---
id: capability
title: Forces and doctrines map to each other
status: blocked
dependsOn: [tactics]
exitCriterion: >
  Selecting a lance for a doctrine and inferring a doctrine from that lance
  round-trips.
---

# capability

Both directions are the same projection. Give each design a capability vector in
the **same basis** as the behavioural features, and then:

- doctrine -> lance is a knapsack under BV, C-bill or availability constraints
- lance -> doctrine is a constrained least squares over the simplex

helm already computes most of it: `max_range`, `heat_efficiency`,
`damage_at_6/7/9/18`, `single_damage_at_15/18` are the range profile, the
sustain-fire signal and the punch-versus-sandblast axis.

- [ ] Capability vector as a pure function of stats and equipment, in the feature
      basis - no hand-labelled unit tiers
- [ ] Selection under multiple constraints: BV, C-bills, faction, era
- [ ] Inference from a lance
- [ ] **Round-trip test**: `infer(select(lens)) ~= lens`, at zero noise. If it
      does not round-trip, the basis is wrong or the capability model is lossy
- [ ] Mismatch score surfaced at authoring time - "this doctrine and this lance
      disagree". Same computation as the runtime `role_conflict`, different input
- [ ] A green commander should select a slightly mismatched lance; run the same
      bias through selection