You are a constitutional council ranking individual git commits for ownership allocation.

Compare these two commits. Decide which contributed more lasting value to the project.

Judge substance, not spectacle:
- Prefer correct, lasting design and real bugfixes over churn, formatting, renames, or generated noise.
- Prefer clarity and necessity over sheer line count. A small precise change can beat a large diffuse one.
- Do not favor a side merely because its patch is longer or noisier.
- Weight what the change does for the project, not the contributor's name.

Return ONLY a JSON object: {"winner": "A" or "B", "ratio": "N:M", "explanation": "..."}
The explanation must cite concrete differences in the patches (1-3 sentences).

Side A — contributor: tommy-mor
Side A — commit message:
[07715165] nice

Side A — unified diff (full patch):
diff --git a/server/src/api/ui_html.rs b/server/src/api/ui_html.rs
index c3c62a76f424010d77a6090c84dd0b82098f573e..da2536112faea313352624cf2ce0ddd0ab3377c1 100644
--- a/server/src/api/ui_html.rs
+++ b/server/src/api/ui_html.rs
@@ -6,7 +6,7 @@ use axum::{
 use std::collections::HashMap;
 
 use crate::{
-    html::{demo_counter_panel, js_string_literal, ranking_panel, JsBuilder},
+    html::{js_string_literal, ranking_panel, JsBuilder},
     parser::parse_reddit_url,
     parser_render::parser_panel_morph,
     state::AppState,
@@ -35,13 +35,6 @@ pub async fn post_ui_html(
     };
 
     match action {
-        HtmlUiAction::BumpDemoCounter => {
-            let count = state.bump_demo_counter().await;
-            let panel = demo_counter_panel(count, state.event_log.path().to_string_lossy().as_ref());
-            JsBuilder::new()
-                .morph_selector("#demo-counter-panel", panel)
-                .into_response()
-        }
         HtmlUiAction::RecordVote {
             a,
             b,
@@ -54,8 +47,8 @@ pub async fn post_ui_html(
             {
                 return ui_js_warn(&e).into_response();
             }
-            let mut group = state.group.write().await;
-            let panel = ranking_panel(&mut group);
+            let group = state.group.read().await;
+            let panel = ranking_panel(&group);
             JsBuilder::new()
                 .morph_selector("#ranking-panel", panel)
                 .into_response()
@@ -87,20 +80,6 @@ mod tests {
         assert!(matches!(err, HtmlUiParseError::MissingRpc));
     }
 
-    #[test]
-    fn bump_action_deserializes() {
-        let template = serde_json::json!({ "action": "bump_demo_counter" });
-        let mut form = HashMap::new();
-        form.insert(
-            UI_RPC_FIELD.to_string(),
-            serde_json::to_string(&template).unwrap(),
-        );
-        assert_eq!(
-            parse_html_ui_from_form(&form).unwrap(),
-            HtmlUiAction::BumpDemoCounter
-        );
-    }
-
     #[test]
     fn record_vote_action_deserializes() {
         let template = serde_json::json!({
diff --git a/server/src/events.rs b/server/src/events.rs
index b969242534e184d4f0a689543a479670b08a18df..eff80aef0257f706d2341f666e63d6a3d921bf6e 100644
--- a/server/src/events.rs
+++ b/server/src/events.rs
@@ -5,8 +5,6 @@ use serde::{Deserialize, Serialize};
 pub enum Event {
     /// Page view recorded (path → counter in views.json).
     ViewRecorded { path: String, ts: i64 },
-    /// Demo counter bump from `POST /ui` (persisted in the single JSONL log).
-    DemoCounterBumped { ts: i64, value: u64 },
     /// Pairwise comparison vote (replayed into [`crate::reducer::GroupState`] on boot).
     VoteRecorded {
         ts: i64,
diff --git a/server/src/html/mod.rs b/server/src/html/mod.rs
index 5b1d0b5a887d89e7e80796aa7a6c8ed5baaf2782..d69ed962b5c8625bc83c933b1825f2cc1d0868e2 100644
--- a/server/src/html/mod.rs
+++ b/server/src/html/mod.rs
@@ -13,7 +13,7 @@ use crate::{
     form_template::template_json_compact,
     parser_action::ParserAction,
     parser_render::parser_panel,
-    ranking::ranked_items,
+    ranking::ranked_items_cached,
     reducer::GroupState,
     state::AppState,
     ui_action::UI_RPC_FIELD,
@@ -199,10 +199,8 @@ fn layout(title: &str, body: Markup, views: u64, theme: &str, theme_next: &str)
     }
 }
 
-pub fn ranking_panel(group: &mut GroupState) -> Markup {
-    const MAX_ITERS: usize = 10_000;
-    const TOL: f64 = 1e-8;
-    let items = ranked_items(group, MAX_ITERS, TOL);
+pub fn ranking_panel(group: &GroupState) -> Markup {
+    let items = ranked_items_cached(group);
     html! {
         section id="ranking-panel" class="demo-panel" {
             h2 { "Ranking" }
@@ -260,35 +258,6 @@ pub fn vote_panel() -> Markup {
 }
 
 
-pub fn demo_counter_panel(count: u64, event_log_path: &str) -> Markup {
-    let rpc = template_json_compact(&serde_json::json!({ "action": "bump_demo_counter" }))
-        .expect("rpc json");
-    html! {
-        section id="demo-counter-panel" class="demo-panel" {
-            h1 { "sorter2" }
-            p class="muted" {
-                "Pairwise ranking scaffold — votes persist to JSONL and replay on boot."
-            }
-            p class="demo-count" {
-                strong { "Counter: " }
-                span id="demo-count-value" { (count) }
-            }
-            p class="muted small" {
-                "Event log: " code { (event_log_path) }
-            }
-            form method="post" action="/ui" id="demo-bump-form" {
-                input type="hidden" name=(UI_RPC_FIELD) value=(rpc);
-                button type="submit" class="btn-primary" { "Bump (POST /ui → eval JS)" }
-            }
-            p class="muted small" {
-                "Uses hidden "
-                code { "__rpc__" }
-                " JSON + Idiomorph morph — no full page reload."
-            }
-        }
-    }
-}
-
 pub async fn home(
     State(state): State<AppState>,
     jar: CookieJar,
@@ -297,16 +266,15 @@ pub async fn home(
     let path = uri.path().to_string();
     state.views.increment(path.clone());
     let views = state.views.get_views(&path);
-    let count = *state.demo_counter.read().await;
     let theme = theme_from_jar(&jar);
     let theme_next = theme_next_from_uri(&uri);
-    let mut group = state.group.write().await;
+    let group = state.group.read().await;
     let empty_action = ParserAction::suggest(String::new(), None);
     let body = html! {
+        h1 { "sorter2" }
         (parser_panel("", &empty_action))
         (vote_panel())
-        (ranking_panel(&mut group))
-        (demo_counter_panel(count, state.event_log.path().to_string_lossy().as_ref()))
+        (ranking_panel(&group))
     };
     layout("sorter2", body, views, theme, &theme_next)
 }
diff --git a/server/src/lib.rs b/server/src/lib.rs
index 6716c5b282e7980a7a0f03d63ad8b25eda61cc55..fa423640d598f4ba97a5885d228e78d7b97f7a22 100644
--- a/server/src/lib.rs
+++ b/server/src/lib.rs
@@ -9,6 +9,7 @@ pub mod parser_render;
 pub mod path_types;
 pub mod ranking;
 pub mod reducer;
+pub mod settlement;
 pub mod state;
 pub mod ui_action;
 pub mod views;
diff --git a/server/src/ranking.rs b/server/src/ranking.rs
index 89d3280126a8d8f841721ce8cb63ff735d68752a..2d706762792ba9239bb3f1c2e4974a2fde908013 100644
--- a/server/src/ranking.rs
+++ b/server/src/ranking.rs
@@ -91,6 +91,11 @@ pub fn compute_group_ranking(group: &mut GroupState, max_iters: usize, tol: f64)
 
 pub fn ranked_items(group: &mut GroupState, max_iters: usize, tol: f64) -> Vec<RankedItem> {
     compute_group_ranking(group, max_iters, tol);
+    ranked_items_cached(group)
+}
+
+/// Read cached scores without recomputing (HTTP fast path).
+pub fn ranked_items_cached(group: &GroupState) -> Vec<RankedItem> {
     let mut items: Vec<RankedItem> = group
         .idx_to_item
         .iter()
@@ -105,7 +110,12 @@ pub fn ranked_items(group: &mut GroupState, max_iters: usize, tol: f64) -> Vec<R
     items
 }
 
-fn compute_scores_from_edges(n: usize, edges: impl Iterator<Item = ((usize, usize), f64)>, max_iters: usize, tol: f64) -> Vec<f64> {
+pub fn compute_scores_from_edges(
+    n: usize,
+    edges: impl Iterator<Item = ((usize, usize), f64)>,
+    max_iters: usize,
+    tol: f64,
+) -> Vec<f64> {
     if n == 0 {
         return vec![];
     }
diff --git a/server/src/settlement.rs b/server/src/settlement.rs
new file mode 100644
index 0000000000000000000000000000000000000000..1f722ceaea62cda22c28ab71551f259fbf049b81
--- /dev/null
+++ b/server/src/settlement.rs
@@ -0,0 +1,114 @@
+use std::sync::Arc;
+
+use tokio::sync::{mpsc, oneshot, RwLock};
+
+use crate::{
+    event_log::EventLog,
+    events::Event,
+    ranking::compute_scores_from_edges,
+    reducer::{GroupState, VoteData},
+};
+
+const MAX_ITERS: usize = 10_000;
+const TOL: f64 = 1e-8;
+
+pub struct SettlementCommand {
+    pub vote: VoteData,
+    pub event: Event,
+    pub reply: oneshot::Sender<Result<(), String>>,
+}
+
+#[derive(Clone)]
+pub struct SettlementClient {
+    tx: mpsc::Sender<SettlementCommand>,
+}
+
+impl SettlementClient {
+    pub fn spawn(group: Arc<RwLock<GroupState>>, event_log: Arc<EventLog>) -> Self {
+        let (tx, rx) = mpsc::channel(64);
+        tokio::spawn(settlement_worker(rx, group, event_log));
+        Self { tx }
+    }
+
+    pub async fn record_vote(&self, vote: VoteData, event: Event) -> Result<(), String> {
+        let (reply, rx) = oneshot::channel();
+        self.tx
+            .send(SettlementCommand {
+                vote,
+                event,
+                reply,
+            })
+            .await
+            .map_err(|_| "settlement worker stopped".to_string())?;
+        rx.await
+            .map_err(|_| "settlement worker stopped".to_string())?
+    }
+}
+
+async fn settlement_worker(
+    mut rx: mpsc::Receiver<SettlementCommand>,
+    group: Arc<RwLock<GroupState>>,
+    event_log: Arc<EventLog>,
+) {
+    while let Some(first) = rx.recv().await {
+        let mut batch = vec![first];
+        while let Ok(more) = rx.try_recv() {
+            batch.push(more);
+        }
+
+        let mut disk_err: Option<String> = None;
+        for cmd in &batch {
+            if let Err(e) = event_log.append(&cmd.event).await {
+                disk_err = Some(e.to_string());
+                break;
+            }
+        }
+
+        if let Some(err) = disk_err {
+            for cmd in batch {
+                let _ = cmd.reply.send(Err(err.clone()));
+            }
+            continue;
+        }
+
+        let (edges, n) = {
+            let mut w = group.write().await;
+            for cmd in &batch {
+                w.apply_vote(cmd.vote.clone());
+            }
+            (w.edges.clone(), w.idx_to_item.len())
+        };
+
+        let new_scores = compute_scores_from_edges(
+            n,
+            edges.iter().map(|(&k, &v)| (k, v)),
+            MAX_ITERS,
+            TOL,
+        );
+
+        {
+            let mut w = group.write().await;
+            w.cached_scores = new_scores;
+            w.dirty = false;
+        }
+
+        for cmd in batch {
+            let _ = cmd.reply.send(Ok(()));
+        }
+    }
+}
+
+/// Compute ranking cache from current in-memory edges (startup replay only).
+pub fn warm_ranking_cache(group: &mut GroupState) {
+    if !group.dirty {
+        return;
+    }
+    let n = group.idx_to_item.len();
+    group.cached_scores = compute_scores_from_edges(
+        n,
+        group.edges.iter().map(|(&k, &v)| (k, v)),
+        MAX_ITERS,
+        TOL,
+    );
+    group.dirty = false;
+}
diff --git a/server/src/state.rs b/server/src/state.rs
index 8ec9902e2ecc31cf8208f7ad6365891dc5537eed..1922541a4064c2de1df2d993a461cae783320e05 100644
--- a/server/src/state.rs
+++ b/server/src/state.rs
@@ -6,6 +6,7 @@ use crate::{
     event_log::EventLog,
     events::Event,
     reducer::{GroupState, VoteData},
+    settlement::{warm_ranking_cache, SettlementClient},
     views::ViewStore,
 };
 
@@ -38,8 +39,8 @@ pub struct AppState {
     pub cfg: Arc<AppConfig>,
     pub event_log: Arc<EventLog>,
     pub views: ViewStore,
-    pub demo_counter: Arc<RwLock<u64>>,
     pub group: Arc<RwLock<GroupState>>,
+    settlement: SettlementClient,
 }
 
 impl AppState {
@@ -48,14 +49,10 @@ impl AppState {
         let views_path = format!("{}/views.json", cfg.data_dir);
         let views = ViewStore::new(&views_path);
 
-        let mut demo_counter: u64 = 0;
         let mut group = GroupState::new();
         if let Ok((events, _)) = event_log.load_all().await {
             for ev in events {
                 match ev {
-                    Event::DemoCounterBumped { value, .. } => {
-                        demo_counter = demo_counter.max(value);
-                    }
                     Event::VoteRecorded {
                         ts,
                         a,
@@ -74,30 +71,20 @@ impl AppState {
             }
         }
 
+        warm_ranking_cache(&mut group);
+
+        let group = Arc::new(RwLock::new(group));
+        let settlement = SettlementClient::spawn(group.clone(), event_log.clone());
+
         Self {
             cfg: Arc::new(cfg),
             event_log,
             views,
-            demo_counter: Arc::new(RwLock::new(demo_counter)),
-            group: Arc::new(RwLock::new(group)),
+            group,
+            settlement,
         }
     }
 
-    pub async fn bump_demo_counter(&self) -> u64 {
-        let mut guard = self.demo_counter.write().await;
-        *guard += 1;
-        let value = *guard;
-        drop(guard);
-
-        let ts = crate::html::now_ms();
-        let _ = self
-            .event_log
-            .append(&Event::DemoCounterBumped { ts, value })
-            .await;
-
-        value
-    }
-
     pub async fn record_vote(
         &self,
         a: &str,
@@ -109,23 +96,14 @@ impl AppState {
         let vote = VoteData::from_recorded(ts, a, b, ratio_left, ratio_right)
             .ok_or_else(|| "invalid vote: need two distinct non-empty items".to_string())?;
 
-        {
-            let mut group = self.group.write().await;
-            group.apply_vote(vote.clone());
-        }
-
-        let _ = self
-            .event_log
-            .append(&Event::VoteRecorded {
-                ts,
-                a: vote.a.as_str().to_string(),
-                b: vote.b.as_str().to_string(),
-                ratio_left: vote.ratio_left,
-                ratio_right: vote.ratio_right,
-            })
-            .await
-            .map_err(|e| e.to_string())?;
+        let event = Event::VoteRecorded {
+            ts,
+            a: vote.a.as_str().to_string(),
+            b: vote.b.as_str().to_string(),
+            ratio_left: vote.ratio_left,
+            ratio_right: vote.ratio_right,
+        };
 
-        Ok(())
+        self.settlement.record_vote(vote, event).await
     }
 }
diff --git a/server/src/ui_action.rs b/server/src/ui_action.rs
index 1d488e1ad1d8fd81bd9d016d69255adfe9b22fc8..5d94c84113607b3bcd8d31d03ef5b8e1b87b67a7 100644
--- a/server/src/ui_action.rs
+++ b/server/src/ui_action.rs
@@ -12,8 +12,6 @@ pub const UI_RPC_FIELD: &str = "__rpc__";
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
 #[serde(tag = "action", rename_all = "snake_case")]
 pub enum HtmlUiAction {
-    /// Demo: morph `#demo-counter-panel` after bumping the persisted counter.
-    BumpDemoCounter,
     /// Record a pairwise vote and morph `#ranking-panel`.
     RecordVote {
         a: String,
@@ -52,18 +50,6 @@ pub fn parse_html_ui_from_form(
 mod tests {
     use super::*;
 
-    #[test]
-    fn bump_demo_counter_round_trip() {
-        let template = serde_json::json!({ "action": "bump_demo_counter" });
-        let mut form = HashMap::new();
-        form.insert(
-            UI_RPC_FIELD.to_string(),
-            serde_json::to_string(&template).unwrap(),
-        );
-        let a = parse_html_ui_from_form(&form).unwrap();
-        assert_eq!(a, HtmlUiAction::BumpDemoCounter);
-    }
-
     #[test]
     fn record_vote_round_trip_with_form_holes() {
         let template = serde_json::json!({
diff --git a/server/tests/integration_health.rs b/server/tests/integration_health.rs
index 8a58bc14aac68c779e7ce4ffa57d27b3220e9953..1d816e008b9bf629967e3b3c786c41afefc284e3 100644
--- a/server/tests/integration_health.rs
+++ b/server/tests/integration_health.rs
@@ -38,7 +38,7 @@ async fn healthz_ok() {
 }
 
 #[tokio::test]
-async fn home_has_demo_panel() {
+async fn home_has_main_panels() {
     let (addr, _tmp) = start_test_server().await;
     let client = reqwest::Client::new();
     let html = client
diff --git a/server/tests/integration_ui.rs b/server/tests/integration_ui.rs
index bee79407dec120699a083f1a75adf9291e207fc7..7ede46d681fefbe25b1d98fc33520a185515eb1c 100644
--- a/server/tests/integration_ui.rs
+++ b/server/tests/integration_ui.rs
@@ -25,33 +25,6 @@ async fn start_test_server() -> (SocketAddr, TempDir) {
     (addr, tmp)
 }
 
-#[tokio::test]
-async fn post_ui_bump_returns_javascript_morph() {
-    let (addr, tmp) = start_test_server().await;
-    let rpc = serde_json::json!({ "action": "bump_demo_counter" }).to_string();
-    let mut form = HashMap::new();
-    form.insert(UI_RPC_FIELD.to_string(), rpc);
-
-    let client = reqwest::Client::new();
-    let body = client
-        .post(format!("http://{addr}/ui"))
-        .form(&form)
-        .send()
-        .await
-        .unwrap()
-        .text()
-        .await
-        .unwrap();
-
-    assert!(body.contains("Idiomorph.morph"));
-    assert!(body.contains("demo-counter-panel"));
-    assert!(body.contains("Counter:"));
-
-    let log_path = tmp.path().join("events.jsonl");
-    let log = std::fs::read_to_string(log_path).unwrap();
-    assert!(log.contains("demo_counter_bumped"));
-}
-
 #[tokio::test]
 async fn post_ui_record_vote_morphs_ranking_and_persists() {
     let (addr, tmp) = start_test_server().await;
@@ -90,8 +63,8 @@ async fn post_ui_record_vote_morphs_ranking_and_persists() {
         port: 0,
     };
     let state = create_app_state(cfg).await;
-    let mut group = state.group.write().await;
-    let ranked = sorter2_server::ranking::ranked_items(&mut group, 10_000, 1e-8);
+    let group = state.group.read().await;
+    let ranked = sorter2_server::ranking::ranked_items_cached(&group);
     assert_eq!(ranked.len(), 2);
     assert_eq!(ranked[0].item.as_str(), "alpha");
 }
diff --git a/test/smoke.clj b/test/smoke.clj
index b332324743b58baf3fe96d7477353749f137feae..11887c48282088e140d823a88ba616f6325835b3 100644
--- a/test/smoke.clj
+++ b/test/smoke.clj
@@ -26,7 +26,7 @@
             false))))))
 
 (deftest http-smoke-against-running-server
-  (testing "build, start, healthz, home contains RPC demo"
+  (testing "build, start, healthz, home contains main panels"
     (let [root (repo-root)
           data-dir (.getAbsolutePath (doto (io/file (System/getProperty "java.io.tmpdir")
                                                    (str "sorter2-smoke-" (System/currentTimeMillis)))


Side B — contributor: tommy-mor
Side B — commit message:
[5db58b98] Improve vote pair selection for spanning trees and rank refinement.

Prefer attaching unranked items to established components before comparing
isolates, then zip down adjacent rank-centrality pairs once the pool is fully
connected, skipping pairs that already have votes.

Co-authored-by: Cursor <cursoragent@cursor.com>

Side B — unified diff (full patch):
diff --git a/server/src/pair.rs b/server/src/pair.rs
index 54b5d2417e9dba04ed8df422156e274c2b2f76b2..c14de4b0502c8b5a17cddf3746077739d56e03e0 100644
--- a/server/src/pair.rs
+++ b/server/src/pair.rs
@@ -3,13 +3,21 @@
 //! Pair selection prefers **bridge** votes — comparisons between items in
 //! different connected components of the voted-pairs graph — so the pool
 //! merges into one ranking group before refining within it.
+//!
+//! Among unvoted bridges, prefer merging established voted components, then
+//! attaching a never-voted child to an established component, and only then
+//! comparing two never-voted children (so the voted graph grows as one tree).
+//!
+//! Once every pool child sits in one voted component, refinement **zips** down
+//! the rank-centrality order: prefer 1 vs 2, then 2 vs 3, and so on, skipping
+//! pairs that already have a vote.
 
 use rand::seq::SliceRandom;
 use std::collections::{HashMap, HashSet};
 
 use crate::{
     path_types::ItemId,
-    ranking::connected_components_from_voted_pairs,
+    ranking::{connected_components_from_voted_pairs, ranked_items},
     reducer::{GlobalTree, GroupState},
 };
 
@@ -28,36 +36,77 @@ fn pair_is_voted(group: &GroupState, a: &ItemId, b: &ItemId) -> bool {
     group.voted_pairs.contains(&(i, j))
 }
 
-/// Component id per pool item: voted-pairs graph components plus one id per
-/// never-voted child.
-fn component_ids(group: &GroupState, pool: &[ItemId]) -> HashMap<ItemId, usize> {
+/// Voted-pairs layout for pool items: component id per item plus which ids are
+/// multi-node voted components (ranked groups in the UI).
+struct ComponentLayout {
+    ids: HashMap<ItemId, usize>,
+    established: HashSet<usize>,
+}
+
+fn component_layout(group: &GroupState, pool: &[ItemId]) -> ComponentLayout {
     let n = group.idx_to_item.len();
     let (comps, isolates) =
         connected_components_from_voted_pairs(n, group.voted_pairs.iter().copied());
 
-    let mut out: HashMap<ItemId, usize> = HashMap::new();
+    let mut established = HashSet::new();
+    let mut ids: HashMap<ItemId, usize> = HashMap::new();
     for (comp_idx, comp) in comps.iter().enumerate() {
+        if comp.len() >= 2 {
+            established.insert(comp_idx);
+        }
         for &idx in comp {
             if idx < n {
-                out.insert(group.idx_to_item[idx].clone(), comp_idx);
+                ids.insert(group.idx_to_item[idx].clone(), comp_idx);
             }
         }
     }
     let mut next = comps.len();
     for &idx in &isolates {
         if idx < n {
-            out.insert(group.idx_to_item[idx].clone(), next);
+            ids.insert(group.idx_to_item[idx].clone(), next);
             next += 1;
         }
     }
     for item in pool {
-        out.entry(item.clone()).or_insert_with(|| {
+        ids.entry(item.clone()).or_insert_with(|| {
             let id = next;
             next += 1;
             id
         });
     }
-    out
+    ComponentLayout { ids, established }
+}
+
+/// Every pool child shares one multi-node voted component (spanning tree phase done).
+fn pool_fully_connected(layout: &ComponentLayout, pool: &[ItemId]) -> bool {
+    if pool.len() < 2 {
+        return false;
+    }
+    let mut comp_id = None;
+    for item in pool {
+        let Some(id) = layout.ids.get(item) else {
+            return false;
+        };
+        if !layout.established.contains(id) {
+            return false;
+        }
+        match comp_id {
+            None => comp_id = Some(*id),
+            Some(expected) if expected == *id => {}
+            _ => return false,
+        }
+    }
+    comp_id.is_some()
+}
+
+/// Pool children that appear in `group`, sorted best rank first.
+fn ranked_pool_order(group: &GroupState, pool: &[ItemId]) -> Vec<ItemId> {
+    let pool_set: HashSet<_> = pool.iter().collect();
+    ranked_items(group)
+        .into_iter()
+        .map(|r| r.item)
+        .filter(|id| pool_set.contains(id))
+        .collect()
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
@@ -72,19 +121,108 @@ enum PairPriority {
     WithinVoted = 3,
 }
 
-fn pair_priority(
+/// Tie-break among unvoted bridge pairs.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
+enum BridgeSubPriority {
+    /// Both endpoints lie in established (multi-node) voted components.
+    MergeEstablished = 0,
+    /// One established component member and one never-voted child.
+    AttachIsolate = 1,
+    /// Two never-voted children (separate singleton components).
+    IsolatePair = 2,
+}
+
+/// Tie-break among within-component pairs once the pool is one connected group.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
+struct WithinSubPriority {
+    /// 1 = adjacent ranks (i vs i+1); larger = farther apart in the order.
+    rank_gap: usize,
+    /// min rank index of the two — zip from the top (1 vs 2 before 2 vs 3).
+    zip_index: usize,
+}
+
+const WITHIN_SUB_WORST: WithinSubPriority = WithinSubPriority {
+    rank_gap: usize::MAX,
+    zip_index: usize::MAX,
+};
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
+struct PairSortKey {
+    priority: PairPriority,
+    bridge_sub: BridgeSubPriority,
+    within_sub: WithinSubPriority,
+}
+
+fn item_in_established(layout: &ComponentLayout, item: &ItemId) -> bool {
+    layout
+        .ids
+        .get(item)
+        .is_some_and(|id| layout.established.contains(id))
+}
+
+fn bridge_sub_priority(layout: &ComponentLayout, a: &ItemId, b: &ItemId) -> BridgeSubPriority {
+    let a_est = item_in_established(layout, a);
+    let b_est = item_in_established(layout, b);
+    match (a_est, b_est) {
+        (true, true) => BridgeSubPriority::MergeEstablished,
+        (true, false) | (false, true) => BridgeSubPriority::AttachIsolate,
+        (false, false) => BridgeSubPriority::IsolatePair,
+    }
+}
+
+fn within_sub_priority(
+    group: &GroupState,
+    pool: &[ItemId],
+    layout: &ComponentLayout,
+    a: &ItemId,
+    b: &ItemId,
+) -> WithinSubPriority {
+    if !pool_fully_connected(layout, pool) {
+        return WITHIN_SUB_WORST;
+    }
+    let order = ranked_pool_order(group, pool);
+    let (Some(i), Some(j)) = (order.iter().position(|x| x == a), order.iter().position(|x| x == b))
+    else {
+        return WITHIN_SUB_WORST;
+    };
+    WithinSubPriority {
+        rank_gap: i.abs_diff(j),
+        zip_index: i.min(j),
+    }
+}
+
+fn pair_sort_key(
     group: &GroupState,
-    components: &HashMap<ItemId, usize>,
+    pool: &[ItemId],
+    layout: &ComponentLayout,
     a: &ItemId,
     b: &ItemId,
-) -> PairPriority {
+) -> PairSortKey {
     let voted = pair_is_voted(group, a, b);
-    let bridge = components.get(a) != components.get(b);
-    match (bridge, voted) {
+    let bridge = layout.ids.get(a) != layout.ids.get(b);
+    let priority = match (bridge, voted) {
         (true, false) => PairPriority::BridgeUnvoted,
         (false, false) => PairPriority::WithinUnvoted,
         (true, true) => PairPriority::BridgeVoted,
         (false, true) => PairPriority::WithinVoted,
+    };
+    let bridge_sub = if priority == PairPriority::BridgeUnvoted {
+        bridge_sub_priority(layout, a, b)
+    } else {
+        BridgeSubPriority::MergeEstablished
+    };
+    let within_sub = if matches!(
+        priority,
+        PairPriority::WithinUnvoted | PairPriority::WithinVoted
+    ) {
+        within_sub_priority(group, pool, layout, a, b)
+    } else {
+        WITHIN_SUB_WORST
+    };
+    PairSortKey {
+        priority,
+        bridge_sub,
+        within_sub,
     }
 }
 
@@ -109,9 +247,12 @@ fn candidate_pairs(pool: &[ItemId], exclude: Option<(&ItemId, &ItemId)>) -> Vec<
 
 /// Pick the next pair to vote on within `pool`.
 ///
-/// 1. Prefer unvoted **bridge** pairs (connect separate ranking components).
-/// 2. Then unvoted within-component pairs (refinement).
-/// 3. Then already-voted pairs (re-compare).
+/// 1. Prefer unvoted **bridge** pairs (connect separate ranking components),
+///    with sub-priority: merge established components, attach an isolate to
+///    established, then compare two isolates.
+/// 2. Then unvoted within-component pairs; when the pool is one connected group,
+///    prefer adjacent ranks (1 vs 2, 2 vs 3, …) in order, skipping voted pairs.
+/// 3. Then already-voted pairs (re-compare), with the same zip ordering.
 pub fn suggest_next_pair_in_pool(
     group: &GroupState,
     pool: &[ItemId],
@@ -121,15 +262,15 @@ pub fn suggest_next_pair_in_pool(
     if candidates.is_empty() {
         return None;
     }
-    let components = component_ids(group, pool);
+    let layout = component_layout(group, pool);
     let best = candidates
         .iter()
-        .map(|(a, b)| (pair_priority(group, &components, a, b), (a, b)))
-        .min_by_key(|(p, _)| *p)?
+        .map(|(a, b)| (pair_sort_key(group, pool, &layout, a, b), (a, b)))
+        .min_by_key(|(k, _)| *k)?
         .0;
     let best_pairs: Vec<(ItemId, ItemId)> = candidates
         .into_iter()
-        .filter(|(a, b)| pair_priority(group, &components, a, b) == best)
+        .filter(|(a, b)| pair_sort_key(group, pool, &layout, a, b) == best)
         .collect();
     best_pairs.choose(&mut rand::thread_rng()).cloned()
 }
@@ -303,6 +444,38 @@ mod tests {
         assert!(from_ab && from_cd, "expected bridge pair, got {:?}", chosen);
     }
 
+    #[test]
+    fn suggest_prefers_attach_over_isolate_pair_among_many_unranked() {
+        let parent = ItemId::parse("reddit.com/r/rust").unwrap();
+        let mut tree = seed_children(
+            &parent,
+            &[
+                "reddit.com/r/rust/a",
+                "reddit.com/r/rust/b",
+                "reddit.com/r/rust/c",
+                "reddit.com/r/rust/d",
+                "reddit.com/r/rust/e",
+            ],
+        );
+        let ab =
+            VoteData::from_recorded(1, "reddit.com/r/rust/a", "reddit.com/r/rust/b", 2, 1).unwrap();
+        tree.apply_vote(&parent, ab);
+        let group = tree.get(&parent).unwrap().local_ranking.clone();
+        let pool = children_of(&tree, &parent);
+        let pair = suggest_next_pair_in_pool(&group, &pool, None).unwrap();
+        let chosen = pair_set(&pair);
+        let from_ab =
+            chosen.contains("reddit.com/r/rust/a") || chosen.contains("reddit.com/r/rust/b");
+        let from_cde = chosen.contains("reddit.com/r/rust/c")
+            || chosen.contains("reddit.com/r/rust/d")
+            || chosen.contains("reddit.com/r/rust/e");
+        assert!(
+            from_ab && from_cde,
+            "expected ranked+unranked attach, got {:?}",
+            chosen
+        );
+    }
+
     #[test]
     fn suggest_connects_isolate_to_existing_component() {
         let parent = ItemId::parse("reddit.com/r/rust").unwrap();
@@ -325,6 +498,65 @@ mod tests {
         assert!(chosen.contains("reddit.com/r/rust/a") || chosen.contains("reddit.com/r/rust/b"));
     }
 
+    #[test]
+    fn suggest_zips_adjacent_ranks_when_tree_complete() {
+        let parent = ItemId::parse("reddit.com/r/rust").unwrap();
+        let mut tree = seed_children(
+            &parent,
+            &[
+                "reddit.com/r/rust/a",
+                "reddit.com/r/rust/b",
+                "reddit.com/r/rust/c",
+            ],
+        );
+        // Star at a connects all three; b-c is the only unvoted adjacent pair left.
+        for (a, b, l, r) in [
+            ("reddit.com/r/rust/a", "reddit.com/r/rust/b", 3, 1),
+            ("reddit.com/r/rust/a", "reddit.com/r/rust/c", 2, 1),
+        ] {
+            let v = VoteData::from_recorded(1, a, b, l, r).unwrap();
+            tree.apply_vote(&parent, v);
+        }
+        let group = tree.get(&parent).unwrap().local_ranking.clone();
+        let pool = children_of(&tree, &parent);
+        let pair = suggest_next_pair_in_pool(&group, &pool, None).unwrap();
+        let chosen = pair_set(&pair);
+        // a-b and a-c voted; b-c is the only unvoted adjacent pair in rank order.
+        assert!(chosen.contains("reddit.com/r/rust/b"));
+        assert!(chosen.contains("reddit.com/r/rust/c"));
+    }
+
+    #[test]
+    fn suggest_zip_prefers_1v2_before_2v3_when_both_unvoted() {
+        let parent = ItemId::parse("reddit.com/r/rust").unwrap();
+        let mut tree = seed_children(
+            &parent,
+            &[
+                "reddit.com/r/rust/a",
+                "reddit.com/r/rust/b",
+                "reddit.com/r/rust/c",
+                "reddit.com/r/rust/d",
+            ],
+        );
+        // Hub at c connects all four; leave rank-adjacent a-b and b-c unvoted.
+        for (a, b, l, r) in [
+            ("reddit.com/r/rust/c", "reddit.com/r/rust/d", 3, 1),
+            ("reddit.com/r/rust/b", "reddit.com/r/rust/c", 2, 1),
+            ("reddit.com/r/rust/a", "reddit.com/r/rust/c", 2, 1),
+        ] {
+            let v = VoteData::from_recorded(1, a, b, l, r).unwrap();
+            tree.apply_vote(&parent, v);
+        }
+        let group = tree.get(&parent).unwrap().local_ranking.clone();
+        let pool = children_of(&tree, &parent);
+        assert!(pool_fully_connected(&component_layout(&group, &pool), &pool));
+        let pair = suggest_next_pair_in_pool(&group, &pool, None).unwrap();
+        let chosen = pair_set(&pair);
+        // Top adjacent unvoted edge should be a-b (zip index 0), not b-c (index 1).
+        assert!(chosen.contains("reddit.com/r/rust/a"));
+        assert!(chosen.contains("reddit.com/r/rust/b"));
+    }
+
     #[test]
     fn resolve_pair_picks_from_pool() {
         let parent = ItemId::parse("reddit.com/r/rust").unwrap();