Phase 3: soft level pressure, less experience far above a zone's band

- Companion mod (zone/LevelPressure.kt): a Pokemon more than 5 levels
  above the band of the zone its trainer is in gets 10% less experience
  per extra level, down to 10%. Exp. Candy and commands are exempt; no
  hard level caps (roadmap).
- Rules in world/zones.json -> level_pressure, shipped in the zone layout.
- Self-test level_pressure_cuts_xp.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/balance.md

@@ -27,6 +27,7 @@ Every tunable lives in a config file or in this table. **Placeholder** means gue
 | Guardian strength | strongest Pokémon spawning in the zone, band top + 5 levels, 1.5× size, uncatchable | Placeholder | `tools/zone_spawns.py` (`GUARDIAN_*`), `world/zones.json` → `guardian.species` | |
 | Guardian drops | Button Isle 10 Poké Balls + 4 Potions; Southwold 6 Great Balls + 4 Exp. Candy S; Westmarch and Jungle Mire Waders + 4 Pecha Berries + 2 Exp. Candy M; Mire and Highlands 3 Icy Rocks + 4 Super Potions; Sunscorch 3 Heat Rocks + 2 Exp. Candy L; Frostpeak and Deep Dark 3 Icy Rocks + 2 Exp. Candy L; Deep Sea Mystic Water + 3 Exp. Candy M | Placeholder | `world/zones.json` → `guardian.drops` | 3 rocks make one full fur or hide set |
 | Mire poison | Poison I for 7 s, renewed every 5 s while in the Mire without Mire Waders | Placeholder | `datapacks/core/data/cobblesurvival/zone_hazards/mire.json` | Vanilla Poison stops at half a heart |
+| Level pressure | full experience up to 5 levels above the zone's band, then 10 % less per level, at least 10 % (Exp. Candy and commands exempt) | Placeholder | `world/zones.json` → `level_pressure` | E.g. on Button Isle (up to Lv 10): Lv 15 full, Lv 20 half, Lv 24+ a tenth |
 | Healing while sleeping | off (`healPercent` 0) | Decided (roadmap) | `config/cobblemon/main.json` | |
 | Loot container refresh | 1 hour (72,000 ticks of game time) after first opened, all containers | Decided (Adrian, 2026-10-29) | `config/lootr-common.toml` | Tiering by structure/biome later |
 | Gamerules in the template | `doMobSpawning false` | Decided (Adrian, 2026-10-28; may be reverted later) | `world/world.json` → `gamerules` | Pokémon spawning is Cobblemon's own `doPokemonSpawning` |

docs/checklists/phase-3.md

@@ -21,7 +21,9 @@ Open `build/zone-map.png` (the island coloured by zone) and read the draft in `d
 
 - **The Mire's poison** (step 5). Mire Waders from the Westmarch and Jungle guardians keep it off. Automated: `mire_poisons_without_waders`.
 
-Still to come: soft level pressure, flyers.
+- **Soft level pressure** (step 6). Pokémon far above a zone's band learn less there. Automated: `level_pressure_cuts_xp`.
+
+Still to come: flyers.
 
 ## In-game
 
@@ -33,3 +35,4 @@ Still to come: soft level pressure, flyers.
 - [ ] **Lowlands:** a night in Southwold or on Button Isle without gear never gets dangerous.
 - [ ] **Guardians:** `/cobblesurvival guardians` (operator) lists each zone's guardian and spot. Walk there: a big Pokémon appears, can't be caught, and beating it puts its drops in your inventory with a gold message. It's gone for 5 hours of play.
 - [ ] **Mire:** walk into the Mangrove Mire: a green warning, then Poison keeps coming back. With Mire Waders on (from the Westmarch or Jungle guardian) nothing happens.
+- [ ] **Level pressure:** bring a Lv 30 Pokémon to Button Isle and win a battle: it gains only a sliver of experience, while a Lv 10 one gains the full amount.

docs/design.md

@@ -111,6 +111,8 @@ Order of play the bands suggest: Button Isle → Southwold → Westmarch or Jung
 
 **The Mire's poison** (Phase 3, step 5): while a player is in the Mangrove Mire without Mire Waders on, the companion mod gives them Poison every 5 seconds (`zone/ZoneHazards.kt`, data in `datapacks/core/data/cobblesurvival/zone_hazards/mire.json`, protection tag `#cobblesurvival:mire_protection`); the first time they walk in unprotected they get a warning. Vanilla Poison never kills, but it pins a player at half a heart, so a fall or a Pokémon's hit becomes deadly; milk, potions and golden apples still help. Mire Waders (leather boots, a KubeJS item) drop from the guardians of Westmarch and the Verdant Jungle, the zones before the Mire. Tested: `mire_poisons_without_waders`.
 
+**Soft level pressure** (Phase 3, step 6; no hard level caps): a Pokémon more than 5 levels above the band of the zone its trainer is in gets 10 % less experience per extra level, down to 10 % (`zone/LevelPressure.kt`, values in `world/zones.json` → `level_pressure`). It counts battle experience and anything else except Exp. Candy and commands. The roadmap also offered a disobedience chance; experience alone is gentler and Cobblemon has nothing to build disobedience on. Tested: `level_pressure_cuts_xp`.
+
 **Alpha guardians** (Phase 3, step 4; Adrian, 2026-10-29: fixed spots, back 5 hours after being beaten):
 - One per zone except the Shallows, Lush Caves and Dripstone; the Basalt Furnace gets its boss in Phase 7. Each stands at its zone's sample point (deep inside the zone; a cave floor for the Deep Dark) and only appears while a player is within 96 blocks; it wanders no further than 24 blocks.
 - The guardian is the strongest Pokémon that spawns walking (or, at sea, swimming) in its zone, five levels above the band, half again as big, and uncatchable: Pachirisu (Button Isle), Sigilyph (Southwold), Carbink (Westmarch), Tangrowth (Jungle), Arcanine (Mire), Cinderace (Highlands), Delphox (Sunscorch), Tyranitar (Frostpeak), Kingdra (Deep Sea), Dusknoir (Deep Dark). `world/zones.json` → `guardian.species` overrides the pick.