diff --git a/docs/superpowers/specs/2026-03-11-daytime-nap-design.md b/docs/superpowers/specs/2026-03-11-daytime-nap-design.md
index 8ce7644..313c8c8 100644
--- a/docs/superpowers/specs/2026-03-11-daytime-nap-design.md
+++ b/docs/superpowers/specs/2026-03-11-daytime-nap-design.md
@@ -11,28 +11,32 @@ When sleeping during daytime, treat it as a **nap**: calculate just enough energ
 ## Nap Target Calculation
 
 ```
+cycleTicks = Math.round((100 / ENERGY_DECAY_PER_TICK) * (1 + 1 / DAY_NIGHT_RATIO))
 remainingDayTicks = (SLEEP_NIGHT_START - gameTime) * cycleTicks
 energyNeeded = remainingDayTicks * ENERGY_DECAY_PER_TICK * constitutionMultiplier
-napTarget = ENERGY_THRESHOLD + energyNeeded + NAP_BUFFER
+napTarget = clamp(ENERGY_THRESHOLD + energyNeeded + NAP_BUFFER, 0, 100)
 ```
 
-- `NAP_BUFFER`: ~15 energy. NPCs arrive at nightfall around 35 energy — above the 20 emergency threshold, below the 60 voluntary night sleep threshold.
-- `constitutionMultiplier`: `1 - (con - 10) * 0.03` (same formula used in needsDecaySystem).
+- `cycleTicks`: derived from runtime constants (`ENERGY_DECAY_PER_TICK`, `DAY_NIGHT_RATIO`), both available via `rc` in npcBrainSystem.
+- `NAP_BUFFER`: 15 energy. NPCs arrive at nightfall around 35 energy — above the 20 emergency threshold, below the 60 voluntary night sleep threshold.
+- `constitutionMultiplier`: `1 - (con - 10) * 0.03` (same formula used in needsDecaySystem). Uses point-in-time CON; transient stat modifiers may shift this slightly, which is acceptable.
+- `energyNeeded` represents the **post-wake awake energy budget** — how much the NPC will burn while awake between nap and nightfall.
+- Note: for early-morning crashes (gameTime ~0.1-0.3), napTarget approaches 85-100 and the nap is effectively identical to full sleep. The nap diverges meaningfully for afternoon crashes.
 
 ## Wake Logic
 
 In the sleep wake check (npcBrainSystem.ts):
 
-1. Determine if this is a **daytime sleep** (gameTime < SLEEP_NIGHT_START).
-2. Calculate nap target.
-3. **Guard**: if napTarget >= SLEEP_VOLUNTARY_ENERGY_THRESHOLD (60), treat as normal full sleep (too close to nightfall for a nap to matter — avoid wake-then-immediately-re-sleep).
-4. **Daytime nap**: wake immediately when energy >= napTarget (clean cutoff, no probabilistic ramp).
+1. Check if it is currently daytime (gameTime < SLEEP_NIGHT_START). This check happens every tick during sleep, not just at entry.
+2. If daytime: calculate nap target.
+3. **Guard**: if napTarget < SLEEP_VOLUNTARY_ENERGY_THRESHOLD (60), the NPC is so close to nightfall that a nap would leave them with too little energy — they'd wake and immediately re-trigger voluntary night sleep. Skip the nap; use normal full sleep instead.
+4. **Daytime nap**: if napTarget >= 60, wake immediately when energy >= napTarget (clean cutoff, no probabilistic ramp).
 5. **Night or guarded**: use existing probabilistic wake (85-100 range).
 
 ## Edge Cases
 
 - **Night arrives while napping**: switch to normal night sleep wake logic (85-100 probabilistic). The NPC was exhausted enough to sleep into night — that's fine.
-- **Close to nightfall**: napTarget would be low (~25-30), which is below 60, so the guard triggers normal full sleep. No silly wake-then-re-sleep.
+- **Close to nightfall**: napTarget would be low (~25-30), which is below the 60 guard threshold, so it falls through to normal full sleep. No silly wake-then-re-sleep.
 - **Constitution variation**: high-CON NPCs decay slower, so shorter naps. Low-CON NPCs need more banked energy, so longer naps. Natural.
 
 ## Recovery Rate
@@ -49,6 +53,14 @@ Same as normal sleep (0.048/tick). No change. A nap is just a shorter sleep.
 - `shared/src/constants.ts` — add NAP_BUFFER
 - `server/src/systems/npcBrainSystem.ts` — modify sleep wake logic
 
+## Tests
+
+- Nap target calculation at various times of day (morning, midday, afternoon)
+- Wake behavior: immediate wake at nap target (no probabilistic ramp)
+- Guard condition: napTarget < 60 triggers full sleep instead of nap
+- Edge case: night arrives during nap → switches to normal wake logic
+- Edge case: napTarget clamped to 100 for very early crashes
+
 ## What Stays the Same
 
 - Sleep entry conditions (emergency < 20, voluntary night < 60)