[BUG] Session recap never auto-fires in Claude for Windows desktop GUI

Summary

Session recap (※ recap: / away-summary) never auto-fires in Claude for Windows desktop (the standalone GUI app), even after weeks of active use across many sessions. The same feature works as expected when claude runs in a real terminal (Linux SSH, Windows Terminal, etc.). Feature is enabled by default; no opt-out via env or /config was applied. Manual /recap not yet tested on the affected host.

Environment

• Host A (broken): Windows 11 + Claude for Windows desktop app v1.5354.0 (9a9e3d), which embeds Claude Code at %APPDATA%\Claude\claude-code\2.1.121\claude.exe. Sessions logged with entrypoint: "claude-desktop".
• Host B (working, control): Ubuntu 24.04 LTS, claude v2.1.123, accessed via SSH from Windows Terminal on a separate workstation. Sessions logged with entrypoint: "cli".
• Both hosts: telemetry on (API Usage Billing), no CLAUDE_CODE_ENABLE_AWAY_SUMMARY set, awaySummaryEnabled not toggled to false, tengu_sedge_lantern: true.

Repro

1. Install Claude for Windows desktop (the GUI app).
2. Open the Code tab, start a chat, run any 5+ user turns over the course of normal work.
3. Switch focus to another window for 5+ minutes, return.
4. Observe: no ※ recap: line is rendered, no system / away_summary event is persisted to the session JSONL.
5. Repeat for any number of sessions/days. Recap never fires.

Run the same flow against claude in a real terminal (Windows Terminal, iTerm2, kitty, gnome-terminal, etc.) and recap does fire normally.

Expected vs actual

• Expected: after focus loss ≥ ~3 min and turn count ≥ 3, recap is generated and rendered on focus return.
• Actual on Host A: recap never fires. Verified across 125 JSONL session files, 0 entries with type: "system" and subtype: "away_summary", including in a single active session containing 74 user turns over 304 lines.
• On Host B (control): recap fires routinely; 2 firings in one same-day interactive session.

Root cause (from claude.exe 2.1.121 string analysis)

The recap-eligibility gate mpH():

function mpH() {
  let H = process.env.CLAUDE_CODE_ENABLE_AWAY_SUMMARY;
  if (isFalsey(H)) return false;
  if (isTruthy(H)) return true;
  if (!growthBook("tengu_sedge_lantern", true)) return false;
  if (Sq()) return false;                 // !isInteractive
  return Cq()?.awaySummaryEnabled !== false;
}

returns true in this setup.

But the focus-tracking init in ensureInteractive:

ensureInteractive = () => {
  if (this.unsubscribeTTYHandlers || !this.options.stdout.isTTY) return;
  // … only here: this.options.stdout.write(qr)  // qr contains \x1B[?1004h
  …
};

bails immediately when process.stdout.isTTY === false.

When Claude for Windows desktop spawns the embedded claude.exe, stdout is wired as a pipe to the host React UI, not a PTY. So:

1. ensureInteractive returns before sending \x1B[?1004h (DECSET 1004, focus reporting).
2. The host UI never echoes back \x1B[I / \x1B[O (focus-in / focus-out).
3. Global Ns6 stays at its initial "unknown" and never transitions to "blurred".
4. The trigger inside function v(R) / function N(R) never fires.
5. Recap is never generated.

Why it is not a config or feature-flag issue

• CLAUDE_CODE_ENABLE_AWAY_SUMMARY is unset on both hosts.
• tengu_sedge_lantern: true on both (from ~/.claude.json / %USERPROFILE%/.claude.json cached GrowthBook features).
• awaySummaryEnabled not set to false.
• Host B with identical user-side state fires recaps; Host A never does. The only structural difference is claude-desktop entrypoint with piped stdout vs cli entrypoint with PTY.

Suggested fix paths (non-prescriptive)

The desktop GUI host needs an alternate channel to feed focus state to the embedded process when stdout is a pipe — e.g.:

• Inject focus-in/focus-out escapes into the child stdin when the host window blur/focus changes.
• Or expose a programmatic setFocusState(blurred|focused) IPC the embedded CLI listens for instead of DECSET 1004.
• Or detect claude-desktop entrypoint and switch focus detection to a non-terminal mechanism.

Workarounds for users

• /recap slash command — manual force, bypasses focus check.
• Run claude directly in Windows Terminal (%USERPROFILE%\AppData\Roaming\Claude\claude-code\2.1.121\claude.exe) instead of the desktop GUI host.

Related issues (different but same MSIX/subprocess plumbing class)

• #36156 — Windows hooks receive stdin as TTY instead of pipe (mirror direction of the same kind of bug).
• #48362 — Claude Desktop MSIX session-persistence EXDEV bug.
• #48084 / #48863 — recap docs gap (not platform-specific but adjacent).