diff --git a/src/simulator/crates/mc-turn/src/formation.rs b/src/simulator/crates/mc-turn/src/formation.rs
new file mode 100644
index 00000000..3670de0c
--- /dev/null
+++ b/src/simulator/crates/mc-turn/src/formation.rs
@@ -0,0 +1,309 @@
+use serde::{Deserialize, Serialize};
+use std::collections::HashMap;
+
+/// Slot role for a unit within a formation. Per `HEX_GEOMETRY.md` §11
+/// formations occupy one centre slot plus a subset of the host hex's
+/// six edge slots. `slot_assignments` on `Formation` records each unit's
+/// role.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize, Deserialize)]
+#[serde(tag = "type", rename_all = "snake_case")]
+pub enum FormationSlot {
+    /// The host hex's centre slot. Holds the formation leader.
+    Centre,
+    /// One of the six edge slots, identified by the direction index `0..6`
+    /// matching `mc-core::algorithms::hex::AXIAL_DIRECTIONS`.
+    Edge { dir: u8 },
+}
+
+impl FormationSlot {
+    /// True if the unit occupies the centre slot.
+    pub fn is_centre(self) -> bool {
+        matches!(self, FormationSlot::Centre)
+    }
+    /// Returns the edge direction if this slot is an edge slot.
+    pub fn edge_dir(self) -> Option<u8> {
+        match self {
+            FormationSlot::Edge { dir } => Some(dir),
+            FormationSlot::Centre => None,
+        }
+    }
+}
+
+/// Ordered grouping of units that move and fight together.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct Formation {
+    pub id: u32,
+    pub owner: u8,
+    /// Stable unit IDs (MapUnit::id) that belong to this formation.
+    pub unit_ids: Vec<u32>,
+    /// The unit that leads this formation (front-most / highest HP).
+    pub leader_id: u32,
+    pub shape: FormationShape,
+    pub command: FormationCommand,
+    /// Hex the formation was told to rally to; None means no active rally.
+    pub rally_origin: Option<(i32, i32)>,
+    /// Per-unit slot role within the formation (centre or edge direction).
+    /// `#[serde(default)]` so existing saves without slot data deserialize
+    /// cleanly — empty map means "slots not yet assigned" and consumers
+    /// fall back to the existing flat-list behaviour.
+    #[serde(default)]
+    pub slot_assignments: HashMap<u32, FormationSlot>,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+#[serde(tag = "type", rename_all = "snake_case")]
+pub enum FormationShape {
+    Line { width: u8 },
+    Column { depth: u8 },
+    Wedge,
+    Diamond,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+#[serde(tag = "type", rename_all = "snake_case")]
+pub enum FormationCommand {
+    Defend,
+    Patrol { waypoints: Vec<(i32, i32)> },
+    Advance { target_hex: (i32, i32) },
+}
+
+/// Request to set or clear a building's rally point. Queued on GameState and
+/// drained each turn — mirrors the AttackRequest pattern.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct RallyPointRequest {
+    pub player_index: u8,
+    pub city_index: usize,
+    pub building_id: String,
+    /// None = clear the rally point.
+    pub hex: Option<(i32, i32)>,
+    /// Standing order for freshly spawned units ("hold", "defend", "fortify",
+    /// "join_formation", "patrol", "advance").
+    pub command: String,
+    /// Second waypoint for Patrol command. -1/-1 = not set (non-Patrol commands).
+    #[serde(default = "default_minus_one")]
+    pub waypoint_2_col: i32,
+    #[serde(default = "default_minus_one")]
+    pub waypoint_2_row: i32,
+}
+
+fn default_minus_one() -> i32 {
+    -1
+}
+
+/// Request to issue a command to a formation. Queued on GameState.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct FormationCommandRequest {
+    pub player_index: u8,
+    pub formation_id: u32,
+    pub destination: (i32, i32),
+    /// "Defend", "Advance", "Patrol"
+    pub command: String,
+}
+
+/// Request to change a formation's tactical shape. Queued on GameState.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct FormationShapeRequest {
+    pub player_index: u8,
+    pub formation_id: u32,
+    /// "line", "column", "wedge", "diamond"
+    pub shape: String,
+}
+
+/// Request to detach a single unit from its formation. Queued on GameState.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct SplitFormationRequest {
+    pub player_index: u8,
+    pub unit_id: u32,
+}
+
+/// Request to toggle auto-join for a unit. Queued on GameState.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct AutoJoinRequest {
+    pub player_index: u8,
+    pub unit_id: u32,
+    pub enabled: bool,
+}
+
+impl Formation {
+    pub fn new(id: u32, owner: u8, leader_id: u32) -> Self {
+        let mut slot_assignments = HashMap::new();
+        // Leader defaults to the centre slot per `HEX_GEOMETRY.md` §11
+        // ("the leader sits at the centre, always") — call sites can
+        // override via `assign_slot` if needed.
+        slot_assignments.insert(leader_id, FormationSlot::Centre);
+        Self {
+            id,
+            owner,
+            unit_ids: vec![leader_id],
+            leader_id,
+            shape: FormationShape::Line { width: 1 },
+            command: FormationCommand::Defend,
+            rally_origin: None,
+            slot_assignments,
+        }
+    }
+
+    pub fn size(&self) -> usize {
+        self.unit_ids.len()
+    }
+
+    /// Assign a unit to a slot. Replaces any prior assignment for that unit.
+    /// Does **not** add the unit to `unit_ids` — callers manage membership
+    /// separately so this is an idempotent slot rebind.
+    pub fn assign_slot(&mut self, unit_id: u32, slot: FormationSlot) {
+        self.slot_assignments.insert(unit_id, slot);
+    }
+
+    /// The unit currently in the centre slot, if any. Defaults to the
+    /// leader for legacy formations without slot data.
+    pub fn centre_unit(&self) -> Option<u32> {
+        if self.slot_assignments.is_empty() {
+            return Some(self.leader_id);
+        }
+        self.slot_assignments
+            .iter()
+            .find(|(_, slot)| slot.is_centre())
+            .map(|(id, _)| *id)
+    }
+
+    /// The unit on the given edge direction, if any.
+    pub fn edge_unit(&self, dir: u8) -> Option<u32> {
+        self.slot_assignments
+            .iter()
+            .find(|(_, slot)| slot.edge_dir() == Some(dir))
+            .map(|(id, _)| *id)
+    }
+
+    /// All edge directions currently occupied, in ascending order.
+    pub fn occupied_edges(&self) -> Vec<u8> {
+        let mut dirs: Vec<u8> = self
+            .slot_assignments
+            .values()
+            .filter_map(|s| s.edge_dir())
+            .collect();
+        dirs.sort_unstable();
+        dirs.dedup();
+        dirs
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn new_formation_assigns_leader_to_centre() {
+        let f = Formation::new(1, 0, 99);
+        assert_eq!(f.centre_unit(), Some(99));
+        assert!(f.occupied_edges().is_empty());
+    }
+
+    #[test]
+    fn assign_edge_then_query() {
+        let mut f = Formation::new(1, 0, 99);
+        f.assign_slot(101, FormationSlot::Edge { dir: 0 });
+        f.assign_slot(102, FormationSlot::Edge { dir: 3 });
+        assert_eq!(f.edge_unit(0), Some(101));
+        assert_eq!(f.edge_unit(3), Some(102));
+        assert_eq!(f.edge_unit(5), None);
+        assert_eq!(f.occupied_edges(), vec![0, 3]);
+    }
+
+    #[test]
+    fn assign_slot_is_idempotent_rebind() {
+        let mut f = Formation::new(1, 0, 99);
+        f.assign_slot(101, FormationSlot::Edge { dir: 0 });
+        f.assign_slot(101, FormationSlot::Edge { dir: 5 });
+        assert_eq!(f.edge_unit(0), None, "old slot must be released");
+        assert_eq!(f.edge_unit(5), Some(101), "new slot must hold the unit");
+    }
+
+    #[test]
+    fn legacy_formation_without_slot_data_defaults_centre_to_leader() {
+        // Simulate a save loaded with #[serde(default)] empty slot_assignments.
+        let f = Formation {
+            id: 1,
+            owner: 0,
+            unit_ids: vec![99],
+            leader_id: 99,
+            shape: FormationShape::Line { width: 1 },
+            command: FormationCommand::Defend,
+            rally_origin: None,
+            slot_assignments: HashMap::new(),
+        };
+        assert_eq!(f.centre_unit(), Some(99));
+    }
+
+    #[test]
+    fn formation_round_trips_through_serde_with_slot_assignments() {
+        let mut f = Formation::new(7, 1, 99);
+        f.assign_slot(101, FormationSlot::Edge { dir: 0 });
+        f.assign_slot(102, FormationSlot::Edge { dir: 3 });
+
+        let json = serde_json::to_string(&f).expect("serialize");
+        let parsed: Formation = serde_json::from_str(&json).expect("deserialize");
+        assert_eq!(parsed.id, 7);
+        assert_eq!(parsed.leader_id, 99);
+        assert_eq!(parsed.slot_assignments.len(), 3);
+        assert_eq!(parsed.centre_unit(), Some(99));
+        assert_eq!(parsed.edge_unit(0), Some(101));
+        assert_eq!(parsed.edge_unit(3), Some(102));
+    }
+
+    #[test]
+    fn formation_slot_centre_serializes_with_stable_json_shape() {
+        // The JSON shape is consumed by GDExtension on the Godot side —
+        // changing the serde attributes (tag name, rename_all) here
+        // would silently break those consumers. This test locks the wire
+        // format.
+        let json = serde_json::to_string(&FormationSlot::Centre).expect("serialize");
+        assert_eq!(json, r#"{"type":"centre"}"#);
+
+        let parsed: FormationSlot = serde_json::from_str(&json).expect("deserialize");
+        assert_eq!(parsed, FormationSlot::Centre);
+    }
+
+    #[test]
+    fn formation_slot_edge_serializes_with_stable_json_shape() {
+        // Struct-variant form: `{"type":"edge","dir":N}`.
+        let slot = FormationSlot::Edge { dir: 5 };
+        let json = serde_json::to_string(&slot).expect("serialize");
+        assert_eq!(json, r#"{"type":"edge","dir":5}"#);
+
+        let parsed: FormationSlot = serde_json::from_str(&json).expect("deserialize");
+        assert_eq!(parsed, slot);
+    }
+
+    #[test]
+    fn legacy_formation_json_without_slot_assignments_deserializes_via_serde_default() {
+        // Save written before Formation::slot_assignments existed —
+        // missing the field entirely. `#[serde(default)]` must let it
+        // deserialize as an empty map; `centre_unit()` falls back to
+        // `leader_id` when the map is empty.
+        let legacy_json = r#"{
+            "id": 5,
+            "owner": 0,
+            "unit_ids": [42],
+            "leader_id": 42,
+            "shape": {"type": "line", "width": 1},
+            "command": {"type": "defend"},
+            "rally_origin": null
+        }"#;
+        let parsed: Formation = serde_json::from_str(legacy_json)
+            .expect("legacy formation JSON without slot_assignments must deserialize");
+        assert!(parsed.slot_assignments.is_empty());
+        assert_eq!(
+            parsed.centre_unit(),
+            Some(42),
+            "legacy formations must fall back to leader_id for centre_unit()"
+        );
+    }
+
+    #[test]
+    fn formation_slot_helpers() {
+        assert!(FormationSlot::Centre.is_centre());
+        assert!(!FormationSlot::Edge { dir: 2 }.is_centre());
+        assert_eq!(FormationSlot::Centre.edge_dir(), None);
+        assert_eq!(FormationSlot::Edge { dir: 2 }.edge_dir(), Some(2));
+    }
+}
diff --git a/src/simulator/crates/mc-turn/src/policy.rs b/src/simulator/crates/mc-turn/src/policy.rs
new file mode 100644
index 00000000..e63144c2
--- /dev/null
+++ b/src/simulator/crates/mc-turn/src/policy.rs
@@ -0,0 +1,390 @@
+//! Task B3 prep — clan-aware rollout policy priors.
+//!
+//! Pure, isolated API. No dependency on `mcts_tree` or a concrete rollout
+//! state yet — those wire in once Task #2 lands the real CPU rollout. For now
+//! this module owns:
+//!   - `ActionKind` — the coarse action taxonomy the rollout policy picks from
+//!   - `PersonalityPriors` — the six raw axes (1..=10) carried per-player
+//!   - `PersonalityPriors::action_prior(kind) -> f32` — raw bias score
+//!   - `PersonalityPriors::action_distribution(&[ActionKind]) -> Vec<f32>` —
+//!     temperature-softmaxed distribution over a candidate set
+//!
+//! The divergence test (Ironhold biases `Build` > 0.4, Blackhammer biases
+//! `Attack` > 0.4) lives in `tests/clan_policy_priors.rs` and runs today.
+//! When Task #2 is green, `mcts_tree::TreeState::prior()` will call
+//! `PersonalityPriors::action_prior` on the action derived from each child.
+
+use std::collections::HashMap;
+use std::path::Path;
+
+use crate::evaluator::{LoadError, PersonalityDef};
+
+/// Coarse action taxonomy the MCTS rollout policy samples from. Concrete
+/// candidates (unit ids, building ids, tech ids, tile targets) are grouped
+/// into these buckets so a single personality prior can bias the whole rollout
+/// without needing per-id knobs.
+///
+/// # Rollout vs. strategic variants
+///
+/// `ActionKind::ALL` contains only the **9 rollout-legal kinds** that the WGSL
+/// shader and `GameRolloutState::active_actions` enumerate. The discriminants
+/// 0–8 are load-bearing: the WGSL `switch` in `action_prior` and
+/// `apply_active` index directly into them — do NOT reorder or insert into
+/// `ALL` without updating `rollout.wgsl` in lockstep.
+///
+/// `CommandFormation` and `SetRallyPoint` are **strategic-planning variants**
+/// used by the MCTS candidate generator (`build_formation_candidates`) and
+/// scored by `score_action`. They are never emitted by `active_actions()` and
+/// therefore never reach the rollout shader.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, serde::Serialize, serde::Deserialize)]
+pub enum ActionKind {
+    /// Queue a production building or non-military improvement.
+    Build,
+    /// Queue a military unit or start an offensive move.
+    Attack,
+    /// Found a new city.
+    Settle,
+    /// Start or continue tech research.
+    Research,
+    /// Queue walls / defensive units / garrison, or fortify in place.
+    Defend,
+    /// Gold-side action: market, trade route, rush-buy.
+    Trade,
+    /// Continue an existing war (ignore peace offer) when grudge is high.
+    ContinueWar,
+    /// Accept a peace offer or decline to re-engage.
+    MakePeace,
+    /// No-op / skip turn.
+    Idle,
+    /// Issue a movement/combat command to an existing formation (p0-43).
+    /// The candidate `choice_id` encodes the target as
+    /// `"cmd_formation:{formation_id}:{command}:{hex_q},{hex_r}"`.
+    /// Not part of the GPU rollout — strategic planning only.
+    CommandFormation,
+    /// Set a rally point on a barracks or military building (p0-43).
+    /// The candidate `choice_id` encodes the target as
+    /// `"set_rally:{city_id}:{building_id}:{hex_q},{hex_r}:{command}"`.
+    /// Not part of the GPU rollout — strategic planning only.
+    SetRallyPoint,
+}
+
+impl ActionKind {
+    /// The 9 rollout-legal action kinds. Order is load-bearing — WGSL
+    /// `action_prior` / `apply_active` switch on discriminant 0..=8 mapped
+    /// to this order. Never extend without updating `rollout.wgsl`.
+    pub const ALL: [ActionKind; 9] = [
+        ActionKind::Build,
+        ActionKind::Attack,
+        ActionKind::Settle,
+        ActionKind::Research,
+        ActionKind::Defend,
+        ActionKind::Trade,
+        ActionKind::ContinueWar,
+        ActionKind::MakePeace,
+        ActionKind::Idle,
+    ];
+
+    /// Best-effort classifier from the loose string tags used by
+    /// `mcts::Candidate::choice_type` today (`"unit"`, `"building"`, `"item"`,
+    /// `"tech"`). Callers that know more context should pass `ActionKind`
+    /// directly instead of round-tripping through this classifier.
+    pub fn from_choice_type(choice_type: &str, combat_type: &str) -> Self {
+        match choice_type {
+            "building" => ActionKind::Build,
+            "unit" => match combat_type {
+                "civilian" | "specialist" => ActionKind::Build,
+                _ => ActionKind::Attack,
+            },
+            "item" => ActionKind::Build,
+            "tech" => ActionKind::Research,
+            "found_city" | "settle" => ActionKind::Settle,
+            "command_formation" => ActionKind::CommandFormation,
+            "set_rally" => ActionKind::SetRallyPoint,
+            _ => ActionKind::Idle,
+        }
+    }
+}
+
+/// Raw six-axis personality payload, kept on the JSON 1..=10 scale (5 = neutral).
+/// This is the rollout-policy's source of truth — `StrategicWeights` is a
+/// lossier five-knob projection used by the state evaluator.
+#[derive(Debug, Clone, Copy, serde::Serialize, serde::Deserialize)]
+pub struct PersonalityPriors {
+    pub aggression: f32,
+    pub expansion: f32,
+    pub production: f32,
+    pub wealth: f32,
+    pub trade_willingness: f32,
+    pub grudge_persistence: f32,
+}
+
+impl Default for PersonalityPriors {
+    /// Neutral personality — every axis at 5 (= 0 after centering).
+    fn default() -> Self {
+        Self {
+            aggression: 5.0,
+            expansion: 5.0,
+            production: 5.0,
+            wealth: 5.0,
+            trade_willingness: 5.0,
+            grudge_persistence: 5.0,
+        }
+    }
+}
+
+impl PersonalityPriors {
+    /// Load from `<data_dir>/ai_personalities.json`, picking the named clan.
+    pub fn from_personality(id: &str, data_dir: &Path) -> Result<Self, LoadError> {
+        let path = data_dir.join("ai_personalities.json");
+        let json = std::fs::read_to_string(&path).map_err(|source| LoadError::Io {
+            path: path.clone(),
+            source,
+        })?;
+        let personalities: HashMap<String, PersonalityDef> =
+            serde_json::from_str(&json).map_err(|source| LoadError::Parse {
+                path: path.clone(),
+                source,
+            })?;
+        let p = personalities
+            .get(id)
+            .ok_or_else(|| LoadError::UnknownClan(id.to_string()))?;
+        Ok(Self::from_axes(&p.strategic_axes))
+    }
+
+    /// Construct from a raw 1..=10 axis map. Missing keys default to 5
+    /// (neutral). Out-of-range values clamp to `[1, 10]`.
+    pub fn from_axes(axes: &HashMap<String, i32>) -> Self {
+        let axis = |key: &str| -> f32 {
+            let raw = *axes.get(key).unwrap_or(&5);
+            raw.clamp(1, 10) as f32
+        };
+        Self {
+            aggression: axis("aggression"),
+            expansion: axis("expansion"),
+            production: axis("production"),
+            wealth: axis("wealth"),
+            trade_willingness: axis("trade_willingness"),
+            grudge_persistence: axis("grudge_persistence"),
+        }
+    }
+
+    /// Return the centered delta for an axis: `axis - 5` clamped to `[-4, +5]`.
+    /// Positive = push, negative = pull. Used as the coefficient on per-kind
+    /// prior contributions below.
+    fn delta(&self, axis: f32) -> f32 {
+        (axis - 5.0).clamp(-4.0, 5.0)
+    }
+
+    /// Raw bias score for a single action kind. Range is roughly `[-2, +3]`
+    /// for realistic personalities (baseline = 0). The policy caller softmaxes
+    /// over a candidate set to produce a probability distribution.
+    ///
+    /// Mapping rationale (each axis contributes ~0.2 per point of delta):
+    /// - Build: + production, + expansion (settlers are build-adjacent)
+    /// - Attack: + aggression, − grudge (wait, grudge pushes war continuation,
+    ///   not initial attacks — so keep Attack driven by aggression alone)
+    /// - Settle: + expansion
+    /// - Research: + wealth × 0.5 (scholarly clans fund research via gold)
+    /// - Defend: − aggression, + production × 0.5
+    /// - Trade: + trade_willingness, + wealth × 0.5
+    /// - ContinueWar: + grudge_persistence, + aggression × 0.5
+    /// - MakePeace: − grudge_persistence, − aggression × 0.5
+    /// - Idle: always 0 (baseline)
+    pub fn action_prior(&self, kind: ActionKind) -> f32 {
+        let prod = self.delta(self.production);
+        let agg = self.delta(self.aggression);
+        let exp = self.delta(self.expansion);
+        let wealth = self.delta(self.wealth);
+        let trade = self.delta(self.trade_willingness);
+        let grudge = self.delta(self.grudge_persistence);
+
+        match kind {
+            ActionKind::Build        => 0.20 * prod + 0.08 * exp,
+            // Attack's coefficient is higher than Build's per-axis weight so
+            // that high-aggression clans (Blackhammer: aggression=9) clear the
+            // B3 bullet of <30% Build rollout mass on a 2B/2A/1S slate, while
+            // low-aggression clans (Ironhold: aggression=6) still land in the
+            // Attack-suppressed regime their production axis wants.
+            ActionKind::Attack       => 0.30 * agg,
+            ActionKind::Settle       => 0.22 * exp,
+            ActionKind::Research     => 0.12 * wealth + 0.05 * prod,
+            ActionKind::Defend       => -0.15 * agg + 0.10 * prod,
+            ActionKind::Trade        => 0.18 * trade + 0.10 * wealth,
+            ActionKind::ContinueWar  => 0.20 * grudge + 0.10 * agg,
+            ActionKind::MakePeace    => -0.20 * grudge - 0.10 * agg,
+            ActionKind::Idle         => 0.0,
+            // Strategic-planning variants (p0-43). Not part of the GPU rollout;
+            // priors are used only when these candidates appear in MCTS selection.
+            // CommandFormation scores with aggression (advancing troops is offensive).
+            ActionKind::CommandFormation => 0.25 * agg,
+            // SetRallyPoint is a mild production-axis action (building infrastructure).
+            // TODO(p2-53c): AI rally-command policy — choose Hold/Defend/Fortify/JoinFormation/Patrol/Advance
+            // based on city threat level, frontier proximity, and strategic axis.
+            // Default for now: all SetRallyPoint uses the same flat prior (Defend behaviour at runtime).
+            ActionKind::SetRallyPoint    => 0.10 * prod,
+        }
+    }
+
+    /// Softmax probability distribution over a candidate set of action kinds.
+    /// `temperature` shapes how sharply the distribution peaks around the
+    /// highest-prior kind; `1.0` is a reasonable default. Lower = sharper.
+    ///
+    /// The returned vector has the same length and order as `kinds` and sums
+    /// to `1.0` (within float precision). Duplicate kinds are allowed — each
+    /// occurrence gets its own slot so callers can feed in one entry per legal
+    /// candidate action without de-duplicating.
+    pub fn action_distribution(&self, kinds: &[ActionKind], temperature: f32) -> Vec<f32> {
+        if kinds.is_empty() {
+            return Vec::new();
+        }
+        let t = temperature.max(0.05);
+        let priors: Vec<f32> = kinds.iter().map(|&k| self.action_prior(k) / t).collect();
+        let max = priors.iter().copied().fold(f32::NEG_INFINITY, f32::max);
+        let exps: Vec<f32> = priors.iter().map(|p| (p - max).exp()).collect();
+        let sum: f32 = exps.iter().sum();
+        if sum <= 0.0 {
+            return vec![1.0 / kinds.len() as f32; kinds.len()];
+        }
+        exps.into_iter().map(|e| e / sum).collect()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn ironhold() -> PersonalityPriors {
+        PersonalityPriors {
+            aggression: 6.0,
+            expansion: 4.0,
+            production: 9.0,
+            wealth: 3.0,
+            trade_willingness: 3.0,
+            grudge_persistence: 7.0,
+        }
+    }
+
+    fn blackhammer() -> PersonalityPriors {
+        PersonalityPriors {
+            aggression: 9.0,
+            expansion: 6.0,
+            production: 7.0,
+            wealth: 2.0,
+            trade_willingness: 2.0,
+            grudge_persistence: 9.0,
+        }
+    }
+
+    fn goldvein() -> PersonalityPriors {
+        PersonalityPriors {
+            aggression: 3.0,
+            expansion: 5.0,
+            production: 5.0,
+            wealth: 9.0,
+            trade_willingness: 9.0,
+            grudge_persistence: 4.0,
+        }
+    }
+
+    #[test]
+    fn neutral_priors_are_zero_across_kinds() {
+        let neutral = PersonalityPriors::default();
+        for k in ActionKind::ALL {
+            let p = neutral.action_prior(k);
+            assert!(p.abs() < 1e-5, "neutral prior for {k:?} was {p}, expected 0");
+        }
+    }
+
+    #[test]
+    fn from_choice_type_classifies_building_as_build() {
+        assert_eq!(ActionKind::from_choice_type("building", ""), ActionKind::Build);
+        assert_eq!(ActionKind::from_choice_type("unit", "melee"), ActionKind::Attack);
+        assert_eq!(ActionKind::from_choice_type("unit", "civilian"), ActionKind::Build);
+        assert_eq!(ActionKind::from_choice_type("tech", ""), ActionKind::Research);
+    }
+
+    #[test]
+    fn distribution_sums_to_one_and_preserves_order() {
+        let kinds = [ActionKind::Build, ActionKind::Attack, ActionKind::Settle];
+        let dist = ironhold().action_distribution(&kinds, 1.0);
+        assert_eq!(dist.len(), kinds.len());
+        let sum: f32 = dist.iter().sum();
+        assert!((sum - 1.0).abs() < 1e-4, "distribution must sum to 1, got {sum}");
+        for p in &dist {
+            assert!(*p > 0.0, "softmax must produce strictly positive probs");
+        }
+    }
+
+    #[test]
+    fn empty_kinds_produces_empty_distribution() {
+        assert!(ironhold().action_distribution(&[], 1.0).is_empty());
+    }
+
+    #[test]
+    fn duplicate_kinds_get_independent_slots() {
+        let kinds = [ActionKind::Build, ActionKind::Build, ActionKind::Attack];
+        let dist = ironhold().action_distribution(&kinds, 1.0);
+        // Two Build slots must be equal (same kind, same prior input).
+        assert!((dist[0] - dist[1]).abs() < 1e-5);
+        // Combined Build mass must exceed Attack mass for Ironhold.
+        assert!(dist[0] + dist[1] > dist[2]);
+    }
+
+    #[test]
+    fn ironhold_biases_build_over_attack() {
+        let iron = ironhold();
+        let build = iron.action_prior(ActionKind::Build);
+        let attack = iron.action_prior(ActionKind::Attack);
+        assert!(
+            build > attack,
+            "ironhold must prefer Build over Attack: build={build} attack={attack}"
+        );
+    }
+
+    #[test]
+    fn blackhammer_biases_attack_over_build() {
+        let bh = blackhammer();
+        let build = bh.action_prior(ActionKind::Build);
+        let attack = bh.action_prior(ActionKind::Attack);
+        assert!(
+            attack > build,
+            "blackhammer must prefer Attack over Build: attack={attack} build={build}"
+        );
+    }
+
+    #[test]
+    fn goldvein_biases_trade_over_attack() {
+        let gv = goldvein();
+        let trade = gv.action_prior(ActionKind::Trade);
+        let attack = gv.action_prior(ActionKind::Attack);
+        assert!(
+            trade > attack,
+            "goldvein must prefer Trade over Attack: trade={trade} attack={attack}"
+        );
+    }
+
+    #[test]
+    fn blackhammer_prefers_continue_war_over_make_peace() {
+        let bh = blackhammer();
+        let cont = bh.action_prior(ActionKind::ContinueWar);
+        let peace = bh.action_prior(ActionKind::MakePeace);
+        assert!(
+            cont > peace,
+            "high-grudge blackhammer must prefer ContinueWar: cont={cont} peace={peace}"
+        );
+    }
+
+    #[test]
+    fn temperature_sharpens_distribution() {
+        let kinds = [ActionKind::Build, ActionKind::Attack];
+        let iron = ironhold();
+        let soft = iron.action_distribution(&kinds, 2.0);
+        let sharp = iron.action_distribution(&kinds, 0.5);
+        // Ironhold prefers Build, so low temperature must concentrate more
+        // probability on the Build slot.
+        assert!(
+            sharp[0] > soft[0],
+            "lower temperature must sharpen toward the preferred action: sharp={sharp:?} soft={soft:?}"
+        );
+    }
+}