CB-WP-0049 T02/T03: a seat that plays its objective, and F27 splits in two

objective() reads GroundState::score (now public) rather than restating
what winning is; a copy in the bot would disagree with the kernel the
first time ground-game rules on F28.

Working out WHERE the modes can differ was most of the task and it
bounds the result: SOLVE always claims for the actor, so own-score and
group-score want the same SOLVE nearly everywhere. That is a fact about
GROUND's action set, not a shortcoming of the bot. Two real divergences,
both readable off the table: SUPPORT regulates someone else (worth less
against a rival, worth MORE under coalitions where a Bond merges them
into my side), and SOLVE's value is the card's value, which greedy
ignores entirely.

THE RESULT — F27 splits in two:
  group success  UNCHANGED in 34 of 36 cells
  who wins       MOVES: BONDED COALITIONS at 4p goes 2.04 -> 2.98,
                 2.12 -> 3.29, 2.05 -> 3.01 winning seats per game

So "the competitive modes are scoring lenses over cooperative play" was
too strong and is withdrawn. The sharper claim: GROUND's scoring modes
change WHO WINS, not WHETHER THE GROUP SUCCEEDS. And the effect is
seat-band dependent -- 2p none, 4p largest, 6p none under coalitions;
two relation slots capping network growth is a candidate explanation and
is untested.

The panel now prints BOTH policies side by side. That was a correction
mid-task: the first version printed only the new one and I compared it
against a figure remembered from CB-WP-0047 -- a comparison against a
board nobody re-ran.

Control that makes the numbers mean anything: under SHARED GROUND the
two policies agree at all but <=2 decision points across 12 boards, so a
moving column is mode-awareness and not simply a different bot.

Also: two T01 tests keyed on `status: proposed`, which ground-game
renamed to `ready-for-implement` mid-session. They now find the module
by asking resolve() -- the structural property is ours and does not move
when another repo edits its vocabulary.

Also: `make vendor` replaces three hand re-vendors with a tool that
regenerates digests by walking editions/, and reports one-sided files
rather than resolving them.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

games/ground/src/bot.rs

@@ -14,7 +14,7 @@
 
 use crate::{
     Action, DarvoTarget, GroundChoice, GroundCommand, GroundMode, GroundState, Relation, RoundStep,
-    Selection, SupportResponse,
+    ScoringMode, Selection, SupportResponse,
 };
 use cb_kernel::{Actor, Aggregate, ChaChaRng, KernelRng, PlayerId, Rejection, Seed};
 
@@ -1100,6 +1100,155 @@ mod tests {
     // than removed, and carries why the numbers changed.
 }
 
+/// What a seat is trying to maximise (CB-WP-0049 T02).
+///
+/// **Read off `GroundState::score`, never restated.** The game already
+/// computes all three answers to build its `Outcome`; a copy in the bot
+/// would be a second definition of winning, and the two would disagree
+/// the first time ground-game rules on F28.
+///
+/// | mode | objective |
+/// |---|---|
+/// | SHARED GROUND | the group total |
+/// | COMMON PROBLEM | own claimed value − own Blame |
+/// | BONDED COALITIONS | own coalition's summed personal score |
+///
+/// It reads only `claimed_by`, `value` of **claimed** Problems and Blame
+/// tokens — all of which are on the table — so it is blind by
+/// construction (ADR-0023) rather than by inspection.
+pub fn objective(state: &GroundState, seat: PlayerId) -> i32 {
+    let o = state.score();
+    match state.mode {
+        ScoringMode::SharedGround => o.total as i32,
+        ScoringMode::CommonProblem => o.personal.get(&seat).copied().unwrap_or(0),
+        ScoringMode::BondedCoalitions => o
+            .coalitions
+            .iter()
+            .find(|c| c.members.contains(&seat))
+            .map(|c| c.score)
+            // A seat in no coalition is a one-seat coalition (GR-E04), so
+            // falling back to its own score is the rule and not a guess.
+            .unwrap_or_else(|| o.personal.get(&seat).copied().unwrap_or(0)),
+    }
+}
+
+/// A seat that plays **its own** objective (CB-WP-0049 T03).
+///
+/// ## Where the modes actually differ, and where they cannot
+///
+/// Working this out was most of the task. **SOLVE always claims for the
+/// actor**, so a seat maximising its own score and a seat maximising the
+/// group's want the same SOLVE in almost every position — which is a
+/// fact about GROUND's action set, not a shortcoming of the bot, and it
+/// bounds how far apart any two policies can get.
+///
+/// Two places the objective really does diverge, both readable off the
+/// table:
+///
+/// - **SUPPORT regulates someone else.** Under SHARED GROUND that is
+///   worth what it is worth to the group. Under COMMON PROBLEM the
+///   beneficiary is a rival, so it is worth less. Under BONDED
+///   COALITIONS a Bond *merges that seat into my coalition*, and my score
+///   becomes the coalition's sum — so it is worth more, and worth most
+///   with a seat not already in my network.
+/// - **SOLVE's value is the Problem's value.** `GreedyPolicy::rank` gives
+///   every legal SOLVE 90 regardless of what the card is worth. Under a
+///   competitive objective the difference between a 2 and a 3 is the
+///   whole margin.
+///
+/// **It delegates.** Every arm this does not name comes from
+/// `GreedyPolicy::rank`. CB-WP-0039 re-typed an abridged copy of greedy
+/// and called it "one preference changed"; it differed in five places and
+/// burned the Freedom token in round one of every game. Delegating makes
+/// "these arms and no others" structurally true instead of a claim in a
+/// comment.
+///
+/// **Blind by construction** (ADR-0023): it reads Problem values only for
+/// face-up Problems, and relations, which are on the table.
+pub struct ObjectivePolicy;
+
+impl ObjectivePolicy {
+    /// The seats whose personal score counts toward `seat`'s objective.
+    fn my_side(state: &GroundState, seat: PlayerId) -> Vec<PlayerId> {
+        match state.mode {
+            // Everyone's claims are my claims.
+            ScoringMode::SharedGround => state.players.keys().copied().collect(),
+            ScoringMode::CommonProblem => vec![seat],
+            ScoringMode::BondedCoalitions => state
+                .score()
+                .coalitions
+                .into_iter()
+                .find(|c| c.members.contains(&seat))
+                .map(|c| c.members)
+                .unwrap_or_else(|| vec![seat]),
+        }
+    }
+
+    pub fn rank(state: &GroundState, seat: PlayerId, cmd: &GroundCommand) -> i32 {
+        let base = GreedyPolicy::rank(state, seat, cmd);
+        match cmd {
+            // SOLVE, weighted by what the card is worth. Face-up only:
+            // `legal_commands` offers SOLVE on face-up Problems, and the
+            // lookup returns nothing for a card this seat cannot read.
+            GroundCommand::SelectAction {
+                action: Action::Solve,
+                problem: Some(n),
+                ..
+            } => {
+                let worth = state
+                    .problems
+                    .get(n)
+                    .filter(|p| p.face_up && p.claimed_by.is_none())
+                    .map(|p| i32::from(p.value))
+                    .unwrap_or(0);
+                base + worth
+            }
+            // SUPPORT, weighted by whether the target is on my side.
+            GroundCommand::SelectAction {
+                action: Action::Support,
+                target: Some(other),
+                ..
+            } => {
+                let side = Self::my_side(state, seat);
+                if side.contains(other) {
+                    base + 5
+                } else {
+                    match state.mode {
+                        // A Bond would bring them onto my side, and my
+                        // score is my side's sum.
+                        ScoringMode::BondedCoalitions => base + 10,
+                        // Regulating a rival is work I do for them.
+                        ScoringMode::CommonProblem => base - 30,
+                        ScoringMode::SharedGround => base,
+                    }
+                }
+            }
+            _ => base,
+        }
+    }
+}
+
+impl Policy for ObjectivePolicy {
+    fn name(&self) -> &'static str {
+        "objective"
+    }
+    fn choose(
+        &mut self,
+        state: &GroundState,
+        seat: PlayerId,
+        legal: &[GroundCommand],
+        _may_pass: bool,
+    ) -> Choice {
+        let mut best = 0;
+        for (i, c) in legal.iter().enumerate() {
+            if Self::rank(state, seat, c) > Self::rank(state, seat, &legal[best]) {
+                best = i;
+            }
+        }
+        Choice::Command(best)
+    }
+}
+
 /// **A policy is bound by what its seat can see** ([ADR-0023]).
 ///
 /// `Policy::choose` takes the whole `GroundState`, which carries every
@@ -1272,6 +1421,135 @@ mod blindness_tests {
         assert!(err.contains("peeker"), "{err}");
     }
 
+    /// The new policy is blind too — the point of T01 being first.
+    #[test]
+    fn the_objective_policy_is_blind() {
+        for seed in [1u64, 7, 42] {
+            for players in [2u8, 4, 6] {
+                for mode in [
+                    ScoringMode::SharedGround,
+                    ScoringMode::CommonProblem,
+                    ScoringMode::BondedCoalitions,
+                ] {
+                    let mut st = deal(players, seed);
+                    st.mode = mode;
+                    for seat in st.players.keys().copied() {
+                        is_blind(|| ObjectivePolicy, &st, seat)
+                            .unwrap_or_else(|e| panic!("{players}p {mode:?} seed {seed}: {e}"));
+                    }
+                }
+            }
+        }
+    }
+
+    /// **The objective is the game's own scoring** (CB-WP-0049 T02).
+    #[test]
+    fn the_objective_agrees_with_the_outcome() {
+        let mut st = deal(4, 5);
+        let seats: Vec<PlayerId> = st.players.keys().copied().collect();
+        // Claim two Problems for two different seats, so group and
+        // personal cannot coincide by accident.
+        let keys: Vec<u32> = st.problems.keys().copied().collect();
+        st.problems.get_mut(&keys[0]).unwrap().claimed_by = Some(seats[0]);
+        st.problems.get_mut(&keys[1]).unwrap().claimed_by = Some(seats[1]);
+        let o = st.score();
+
+        st.mode = ScoringMode::SharedGround;
+        assert_eq!(objective(&st, seats[0]), o.total as i32);
+        // Everyone shares one number.
+        assert_eq!(objective(&st, seats[0]), objective(&st, seats[2]));
+
+        st.mode = ScoringMode::CommonProblem;
+        assert_eq!(objective(&st, seats[0]), o.personal[&seats[0]]);
+        // **And a seat's objective is NOT the group's** — the claim that
+        // makes a competitive mode competitive, asserted on a board
+        // rather than argued.
+        assert_ne!(
+            objective(&st, seats[0]),
+            st.score().total as i32,
+            "under COMMON PROBLEM a seat's objective coincided with the group's"
+        );
+        assert_ne!(
+            objective(&st, seats[0]),
+            objective(&st, seats[2]),
+            "a claiming seat and an empty-handed seat had the same objective"
+        );
+
+        st.mode = ScoringMode::BondedCoalitions;
+        let mine = st
+            .score()
+            .coalitions
+            .into_iter()
+            .find(|c| c.members.contains(&seats[0]))
+            .expect("every seat is in a coalition");
+        assert_eq!(objective(&st, seats[0]), mine.score);
+    }
+
+    /// **Under SHARED GROUND the objective policy IS greedy** — the
+    /// control that separates "attends to the objective" from "plays
+    /// differently".
+    ///
+    /// Without it, any change in the panel could be the new policy simply
+    /// being a different bot. The two must agree wherever the objective
+    /// is the group's, and diverge only where it is not.
+    #[test]
+    fn under_shared_ground_the_objective_policy_and_greedy_want_the_same_thing() {
+        let mut differed = 0;
+        for seed in [1u64, 7, 42, 99] {
+            for players in [2u8, 4, 6] {
+                let mut st = deal(players, seed);
+                st.mode = ScoringMode::SharedGround;
+                for seat in st.players.keys().copied() {
+                    let legal = legal_commands(&st, seat);
+                    if legal.is_empty() {
+                        continue;
+                    }
+                    let a = GreedyPolicy.choose(&st, seat, &legal, false);
+                    let b = ObjectivePolicy.choose(&st, seat, &legal, false);
+                    if a != b {
+                        differed += 1;
+                    }
+                }
+            }
+        }
+        // SOLVE is weighted by card value in every mode, so a tie greedy
+        // broke by order can break the other way here. That is a
+        // refinement of greedy's own objective, not a different one — so
+        // the assertion is that divergence is RARE, with the number
+        // stated rather than a vague "mostly".
+        assert!(
+            differed <= 2,
+            "under SHARED GROUND the two policies differed at {differed} decision points;              they are supposed to share an objective"
+        );
+    }
+
+    /// **Under COMMON PROBLEM they do NOT** — and the reason is Support.
+    #[test]
+    fn a_competitive_seat_values_supporting_a_rival_less() {
+        let mut st = deal(4, 5);
+        let seat = PlayerId(0);
+        let other = PlayerId(1);
+        let support = GroundCommand::SelectAction {
+            action: Action::Support,
+            target: Some(other),
+            problem: None,
+        };
+        st.mode = ScoringMode::SharedGround;
+        let shared = ObjectivePolicy::rank(&st, seat, &support);
+        st.mode = ScoringMode::CommonProblem;
+        let selfish = ObjectivePolicy::rank(&st, seat, &support);
+        st.mode = ScoringMode::BondedCoalitions;
+        let coalition = ObjectivePolicy::rank(&st, seat, &support);
+        assert!(
+            selfish < shared,
+            "a seat scoring only its own claims valued regulating a rival              the same as a cooperative seat did ({selfish} vs {shared})"
+        );
+        assert!(
+            coalition > shared,
+            "under BONDED COALITIONS a Bond brings that seat's score into              mine, so Support is worth MORE, not the same ({coalition} vs {shared})"
+        );
+    }
+
     /// And the shipped policies are blind.
     #[test]
     fn every_shipped_policy_is_blind_to_what_its_seat_cannot_see() {