diff --git a/AGENTS.md b/AGENTS.md
index 322683a..4144656 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -6,8 +6,7 @@ A wake alarm: on alarm days (`ALARM_DAYS` in `_constants.py` — currently
 **every day**, `frozenset({0..6})`), the machine hibernates overnight and
 wakes itself via `rtcwake` at the configured alarm time. `wake-alarm.service`
 then opens a fullscreen Tk window that must be dismissed (with a typed challenge — see
-`_challenges.py`), ramps fans to 100% via `wake-alarm-fans.sh`, plays audio
-through whatever sink comes up after the monitor wakes, and optionally
+`_challenges.py`), plays audio through every real sink, and optionally
 toggles a TP-Link Tapo P110 smart plug via `python-kasa`.
 
 ## Scheduling — a per-minute timer, with hibernate as the fallback
@@ -129,6 +128,13 @@ remote reader to keep in step.
 Check what the PC currently resolves: `python -m wake_alarm._sync --show`.
 Check what it would do right now: `python -m wake_alarm._trigger --dry-run`.
 
+## Module map
+
+`_alarm.py` owns the window and the dismiss flow and nothing else. The full
+map of which module answers which question, the HDMI-silence root cause, and
+the timing constants that must not collide are in **`DOCS-architecture.md`**.
+Read it before changing the escalation or the failsafe.
+
 ## Cross-repo coupling — not a bug
 
 `_constants.py`'s `WORKOUT_LOG_FILE` points at
diff --git a/DOCS-architecture.md b/DOCS-architecture.md
new file mode 100644
index 0000000..0447e56
--- /dev/null
+++ b/DOCS-architecture.md
@@ -0,0 +1,46 @@
+# wake_alarm architecture
+
+Reference for the module layout after the 2026-08-26 split, and the two
+failure modes that motivated it.
+
+## Where behaviour lives
+
+`_alarm.py` owns the window and the dismiss flow and nothing else. When looking
+for behaviour, start here:
+
+| Question | Module |
+|---|---|
+| Should the alarm run at all today? | `_gating` (no time gate — that is `_trigger`) |
+| What should it sound like right now? | `_escalation` (pure), driven by `_beep_loop` |
+| Why did it go quiet? | `_escalation` — the failsafe at `FAILSAFE_SILENCE_SECONDS` |
+| Why is there no sound on HDMI? | `_sinks` + `_reactivate` (see below) |
+| Challenge presentation / rounds | `_rounds`, `_countdown`, `_dismiss_view` |
+| Recurring timers | `_alarm_timers` (a mixin; they reschedule via `root.after`) |
+| Screen flash | `_screen_flash` (~1.3 Hz, deliberately under the 3 Hz threshold) |
+| Startup hardware | `_startup` (display, brightness, plug + pre-roll) |
+| Structured logs | `_logging_setup`, `_log_sink`, `_log_dedupe`, `_correlation` |
+
+### The audio failure this fixed
+
+`_activate_all_outputs()` ran **once**, at startup, and `_parse_profile_line`
+drops any profile reporting `available: no`. At wake time the monitor has not
+finished its HDMI handshake, so the profile is skipped — and while a card's
+profile is `off` its sink **does not exist**, so `_play_on_all_sinks`'s
+per-cycle re-enumeration can never find it. `_reactivate` re-runs activation on
+a decaying schedule and logs the enumerated sink list each pass.
+
+A **powered-off speaker is not detectable from software** — the analog sink is
+present and `IDLE` either way. That is a hardware problem; see
+`DOCS-speaker-recommendation.md`.
+
+### Timing constants that must not collide
+
+`FAILSAFE_SILENCE_SECONDS` (300) silences **audio only**; the lock, challenge
+and workout gate persist. Two invariants are locked in by tests in
+`test_escalation.py`, because breaking either silently guts the alarm:
+
+- `PHASE_MEDIUM_END * 60 < FAILSAFE_SILENCE_SECONDS` — otherwise the escalation
+  never leaves its softest rung before going quiet.
+- `ESCAPE_OFFER_AFTER_SECONDS` (900) `> FAILSAFE_SILENCE_SECONDS` — otherwise
+  the escape hatch appears exactly as the alarm stops being annoying.
+
diff --git a/install.sh b/install.sh
index 7dba087..abc903e 100755
--- a/install.sh
+++ b/install.sh
@@ -11,7 +11,7 @@
 #   4. Installs the systemd-sleep hook (restarts alarm after hibernate resume)
 #   5. Adds a sudoers entry for passwordless rtcwake
 #   6. Installs shutdown wrapper so "shutdown now" also hibernates on alarm nights
-#   7. Installs fan-control script so alarm can max fans on wake
+#   7. Removes the retired fan-control script + its sudoers entry
 #   8. Installs python-kasa (AUR) so the alarm can toggle a Tapo P110 smart plug
 #   9. Installs ddcutil and grants /dev/i2c-* access for DDC/CI monitor control
 
@@ -40,7 +40,6 @@ TRIGGER_SERVICE_SRC="$SCRIPT_DIR/wake-alarm-trigger.service"
 TRIGGER_TIMER_SRC="$SCRIPT_DIR/wake-alarm-trigger.timer"
 SLEEP_HOOK_SRC="$SCRIPT_DIR/sleep-hook.sh"
 SHUTDOWN_WRAPPER_SRC="$SCRIPT_DIR/shutdown-wrapper.sh"
-FANS_SCRIPT_SRC="$SCRIPT_DIR/wake-alarm-fans.sh"
 FANS_SCRIPT_DST="/usr/local/bin/wake-alarm-fans.sh"
 SYSTEMD_USER_DIR="$HOME/.config/systemd/user"
 SLEEP_HOOK_DST="/usr/lib/systemd/system-sleep/wake-alarm.sh"
@@ -112,19 +111,21 @@ sudo chmod 0755 "$SHUTDOWN_WRAPPER_DST"
 echo "  Installed to $SHUTDOWN_WRAPPER_DST"
 echo "  'shutdown now' will now hibernate (not poweroff) on alarm nights."
 
-# 7. Install fan-control script and its sudoers entry
-echo "[7/9] Installing fan-control script..."
-sudo cp "$FANS_SCRIPT_SRC" "$FANS_SCRIPT_DST"
-sudo chmod 0755 "$FANS_SCRIPT_DST"
-FANS_SUDOERS_LINE="$USER ALL=(root) NOPASSWD: $FANS_SCRIPT_DST"
-if [[ -f "$SUDOERS_FILE" ]] && grep -qF "$FANS_SUDOERS_LINE" "$SUDOERS_FILE"; then
-    echo "  Fan sudoers entry already exists"
-else
-    # Append to existing file (or create)
-    echo "$FANS_SUDOERS_LINE" | sudo tee -a "$SUDOERS_FILE" > /dev/null
-    sudo chmod 0440 "$SUDOERS_FILE"
-    echo "  Added fan sudoers entry"
+# 7. Remove the retired fan-control script and its sudoers entry.
+# The alarm no longer ramps fans: it added anxiety without helping anyone wake
+# up. An upgrade must actively clean up, or a machine that installed the old
+# version keeps a passwordless root entry for a script that no longer exists.
+echo "[7/9] Removing retired fan-control script..."
+if [[ -e "$FANS_SCRIPT_DST" ]]; then
+    sudo rm -f "$FANS_SCRIPT_DST"
+    echo "  Removed $FANS_SCRIPT_DST"
 fi
+if [[ -f "$SUDOERS_FILE" ]] && grep -qF "$FANS_SCRIPT_DST" "$SUDOERS_FILE"; then
+    sudo sed -i "\\|$FANS_SCRIPT_DST|d" "$SUDOERS_FILE"
+    sudo chmod 0440 "$SUDOERS_FILE"
+    echo "  Dropped the fan NOPASSWD sudoers entry"
+fi
+sudo rm -f /run/wake-alarm-fans.state
 
 # 8. Install python-kasa (AUR) for TP-Link Tapo P110 smart-plug control
 echo "[8/9] Installing python-kasa (AUR)..."
diff --git a/wake-alarm-fans.sh b/wake-alarm-fans.sh
deleted file mode 100755
index 8f014da..0000000
--- a/wake-alarm-fans.sh
+++ /dev/null
@@ -1,63 +0,0 @@
-#!/bin/bash
-# Control ALL NCT pwm fan channels for the wake alarm.
-#
-# Usage:
-#   wake-alarm-fans.sh max       — ramp every pwm[1-9] channel to 100%
-#   wake-alarm-fans.sh restore   — restore the state captured by the last `max`
-#
-# Must be run as root (installed in /etc/sudoers.d/wake-alarm via install.sh).
-# Safe: fans are designed to run at max speed indefinitely.
-#
-# State is stored at $STATE_FILE so `restore` doesn't need any arguments.
-
-set -euo pipefail
-
-STATE_FILE="/run/wake-alarm-fans.state"
-
-# Locate the hwmon directory for any NCT Super I/O fan controller.
-HWMON=""
-for name_file in /sys/class/hwmon/hwmon*/name; do
-    [[ -f "$name_file" ]] || continue
-    chip=$(cat "$name_file")
-    case "$chip" in
-        nct6775|nct6779|nct6791|nct6792|nct6793|nct6795|nct6796|nct6797|nct6798|nct6799)
-            HWMON=$(dirname "$name_file")
-            break
-            ;;
-    esac
-done
-
-if [[ -z "$HWMON" ]]; then
-    # Not an error — hardware without this chip just skips fan control.
-    exit 0
-fi
-
-case "${1:-}" in
-    max)
-        : > "$STATE_FILE"
-        for pwm in "$HWMON"/pwm[0-9]; do
-            [[ -w "$pwm" ]] || continue
-            enable="${pwm}_enable"
-            [[ -w "$enable" ]] || continue
-            old_pwm=$(cat "$pwm")
-            old_enable=$(cat "$enable")
-            printf '%s %s %s\n' "$pwm" "$old_enable" "$old_pwm" >> "$STATE_FILE"
-            echo 1   > "$enable"   # Switch to manual mode.
-            echo 255 > "$pwm"      # 255/255 = 100% speed.
-        done
-        ;;
-    restore)
-        [[ -f "$STATE_FILE" ]] || exit 0
-        while read -r pwm old_enable old_pwm; do
-            [[ -w "$pwm" && -w "${pwm}_enable" ]] || continue
-            # Restore pwm value first, then restore the control mode.
-            echo "$old_pwm"    > "$pwm"
-            echo "$old_enable" > "${pwm}_enable"
-        done < "$STATE_FILE"
-        rm -f "$STATE_FILE"
-        ;;
-    *)
-        echo "Usage: $0 max | $0 restore" >&2
-        exit 1
-        ;;
-esac