diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9630b674..ba2b6854 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -62,6 +62,17 @@ auto-generated per-PR notes; this file is the curated, human-readable history.
   uses in production. Verified no raw NUL bytes remain anywhere under `src/`
   or `tests/`; no code change was needed.
 
+### Changed
+- **Sidebar tab headers go text-only once the sidebar is dragged to 220px or
+  narrower** (#552) — both the upper Databases/Dashboards role switcher and
+  the lower Library/History switcher hide their icons and `· N` counts at
+  that width, keeping the four labels readable, aligned and clickable with no
+  clipping or overlap even at the sidebar's 180px drag minimum. A pure CSS
+  container-query gate (`@container sidebar (max-width: 220px)`, named/scoped
+  on `.sidebar`'s new `container-type: inline-size`) restores the full
+  presentation the instant the sidebar widens past the threshold, with no JS
+  state to reconcile.
+
 ## [0.7.2] - 2026-07-29
 
 ### Fixed
diff --git a/src/styles.css b/src/styles.css
index 6319f161..b5ecc332 100644
--- a/src/styles.css
+++ b/src/styles.css
@@ -866,6 +866,13 @@ h1, h2, h3, h4, h5, h6 {
   display: flex; flex-direction: column;
   background: var(--bg-side);
   min-height: 0; flex-shrink: 0;
+  /* #552: a container-query axis (not a viewport media query — the sidebar's
+     width is a dragged pixel value on `sidebar.style.width`, invisible to
+     `@media`) so the tab headers — and any future sidebar content, e.g. the
+     Dashboard tree rows — can react to the actual dragged width. Named
+     `sidebar`/220px is the shared axis; see `@container sidebar` below for
+     the first consumer. */
+  container-type: inline-size; container-name: sidebar;
 }
 .col-resize, .row-resize {
   position: relative; flex-shrink: 0; z-index: 1;
@@ -999,6 +1006,18 @@ h1, h2, h3, h4, h5, h6 {
 .saved-row:hover .sv-act { display: inline-flex; }
 .sv-act:hover { color: var(--fg); background: var(--bg-hover); }
 .side-count { color: var(--fg-faint); font-weight: var(--fw-regular); }
+/* #552: at a narrow sidebar (bottom quarter of the 180–420px drag range —
+   `src/ui/splitters.ts`'s `clamp(ev.clientX, 180, 420)`), both tab rows
+   (`.upper-role-tabs`'s Databases/Dashboard and this row's Library/History)
+   drop to text-only labels: the icon, and `.side-count`'s "· N" (the count AND
+   its separator dot share one text node, so hiding the element hides both).
+   Widening the sidebar past 220px restores the icon/count with no JS state —
+   see `.sidebar`'s container-type/-name declaration above, alongside
+   `.query-host`/`.dashboard-host`. */
+@container sidebar (max-width: 220px) {
+  .side-tab svg { display: none; }
+  .side-tab .side-count { display: none; }
+}
 .history-row {
   position: relative;
   padding: 8px 10px; cursor: pointer; user-select: none;
diff --git a/tests/e2e/sidebar-tabs-narrow.spec.js b/tests/e2e/sidebar-tabs-narrow.spec.js
new file mode 100644
index 00000000..0cc5c44d
--- /dev/null
+++ b/tests/e2e/sidebar-tabs-narrow.spec.js
@@ -0,0 +1,140 @@
+import { test, expect } from '@playwright/test';
+
+// #552 — compact text-only tab headers at a narrow sidebar. happy-dom cannot
+// see CSS layout (the `@container sidebar (max-width: 220px)` gate lives in
+// `src/styles.css`), so this is the only place the breakpoint is provable:
+// dragging the real `.col-resize` handle the way the app does (mousedown on
+// the handle, then a real `mousemove`/`mouseup` — `src/ui/splitters.ts`'s
+// `dragValue('col', ev)` reads `ev.clientX` directly, unclamped by any rect),
+// and reading the resulting `getComputedStyle` on both tab rows.
+//
+// Reuses `dashboard-tree.html` (#426's fixture): it already mounts the real
+// `mountAppShell` with both tab rows live — the upper role tabs (Databases ·2
+// / Dashboards ·3, from its stub schema + seeded workspace) and the lower
+// Library/History switcher (its seed leaves one Library query, `q-lib`).
+
+const open = async (page) => {
+  await page.setViewportSize({ width: 1280, height: 800 });
+  await page.goto('/tests/e2e/dashboard-tree.html');
+  await page.waitForFunction(() => window.__ready === true);
+};
+
+/** Drag `.col-resize` to `targetX` the way a real user does: press on the
+ *  handle, move the pointer, release. `dragValue`'s 'col' branch reads only
+ *  `ev.clientX`, so the resulting sidebar width IS `targetX`. */
+const dragSidebarTo = async (page, targetX) => {
+  const handle = page.locator('.col-resize');
+  const box = await handle.boundingBox();
+  await page.mouse.move(box.x + box.width / 2, box.y + box.height / 2);
+  await page.mouse.down();
+  await page.mouse.move(targetX, box.y + box.height / 2, { steps: 5 });
+  await page.mouse.up();
+};
+
+const tabsGeometry = () => {
+  const rows = [...document.querySelectorAll('.side-tabs')];
+  return rows.map((row) => ({
+    row: row.className,
+    width: row.getBoundingClientRect().width,
+    rowScrollWidth: row.scrollWidth,
+    rowClientWidth: row.clientWidth,
+    tabs: [...row.querySelectorAll('.side-tab')].map((tab) => {
+      const label = tab.querySelector('span');
+      const icon = tab.querySelector('svg');
+      const count = tab.querySelector('.side-count');
+      return {
+        text: label.textContent,
+        iconDisplay: icon ? getComputedStyle(icon).display : 'none',
+        countDisplay: count ? getComputedStyle(count).display : 'none',
+        labelClipped: label.scrollWidth > label.clientWidth,
+        tabRect: tab.getBoundingClientRect(),
+        labelRect: label.getBoundingClientRect(),
+      };
+    }),
+  }));
+};
+
+test.describe('sidebar tab headers at narrow widths (#552)', () => {
+  test('the wide (default) sidebar keeps icons and counts on both tab rows', async ({ page }) => {
+    await open(page);
+    const [upper, lower] = await page.evaluate(tabsGeometry);
+    for (const row of [upper, lower]) {
+      expect(row.tabs.length).toBeGreaterThan(0);
+      for (const tab of row.tabs) {
+        expect(tab.iconDisplay).not.toBe('none');
+      }
+    }
+    // Databases carries a count from the stub schema; Library carries one from
+    // the seed's sole unowned query — both are the "not yet compacted" signal.
+    expect(upper.tabs.find((t) => t.text === 'Databases').countDisplay).not.toBe('none');
+    expect(lower.tabs.find((t) => t.text === 'Library').countDisplay).not.toBe('none');
+  });
+
+  test('dragging the sidebar to <=220px switches both rows to text-only labels, with no overflow, clipping or overlap', async ({ page }) => {
+    await open(page);
+    await dragSidebarTo(page, 200);
+    await expect.poll(() => page.locator('.sidebar').evaluate((el) => el.getBoundingClientRect().width)).toBeLessThanOrEqual(220);
+
+    const [upper, lower] = await page.evaluate(tabsGeometry);
+    for (const row of [upper, lower]) {
+      // No horizontal overflow within the tab row itself.
+      expect(row.rowScrollWidth).toBeLessThanOrEqual(row.rowClientWidth + 1);
+      let prevRight = -Infinity;
+      for (const tab of row.tabs) {
+        expect(tab.iconDisplay).toBe('none');
+        expect(tab.countDisplay).toBe('none');
+        expect(tab.labelClipped).toBe(false);
+        // The label fits inside its own tab's box (no bleed past the button).
+        expect(tab.labelRect.left).toBeGreaterThanOrEqual(tab.tabRect.left - 0.5);
+        expect(tab.labelRect.right).toBeLessThanOrEqual(tab.tabRect.right + 0.5);
+        // Tabs are laid out left-to-right with no horizontal overlap.
+        expect(tab.tabRect.left).toBeGreaterThanOrEqual(prevRight - 0.5);
+        prevRight = tab.tabRect.right;
+      }
+    }
+    // The four labels stay readable and clickable.
+    await expect(page.locator('.upper-role-tabs .side-tab', { hasText: 'Databases' })).toBeVisible();
+    await expect(page.locator('.upper-role-tabs .side-tab', { hasText: 'Dashboards' })).toBeVisible();
+    await expect(page.locator('.saved-pane > .side-tabs .side-tab', { hasText: 'Library' })).toBeVisible();
+    await expect(page.locator('.saved-pane > .side-tabs .side-tab', { hasText: 'History' })).toBeVisible();
+    await page.locator('.saved-pane > .side-tabs .side-tab', { hasText: 'History' }).click();
+    await expect(page.locator('.saved-pane > .side-tabs .side-tab', { hasText: 'History' })).toHaveClass(/active/);
+  });
+
+  test('the 180px minimum sidebar still shows compact, unclipped, non-overlapping labels', async ({ page }) => {
+    await open(page);
+    await dragSidebarTo(page, 100); // below the 180px floor — dragValue clamps it there
+    await expect.poll(() => page.locator('.sidebar').evaluate((el) => el.getBoundingClientRect().width)).toBeCloseTo(180, 0);
+
+    const [upper, lower] = await page.evaluate(tabsGeometry);
+    for (const row of [upper, lower]) {
+      expect(row.rowScrollWidth).toBeLessThanOrEqual(row.rowClientWidth + 1);
+      let prevRight = -Infinity;
+      for (const tab of row.tabs) {
+        expect(tab.iconDisplay).toBe('none');
+        expect(tab.countDisplay).toBe('none');
+        expect(tab.labelClipped).toBe(false);
+        expect(tab.tabRect.left).toBeGreaterThanOrEqual(prevRight - 0.5);
+        prevRight = tab.tabRect.right;
+      }
+    }
+  });
+
+  test('widening the sidebar back past 220px restores the full tab presentation', async ({ page }) => {
+    await open(page);
+    await dragSidebarTo(page, 200);
+    await expect.poll(() => page.locator('.sidebar').evaluate((el) => el.getBoundingClientRect().width)).toBeLessThanOrEqual(220);
+
+    await dragSidebarTo(page, 300);
+    await expect.poll(() => page.locator('.sidebar').evaluate((el) => el.getBoundingClientRect().width)).toBeGreaterThan(220);
+
+    const [upper, lower] = await page.evaluate(tabsGeometry);
+    for (const row of [upper, lower]) {
+      for (const tab of row.tabs) {
+        expect(tab.iconDisplay).not.toBe('none');
+      }
+    }
+    expect(upper.tabs.find((t) => t.text === 'Databases').countDisplay).not.toBe('none');
+    expect(lower.tabs.find((t) => t.text === 'Library').countDisplay).not.toBe('none');
+  });
+});