---
id: objectives
title: What winning means, and what to do when it stops being available
status: blocked
dependsOn: [tactics]
exitCriterion: >
  A losing force switches to preserving what it has, does so on a stated
  threshold rather than a guess, and does not oscillate across that threshold.
---

# objectives

An objective is what the side is currently trying to do. It is the **utility
function**, not a constraint list: under `WinOnBattleValue` a withdrawal is
terrible, and under `PreserveByRouting` an advance is. The same tactics are legal
either way; what changes is what they are worth.

That distinction is load-bearing. A `TaskOverride` removes options from a set
after they are scored. An objective changes the scoring. Collapsing the two
loses the difference between "forbidden" and "bad".

There is a third, and it sits between them. A `TacticOverride` replaces one
unit's weights with a named profile, so it changes the scoring like an objective
but for a single machine rather than for the side. The pair is what a spotter
needs: the profile sends it somewhere it can see, and the duty stops it shooting
once it arrives. A profile a force hands out is normally one no unit could
choose for itself - spotting, screening, drawing fire - which is how a force
expresses sacrifice, and `Status::OverrideEligible` is what keeps such a profile
out of the set a force may transition into.

Absent objectives, `Engage` is the whole game and half the tactic vocabulary is
unreachable - which is the state today.

## Two to start

- `WinOnBattleValue` - the current victory rule. Makes `Retreat` unreachable,
  `Reposition` nearly so, and `Screen` unavailable to a side with only one force.
- `PreserveByRouting` - reached when the match is lost. Admits `Retreat`,
  `Reposition`, `Screen` above one force, and `Break`, which is how a
  disengagement survives: losing line of sight is what buys the turn in which
  withdrawing is not fatal.

`Break` sits in both sets, which is right - breaking contact serves winning and
losing equally.

- [ ] The transition is a **threshold**, not a judgement: remaining battle value,
      or a count of crippled units. A threshold can be stated, tested and shown
      to a player; a learned judgement cannot yet
- [ ] Verify it does not oscillate. Flip at 30% and check the behaviour at 31%
      is stable. This is the cheapest available test of the hysteresis in
      `plan/tactics.md`, and losing is easy to produce on demand
- [ ] An objective may also **bias** rather than only constrain, including by
      which side of the scenario we are on - an attacker and a defender have
      different utility, not different legal moves

## Scenario-derived objectives, later

MegaMek already carries this. MMS V2 has per-player `victory:` conditions and
composable triggers, and `UnitPositionTrigger` is literally an extraction
objective. None of our maps declare one yet, so the objective layer cannot be
exercised beyond the two above.

- [ ] Read objectives from the scenario rather than inventing a vocabulary
- [ ] Objectives decompose by **assignment** - first lance screens while second
      exits - which is the coordinator's relational assignment, not a blend