fix(mobile): make every session tab reachable in the tab strip (#257)

With five tabs open on a phone, the right-hand tabs were effectively
unreachable. Selecting a tab only toggled the .active class, so the strip
never moved, and every full rebuild (a task badge appearing, a session
created elsewhere) replaced the strip's innerHTML, which resets scrollLeft
to 0 and yanked a mid-swipe strip back to the first tab.

Three changes, which only work together:

* computeTabScrollLeft() (pure, constants.js) decides the scroll target from
  measured rects, and _scrollActiveTabIntoView() applies it on selection.
  Rect math on the strip's own scrollLeft rather than scrollIntoView(), which
  also scrolls ancestors: on a phone that is the document, under a fixed
  header and possibly an open keyboard.
* _fullRenderSessionTabs() saves and restores scrollLeft across the rebuild,
  and re-reveals the active tab only when it actually changed
  (_lastRenderedActiveTabId), so a background render never undoes a manual
  swipe.
* Mobile no longer hoists the active session to the front of the strip. That
  reordering ran on full renders only, so tab order flipped depending on
  which render path fired, and it renumbered the Alt+N badges. Scrolling the
  active tab into view replaces it.

Also sets overscroll-behavior-x: contain on the strip so a swipe that runs
past the last tab stays in the strip instead of becoming the browser's back
gesture.

Tests: scroll-target math in test/tab-overflow.test.ts (runs in CI), plus
five browser regressions in test/mobile/tabs.test.ts covering reveal-on-
select in both directions, scroll preservation across an ambient rebuild,
sessionOrder rendering on phones, and a real touch drag reaching the last
tab.

Closes #257

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

CHANGELOG.md

@@ -1,5 +1,21 @@
 # aicodeman
 
+## 1.16.2
+
+### Patch Changes
+
+- Clone a Git repository straight into a case, predict the prompt you were about to type, and point a session at a separate Claude account.
+
+  **Clone Repo (#251, proposed by @DodgyBadger in #236)**: Add Case gains a **Clone Repo** tab that clones a repository into `codeman-cases/<name>` and registers it as a normal local case. A live verdict under the URL field answers, while you type, whether the URL is cloneable without credentials, what its default branch is, and which branches and tags exist (`POST /api/cases/clone-preflight` behind `git ls-remote --symref`). The case name fills in from the parsed repo, refs come from the remote as a datalist, shallow clone is optional, and a Brain picker (installed CLIs only) points the Run button at the agent you chose. Starting a session stays opt-in, and the tab hides itself when the server has no `git`.
+
+  **Every settings writer now refuses to write through a symlink (from the #251 review, affects existing cases too)**: case contents can be foreign, and a repository can ship `.claude` or `.claude/settings.local.json` as a symlink pointing anywhere on this machine. Since `writeFile` follows links, a scaffold write could land outside the case, up to and including replacing your own `~/.claude/settings.json`. All seven writers that touch a case's `settings.local.json` (`writeHooksConfig`, `ensureCodemanHooks`, `refreshStaleCodemanHooks`, `updateCaseModel`, `updateCaseEnvVars`, `stripCaseEnvKeys`, `applyStatusLineConfig`) now go through one `withSafeSettingsWrite()` gate that runs the symlink check inside the per-path settings lock. A refusal is a warning rather than a throw, so hooks degrade to output-based idle detection instead of failing the operation. If you have deliberately symlinked a case's `.claude` or its `settings.local.json`, Codeman will now decline to write there and say so; replace the link with a real file or directory to get hooks, model and statusLine writes back.
+
+  The clone endpoint (`POST /api/cases/clone`) is synchronous by design: no job store, no polling, bounded by `GIT_CLONE_TIMEOUT_MS` (default 5 minutes). Security decisions live in a pure half of `src/git-clone.ts` so each is unit-testable without spawning anything: `<name>::<payload>` transports are refused as a family (any of them dispatches to a `git-remote-<name>` helper, which turns a clone into arbitrary command execution), a leading `-` is refused and `--` precedes every operand, argv arrays are used rather than a shell, URLs carrying credentials are refused, and non-interactive means more than `GIT_TERMINAL_PROMPT=0` (empty `GIT_ASKPASS`/`SSH_ASKPASS`, `SSH_ASKPASS_REQUIRE=never`, empty `DISPLAY`, `GCM_INTERACTIVE=never`, `ssh -oBatchMode=yes`), since with the request held open any one of those left open is a hang instead of an error. Timeouts signal the process group, because `git clone` fans out into `git-remote-https`/`index-pack` and SIGTERM to the parent alone can leave the fetch running. Repository contents beat scaffolding: an existing `CLAUDE.md` is kept, hooks merge into whatever `.claude/settings.local.json` the repo shipped, and a repo shipping its own `.claude/settings*` is reported back as a warning, because those hooks run locally as soon as a session starts.
+
+  **Read My Mind phase 2 (#256)**: phase 1 (1.16.1) gave each case an intent profile; this turns it into the feature as pitched. Press 🧠 on a Claude session and Codeman predicts the prompt you were about to type, from your stated goals, your recent prompts in your own voice, the last assistant reply, tool activity, git state, away context, sibling sessions, and any dialog the session is waiting on. The context assembler is pure and budgeted with trust tiers, so user-stated intent outranks observed content and terminal output alone can never justify a suggestion. One shot at opus (`readMyMindModel` overrides), a strict JSON contract, and 1 to 3 suggestions typed continue / verify / redirect. The modal keeps the suggestion editable: Send, Insert (drops it on the composer without Enter), Rethink (rejections feed back into the next attempt), Dismiss. Nothing is ever auto-sent, the click is the boundary. Opt-in via App Settings, Panels (synced, default OFF), desktop header only. Agents get the same verb through the Codeman skill (`POST /api/sessions/:id/readmymind`).
+
+  **Per-session `CLAUDE_CONFIG_DIR` (#255, designed and specified by @jordan8037310)**: `schemas.ts` gains an exact-key tier (`ALLOWED_ENV_KEYS`) beside `ALLOWED_ENV_PREFIXES`, admitting `CLAUDE_CONFIG_DIR` so a case can run on a separate Claude subscription (client-billed accounts). Exact match only: other `CLAUDE_*` keys and near misses like `CLAUDE_CONFIG_DIR_EXTRA` stay rejected, blocked keys stay blocked. The key survives `getEnvOverridesForPersist()` because it is a path rather than a secret, and dropping it would silently switch a rebuilt session back to the default account after a reboot. Caveat worth knowing: a relocated config dir writes transcripts outside `~/.claude/projects`, so the response viewer, subagent windows, ultracode panel and Read My Mind go blind for that session unless `projects` is symlinked back into the shared tree.
+
 ## 1.16.1
 
 ### Patch Changes

CLAUDE.md

@@ -74,7 +74,7 @@ When user says "COM":
 
 CI runs `npm run check:lockfile` on every push/PR, so lockfile drift fails the build even if the `version-packages` script is bypassed.
 
-**Version**: 1.16.1 (must match `package.json`)
+**Version**: 1.16.2 (must match `package.json`)
 
 ## Project Overview
 
@@ -252,6 +252,8 @@ Frontend JS modules have `@fileoverview` with `@dependency`/`@loadorder` tags. L
 
 **Entrance animations** (`entrance-animations.js`, all OFF by default): opt-in animations for the four things that appear when work starts, chosen per surface via `data-tab-anim` / `data-term-anim` / `data-win-anim` / `data-line-anim` on `<html>`. Defaults are the `legacy` theme, so an untouched install behaves exactly as before and every hook short-circuits on its first line. ⚠️ Tabs and connection lines are **destroyed mid-animation** on every re-render (`_fullRenderSessionTabs()` replaces the strip's innerHTML; `_updateConnectionLinesImmediate()` does `svg.innerHTML = ''`), so both are tracked by id and re-applied to the fresh element with a **negative `animation-delay`** to resume rather than restart. ⚠️ The terminal-pane styles may animate **transform / opacity / clip-path only**, xterm's FitAddon derives rows+cols from `getComputedStyle(parent).width/height`, so animating width/height/padding there would resize the PTY. ⚠️ Window styles other than `beam` transform the window, which moves the rect its connection line is aimed at; `beam` deliberately animates opacity/filter only so its line can draw toward a stable target. Persisted to its own `codeman:*Anim` localStorage keys (per-device, deliberately NOT in the `.strict()` `SettingsUpdateSchema`); picker in App Settings → Appearance, full per-surface lab at `?animlab=1`.
 
+**Mobile tab strip scrolling** (issue #257): under 768px the tab strip is a horizontal scroller (desktop wraps to a second row instead), so the active tab can sit off-screen. Three rules keep it reachable and they only work together: `_updateActiveTabImmediate()` scrolls the selected tab into view via `computeTabScrollLeft()` (pure, in constants.js) using **rect math on the strip's own `scrollLeft`**, never `scrollIntoView()`, which would also scroll the document under a fixed header; `_fullRenderSessionTabs()` **restores `scrollLeft`** across the `innerHTML` rebuild, since ambient rebuilds (a task badge appearing, a session created elsewhere) otherwise snap a mid-swipe strip back to 0; and it re-reveals the active tab **only when it changed** (`_lastRenderedActiveTabId`), so browsing the far end of the strip is not undone by background renders. ⚠️ Mobile no longer hoists the active session to the front of the strip: that reordering ran on full renders only, so tab order flipped depending on which render path fired, and it renumbered the Alt+N badges. Scroll-into-view replaces it; do not reintroduce it.
+
 **Phone overview home screen** (`mobile-overview.js`, phones only, per-device `mobileOverviewEnabled`, default ON): under 430px the "C" logo shows a session overview (NEEDS YOU / CURRENT SESSIONS / PAST SESSIONS) instead of the welcome overlay; tablet and desktop are unchanged. The branch lives in `showWelcome()`/`hideWelcome()` (terminal-ui.js) behind `shouldUseMobileOverview()`, which is **width-driven** (`getDeviceType() === 'mobile'`) because this is a layout decision, unlike the settings namespace which stays handheld-based. ⚠️ The container ships with the `hidden` attribute and only this module removes it: never give `.mobile-overview` a bare `display` rule, since desktop does not load `mobile.css` (`media="(max-width: 1023px)"`) and would then render it unstyled. Live re-renders ride on the tail of `_renderSessionTabsImmediate()` (every state change it needs already funnels there); PAST rows come from one `_fetchUnifiedSessions(60)` per home-screen visit and resume through the shared `resumeHistorySession()`, so they behave exactly like the welcome screen's Resume list. ⚠️ Two things must stay in lockstep with surfaces outside this module, because divergence reads as a bug rather than a style: the split Run button carries the **toolbar's own classes** (`btn-toolbar btn-run mode-<backend>` / `btn-run-gear`) so the per-backend gradient and the light-skin overrides apply unchanged (mobile.css must therefore set no `background`/`color` on it), and row status uses the **session-tab language** (green dot when fine, `pulse` while working, yellow blinking row when waiting for input, red blinking row when a question is pending, mirroring `tab-alert-idle`/`tab-alert-action`). The picker mirrors the toolbar run-mode menu (`setRunMode()` + `run()`, `openWebviewFromMenu()` for saved dashboards) and deliberately omits its Recent-Sessions block, since PAST SESSIONS is that. Status pills carry `data-i18n-skip` (generic words like "idle" collide with state strings elsewhere).
 
 **Desktop home tab column** (`home-sessions.js`, desktop only): the welcome overlay centers ~560px of content in a ~1400px window, so its left gutter is dead space; it now carries the open tabs as a vertical list. Rows are in **tab order**, not sorted by urgency like the phone overview, because the row badges are the Alt+1..9 indices. State classification is REUSED from mobile-overview.js (`_mobileOverviewState`/`_mobileOverviewCaseFor`), which is why the module loads after it. ⚠️ The column is `position: absolute` so the centered content never moves, which is exactly why it needs a **width gate in two places** — `HOME_SESSIONS_MIN_WIDTH` (1180) in the JS plus a `max-width: 1179px` media query as the backstop for a resize that outruns the matchMedia listener; drift between them means a column overlapping the search panel, and `test/home-sessions.test.ts` pins them equal. ⚠️ `.home-sessions` is `display: flex`, so `[hidden]` must be re-asserted as `display: none` or the module's only visibility lever does nothing. Working state is deliberately byte-identical to the phone's: pulsing green dot + the `tab-load-spin` ring reused from the tab strip + the same green halo (added to `.mobile-overview-dot--working` at the same time), so "working" reads the same on every surface. Live re-renders ride the tail of `_renderSessionTabsImmediate()` alongside the phone overview.

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "aicodeman",
-  "version": "1.16.1",
+  "version": "1.16.2",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "aicodeman",
-      "version": "1.16.1",
+      "version": "1.16.2",
       "hasInstallScript": true,
       "license": "MIT",
       "workspaces": [

package.json

@@ -1,6 +1,6 @@
 {
   "name": "aicodeman",
-  "version": "1.16.1",
+  "version": "1.16.2",
   "description": "Mission control for AI coding agents - run 20 autonomous agents with real-time monitoring and session persistence",
   "type": "module",
   "main": "dist/index.js",

src/web/public/app.js

@@ -3461,6 +3461,54 @@ class CodemanApp {
         tab.classList.remove('active');
       }
     }
+    // #257: selection used to stop at the class toggle. On phones/tablets the
+    // strip scrolls horizontally, so a tab selected from the palette, a swipe,
+    // Alt+N or a push notification could stay parked off-screen.
+    this._scrollActiveTabIntoView(sessionId);
+  }
+
+  /**
+   * Scroll the tab strip so the given (default: active) tab is visible.
+   *
+   * Only phones/tablets scroll the strip (desktop wraps to a second row), and
+   * the pure policy no-ops whenever there is nothing to scroll, so this is a
+   * cheap call on every device.
+   *
+   * Deliberately NOT scrollIntoView(): that also scrolls every scrollable
+   * ANCESTOR, which on a phone is the document itself. With the header fixed
+   * and the keyboard possibly open, a vertical nudge there shifts the whole
+   * app. Rect math + scrollLeft touches exactly one scroller.
+   */
+  _scrollActiveTabIntoView(sessionId, behavior = 'smooth') {
+    const container = this.$('sessionTabs');
+    if (!container) return;
+    const tab =
+      (sessionId && container.querySelector(`.session-tab[data-id="${sessionId}"]`)) ||
+      container.querySelector('.session-tab.active');
+    if (!tab) return;
+
+    const policy = window.CodemanTabOverflow?.computeTabScrollLeft;
+    if (!policy) return;
+    const containerRect = container.getBoundingClientRect();
+    const tabRect = tab.getBoundingClientRect();
+    const target = policy({
+      scrollLeft: container.scrollLeft,
+      clientWidth: container.clientWidth,
+      scrollWidth: container.scrollWidth,
+      // Offsets are relative to the SCROLL CONTENT, not the offsetParent: the
+      // tabs' offsetParent is the positioned header, so offsetLeft would carry
+      // the brand column's width into the math.
+      tabLeft: tabRect.left - containerRect.left + container.scrollLeft,
+      tabWidth: tabRect.width,
+    });
+    if (Math.abs(target - container.scrollLeft) < 1) return;
+
+    const reduceMotion = window.matchMedia?.('(prefers-reduced-motion: reduce)')?.matches;
+    if (typeof container.scrollTo === 'function') {
+      container.scrollTo({ left: target, behavior: reduceMotion ? 'auto' : behavior });
+    } else {
+      container.scrollLeft = target;
+    }
   }
 
   _setTerminalLoadState(sessionId, selectGen, phase) {
@@ -3678,6 +3726,11 @@ class CodemanApp {
       this._fullRenderSessionTabs();
     }
 
+    // Keep the reveal-on-change bookkeeping honest when only the incremental
+    // branch ran: _updateActiveTabImmediate has already scrolled the new active
+    // tab into view, so the next full rebuild must not treat it as a change.
+    this._lastRenderedActiveTabId = this.activeSessionId;
+
     this.updateTabOverflowMode();
     // After the wrap measurement: the `unroll` style starts tabs at max-width 0,
     // so measuring mid-animation would decide the wrap on collapsed widths.
@@ -3749,15 +3802,25 @@ class CodemanApp {
     document.querySelectorAll('body > .subagent-dropdown').forEach(d => d.remove());
     this.cancelHideSubagentDropdown();
 
-    // Build tabs HTML using array for better string concatenation performance
-    // Iterate in sessionOrder to respect user's custom tab arrangement
-    // On mobile: put active session first (only one tab visible anyway)
+    // #257: replacing innerHTML below resets scrollLeft to 0. On phones the
+    // strip scrolls, and ambient rebuilds (a task badge appearing, a session
+    // created elsewhere) fire often enough that a user swiping toward the
+    // right-hand tabs kept getting yanked back to the first one. Remember
+    // where the strip was; the browser clamps the restore to the new content.
+    const prevScrollLeft = container.scrollLeft;
+    const prevActiveTabId = this._lastRenderedActiveTabId;
+    const isFirstRender = !container.querySelector('.session-tab');
+
+    // Build tabs HTML using array for better string concatenation performance.
+    // Iterate in sessionOrder to respect the user's custom tab arrangement, on
+    // EVERY device: mobile used to hoist the active session to the front, from
+    // when only one tab fit on screen. With five tabs it made the strip jump
+    // under the user's finger (and renumbered the Alt+N badges) on every full
+    // rebuild, while the incremental path left the order alone, so the order
+    // depended on which render path happened to run. Scrolling the active tab
+    // into view replaces it.
     const parts = [];
-    let tabOrder = this.sessionOrder;
-    if (MobileDetection.getDeviceType() === 'mobile' && this.activeSessionId) {
-      // Reorder to put active tab first
-      tabOrder = [this.activeSessionId, ...this.sessionOrder.filter(id => id !== this.activeSessionId)];
-    }
+    const tabOrder = this.sessionOrder;
     let _tabIdx = 0;
     for (const id of tabOrder) {
       const session = this.sessions.get(id);
@@ -3826,6 +3889,17 @@ class CodemanApp {
 
     container.innerHTML = parts.join('');
 
+    // Put the strip back where the user left it, then reveal the active tab
+    // only when it CHANGED (or on the first paint). Restoring unconditionally
+    // and revealing conditionally is what lets someone browse the far end of
+    // the strip while a background rebuild fires, without the active tab ever
+    // being stranded off-screen after a switch.
+    container.scrollLeft = prevScrollLeft;
+    this._lastRenderedActiveTabId = this.activeSessionId;
+    if (isFirstRender || prevActiveTabId !== this.activeSessionId) {
+      this._scrollActiveTabIntoView(this.activeSessionId, isFirstRender ? 'auto' : 'smooth');
+    }
+
     // Set up drag-and-drop handlers for tab reordering
     this.setupTabDragHandlers();
 

src/web/public/constants.js

@@ -156,6 +156,47 @@ function shouldAutoWrapTabs(input) {
   return scrollWidth > clientWidth + 1;
 }
 
+// Sliver of the neighbouring tab left visible when the strip scrolls a tab into
+// view. Landing a tab flush against the edge reads as "this is the last one";
+// the gap is what tells the user there is more strip to swipe to.
+const TAB_SCROLL_REVEAL_PX = 16;
+
+// Phone/tablet tab-strip scroll policy (issue #257). Those breakpoints scroll
+// the strip horizontally (desktop wraps to a second row instead and never
+// scrolls), so the active tab can sit entirely outside the visible slice with
+// no way back except a swipe the user may not know is possible.
+//
+// Returns the scrollLeft that puts the tab inside the window, clamped to the
+// scrollable range, and returns the CURRENT scrollLeft when the tab is already
+// visible: callers compare and skip the write, so an already-correct strip is
+// never nudged. Pure: the caller measures, this decides.
+function computeTabScrollLeft(input) {
+  const scrollWidth = Number(input?.scrollWidth) || 0;
+  const clientWidth = Number(input?.clientWidth) || 0;
+  const maxScroll = Math.max(0, scrollWidth - clientWidth);
+  if (maxScroll === 0 || clientWidth <= 0) return 0;
+
+  const pad = input?.padding == null ? TAB_SCROLL_REVEAL_PX : Number(input.padding) || 0;
+  const tabLeft = Number(input?.tabLeft) || 0;
+  const tabWidth = Number(input?.tabWidth) || 0;
+  const tabRight = tabLeft + tabWidth;
+  const viewLeft = Math.min(Math.max(Number(input?.scrollLeft) || 0, 0), maxScroll);
+  const viewRight = viewLeft + clientWidth;
+
+  let target = viewLeft;
+  if (tabWidth + pad >= clientWidth) {
+    // Tab is as wide as the window (long session name on a narrow phone):
+    // there is no position that shows all of it plus padding, so align its
+    // start, since the name matters more than the trailing badges.
+    target = tabLeft;
+  } else if (tabLeft - pad < viewLeft) {
+    target = tabLeft - pad;
+  } else if (tabRight + pad > viewRight) {
+    target = tabRight + pad - clientWidth;
+  }
+  return Math.min(Math.max(Math.round(target), 0), maxScroll);
+}
+
 // COD-134 — Terminal WebSocket reconnect policy.
 //
 // Decide what to do after a terminal WebSocket closes, given the close `code`
@@ -261,6 +302,8 @@ if (typeof window !== 'undefined') {
   window.shouldSkipWebGL = shouldSkipWebGL;
   window.CodemanTabOverflow = {
     shouldAutoWrapTabs,
+    computeTabScrollLeft,
+    TAB_SCROLL_REVEAL_PX,
   };
   window.CodemanWsReconnect = {
     plan: planWsReconnect,

src/web/public/mobile.css

@@ -115,13 +115,17 @@ html.mobile-init .file-browser-panel {
   }
 
   /* Compact session tabs — .tabs-two-rows override needed to match
-     specificity of .session-tabs.tabs-two-rows in styles.css (0,2,0) */
+     specificity of .session-tabs.tabs-two-rows in styles.css (0,2,0).
+     overscroll-behavior-x keeps a swipe that runs past the last tab inside the
+     strip: chained to the page it becomes the browser's back gesture, which is
+     exactly the swipe someone makes reaching for the rightmost tabs (#257). */
   .session-tabs,
   .session-tabs.tabs-two-rows {
     flex-wrap: nowrap;
     overflow-x: auto;
     overflow-y: hidden;
     -webkit-overflow-scrolling: touch;
+    overscroll-behavior-x: contain;
     scrollbar-width: none;
     max-height: 52px;
     gap: 3px;
@@ -643,6 +647,7 @@ html.mobile-init .file-browser-panel {
     overflow-x: auto;
     overflow-y: hidden;
     -webkit-overflow-scrolling: touch;
+    overscroll-behavior-x: contain;
     scrollbar-width: none;
     max-height: 36px;
     gap: 2px;

test/mobile/tabs.test.ts

@@ -183,6 +183,171 @@ describe('Tab Navigation', () => {
     });
   });
 
+  // ─── Tab Strip Scrolling (issue #257) ────────────────────────────────────
+
+  describe('Tab Strip Scrolling', () => {
+    /**
+     * Seed `count` real sessions and render the strip through the production
+     * code path (_fullRenderSessionTabs), so the tabs carry the real markup,
+     * widths and CSS rather than hand-built stand-ins.
+     */
+    async function seedTabs(page: Page, count: number, activeIndex = 0): Promise<void> {
+      await page.evaluate(`(function (n, activeIndex) {
+        app.sessions.clear();
+        app.sessionOrder = [];
+        for (let i = 1; i <= n; i++) {
+          const id = 'scroll-sess-' + i;
+          app.sessions.set(id, { id, name: 'w' + i + '-project', status: 'idle', mode: 'claude', workingDir: '/tmp/p' + i });
+          app.sessionOrder.push(id);
+        }
+        app.activeSessionId = app.sessionOrder[activeIndex];
+        app._lastRenderedActiveTabId = null;
+        app._fullRenderSessionTabs();
+      })(${count}, ${activeIndex})`);
+      await page.waitForTimeout(200);
+    }
+
+    async function stripState(page: Page, sessionId: string) {
+      return page.evaluate(`(function (id) {
+        const c = document.getElementById('sessionTabs');
+        const tab = c.querySelector('.session-tab[data-id="' + id + '"]');
+        const cRect = c.getBoundingClientRect();
+        const tRect = tab ? tab.getBoundingClientRect() : null;
+        return {
+          scrollLeft: Math.round(c.scrollLeft),
+          maxScroll: Math.round(c.scrollWidth - c.clientWidth),
+          order: [...c.querySelectorAll('.session-tab[data-id]')].map((t) => t.dataset.id),
+          visible: tRect ? tRect.left >= cRect.left - 1 && tRect.right <= cRect.right + 1 : false,
+        };
+      })('${sessionId}')`) as Promise<{ scrollLeft: number; maxScroll: number; order: string[]; visible: boolean }>;
+    }
+
+    it('reveals a rightmost tab that selection would otherwise leave off-screen', async () => {
+      const { context, page } = await createDevicePage(standardPhone, BASE_URL, 'chromium');
+      try {
+        await page.waitForTimeout(WAIT.PAGE_SETTLE);
+        await seedTabs(page, 5);
+
+        const before = await stripState(page, 'scroll-sess-5');
+        // Precondition: the strip really does overflow and the last tab is hidden.
+        expect(before.maxScroll).toBeGreaterThan(0);
+        expect(before.visible).toBe(false);
+
+        // The selection path selectSession() uses (class toggle, no rebuild).
+        await page.evaluate(`(function () {
+          app.activeSessionId = 'scroll-sess-5';
+          app._updateActiveTabImmediate('scroll-sess-5');
+        })()`);
+        await page.waitForTimeout(600); // smooth scroll
+
+        const after = await stripState(page, 'scroll-sess-5');
+        expect(after.visible).toBe(true);
+        expect(after.scrollLeft).toBeGreaterThan(before.scrollLeft);
+      } finally {
+        await context.close();
+      }
+    });
+
+    it('scrolls back to reveal a leftmost tab', async () => {
+      const { context, page } = await createDevicePage(standardPhone, BASE_URL, 'chromium');
+      try {
+        await page.waitForTimeout(WAIT.PAGE_SETTLE);
+        await seedTabs(page, 5);
+        await page.evaluate(`document.getElementById('sessionTabs').scrollLeft = 9999`);
+
+        await page.evaluate(`(function () {
+          app.activeSessionId = 'scroll-sess-1';
+          app._updateActiveTabImmediate('scroll-sess-1');
+        })()`);
+        await page.waitForTimeout(600);
+
+        const after = await stripState(page, 'scroll-sess-1');
+        expect(after.visible).toBe(true);
+        expect(after.scrollLeft).toBe(0);
+      } finally {
+        await context.close();
+      }
+    });
+
+    it('keeps the scroll position across an ambient full re-render', async () => {
+      const { context, page } = await createDevicePage(standardPhone, BASE_URL, 'chromium');
+      try {
+        await page.waitForTimeout(WAIT.PAGE_SETTLE);
+        await seedTabs(page, 5);
+
+        // User swipes to the end of the strip, then a background rebuild fires
+        // (a task badge appearing forces the full-render path).
+        await page.evaluate(`document.getElementById('sessionTabs').scrollLeft = 9999`);
+        const scrolled = await stripState(page, 'scroll-sess-5');
+        expect(scrolled.scrollLeft).toBeGreaterThan(0);
+
+        await page.evaluate(`(function () {
+          app.sessions.get('scroll-sess-2').taskStats = { running: 2, total: 3 };
+          app._fullRenderSessionTabs();
+        })()`);
+        await page.waitForTimeout(200);
+
+        const after = await stripState(page, 'scroll-sess-5');
+        expect(after.scrollLeft).toBe(scrolled.scrollLeft);
+      } finally {
+        await context.close();
+      }
+    });
+
+    it('renders tabs in sessionOrder on phones instead of hoisting the active one', async () => {
+      const { context, page } = await createDevicePage(standardPhone, BASE_URL, 'chromium');
+      try {
+        await page.waitForTimeout(WAIT.PAGE_SETTLE);
+        await seedTabs(page, 5, 3); // 4th tab active
+
+        const state = await stripState(page, 'scroll-sess-4');
+        expect(state.order).toEqual([
+          'scroll-sess-1',
+          'scroll-sess-2',
+          'scroll-sess-3',
+          'scroll-sess-4',
+          'scroll-sess-5',
+        ]);
+        // ...and the active tab is still brought into view by the render.
+        expect(state.visible).toBe(true);
+      } finally {
+        await context.close();
+      }
+    });
+
+    it('reaches the last tab with a horizontal touch drag', async () => {
+      const { context, page } = await createDevicePage(standardPhone, BASE_URL, 'chromium');
+      try {
+        await page.waitForTimeout(WAIT.PAGE_SETTLE);
+        await seedTabs(page, 5);
+
+        const cdp = await context.newCDPSession(page);
+        const box = await page.locator(SELECTORS.TABS_CONTAINER).boundingBox();
+        if (!box) throw new Error('tab strip not found');
+        const y = box.y + box.height / 2;
+        const startX = box.x + box.width * 0.85;
+        const endX = box.x + box.width * 0.1;
+
+        await cdp.send('Input.dispatchTouchEvent', { type: 'touchStart', touchPoints: [{ x: startX, y }] });
+        for (let i = 1; i <= 10; i++) {
+          await cdp.send('Input.dispatchTouchEvent', {
+            type: 'touchMove',
+            touchPoints: [{ x: startX + ((endX - startX) * i) / 10, y }],
+          });
+          await page.waitForTimeout(16);
+        }
+        await cdp.send('Input.dispatchTouchEvent', { type: 'touchEnd', touchPoints: [] });
+        await page.waitForTimeout(400);
+
+        const after = await stripState(page, 'scroll-sess-5');
+        expect(after.scrollLeft).toBeGreaterThan(0);
+        expect(after.visible).toBe(true);
+      } finally {
+        await context.close();
+      }
+    });
+  });
+
   // ─── Swipe Navigation (CDP - Chromium) ───────────────────────────────────
 
   describe('Swipe Navigation (CDP - Chromium)', () => {

test/tab-overflow.test.ts

@@ -3,12 +3,28 @@ import { resolve } from 'node:path';
 import vm from 'node:vm';
 import { describe, expect, it } from 'vitest';
 
+type ScrollInput = {
+  scrollLeft?: number;
+  clientWidth?: number;
+  scrollWidth?: number;
+  tabLeft?: number;
+  tabWidth?: number;
+  padding?: number;
+};
+
 function loadTabOverflowHelper() {
   const context = vm.createContext({ window: {}, globalThis: {} });
   const source = readFileSync(resolve(import.meta.dirname, '../src/web/public/constants.js'), 'utf8');
   vm.runInContext(source, context, { filename: 'constants.js' });
-  return (context.window as { CodemanTabOverflow: { shouldAutoWrapTabs: (input: unknown) => boolean } })
-    .CodemanTabOverflow;
+  return (
+    context.window as {
+      CodemanTabOverflow: {
+        shouldAutoWrapTabs: (input: unknown) => boolean;
+        computeTabScrollLeft: (input: ScrollInput) => number;
+        TAB_SCROLL_REVEAL_PX: number;
+      };
+    }
+  ).CodemanTabOverflow;
 }
 
 describe('tab overflow layout policy', () => {
@@ -63,3 +79,64 @@ describe('tab overflow layout policy', () => {
     expect(helper.shouldAutoWrapTabs({ ...base, tabCount: 1, scrollWidth: 1400, clientWidth: 760 })).toBe(false);
   });
 });
+
+// Issue #257: the phone tab strip scrolls horizontally, so the active tab can
+// sit entirely outside the visible slice. These pin the scroll target math that
+// _scrollActiveTabIntoView() feeds with measured rects.
+describe('mobile tab strip scroll-into-view policy', () => {
+  // A 5-tab phone strip: 335px visible of 558px of tabs.
+  const strip = { clientWidth: 335, scrollWidth: 558 };
+  const pad = 16;
+
+  it('scrolls right to reveal a tab past the right edge, leaving the reveal sliver', () => {
+    const helper = loadTabOverflowHelper();
+    // Last tab: 458..558, strip parked at 0.
+    const target = helper.computeTabScrollLeft({ ...strip, scrollLeft: 0, tabLeft: 458, tabWidth: 100 });
+    // 558 + 16 - 335 = 239, clamped to the 223px maximum.
+    expect(target).toBe(223);
+    // The revealed tab is now inside the window.
+    expect(458).toBeGreaterThanOrEqual(target);
+    expect(558).toBeLessThanOrEqual(target + strip.clientWidth);
+  });
+
+  it('scrolls left to reveal a tab before the left edge', () => {
+    const helper = loadTabOverflowHelper();
+    // First tab: 0..150, strip scrolled to the end.
+    expect(helper.computeTabScrollLeft({ ...strip, scrollLeft: 223, tabLeft: 0, tabWidth: 150 })).toBe(0);
+    // A middle tab partially cut off on the left: reveal it with the sliver.
+    expect(helper.computeTabScrollLeft({ ...strip, scrollLeft: 223, tabLeft: 200, tabWidth: 100 })).toBe(200 - pad);
+  });
+
+  it('leaves an already-visible tab alone (callers skip the write)', () => {
+    const helper = loadTabOverflowHelper();
+    expect(helper.computeTabScrollLeft({ ...strip, scrollLeft: 100, tabLeft: 152, tabWidth: 100 })).toBe(100);
+  });
+
+  it('never scrolls a strip that fits, and never leaves the scrollable range', () => {
+    const helper = loadTabOverflowHelper();
+    // Everything fits: nothing to scroll, whatever the tab geometry says.
+    expect(
+      helper.computeTabScrollLeft({ clientWidth: 900, scrollWidth: 400, scrollLeft: 0, tabLeft: 300, tabWidth: 100 })
+    ).toBe(0);
+    // Clamped at both ends.
+    const low = helper.computeTabScrollLeft({ ...strip, scrollLeft: 40, tabLeft: 4, tabWidth: 100 });
+    expect(low).toBe(0);
+    const high = helper.computeTabScrollLeft({ ...strip, scrollLeft: 0, tabLeft: 500, tabWidth: 58 });
+    expect(high).toBeLessThanOrEqual(strip.scrollWidth - strip.clientWidth);
+  });
+
+  it('aligns the start of a tab too wide to fit the window', () => {
+    const helper = loadTabOverflowHelper();
+    // 330px tab in a 335px window: no position shows it plus padding.
+    expect(
+      helper.computeTabScrollLeft({ clientWidth: 335, scrollWidth: 900, scrollLeft: 0, tabLeft: 400, tabWidth: 330 })
+    ).toBe(400);
+  });
+
+  it('tolerates missing measurements instead of producing NaN', () => {
+    const helper = loadTabOverflowHelper();
+    expect(helper.computeTabScrollLeft({})).toBe(0);
+    expect(helper.computeTabScrollLeft(undefined as unknown as ScrollInput)).toBe(0);
+    expect(helper.TAB_SCROLL_REVEAL_PX).toBe(pad);
+  });
+});