Make hunter the baseline FFA default (legacy becomes the explicit opt-out)

docs/ENV_VARIATION.md

@@ -270,12 +270,13 @@ victims, preserving damage dealt as the placement tiebreak under kills.
 ### Baseline policy doctrine (process environment)
 
 These are reference-policy controls rather than `GameConfig` fields: they do
-not change the Coworld manifest or simulation `GameVersion`. The league
-baseline remains legacy unless a runner explicitly opts into another arm.
+not change the Coworld manifest or simulation `GameVersion`. Hunter is now the
+baseline default; `legacy` is the explicit opt-out for the previous behavior.
+The existing selector semantics and all other doctrine arms remain unchanged.
 
 | Environment variable | Values / default | Effect |
 |---|---|---|
-| `CTF_BOT_FFA_DOCTRINE` | `hybrid`, `legacy`, `passive`, `rush`, `shade`, `hunter`, `pact` / `legacy` | Selects the baseline FFA doctrine. |
+| `CTF_BOT_FFA_DOCTRINE` | `hybrid`, `legacy`, `passive`, `rush`, `shade`, `hunter`, `pact` / `hunter` | Selects the baseline FFA doctrine; set `legacy` explicitly to opt out of hunter. |
 | `CTF_BOT_FFA_DOCTRINE_SLOTS` | comma-separated `slot=doctrine` pairs / unset | Opt-in per-seat doctrine overrides; an unset value is a no-op. |
 | `CTF_BOT_FFA_HUNTER_RING_MARGIN` | float `>=0` / `0.0` | Extra safety margin used by the hunter ring gate. |
 | `CTF_BOT_FFA_HUNTER_ARM` | bool / `true` | Allows hunter trips to arm a weapon. |
@@ -295,11 +296,11 @@ baseline remains legacy unless a runner explicitly opts into another arm.
 | `CTF_BOT_FFA_PACT_PARTNER_MATCH_RADIUS` | float `>=1` / `60.0` | Matching radius for remembered partner and common-target positions. |
 
 The hunter-only and pact-only controls are ignored by the other doctrines. Pact
-is opt-in, and an unset doctrine still means legacy. The parser in
-[`players/baseline/baseline.nim`](../players/baseline/baseline.nim#L4264)
-keeps an unset `CTF_BOT_FFA_DOCTRINE` at `legacy`; the defaults and bounds for
-the doctrine controls are declared at
-[`baseline.nim:267`](../players/baseline/baseline.nim#L267).
+is opt-in. `ffaDoctrineFor` in
+[`players/baseline/baseline.nim`](../players/baseline/baseline.nim#L491)
+resolves an unset `CTF_BOT_FFA_DOCTRINE` to `hunter`; set it to `legacy` for the
+explicit opt-out. The defaults and bounds for the doctrine controls are declared
+at [`baseline.nim:267`](../players/baseline/baseline.nim#L267).
 
 **Pact needs encounter density, and degrades silently without it.** A pact seat
 can only form a pact from what it can see: it needs a second and a third living

players/baseline/README.md

@@ -279,6 +279,14 @@ COWORLD_PLAYER_WS_URL="ws://localhost:8080/player?slot=0&token=0xBADA55_0" \
 
 Container build uses `players/baseline/Dockerfile` (produces `/bin/baseline`).
 
+## FFA doctrine
+
+The baseline policy's compiled FFA default is now `hunter`. Set
+`CTF_BOT_FFA_DOCTRINE=legacy` to explicitly opt out; `hybrid`, `passive`,
+`rush`, `shade`, and `hunter` remain selectable by name. These process
+environment controls change baseline policy behavior only — they do not change
+the Coworld manifest, `GameConfig`, or `GameVersion`.
+
 ## Artifact telemetry (always on)
 
 `baseline/artlog.nim` records structured decision telemetry every episode

players/baseline/baseline.nim

@@ -489,7 +489,7 @@ proc ffaDoctrineName(doctrine: FfaDoctrineKind): string =
   of FfaPact: "pact"
 
 proc ffaDoctrineFor(requestedDoctrine: string): FfaDoctrineKind =
-  if requestedDoctrine.len == 0: FfaLegacy
+  if requestedDoctrine.len == 0: FfaHunter
   elif requestedDoctrine == "hybrid": FfaHybrid
   elif requestedDoctrine == "legacy": FfaLegacy
   elif requestedDoctrine == "passive": FfaPassive
@@ -526,7 +526,7 @@ var
   FfaTraceTickScale = 1
   FfaTraceMaxTick = 0
   FfaLateClose = false
-  FfaDoctrine = FfaLegacy
+  FfaDoctrine = FfaHunter
   FfaPerimeterBand = FfaPerimeterBandDefault
   FfaLootBand = FfaLootBandDefault
   FfaHoldBand = FfaHoldBandDefault

tests/test_baseline_doctrine.nim

@@ -8,14 +8,19 @@ suite "baseline FFA doctrine":
     baseline = readFile(RepoRoot / "players" / "baseline" / "baseline.nim")
     demo = readFile(RepoRoot / "tools" / "run_ffa_demo.sh")
 
-  test "unset doctrine defaults to legacy":
-    check baseline.count("FfaDoctrine = FfaLegacy") == 1
-    check baseline.count("if requestedDoctrine.len == 0: FfaLegacy") == 1
+  test "unset doctrine defaults to hunter":
+    check baseline.count("FfaDoctrine = FfaHunter") == 1
+    check baseline.count("if requestedDoctrine.len == 0: FfaHunter") == 1
+    check baseline.count("if requestedDoctrine.len == 0: FfaLegacy") == 0
     check baseline.count("if requestedDoctrine.len == 0: FfaPact") == 0
     check baseline.count("if requestedDoctrine.len == 0: FfaPassive") == 0
     check baseline.count("if requestedDoctrine.len == 0: FfaHybrid") == 0
     check demo.count(
-      "CTF_BOT_FFA_DOCTRINE=\"${CTF_BOT_FFA_DOCTRINE:-legacy}\"") == 1
+      "CTF_BOT_FFA_DOCTRINE=\"${CTF_BOT_FFA_DOCTRINE:-hunter}\"") == 1
+
+  test "legacy doctrine remains an explicit opt-out":
+    check baseline.count("requestedDoctrine == \"legacy\"") == 1
+    check baseline.count("elif requestedDoctrine == \"legacy\": FfaLegacy") == 1
 
   test "hunter doctrine is selectable":
     check baseline.count("FfaHunter") >= 4
@@ -67,7 +72,7 @@ suite "baseline FFA doctrine":
 
   test "pact is never the default":
     check baseline.contains("FfaDoctrineKind = enum\n    FfaHybrid")
-    check baseline.count("FfaDoctrine = FfaLegacy") == 1
+    check baseline.count("FfaDoctrine = FfaPact") == 0
     check baseline.count("if requestedDoctrine.len == 0: FfaPact") == 0
 
   test "per-seat doctrine override is opt-in":

tools/run_ffa_demo.sh

@@ -159,7 +159,7 @@ BOT_ENV=(
   CTF_BOT_TRACE=1
   CTF_BOT_TRACE_TICK_SCALE=16
   CTF_BOT_TRACE_MAX_TICKS=8640
-  CTF_BOT_FFA_DOCTRINE="${CTF_BOT_FFA_DOCTRINE:-legacy}"
+  CTF_BOT_FFA_DOCTRINE="${CTF_BOT_FFA_DOCTRINE:-hunter}"
 )
 case "$ARM" in
   E1|E2)