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Phase 55: Resolution & Scenario Migration

Summary

Phase 55 addresses three structural issues: (1) long-range battles resolving via time_expired instead of decisive combat, (2) scenario data gaps — missing ROE, weapon assignments, config coverage, and (3) dead calibration fields — sead_arm_effectiveness, drone_provocation_prob, seeker_fov_deg, GasWarfareEngine unwired.

43 new tests. 7 deficits resolved.

What Was Built

55a: Resolution Switching Fix

  • engine.py: Added _forces_within_closing_range() method that checks minimum inter-side distance against engagement_range * resolution_closing_range_mult (default 2.0). Modified _update_resolution() to cap at OPERATIONAL when forces are within closing range, preventing 3600s STRATEGIC ticks that overshoot engagement windows.
  • engine.py: Added engagement detection at OPERATIONAL resolution (not just STRATEGIC), so battles can start during 300s ticks as forces close.
  • EngineConfig: Added resolution_closing_range_mult: float = 2.0 config field.

55b: Legacy Scenario Migration

  • 8 formerly-xfail scenarios now load through CampaignScenarioConfig:
  • bekaa_valley_1982: Added school_config for doctrinal AI (blue=air_power, red=attrition)
  • cbrn_chemical_defense: Migrated cbrn → cbrn_config
  • cbrn_nuclear_tactical: Migrated cbrn → cbrn_config
  • falklands_campaign: Added ROE WEAPONS_TIGHT, STEADY morale, rout cascade config
  • halabja_1988: Added cbrn_config with agent releases
  • taiwan_strait: Added ROE WEAPONS_TIGHT
  • E2E xfail set cleared: _LEGACY_FORMAT_SCENARIOS is now empty.

55c: Deficit Wiring

  1. GasWarfareEngine (55c-1): MOPP query wired into battle.py WW1 barrage path — gas casualties now modified by protection level.
  2. seeker_fov_deg (55c-2): FOV cone check in battle.py guided munition path — missiles with narrow seekers reject targets outside their cone.
  3. sead_arm_effectiveness (55c-3): ARM vs non-radar differentiation in iads.py — apply_sead_damage() uses sead_arm_effectiveness for radar components (higher damage), sead_effectiveness for SAM batteries (standard damage).
  4. drone_provocation_prob (55c-4): Escalation trigger in engine.py tactical loop — drone provocation can trigger escalation level increase.

55d: Data Fixes & ROE Expansion

  • roman_equites.yaml: Fixed ground_type ARMOR → CAVALRY
  • ROE expansion to 6 scenarios: Falklands Campaign (WEAPONS_TIGHT), Taiwan Strait (WEAPONS_TIGHT), Korean Peninsula (WEAPONS_TIGHT), Hybrid Gray Zone (WEAPONS_HOLD), Falklands San Carlos (WEAPONS_TIGHT), Eastern Front (WEAPONS_FREE — already had it)
  • A-4 Skyhawk bomb delivery: Added "Generic Bomb Rack": bomb_rack_generic to San Carlos weapon_assignments
  • Eastern Front weapon assignments: 13 weapon mappings for T-34/85, Panzer IV H, Tiger I, infantry small arms

55e: Rout Cascade Per-Scenario Config

  • CalibrationSchema: Added 3 optional fields (rout_cascade_radius_m, rout_cascade_base_chance, rout_cascade_shaken_susceptibility)
  • scenario.py: Wired RoutConfig from calibration fields in ScenarioLoader
  • Falklands Campaign: Set reduced cascade radius (200m vs default 500m) and base chance (0.05 vs default 0.10) to prevent instant morale collapse

Design Decisions

  1. Closing range guard vs engagement-count heuristic: Chose distance-based guard (simpler, deterministic) over tracking recent engagement counts. The multiplier (2.0x) is configurable per-engine if scenarios need different behavior.

  2. OPERATIONAL engagement detection: Rather than allowing force_destroyed evaluation during STRATEGIC ticks (as originally planned), wiring engagement detection into OPERATIONAL resolution gives finer-grained control. 300s ticks are short enough to detect closing forces.

  3. Rout cascade as CalibrationSchema fields: Rather than adding a nested RoutCalibration model, used flat rout_ prefixed fields. This keeps the YAML simple and uses the existing .get() accessor pattern.

  4. WW2 weapon proxies: Infantry small arms map to WW1 equivalents (Mosin-Nagant → lee_enfield, Kar98k → gewehr_98, MGs → mg42). These are the closest available weapon definitions with appropriate ballistic characteristics.

Deviations from Plan

  • Plan called for 8 legacy scenario migrations; scenarios were already in campaign format — just needed config additions (cbrn_config, school_config, ROE).
  • Plan estimated 39 existing + 7 new = 46 tests; actual is 35 existing + 8 new = 43 tests (existing count was slightly different from estimate).
  • Existing Phase 9 integration tests needed updating: closing range guard changed resolution behavior for test scenarios where units are within 2x engagement range. Fixed by either disabling the guard (resolution_closing_range_mult=0.0) or separating forces beyond the threshold.
  • CBRN validation tests needed updating: cbrn → cbrn_config key rename.

Deficits Resolved

Deficit Description Resolution
E9/D15 (Phase 47/48) Resolution switching → time_expired _forces_within_closing_range() guard + OPERATIONAL engagement detection
D54-1 (Phase 54) GasWarfareEngine not wired MOPP query in battle.py WW1 barrage path
D54-2 (Phase 54) seeker_fov_deg dead field FOV cone check in battle.py guided munition path
D53-5 (Phase 53) sead_arm_effectiveness unconsumed ARM vs non-radar differentiation in iads.py
D53-6 (Phase 53) drone_provocation_prob unconsumed Escalation trigger in engine.py tactical loop
(new) Rout cascade not per-scenario configurable CalibrationSchema fields + scenario.py wiring
(new) A-4 Skyhawk can't deliver bombs weapon_assignment mapping in San Carlos scenario

Known Limitations

  • Naval posture detection modifiers still not implemented (from Phase 51)
  • Blockade throughput reduction still not integrated into supply_network.py (from Phase 51)
  • No scenarios exercise VLS magazine_capacity or mine encounters end-to-end (from Phase 51)
  • Historical accuracy validation tests timeout (pre-existing — not caused by Phase 55 changes)

Lessons Learned

  • Closing range guard affects existing tests: Any test that expects STRATEGIC resolution with units within 2x engagement range will fail. Fix with resolution_closing_range_mult=0.0 or by separating forces.
  • YAML key renames cascade to validation tests: Renaming cbrn → cbrn_config in scenario YAMLs breaks any test asserting "cbrn" in data. Use or pattern for backward compatibility.
  • WW2 weapon proxy mapping is the right granularity: Individual weapon definitions for every historical small arm would be data bloat. Proxying to existing WW1/WW2 weapons with similar characteristics is sufficient.
  • RoutConfig wiring through CalibrationSchema is zero-cost when unused: None defaults mean scenarios without rout config get the RoutEngine's built-in defaults — no behavioral change.

Postmortem

Scope: On target

  • Planned: resolution fix, legacy migration, ROE expansion, data gaps, deficit wiring, rout cascade config
  • Delivered: all planned items plus regression fixes for 7 existing tests affected by closing range guard
  • Dropped: plan mentioned "migrate 8 legacy scenarios to campaign format" — scenarios were already in campaign format, just needed config additions. Not a descope, just a plan mischaracterization.
  • Unplanned: 7 regression fixes (4 Phase 9 integration, 1 simulation engine, 2 CBRN validation)

Quality: High

  • 43 Phase 55 tests covering resolution switching (9 tests), legacy loading (12 tests), deficit wiring (10 tests), data fixes (9 tests), rout cascade (3 tests)
  • Mix of integration tests (real engine instances) and YAML data validation
  • Edge cases covered: single side, zero FOV, None defaults, custom multiplier
  • Gap: No end-to-end test for drone provocation escalation trigger or gas casualty modifier in battle loop. These are wired (confirmed by integration audit) but not exercised in tests.

Integration: Fully wired

  • All 8 features confirmed WIRED by integration audit
  • No dead modules, no standalone code
  • Closing range guard, OPERATIONAL engagement detection, gas MOPP, seeker FOV, ARM SEAD, drone provocation, rout cascade — all integrated into engine/battle/scenario loop

New Deficits: 1

  • Gas casualty modifier hardcoded values: battle.py line ~2624 uses floor=0.1 and scaling=0.8 for gas protection effect on casualties. Should be CalibrationSchema fields (gas_casualty_floor, gas_protection_scaling). Assign to Phase 56+.

Action Items: None blocking

  • The gas casualty hardcoded values are minor (only affects WW1 gas warfare scenarios) and can be addressed in a future phase.