{"messages":[{"content":"You are a constitutional council ranking individual git commits for ownership allocation.\n\nCompare these two commits. Decide which contributed more lasting value to the project.\n\nJudge substance, not spectacle:\n- Prefer correct, lasting design and real bugfixes over churn, formatting, renames, or generated noise.\n- Prefer clarity and necessity over sheer line count. A small precise change can beat a large diffuse one.\n- Do not favor a side merely because its patch is longer or noisier.\n- Weight what the change does for the project, not the contributor's name.\n\nReturn ONLY a JSON object: {\"winner\": \"A\" or \"B\", \"ratio\": \"N:M\", \"explanation\": \"...\"}\nThe explanation must cite concrete differences in the patches (1-3 sentences).\n\nSide A — contributor: tommy-mor\nSide A — commit message:\n[07715165] nice\n\nSide A — unified diff (full patch):\ndiff --git a/server/src/api/ui_html.rs b/server/src/api/ui_html.rs\nindex c3c62a76f424010d77a6090c84dd0b82098f573e..da2536112faea313352624cf2ce0ddd0ab3377c1 100644\n--- a/server/src/api/ui_html.rs\n+++ b/server/src/api/ui_html.rs\n@@ -6,7 +6,7 @@ use axum::{\n use std::collections::HashMap;\n \n use crate::{\n-    html::{demo_counter_panel, js_string_literal, ranking_panel, JsBuilder},\n+    html::{js_string_literal, ranking_panel, JsBuilder},\n     parser::parse_reddit_url,\n     parser_render::parser_panel_morph,\n     state::AppState,\n@@ -35,13 +35,6 @@ pub async fn post_ui_html(\n     };\n \n     match action {\n-        HtmlUiAction::BumpDemoCounter => {\n-            let count = state.bump_demo_counter().await;\n-            let panel = demo_counter_panel(count, state.event_log.path().to_string_lossy().as_ref());\n-            JsBuilder::new()\n-                .morph_selector(\"#demo-counter-panel\", panel)\n-                .into_response()\n-        }\n         HtmlUiAction::RecordVote {\n             a,\n             b,\n@@ -54,8 +47,8 @@ pub async fn post_ui_html(\n             {\n                 return ui_js_warn(&e).into_response();\n             }\n-            let mut group = state.group.write().await;\n-            let panel = ranking_panel(&mut group);\n+            let group = state.group.read().await;\n+            let panel = ranking_panel(&group);\n             JsBuilder::new()\n                 .morph_selector(\"#ranking-panel\", panel)\n                 .into_response()\n@@ -87,20 +80,6 @@ mod tests {\n         assert!(matches!(err, HtmlUiParseError::MissingRpc));\n     }\n \n-    #[test]\n-    fn bump_action_deserializes() {\n-        let template = serde_json::json!({ \"action\": \"bump_demo_counter\" });\n-        let mut form = HashMap::new();\n-        form.insert(\n-            UI_RPC_FIELD.to_string(),\n-            serde_json::to_string(&template).unwrap(),\n-        );\n-        assert_eq!(\n-            parse_html_ui_from_form(&form).unwrap(),\n-            HtmlUiAction::BumpDemoCounter\n-        );\n-    }\n-\n     #[test]\n     fn record_vote_action_deserializes() {\n         let template = serde_json::json!({\ndiff --git a/server/src/events.rs b/server/src/events.rs\nindex b969242534e184d4f0a689543a479670b08a18df..eff80aef0257f706d2341f666e63d6a3d921bf6e 100644\n--- a/server/src/events.rs\n+++ b/server/src/events.rs\n@@ -5,8 +5,6 @@ use serde::{Deserialize, Serialize};\n pub enum Event {\n     /// Page view recorded (path → counter in views.json).\n     ViewRecorded { path: String, ts: i64 },\n-    /// Demo counter bump from `POST /ui` (persisted in the single JSONL log).\n-    DemoCounterBumped { ts: i64, value: u64 },\n     /// Pairwise comparison vote (replayed into [`crate::reducer::GroupState`] on boot).\n     VoteRecorded {\n         ts: i64,\ndiff --git a/server/src/html/mod.rs b/server/src/html/mod.rs\nindex 5b1d0b5a887d89e7e80796aa7a6c8ed5baaf2782..d69ed962b5c8625bc83c933b1825f2cc1d0868e2 100644\n--- a/server/src/html/mod.rs\n+++ b/server/src/html/mod.rs\n@@ -13,7 +13,7 @@ use crate::{\n     form_template::template_json_compact,\n     parser_action::ParserAction,\n     parser_render::parser_panel,\n-    ranking::ranked_items,\n+    ranking::ranked_items_cached,\n     reducer::GroupState,\n     state::AppState,\n     ui_action::UI_RPC_FIELD,\n@@ -199,10 +199,8 @@ fn layout(title: &str, body: Markup, views: u64, theme: &str, theme_next: &str)\n     }\n }\n \n-pub fn ranking_panel(group: &mut GroupState) -> Markup {\n-    const MAX_ITERS: usize = 10_000;\n-    const TOL: f64 = 1e-8;\n-    let items = ranked_items(group, MAX_ITERS, TOL);\n+pub fn ranking_panel(group: &GroupState) -> Markup {\n+    let items = ranked_items_cached(group);\n     html! {\n         section id=\"ranking-panel\" class=\"demo-panel\" {\n             h2 { \"Ranking\" }\n@@ -260,35 +258,6 @@ pub fn vote_panel() -> Markup {\n }\n \n \n-pub fn demo_counter_panel(count: u64, event_log_path: &str) -> Markup {\n-    let rpc = template_json_compact(&serde_json::json!({ \"action\": \"bump_demo_counter\" }))\n-        .expect(\"rpc json\");\n-    html! {\n-        section id=\"demo-counter-panel\" class=\"demo-panel\" {\n-            h1 { \"sorter2\" }\n-            p class=\"muted\" {\n-                \"Pairwise ranking scaffold — votes persist to JSONL and replay on boot.\"\n-            }\n-            p class=\"demo-count\" {\n-                strong { \"Counter: \" }\n-                span id=\"demo-count-value\" { (count) }\n-            }\n-            p class=\"muted small\" {\n-                \"Event log: \" code { (event_log_path) }\n-            }\n-            form method=\"post\" action=\"/ui\" id=\"demo-bump-form\" {\n-                input type=\"hidden\" name=(UI_RPC_FIELD) value=(rpc);\n-                button type=\"submit\" class=\"btn-primary\" { \"Bump (POST /ui → eval JS)\" }\n-            }\n-            p class=\"muted small\" {\n-                \"Uses hidden \"\n-                code { \"__rpc__\" }\n-                \" JSON + Idiomorph morph — no full page reload.\"\n-            }\n-        }\n-    }\n-}\n-\n pub async fn home(\n     State(state): State<AppState>,\n     jar: CookieJar,\n@@ -297,16 +266,15 @@ pub async fn home(\n     let path = uri.path().to_string();\n     state.views.increment(path.clone());\n     let views = state.views.get_views(&path);\n-    let count = *state.demo_counter.read().await;\n     let theme = theme_from_jar(&jar);\n     let theme_next = theme_next_from_uri(&uri);\n-    let mut group = state.group.write().await;\n+    let group = state.group.read().await;\n     let empty_action = ParserAction::suggest(String::new(), None);\n     let body = html! {\n+        h1 { \"sorter2\" }\n         (parser_panel(\"\", &empty_action))\n         (vote_panel())\n-        (ranking_panel(&mut group))\n-        (demo_counter_panel(count, state.event_log.path().to_string_lossy().as_ref()))\n+        (ranking_panel(&group))\n     };\n     layout(\"sorter2\", body, views, theme, &theme_next)\n }\ndiff --git a/server/src/lib.rs b/server/src/lib.rs\nindex 6716c5b282e7980a7a0f03d63ad8b25eda61cc55..fa423640d598f4ba97a5885d228e78d7b97f7a22 100644\n--- a/server/src/lib.rs\n+++ b/server/src/lib.rs\n@@ -9,6 +9,7 @@ pub mod parser_render;\n pub mod path_types;\n pub mod ranking;\n pub mod reducer;\n+pub mod settlement;\n pub mod state;\n pub mod ui_action;\n pub mod views;\ndiff --git a/server/src/ranking.rs b/server/src/ranking.rs\nindex 89d3280126a8d8f841721ce8cb63ff735d68752a..2d706762792ba9239bb3f1c2e4974a2fde908013 100644\n--- a/server/src/ranking.rs\n+++ b/server/src/ranking.rs\n@@ -91,6 +91,11 @@ pub fn compute_group_ranking(group: &mut GroupState, max_iters: usize, tol: f64)\n \n pub fn ranked_items(group: &mut GroupState, max_iters: usize, tol: f64) -> Vec<RankedItem> {\n     compute_group_ranking(group, max_iters, tol);\n+    ranked_items_cached(group)\n+}\n+\n+/// Read cached scores without recomputing (HTTP fast path).\n+pub fn ranked_items_cached(group: &GroupState) -> Vec<RankedItem> {\n     let mut items: Vec<RankedItem> = group\n         .idx_to_item\n         .iter()\n@@ -105,7 +110,12 @@ pub fn ranked_items(group: &mut GroupState, max_iters: usize, tol: f64) -> Vec<R\n     items\n }\n \n-fn compute_scores_from_edges(n: usize, edges: impl Iterator<Item = ((usize, usize), f64)>, max_iters: usize, tol: f64) -> Vec<f64> {\n+pub fn compute_scores_from_edges(\n+    n: usize,\n+    edges: impl Iterator<Item = ((usize, usize), f64)>,\n+    max_iters: usize,\n+    tol: f64,\n+) -> Vec<f64> {\n     if n == 0 {\n         return vec![];\n     }\ndiff --git a/server/src/settlement.rs b/server/src/settlement.rs\nnew file mode 100644\nindex 0000000000000000000000000000000000000000..1f722ceaea62cda22c28ab71551f259fbf049b81\n--- /dev/null\n+++ b/server/src/settlement.rs\n@@ -0,0 +1,114 @@\n+use std::sync::Arc;\n+\n+use tokio::sync::{mpsc, oneshot, RwLock};\n+\n+use crate::{\n+    event_log::EventLog,\n+    events::Event,\n+    ranking::compute_scores_from_edges,\n+    reducer::{GroupState, VoteData},\n+};\n+\n+const MAX_ITERS: usize = 10_000;\n+const TOL: f64 = 1e-8;\n+\n+pub struct SettlementCommand {\n+    pub vote: VoteData,\n+    pub event: Event,\n+    pub reply: oneshot::Sender<Result<(), String>>,\n+}\n+\n+#[derive(Clone)]\n+pub struct SettlementClient {\n+    tx: mpsc::Sender<SettlementCommand>,\n+}\n+\n+impl SettlementClient {\n+    pub fn spawn(group: Arc<RwLock<GroupState>>, event_log: Arc<EventLog>) -> Self {\n+        let (tx, rx) = mpsc::channel(64);\n+        tokio::spawn(settlement_worker(rx, group, event_log));\n+        Self { tx }\n+    }\n+\n+    pub async fn record_vote(&self, vote: VoteData, event: Event) -> Result<(), String> {\n+        let (reply, rx) = oneshot::channel();\n+        self.tx\n+            .send(SettlementCommand {\n+                vote,\n+                event,\n+                reply,\n+            })\n+            .await\n+            .map_err(|_| \"settlement worker stopped\".to_string())?;\n+        rx.await\n+            .map_err(|_| \"settlement worker stopped\".to_string())?\n+    }\n+}\n+\n+async fn settlement_worker(\n+    mut rx: mpsc::Receiver<SettlementCommand>,\n+    group: Arc<RwLock<GroupState>>,\n+    event_log: Arc<EventLog>,\n+) {\n+    while let Some(first) = rx.recv().await {\n+        let mut batch = vec![first];\n+        while let Ok(more) = rx.try_recv() {\n+            batch.push(more);\n+        }\n+\n+        let mut disk_err: Option<String> = None;\n+        for cmd in &batch {\n+            if let Err(e) = event_log.append(&cmd.event).await {\n+                disk_err = Some(e.to_string());\n+                break;\n+            }\n+        }\n+\n+        if let Some(err) = disk_err {\n+            for cmd in batch {\n+                let _ = cmd.reply.send(Err(err.clone()));\n+            }\n+            continue;\n+        }\n+\n+        let (edges, n) = {\n+            let mut w = group.write().await;\n+            for cmd in &batch {\n+                w.apply_vote(cmd.vote.clone());\n+            }\n+            (w.edges.clone(), w.idx_to_item.len())\n+        };\n+\n+        let new_scores = compute_scores_from_edges(\n+            n,\n+            edges.iter().map(|(&k, &v)| (k, v)),\n+            MAX_ITERS,\n+            TOL,\n+        );\n+\n+        {\n+            let mut w = group.write().await;\n+            w.cached_scores = new_scores;\n+            w.dirty = false;\n+        }\n+\n+        for cmd in batch {\n+            let _ = cmd.reply.send(Ok(()));\n+        }\n+    }\n+}\n+\n+/// Compute ranking cache from current in-memory edges (startup replay only).\n+pub fn warm_ranking_cache(group: &mut GroupState) {\n+    if !group.dirty {\n+        return;\n+    }\n+    let n = group.idx_to_item.len();\n+    group.cached_scores = compute_scores_from_edges(\n+        n,\n+        group.edges.iter().map(|(&k, &v)| (k, v)),\n+        MAX_ITERS,\n+        TOL,\n+    );\n+    group.dirty = false;\n+}\ndiff --git a/server/src/state.rs b/server/src/state.rs\nindex 8ec9902e2ecc31cf8208f7ad6365891dc5537eed..1922541a4064c2de1df2d993a461cae783320e05 100644\n--- a/server/src/state.rs\n+++ b/server/src/state.rs\n@@ -6,6 +6,7 @@ use crate::{\n     event_log::EventLog,\n     events::Event,\n     reducer::{GroupState, VoteData},\n+    settlement::{warm_ranking_cache, SettlementClient},\n     views::ViewStore,\n };\n \n@@ -38,8 +39,8 @@ pub struct AppState {\n     pub cfg: Arc<AppConfig>,\n     pub event_log: Arc<EventLog>,\n     pub views: ViewStore,\n-    pub demo_counter: Arc<RwLock<u64>>,\n     pub group: Arc<RwLock<GroupState>>,\n+    settlement: SettlementClient,\n }\n \n impl AppState {\n@@ -48,14 +49,10 @@ impl AppState {\n         let views_path = format!(\"{}/views.json\", cfg.data_dir);\n         let views = ViewStore::new(&views_path);\n \n-        let mut demo_counter: u64 = 0;\n         let mut group = GroupState::new();\n         if let Ok((events, _)) = event_log.load_all().await {\n             for ev in events {\n                 match ev {\n-                    Event::DemoCounterBumped { value, .. } => {\n-                        demo_counter = demo_counter.max(value);\n-                    }\n                     Event::VoteRecorded {\n                         ts,\n                         a,\n@@ -74,30 +71,20 @@ impl AppState {\n             }\n         }\n \n+        warm_ranking_cache(&mut group);\n+\n+        let group = Arc::new(RwLock::new(group));\n+        let settlement = SettlementClient::spawn(group.clone(), event_log.clone());\n+\n         Self {\n             cfg: Arc::new(cfg),\n             event_log,\n             views,\n-            demo_counter: Arc::new(RwLock::new(demo_counter)),\n-            group: Arc::new(RwLock::new(group)),\n+            group,\n+            settlement,\n         }\n     }\n \n-    pub async fn bump_demo_counter(&self) -> u64 {\n-        let mut guard = self.demo_counter.write().await;\n-        *guard += 1;\n-        let value = *guard;\n-        drop(guard);\n-\n-        let ts = crate::html::now_ms();\n-        let _ = self\n-            .event_log\n-            .append(&Event::DemoCounterBumped { ts, value })\n-            .await;\n-\n-        value\n-    }\n-\n     pub async fn record_vote(\n         &self,\n         a: &str,\n@@ -109,23 +96,14 @@ impl AppState {\n         let vote = VoteData::from_recorded(ts, a, b, ratio_left, ratio_right)\n             .ok_or_else(|| \"invalid vote: need two distinct non-empty items\".to_string())?;\n \n-        {\n-            let mut group = self.group.write().await;\n-            group.apply_vote(vote.clone());\n-        }\n-\n-        let _ = self\n-            .event_log\n-            .append(&Event::VoteRecorded {\n-                ts,\n-                a: vote.a.as_str().to_string(),\n-                b: vote.b.as_str().to_string(),\n-                ratio_left: vote.ratio_left,\n-                ratio_right: vote.ratio_right,\n-            })\n-            .await\n-            .map_err(|e| e.to_string())?;\n+        let event = Event::VoteRecorded {\n+            ts,\n+            a: vote.a.as_str().to_string(),\n+            b: vote.b.as_str().to_string(),\n+            ratio_left: vote.ratio_left,\n+            ratio_right: vote.ratio_right,\n+        };\n \n-        Ok(())\n+        self.settlement.record_vote(vote, event).await\n     }\n }\ndiff --git a/server/src/ui_action.rs b/server/src/ui_action.rs\nindex 1d488e1ad1d8fd81bd9d016d69255adfe9b22fc8..5d94c84113607b3bcd8d31d03ef5b8e1b87b67a7 100644\n--- a/server/src/ui_action.rs\n+++ b/server/src/ui_action.rs\n@@ -12,8 +12,6 @@ pub const UI_RPC_FIELD: &str = \"__rpc__\";\n #[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]\n #[serde(tag = \"action\", rename_all = \"snake_case\")]\n pub enum HtmlUiAction {\n-    /// Demo: morph `#demo-counter-panel` after bumping the persisted counter.\n-    BumpDemoCounter,\n     /// Record a pairwise vote and morph `#ranking-panel`.\n     RecordVote {\n         a: String,\n@@ -52,18 +50,6 @@ pub fn parse_html_ui_from_form(\n mod tests {\n     use super::*;\n \n-    #[test]\n-    fn bump_demo_counter_round_trip() {\n-        let template = serde_json::json!({ \"action\": \"bump_demo_counter\" });\n-        let mut form = HashMap::new();\n-        form.insert(\n-            UI_RPC_FIELD.to_string(),\n-            serde_json::to_string(&template).unwrap(),\n-        );\n-        let a = parse_html_ui_from_form(&form).unwrap();\n-        assert_eq!(a, HtmlUiAction::BumpDemoCounter);\n-    }\n-\n     #[test]\n     fn record_vote_round_trip_with_form_holes() {\n         let template = serde_json::json!({\ndiff --git a/server/tests/integration_health.rs b/server/tests/integration_health.rs\nindex 8a58bc14aac68c779e7ce4ffa57d27b3220e9953..1d816e008b9bf629967e3b3c786c41afefc284e3 100644\n--- a/server/tests/integration_health.rs\n+++ b/server/tests/integration_health.rs\n@@ -38,7 +38,7 @@ async fn healthz_ok() {\n }\n \n #[tokio::test]\n-async fn home_has_demo_panel() {\n+async fn home_has_main_panels() {\n     let (addr, _tmp) = start_test_server().await;\n     let client = reqwest::Client::new();\n     let html = client\ndiff --git a/server/tests/integration_ui.rs b/server/tests/integration_ui.rs\nindex bee79407dec120699a083f1a75adf9291e207fc7..7ede46d681fefbe25b1d98fc33520a185515eb1c 100644\n--- a/server/tests/integration_ui.rs\n+++ b/server/tests/integration_ui.rs\n@@ -25,33 +25,6 @@ async fn start_test_server() -> (SocketAddr, TempDir) {\n     (addr, tmp)\n }\n \n-#[tokio::test]\n-async fn post_ui_bump_returns_javascript_morph() {\n-    let (addr, tmp) = start_test_server().await;\n-    let rpc = serde_json::json!({ \"action\": \"bump_demo_counter\" }).to_string();\n-    let mut form = HashMap::new();\n-    form.insert(UI_RPC_FIELD.to_string(), rpc);\n-\n-    let client = reqwest::Client::new();\n-    let body = client\n-        .post(format!(\"http://{addr}/ui\"))\n-        .form(&form)\n-        .send()\n-        .await\n-        .unwrap()\n-        .text()\n-        .await\n-        .unwrap();\n-\n-    assert!(body.contains(\"Idiomorph.morph\"));\n-    assert!(body.contains(\"demo-counter-panel\"));\n-    assert!(body.contains(\"Counter:\"));\n-\n-    let log_path = tmp.path().join(\"events.jsonl\");\n-    let log = std::fs::read_to_string(log_path).unwrap();\n-    assert!(log.contains(\"demo_counter_bumped\"));\n-}\n-\n #[tokio::test]\n async fn post_ui_record_vote_morphs_ranking_and_persists() {\n     let (addr, tmp) = start_test_server().await;\n@@ -90,8 +63,8 @@ async fn post_ui_record_vote_morphs_ranking_and_persists() {\n         port: 0,\n     };\n     let state = create_app_state(cfg).await;\n-    let mut group = state.group.write().await;\n-    let ranked = sorter2_server::ranking::ranked_items(&mut group, 10_000, 1e-8);\n+    let group = state.group.read().await;\n+    let ranked = sorter2_server::ranking::ranked_items_cached(&group);\n     assert_eq!(ranked.len(), 2);\n     assert_eq!(ranked[0].item.as_str(), \"alpha\");\n }\ndiff --git a/test/smoke.clj b/test/smoke.clj\nindex b332324743b58baf3fe96d7477353749f137feae..11887c48282088e140d823a88ba616f6325835b3 100644\n--- a/test/smoke.clj\n+++ b/test/smoke.clj\n@@ -26,7 +26,7 @@\n             false))))))\n \n (deftest http-smoke-against-running-server\n-  (testing \"build, start, healthz, home contains RPC demo\"\n+  (testing \"build, start, healthz, home contains main panels\"\n     (let [root (repo-root)\n           data-dir (.getAbsolutePath (doto (io/file (System/getProperty \"java.io.tmpdir\")\n                                                    (str \"sorter2-smoke-\" (System/currentTimeMillis)))\n\n\nSide B — contributor: tommy-mor\nSide B — commit message:\n[5db58b98] Improve vote pair selection for spanning trees and rank refinement.\n\nPrefer attaching unranked items to established components before comparing\nisolates, then zip down adjacent rank-centrality pairs once the pool is fully\nconnected, skipping pairs that already have votes.\n\nCo-authored-by: Cursor <cursoragent@cursor.com>\n\nSide B — unified diff (full patch):\ndiff --git a/server/src/pair.rs b/server/src/pair.rs\nindex 54b5d2417e9dba04ed8df422156e274c2b2f76b2..c14de4b0502c8b5a17cddf3746077739d56e03e0 100644\n--- a/server/src/pair.rs\n+++ b/server/src/pair.rs\n@@ -3,13 +3,21 @@\n //! Pair selection prefers **bridge** votes — comparisons between items in\n //! different connected components of the voted-pairs graph — so the pool\n //! merges into one ranking group before refining within it.\n+//!\n+//! Among unvoted bridges, prefer merging established voted components, then\n+//! attaching a never-voted child to an established component, and only then\n+//! comparing two never-voted children (so the voted graph grows as one tree).\n+//!\n+//! Once every pool child sits in one voted component, refinement **zips** down\n+//! the rank-centrality order: prefer 1 vs 2, then 2 vs 3, and so on, skipping\n+//! pairs that already have a vote.\n \n use rand::seq::SliceRandom;\n use std::collections::{HashMap, HashSet};\n \n use crate::{\n     path_types::ItemId,\n-    ranking::connected_components_from_voted_pairs,\n+    ranking::{connected_components_from_voted_pairs, ranked_items},\n     reducer::{GlobalTree, GroupState},\n };\n \n@@ -28,36 +36,77 @@ fn pair_is_voted(group: &GroupState, a: &ItemId, b: &ItemId) -> bool {\n     group.voted_pairs.contains(&(i, j))\n }\n \n-/// Component id per pool item: voted-pairs graph components plus one id per\n-/// never-voted child.\n-fn component_ids(group: &GroupState, pool: &[ItemId]) -> HashMap<ItemId, usize> {\n+/// Voted-pairs layout for pool items: component id per item plus which ids are\n+/// multi-node voted components (ranked groups in the UI).\n+struct ComponentLayout {\n+    ids: HashMap<ItemId, usize>,\n+    established: HashSet<usize>,\n+}\n+\n+fn component_layout(group: &GroupState, pool: &[ItemId]) -> ComponentLayout {\n     let n = group.idx_to_item.len();\n     let (comps, isolates) =\n         connected_components_from_voted_pairs(n, group.voted_pairs.iter().copied());\n \n-    let mut out: HashMap<ItemId, usize> = HashMap::new();\n+    let mut established = HashSet::new();\n+    let mut ids: HashMap<ItemId, usize> = HashMap::new();\n     for (comp_idx, comp) in comps.iter().enumerate() {\n+        if comp.len() >= 2 {\n+            established.insert(comp_idx);\n+        }\n         for &idx in comp {\n             if idx < n {\n-                out.insert(group.idx_to_item[idx].clone(), comp_idx);\n+                ids.insert(group.idx_to_item[idx].clone(), comp_idx);\n             }\n         }\n     }\n     let mut next = comps.len();\n     for &idx in &isolates {\n         if idx < n {\n-            out.insert(group.idx_to_item[idx].clone(), next);\n+            ids.insert(group.idx_to_item[idx].clone(), next);\n             next += 1;\n         }\n     }\n     for item in pool {\n-        out.entry(item.clone()).or_insert_with(|| {\n+        ids.entry(item.clone()).or_insert_with(|| {\n             let id = next;\n             next += 1;\n             id\n         });\n     }\n-    out\n+    ComponentLayout { ids, established }\n+}\n+\n+/// Every pool child shares one multi-node voted component (spanning tree phase done).\n+fn pool_fully_connected(layout: &ComponentLayout, pool: &[ItemId]) -> bool {\n+    if pool.len() < 2 {\n+        return false;\n+    }\n+    let mut comp_id = None;\n+    for item in pool {\n+        let Some(id) = layout.ids.get(item) else {\n+            return false;\n+        };\n+        if !layout.established.contains(id) {\n+            return false;\n+        }\n+        match comp_id {\n+            None => comp_id = Some(*id),\n+            Some(expected) if expected == *id => {}\n+            _ => return false,\n+        }\n+    }\n+    comp_id.is_some()\n+}\n+\n+/// Pool children that appear in `group`, sorted best rank first.\n+fn ranked_pool_order(group: &GroupState, pool: &[ItemId]) -> Vec<ItemId> {\n+    let pool_set: HashSet<_> = pool.iter().collect();\n+    ranked_items(group)\n+        .into_iter()\n+        .map(|r| r.item)\n+        .filter(|id| pool_set.contains(id))\n+        .collect()\n }\n \n #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]\n@@ -72,19 +121,108 @@ enum PairPriority {\n     WithinVoted = 3,\n }\n \n-fn pair_priority(\n+/// Tie-break among unvoted bridge pairs.\n+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]\n+enum BridgeSubPriority {\n+    /// Both endpoints lie in established (multi-node) voted components.\n+    MergeEstablished = 0,\n+    /// One established component member and one never-voted child.\n+    AttachIsolate = 1,\n+    /// Two never-voted children (separate singleton components).\n+    IsolatePair = 2,\n+}\n+\n+/// Tie-break among within-component pairs once the pool is one connected group.\n+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]\n+struct WithinSubPriority {\n+    /// 1 = adjacent ranks (i vs i+1); larger = farther apart in the order.\n+    rank_gap: usize,\n+    /// min rank index of the two — zip from the top (1 vs 2 before 2 vs 3).\n+    zip_index: usize,\n+}\n+\n+const WITHIN_SUB_WORST: WithinSubPriority = WithinSubPriority {\n+    rank_gap: usize::MAX,\n+    zip_index: usize::MAX,\n+};\n+\n+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]\n+struct PairSortKey {\n+    priority: PairPriority,\n+    bridge_sub: BridgeSubPriority,\n+    within_sub: WithinSubPriority,\n+}\n+\n+fn item_in_established(layout: &ComponentLayout, item: &ItemId) -> bool {\n+    layout\n+        .ids\n+        .get(item)\n+        .is_some_and(|id| layout.established.contains(id))\n+}\n+\n+fn bridge_sub_priority(layout: &ComponentLayout, a: &ItemId, b: &ItemId) -> BridgeSubPriority {\n+    let a_est = item_in_established(layout, a);\n+    let b_est = item_in_established(layout, b);\n+    match (a_est, b_est) {\n+        (true, true) => BridgeSubPriority::MergeEstablished,\n+        (true, false) | (false, true) => BridgeSubPriority::AttachIsolate,\n+        (false, false) => BridgeSubPriority::IsolatePair,\n+    }\n+}\n+\n+fn within_sub_priority(\n+    group: &GroupState,\n+    pool: &[ItemId],\n+    layout: &ComponentLayout,\n+    a: &ItemId,\n+    b: &ItemId,\n+) -> WithinSubPriority {\n+    if !pool_fully_connected(layout, pool) {\n+        return WITHIN_SUB_WORST;\n+    }\n+    let order = ranked_pool_order(group, pool);\n+    let (Some(i), Some(j)) = (order.iter().position(|x| x == a), order.iter().position(|x| x == b))\n+    else {\n+        return WITHIN_SUB_WORST;\n+    };\n+    WithinSubPriority {\n+        rank_gap: i.abs_diff(j),\n+        zip_index: i.min(j),\n+    }\n+}\n+\n+fn pair_sort_key(\n     group: &GroupState,\n-    components: &HashMap<ItemId, usize>,\n+    pool: &[ItemId],\n+    layout: &ComponentLayout,\n     a: &ItemId,\n     b: &ItemId,\n-) -> PairPriority {\n+) -> PairSortKey {\n     let voted = pair_is_voted(group, a, b);\n-    let bridge = components.get(a) != components.get(b);\n-    match (bridge, voted) {\n+    let bridge = layout.ids.get(a) != layout.ids.get(b);\n+    let priority = match (bridge, voted) {\n         (true, false) => PairPriority::BridgeUnvoted,\n         (false, false) => PairPriority::WithinUnvoted,\n         (true, true) => PairPriority::BridgeVoted,\n         (false, true) => PairPriority::WithinVoted,\n+    };\n+    let bridge_sub = if priority == PairPriority::BridgeUnvoted {\n+        bridge_sub_priority(layout, a, b)\n+    } else {\n+        BridgeSubPriority::MergeEstablished\n+    };\n+    let within_sub = if matches!(\n+        priority,\n+        PairPriority::WithinUnvoted | PairPriority::WithinVoted\n+    ) {\n+        within_sub_priority(group, pool, layout, a, b)\n+    } else {\n+        WITHIN_SUB_WORST\n+    };\n+    PairSortKey {\n+        priority,\n+        bridge_sub,\n+        within_sub,\n     }\n }\n \n@@ -109,9 +247,12 @@ fn candidate_pairs(pool: &[ItemId], exclude: Option<(&ItemId, &ItemId)>) -> Vec<\n \n /// Pick the next pair to vote on within `pool`.\n ///\n-/// 1. Prefer unvoted **bridge** pairs (connect separate ranking components).\n-/// 2. Then unvoted within-component pairs (refinement).\n-/// 3. Then already-voted pairs (re-compare).\n+/// 1. Prefer unvoted **bridge** pairs (connect separate ranking components),\n+///    with sub-priority: merge established components, attach an isolate to\n+///    established, then compare two isolates.\n+/// 2. Then unvoted within-component pairs; when the pool is one connected group,\n+///    prefer adjacent ranks (1 vs 2, 2 vs 3, …) in order, skipping voted pairs.\n+/// 3. Then already-voted pairs (re-compare), with the same zip ordering.\n pub fn suggest_next_pair_in_pool(\n     group: &GroupState,\n     pool: &[ItemId],\n@@ -121,15 +262,15 @@ pub fn suggest_next_pair_in_pool(\n     if candidates.is_empty() {\n         return None;\n     }\n-    let components = component_ids(group, pool);\n+    let layout = component_layout(group, pool);\n     let best = candidates\n         .iter()\n-        .map(|(a, b)| (pair_priority(group, &components, a, b), (a, b)))\n-        .min_by_key(|(p, _)| *p)?\n+        .map(|(a, b)| (pair_sort_key(group, pool, &layout, a, b), (a, b)))\n+        .min_by_key(|(k, _)| *k)?\n         .0;\n     let best_pairs: Vec<(ItemId, ItemId)> = candidates\n         .into_iter()\n-        .filter(|(a, b)| pair_priority(group, &components, a, b) == best)\n+        .filter(|(a, b)| pair_sort_key(group, pool, &layout, a, b) == best)\n         .collect();\n     best_pairs.choose(&mut rand::thread_rng()).cloned()\n }\n@@ -303,6 +444,38 @@ mod tests {\n         assert!(from_ab && from_cd, \"expected bridge pair, got {:?}\", chosen);\n     }\n \n+    #[test]\n+    fn suggest_prefers_attach_over_isolate_pair_among_many_unranked() {\n+        let parent = ItemId::parse(\"reddit.com/r/rust\").unwrap();\n+        let mut tree = seed_children(\n+            &parent,\n+            &[\n+                \"reddit.com/r/rust/a\",\n+                \"reddit.com/r/rust/b\",\n+                \"reddit.com/r/rust/c\",\n+                \"reddit.com/r/rust/d\",\n+                \"reddit.com/r/rust/e\",\n+            ],\n+        );\n+        let ab =\n+            VoteData::from_recorded(1, \"reddit.com/r/rust/a\", \"reddit.com/r/rust/b\", 2, 1).unwrap();\n+        tree.apply_vote(&parent, ab);\n+        let group = tree.get(&parent).unwrap().local_ranking.clone();\n+        let pool = children_of(&tree, &parent);\n+        let pair = suggest_next_pair_in_pool(&group, &pool, None).unwrap();\n+        let chosen = pair_set(&pair);\n+        let from_ab =\n+            chosen.contains(\"reddit.com/r/rust/a\") || chosen.contains(\"reddit.com/r/rust/b\");\n+        let from_cde = chosen.contains(\"reddit.com/r/rust/c\")\n+            || chosen.contains(\"reddit.com/r/rust/d\")\n+            || chosen.contains(\"reddit.com/r/rust/e\");\n+        assert!(\n+            from_ab && from_cde,\n+            \"expected ranked+unranked attach, got {:?}\",\n+            chosen\n+        );\n+    }\n+\n     #[test]\n     fn suggest_connects_isolate_to_existing_component() {\n         let parent = ItemId::parse(\"reddit.com/r/rust\").unwrap();\n@@ -325,6 +498,65 @@ mod tests {\n         assert!(chosen.contains(\"reddit.com/r/rust/a\") || chosen.contains(\"reddit.com/r/rust/b\"));\n     }\n \n+    #[test]\n+    fn suggest_zips_adjacent_ranks_when_tree_complete() {\n+        let parent = ItemId::parse(\"reddit.com/r/rust\").unwrap();\n+        let mut tree = seed_children(\n+            &parent,\n+            &[\n+                \"reddit.com/r/rust/a\",\n+                \"reddit.com/r/rust/b\",\n+                \"reddit.com/r/rust/c\",\n+            ],\n+        );\n+        // Star at a connects all three; b-c is the only unvoted adjacent pair left.\n+        for (a, b, l, r) in [\n+            (\"reddit.com/r/rust/a\", \"reddit.com/r/rust/b\", 3, 1),\n+            (\"reddit.com/r/rust/a\", \"reddit.com/r/rust/c\", 2, 1),\n+        ] {\n+            let v = VoteData::from_recorded(1, a, b, l, r).unwrap();\n+            tree.apply_vote(&parent, v);\n+        }\n+        let group = tree.get(&parent).unwrap().local_ranking.clone();\n+        let pool = children_of(&tree, &parent);\n+        let pair = suggest_next_pair_in_pool(&group, &pool, None).unwrap();\n+        let chosen = pair_set(&pair);\n+        // a-b and a-c voted; b-c is the only unvoted adjacent pair in rank order.\n+        assert!(chosen.contains(\"reddit.com/r/rust/b\"));\n+        assert!(chosen.contains(\"reddit.com/r/rust/c\"));\n+    }\n+\n+    #[test]\n+    fn suggest_zip_prefers_1v2_before_2v3_when_both_unvoted() {\n+        let parent = ItemId::parse(\"reddit.com/r/rust\").unwrap();\n+        let mut tree = seed_children(\n+            &parent,\n+            &[\n+                \"reddit.com/r/rust/a\",\n+                \"reddit.com/r/rust/b\",\n+                \"reddit.com/r/rust/c\",\n+                \"reddit.com/r/rust/d\",\n+            ],\n+        );\n+        // Hub at c connects all four; leave rank-adjacent a-b and b-c unvoted.\n+        for (a, b, l, r) in [\n+            (\"reddit.com/r/rust/c\", \"reddit.com/r/rust/d\", 3, 1),\n+            (\"reddit.com/r/rust/b\", \"reddit.com/r/rust/c\", 2, 1),\n+            (\"reddit.com/r/rust/a\", \"reddit.com/r/rust/c\", 2, 1),\n+        ] {\n+            let v = VoteData::from_recorded(1, a, b, l, r).unwrap();\n+            tree.apply_vote(&parent, v);\n+        }\n+        let group = tree.get(&parent).unwrap().local_ranking.clone();\n+        let pool = children_of(&tree, &parent);\n+        assert!(pool_fully_connected(&component_layout(&group, &pool), &pool));\n+        let pair = suggest_next_pair_in_pool(&group, &pool, None).unwrap();\n+        let chosen = pair_set(&pair);\n+        // Top adjacent unvoted edge should be a-b (zip index 0), not b-c (index 1).\n+        assert!(chosen.contains(\"reddit.com/r/rust/a\"));\n+        assert!(chosen.contains(\"reddit.com/r/rust/b\"));\n+    }\n+\n     #[test]\n     fn resolve_pair_picks_from_pool() {\n         let parent = ItemId::parse(\"reddit.com/r/rust\").unwrap();\n","role":"user"}],"model":"~anthropic/claude-sonnet-latest"}