIsLessThan).toBe('2027-03-01T00:00:00Z');
+    });
+
+    it('compares against midnight UTC for before and after', () => {
+      expect(x({ created: '2026-03-14', createdOp: 'gt' })).toEqual({ createdIsGreaterThan: '2026-03-14T00:00:00Z' });
+      expect(x({ created: '2026-03-14', createdOp: 'lt' })).toEqual({ createdIsLessThan: '2026-03-14T00:00:00Z' });
+    });
+
+    it('sends a full date and time as it is, with the operator', () => {
+      expect(x({ created: '2026-03-14T08:30:00Z', createdOp: 'gte' })).toEqual({
+        createdIsGreaterThanOrEqual: '2026-03-14T08:30:00Z',
+      });
+      expect(x({ created: '2026-03-14T08:30:00Z' })).toEqual({ created: '2026-03-14T08:30:00Z' });
+    });
+  });
+
+  describe('a date on an object without operators', () => {
+    const plain = (appliedFilters: Record<string, string>) =>
+      buildJmapFilter({ appliedFilters, filters: dateFilter, isXPrefixed: false });
+
+    it('matches midnight UTC of that day exactly', () => {
+      expect(plain({ created: '2026-03-14' })).toEqual({ created: '2026-03-14T00:00:00Z' });
+    });
+
+    it('sends a full date and time as it is, ignoring any operator', () => {
+      expect(plain({ created: '2026-03-14T08:30:00Z', createdOp: 'gt' })).toEqual({
+        created: '2026-03-14T08:30:00Z',
       });
-      expect(filter).toEqual({ timestamp: '2026-06-17T00:00:00Z' });
     });
   });
 });
diff --git a/src/lib/listFilter.ts b/src/lib/listFilter.ts
index 720237e..2d93eca 100644
--- a/src/lib/listFilter.ts
+++ b/src/lib/listFilter.ts
@@ -1,97 +1,74 @@
 /*
- * SPDX-FileCopyrightText: 2020 Stalwart Labs LLC <hello@stalw.art>
+ * SPDX-FileCopyrightText: 2026 Coffey Labs LLC
  *
- * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-SEL
+ * SPDX-License-Identifier: AGPL-3.0-only
  */
 
+/**
+ * Turns the filters a reader picked above a list into a JMAP `/query`
+ * filter. A filter `size` with operator `sizeOp: 'gt'` becomes
+ * `sizeIsGreaterThan`. Dates picked as a day become midnight UTC, and on x:
+ * objects a plain day means the whole day.
+ */
 import type { Filter } from '@/types/schema';
 
-const OP_SUFFIX: Record<string, string> = {
-  eq: '',
+const OPERATOR_SUFFIX: Record<string, string> = {
   gt: 'IsGreaterThan',
   gte: 'IsGreaterThanOrEqual',
   lt: 'IsLessThan',
   lte: 'IsLessThanOrEqual',
 };
 
-const DATE_ONLY = /^\d{4}-\d{2}-\d{2}$/;
+const suffixFor = (op: string | undefined) => (op ? (OPERATOR_SUFFIX[op] ?? '') : '');
 
-function utcDayStart(date: string): string {
-  return `${date}T00:00:00Z`;
+const isDay = (value: string) => /^\d{4}-\d{2}-\d{2}$/.test(value);
+
+const midnight = (day: string) => `${day}T00:00:00Z`;
+
+function nextMidnight(day: string) {
+  const next = new Date(Date.parse(midnight(day)) + 86_400_000);
+  return `${next.toISOString().slice(0, 10)}T00:00:00Z`;
 }
 
-function utcNextDayStart(date: string): string {
-  const dt = new Date(`${date}T00:00:00Z`);
-  dt.setUTCDate(dt.getUTCDate() + 1);
-  const y = dt.getUTCFullYear();
-  const m = String(dt.getUTCMonth() + 1).padStart(2, '0');
-  const d = String(dt.getUTCDate()).padStart(2, '0');
-  return `${y}-${m}-${d}T00:00:00Z`;
-}
-
-function applyDateFilter(
-  filter: Record<string, unknown>,
-  field: string,
-  value: string,
-  op: string | undefined,
-  isXPrefixed: boolean,
-): void {
-  if (!DATE_ONLY.test(value)) {
-    const suffix = isXPrefixed && op ? (OP_SUFFIX[op] ?? '') : '';
-    filter[`${field}${suffix}`] = value;
-    return;
+/** The filter entries for one date field. */
+function dateEntries(field: string, value: string, op: string | undefined, withOps: boolean): [string, string][] {
+  if (!isDay(value)) return [[field + (withOps ? suffixFor(op) : ''), value]];
+  if (!withOps) return [[field, midnight(value)]];
+  if (!op || op === 'eq') {
+    return [
+      [`${field}IsGreaterThanOrEqual`, midnight(value)],
+      [`${field}IsLessThan`, nextMidnight(value)],
+    ];
   }
-
-  if (!isXPrefixed) {
-    filter[field] = utcDayStart(value);
-    return;
-  }
-
-  const effectiveOp = op ?? 'eq';
-  if (effectiveOp === 'eq') {
-    filter[`${field}IsGreaterThanOrEqual`] = utcDayStart(value);
-    filter[`${field}IsLessThan`] = utcNextDayStart(value);
-    return;
-  }
-
-  const suffix = OP_SUFFIX[effectiveOp] ?? '';
-  filter[`${field}${suffix}`] = utcDayStart(value);
+  return [[field + suffixFor(op), midnight(value)]];
 }
 
 export interface BuildJmapFilterArgs {
+  /** What the reader picked: `field: value`, and `fieldOp: operator`. */
   appliedFilters: Record<string, string>;
+  /** The list's filter definitions; they say which fields are dates. */
   filters?: Filter[];
+  /** Always part of the query. */
   filtersStatic?: Record<string, unknown>;
+  /** x: objects take operators and date ranges; others match exactly. */
   isXPrefixed: boolean;
 }
 
 export function buildJmapFilter({
   appliedFilters,
-  filters,
+  filters = [],
   filtersStatic,
   isXPrefixed,
 }: BuildJmapFilterArgs): Record<string, unknown> {
-  const filter: Record<string, unknown> = {};
-  if (filtersStatic) {
-    Object.assign(filter, filtersStatic);
+  const dates = new Set(filters.filter((f) => f.type === 'date').map((f) => f.field));
+  const out: Record<string, unknown> = { ...filtersStatic };
+  for (const [field, value] of Object.entries(appliedFilters)) {
+    if (!value || field.endsWith('Op')) continue;
+    const op = appliedFilters[`${field}Op`];
+    const entries: [string, string][] = dates.has(field)
+      ? dateEntries(field, value, op, isXPrefixed)
+      : [[field + suffixFor(op), value]];
+    for (const [key, v] of entries) out[key] = v;
   }
-
-  const dateFields = new Set((filters ?? []).filter((f) => f.type === 'date').map((f) => f.field));
-
-  for (const [key, val] of Object.entries(appliedFilters)) {
-    if (val === '' || val == null) continue;
-    if (key.endsWith('Op')) continue;
-
-    const op = appliedFilters[`${key}Op`];
-
-    if (dateFields.has(key)) {
-      applyDateFilter(filter, key, val, op, isXPrefixed);
-      continue;
-    }
-
-    const suffix = op ? (OP_SUFFIX[op] ?? '') : '';
-    filter[`${key}${suffix}`] = val;
-  }
-
-  return filter;
+  return out;
 }
diff --git a/src/lib/logoCache.test.ts b/src/lib/logoCache.test.ts
new file mode 100644
index 0000000..ae7b424
--- /dev/null
+++ b/src/lib/logoCache.test.ts
@@ -0,0 +1,45 @@
+/*
+ * SPDX-FileCopyrightText: 2026 Coffey Labs LLC
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import { afterEach, describe, expect, it, vi } from 'vitest';
+
+vi.mock('@/services/api', () => ({ getApiBaseUrl: () => 'https://mail.example' }));
+
+/** A fresh copy of the module, since it fetches once per page load. */
+async function load(response: Response | Error) {
+  vi.resetModules();
+  const fetchMock = vi.fn(() => (response instanceof Error ? Promise.reject(response) : Promise.resolve(response)));
+  vi.stubGlobal('fetch', fetchMock);
+  const mod = await import('./logoCache');
+  const changed = vi.fn();
+  mod.subscribeToLogo(changed);
+  mod.loadLogoOnce();
+  mod.loadLogoOnce();
+  await vi.waitFor(() => expect(changed).toHaveBeenCalled());
+  return { state: mod.getLogoState(), fetchMock };
+}
+
+describe('logo cache', () => {
+  afterEach(() => vi.unstubAllGlobals());
+
+  it('uses an image the server sends, fetching it only once', async () => {
+    URL.createObjectURL = vi.fn(() => 'blob:logo');
+    const { state, fetchMock } = await load(
+      new Response(new Blob(['png']), { headers: { 'content-type': 'image/png' } }),
+    );
+    expect(state).toEqual({ status: 'custom', url: 'blob:logo' });
+    expect(fetchMock).toHaveBeenCalledTimes(1);
+    expect(fetchMock).toHaveBeenCalledWith('https://mail.example/logo');
+  });
+
+  it('falls back to the inbuxa logo for anything else', async () => {
+    expect((await load(new Response('nope', { status: 404 }))).state).toEqual({ status: 'default' });
+    expect((await load(new Response('<html>', { headers: { 'content-type': 'text/html' } }))).state).toEqual({
+      status: 'default',
+    });
+    expect((await load(new Error('offline'))).state).toEqual({ status: 'default' });
+  });
+});
diff --git a/src/lib/logoCache.ts b/src/lib/logoCache.ts
index 457706f..aae71af 100644
--- a/src/lib/logoCache.ts
+++ b/src/lib/logoCache.ts
@@ -1,40 +1,45 @@
 /*
- * SPDX-FileCopyrightText: 2020 Stalwart Labs LLC <hello@stalw.art>
+ * SPDX-FileCopyrightText: 2026 Coffey Labs LLC
  *
- * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-SEL
+ * SPDX-License-Identifier: AGPL-3.0-only
  */
 
+/**
+ * The server's own logo, if an admin set one: fetched once per page load
+ * from `/logo` and kept as an object URL. Anything but an image (no logo, an
+ * error page, no answer) means the inbuxa logo.
+ */
 import { getApiBaseUrl } from '@/services/api';
 
 export type LogoState = { status: 'loading' } | { status: 'custom'; url: string } | { status: 'default' };
 
-let state: LogoState = { status: 'loading' };
-let started = false;
-const listeners = new Set<() => void>();
+let logo: LogoState = { status: 'loading' };
+let requested = false;
+const watchers = new Set<() => void>();
 
-export function getLogoState(): LogoState {
-  return state;
+export const getLogoState = (): LogoState => logo;
+
+export function subscribeToLogo(watch: () => void): () => void {
+  watchers.add(watch);
+  return () => void watchers.delete(watch);
 }
 
-export function subscribeToLogo(listener: () => void): () => void {
-  listeners.add(listener);
-  return () => {
-    listeners.delete(listener);
-  };
+async function fetchLogo(): Promise<string | null> {
+  try {
+    const res = await fetch(`${getApiBaseUrl()}/logo`);
+    if (!res.ok || !res.headers.get('content-type')?.startsWith('image/')) return null;
+    return URL.createObjectURL(await res.blob());
+  } catch {
+    return null;
+  }
 }
 
+/** Starts the fetch; later calls do nothing. */
 export function loadLogoOnce(): void {
-  if (started) return;
-  started = true;
-  fetch(`${getApiBaseUrl()}/logo`)
-    .then(async (response) => {
-      const contentType = response.headers.get('content-type') ?? '';
-      if (!response.ok || !contentType.startsWith('image/')) return null;
-      return URL.createObjectURL(await response.blob());
-    })
-    .catch(() => null)
-    .then((url) => {
-      state = url ? { status: 'custom', url } : { status: 'default' };
-      listeners.forEach((notify) => notify());
-    });
+  if (requested) return;
+  requested = true;
+  void fetchLogo().then((url) => {
+    logo = url ? { status: 'custom', url } : { status: 'default' };
+    for (const watch of watchers) watch();
+  });
 }
diff --git a/src/lib/sievepad.test.ts b/src/lib/sievepad.test.ts
index e7cbf7c..5ae8693 100644
--- a/src/lib/sievepad.test.ts
+++ b/src/lib/sievepad.test.ts
@@ -1,10 +1,7 @@
 /*
- * SPDX-FileCopyrightText: 2020 Stalwart Labs LLC <hello@stalw.art>
  * SPDX-FileCopyrightText: 2026 Coffey Labs LLC
  *
- * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-SEL
- *
- * Modified by Coffey Labs in 2026 for INBUXA.
+ * SPDX-License-Identifier: AGPL-3.0-only
  */
 
 import { inflateRawSync } from 'node:zlib';
@@ -12,52 +9,56 @@ import { describe, expect, it } from 'vitest';
 
 import { isSieveScriptField, playgroundUrl, sievepadLink } from './sievepad';
 
-function decode(link: string): unknown {
-  const token = new URLSearchParams(new URL(link).hash.slice(1)).get('w') ?? '';
-  return JSON.parse(inflateRawSync(Buffer.from(token, 'base64url')).toString('utf8'));
+/** What the playground reads back out of a link. */
+function workspaceIn(link: string) {
+  const w = new URL(link).hash.match(/^#w=([A-Za-z0-9_-]+)$/)?.[1];
+  if (!w) throw new Error(`no workspace in ${link}`);
+  return JSON.parse(inflateRawSync(Buffer.from(w, 'base64url')).toString('utf8'));
 }
 
-describe('playgroundUrl', () => {
-  it('names the bundled playground, by content hash, beside the console', () => {
+describe('the playground link', () => {
+  it('points at the playground shipped beside the console', () => {
     const url = new URL(playgroundUrl());
     expect(url.origin).toBe(new URL(document.baseURI).origin);
     expect(url.pathname).toMatch(/\/sieve-playground\/[0-9a-f]{16}\/index\.html$/);
   });
-});
-
-describe('sievepadLink', () => {
-  it('encodes the script as a single main entry', async () => {
-    const source = 'require "imap4flags";\r\naddflag "\\\\Seen";\r\n';
-    const link = await sievepadLink('Filters é', source);
 
+  it('carries the script as the main entry, with Unix line ends', async () => {
+    const link = await sievepadLink('Vacation ✈', 'if true {\r\n  keep;\r\n}\r\n');
     expect(link.startsWith(`${playgroundUrl()}#w=`)).toBe(true);
-    expect(link.slice(`${playgroundUrl()}#w=`.length)).toMatch(/^[A-Za-z0-9_-]+$/);
-    expect(decode(link)).toEqual({
+    expect(workspaceIn(link)).toEqual({
       v: 1,
-      name: 'Filters é',
-      scripts: [{ name: 'main', source: 'require "imap4flags";\naddflag "\\\\Seen";\n' }],
+      name: 'Vacation ✈',
+      scripts: [{ name: 'main', source: 'if true {\n  keep;\n}\n' }],
       messages: [],
       settings: {},
     });
   });
 
-  it('carries the interpreter settings it is given', async () => {
-    const link = await sievepadLink('Filters', 'keep;', { cpuLimit: 5000, capabilities: ['fileinto'] });
-    expect((decode(link) as { settings: unknown }).settings).toEqual({ cpuLimit: 5000, capabilities: ['fileinto'] });
+  it("carries the interpreter's settings", async () => {
+    const settings = { maxInstructions: 1000, extensions: ['vacation'] };
+    expect(workspaceIn(await sievepadLink('s', 'keep;', settings)).settings).toEqual(settings);
   });
 
-  it('truncates long workspace names', async () => {
-    const link = await sievepadLink('x'.repeat(200), 'keep;');
-    expect((decode(link) as { name: string }).name).toHaveLength(80);
+  it('cuts the name to 80 characters', async () => {
+    expect(workspaceIn(await sievepadLink('n'.repeat(81), 'keep;')).name).toBe('n'.repeat(80));
+  });
+
+  it('holds a large script', async () => {
+    const source = Array.from({ length: 5000 }, (_, i) => `# rule ${i} ${Math.random()}`).join('\n');
+    expect(workspaceIn(await sievepadLink('big', source)).scripts[0].source).toBe(source);
   });
 });
 
 describe('isSieveScriptField', () => {
-  it('matches only the known script fields', () => {
-    expect(isSieveScriptField('x:SieveUserScript', 'contents')).toBe(true);
-    expect(isSieveScriptField('x:SieveSystemScript', 'contents')).toBe(true);
-    expect(isSieveScriptField('SieveScript', 'blobId')).toBe(true);
-    expect(isSieveScriptField('SieveScript', 'name')).toBe(false);
-    expect(isSieveScriptField('x:Domain', 'contents')).toBe(false);
+  it.each([
+    ['x:SieveUserScript', 'contents', true],
+    ['x:SieveSystemScript', 'contents', true],
+    ['SieveScript', 'blobId', true],
+    ['SieveScript', 'contents', false],
+    ['x:SieveUserScript', 'name', false],
+    ['x:Domain', 'contents', false],
+  ])('%s.%s → %s', (object, field, expected) => {
+    expect(isSieveScriptField(object, field)).toBe(expected);
   });
 });
diff --git a/src/lib/sievepad.ts b/src/lib/sievepad.ts
index 35f2f84..9862acc 100644
--- a/src/lib/sievepad.ts
+++ b/src/lib/sievepad.ts
@@ -1,64 +1,69 @@
 /*
- * SPDX-FileCopyrightText: 2020 Stalwart Labs LLC <hello@stalw.art>
  * SPDX-FileCopyrightText: 2026 Coffey Labs LLC
  *
- * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-SEL
- *
- * Modified by Coffey Labs in 2026 for INBUXA.
+ * SPDX-License-Identifier: AGPL-3.0-only
  */
 
+/**
+ * Opening a Sieve script in the playground that ships with the console
+ * (`tools/sieve-playground`). The script travels in the link's fragment, so
+ * it never leaves the browser, and runs under the limits of the interpreter
+ * that runs it on the server (sieveLimits.ts).
+ */
 import { fetchPlaygroundSettings, type SieveInterpreter } from './sieveLimits';
 
-// inbuxa: the Sieve playground ships with the console (sieve-playground.ts)
-// and runs the server's own interpreter, so the script never leaves the
-// console's origin.
-export function playgroundUrl(): string {
-  return new URL(__SIEVE_PLAYGROUND__, document.baseURI).href;
-}
+/** The playground beside the console, at its content-hashed path. */
+export const playgroundUrl = (): string => new URL(__SIEVE_PLAYGROUND__, document.baseURI).href;
 
-const SIEVEPAD_FORMAT_VERSION = 1;
-const SIEVEPAD_MAX_NAME_LENGTH = 80;
-const SIEVEPAD_MAIN_SCRIPT = 'main';
-const BASE64_CHUNK_SIZE = 0x8000;
-
-const SIEVE_SCRIPT_FIELDS: Record<string, string> = {
+/** Which field holds the script, for each object that has one. */
+const SCRIPT_FIELD: Record<string, string> = {
   'x:SieveSystemScript': 'contents',
   'x:SieveUserScript': 'contents',
   SieveScript: 'blobId',
 };
 
-export function isSieveScriptField(objectName: string, fieldName: string): boolean {
-  return SIEVE_SCRIPT_FIELDS[objectName] === fieldName;
+export const isSieveScriptField = (objectName: string, fieldName: string): boolean =>
+  SCRIPT_FIELD[objectName] === fieldName;
+
+async function deflateRaw(text: string): Promise<Uint8Array> {
+  const compressed = new Blob([text]).stream().pipeThrough(new CompressionStream('deflate-raw'));
+  return new Uint8Array(await new Response(compressed).arrayBuffer());
 }
 
-function toBase64Url(bytes: Uint8Array): string {
+function base64Url(bytes: Uint8Array): string {
   let binary = '';
-  for (let i = 0; i < bytes.length; i += BASE64_CHUNK_SIZE) {
-    binary += String.fromCharCode(...bytes.subarray(i, i + BASE64_CHUNK_SIZE));
+  // In slices, so a large script doesn't overflow the argument list.
+  for (let at = 0; at < bytes.length; at += 32_768) {
+    binary += String.fromCharCode(...bytes.subarray(at, at + 32_768));
   }
-  return btoa(binary).replace(/\+/g, '-').replace(/\//g, '_').replace(/=+$/, '');
+  return btoa(binary).replaceAll('+', '-').replaceAll('/', '_').replace(/=+$/, '');
 }
 
+/**
+ * A playground link holding one workspace: the script as its `main` entry,
+ * no test messages, and the interpreter settings. This is the playground's
+ * format version 1, deflated and base64url-encoded into `#w=`.
+ */
 export async function sievepadLink(
   name: string,
   source: string,
   settings: Record<string, unknown> = {},
   base = playgroundUrl(),
 ): Promise<string> {
-  const json = JSON.stringify({
-    v: SIEVEPAD_FORMAT_VERSION,
-    name: name.slice(0, SIEVEPAD_MAX_NAME_LENGTH),
-    scripts: [{ name: SIEVEPAD_MAIN_SCRIPT, source: source.replace(/\r\n/g, '\n') }],
+  const workspace = {
+    v: 1,
+    name: name.slice(0, 80),
+    scripts: [{ name: 'main', source: source.replaceAll('\r\n', '\n') }],
     messages: [],
     settings,
-  });
-  const stream = new Blob([new TextEncoder().encode(json)]).stream().pipeThrough(new CompressionStream('deflate-raw'));
-  const packed = new Uint8Array(await new Response(stream).arrayBuffer());
-  return `${base}#w=${toBase64Url(packed)}`;
+  };
+  return `${base}#w=${base64Url(await deflateRaw(JSON.stringify(workspace)))}`;
 }
 
-// inbuxa: the script runs under the limits of the interpreter that runs it
-// on the server (sieveLimits.ts).
+/**
+ * Opens the script in a new tab. The tab opens first, while the click still
+ * counts as the reader's, and is pointed at the link once it is built.
+ */
 export async function openInSievepad(name: string, source: string, interpreter: SieveInterpreter): Promise<void> {
   const tab = window.open('about:blank', '_blank');
   if (tab) tab.opener = null;
@@ -69,9 +74,6 @@ export async function openInSievepad(name: string, source: string, interpreter:
     tab?.close();
     throw err;
   }
-  if (tab) {
-    tab.location.replace(link);
-  } else {
-    window.open(link, '_blank', 'noopener,noreferrer');
-  }
+  if (tab) tab.location.replace(link);
+  else window.open(link, '_blank', 'noopener,noreferrer');
 }
diff --git a/src/lib/utils.ts b/src/lib/utils.ts
index 39df27b..4a3d9c1 100644
--- a/src/lib/utils.ts
+++ b/src/lib/utils.ts
@@ -1,12 +1,11 @@
 /*
- * SPDX-FileCopyrightText: 2020 Stalwart Labs LLC <hello@stalw.art>
+ * SPDX-FileCopyrightText: 2026 Coffey Labs LLC
  *
- * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-SEL
+ * SPDX-License-Identifier: AGPL-3.0-only
  */
 
 import { clsx, type ClassValue } from 'clsx';
 import { twMerge } from 'tailwind-merge';
 
-export function cn(...inputs: ClassValue[]) {
-  return twMerge(clsx(inputs));
-}
+/** Joins class names; where two Tailwind classes set the same thing, the later one wins. */
+export const cn = (...classes: ClassValue[]): string => twMerge(clsx(classes));