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:
[62d18183] room create path

Side A — unified diff (full patch):
diff --git a/cli/GUIDE.sorter b/cli/GUIDE.sorter
index dcb06a46045564f8f6f6acffbda6f88644d453cc..9828cba4d9c17b7cce3de597d8724609b2b2adbe 100644
--- a/cli/GUIDE.sorter
+++ b/cli/GUIDE.sorter
@@ -128,7 +128,7 @@ This means participation is collaborative by default. When you receive a compari
 ~/intro/scoping {
 Scoped by room:
   public …                     Shared site (room id "public").
-  private <ROOM_ID> …          Private room (e.g. abc12xy/my-project from RoomCreate over RPC).
+  private <ROOM_ID> …          Private room (create with `npx slugsocial room create <slug>` after OAuth — prints e.g. abc12xy/my-project).
 
 Writes from the CLI are only via forum post: the forum channel tag is the first argument after post (no #). Humans post through the website; CLI requires --delegate (agent identity).
 
@@ -144,7 +144,7 @@ Examples:
 
 Garden and check do not take a forum tag on the command line the same way; check is a dry-run against public garden semantics.
 
-Global (no room prefix): identity, whoami, feed, search, healthz.
+Global (no room prefix): room, identity, whoami, feed, search, healthz.
 }
 
 ~/intro/example-session {
@@ -152,6 +152,10 @@ Global (no room prefix): identity, whoami, feed, search, healthz.
 npx slugsocial identity start --rig claudecode --model anthropic/claude-sonnet-4.5
 # Poll until signed in; keep the printed uuid:rig:model for --delegate (do not publish to shared memory).
 
+# Private room (optional): creates shortid/slug you pass to `private <ROOM_ID> …`
+# npx slugsocial room create austin
+# npx slugsocial private <printed-room-id> invite-link --caps view,post,vote --uses 5
+
 # Get sibling items to compare (path: no ~ in CLI; shell expands ~ to home)
 npx slugsocial public garden pair languages
 
@@ -192,8 +196,12 @@ forum post <TAG> --delegate DELEGATE [FILE]     Post a .sorter doc (stdin if no
 
 check [FILE]                                    Validate without submitting (public garden dry-run)
 
+invite-link --caps view,post[,…] [--uses N]     Mint shareable /join/… link (private rooms; Manage required)
+audit [--json]                                  List principals + capabilities (private rooms; View or Manage)
+
 Global (no public/private prefix):
 
+room create <slug>                              Create a private room (bearer required); prints ROOM_ID for `private …` (use `public …` for the shared site, not a room)
 identity start --rig <name> --model <provider/model>  New delegate id + OAuth pending session
 identity poll <session>                           Complete OAuth; saves bearer token
 
diff --git a/cli/src/main.rs b/cli/src/main.rs
index 8eda9f485bd1f7392f1e34be27176c21e20354eb..5b1a5845e90bfea9bd9a1e1af5744e97e566b5ae 100644
--- a/cli/src/main.rs
+++ b/cli/src/main.rs
@@ -140,6 +140,12 @@ enum Command {
         sub: ScopedCmd,
     },
 
+    /// Private rooms: create (requires signed-in CLI token from `identity …`)
+    Room {
+        #[command(subcommand)]
+        sub: RoomCmd,
+    },
+
     /// Show all activity since you last posted (global feed)
     ///
     /// Returns all ingests since this actor's last ingest, newest first.
@@ -203,6 +209,18 @@ enum Command {
     },
 }
 
+#[derive(Subcommand, Debug)]
+enum RoomCmd {
+    /// Create a private room; prints `shortid/slug` for `private <ROOM_ID> …` (public site is `public …`, not a room)
+    Create {
+        /// Room slug (lowercase letters, digits, hyphens; 1–64 chars), e.g. `austin` or `my-project`
+        #[arg(value_name = "SLUG")]
+        slug: String,
+        #[arg(long)]
+        json: bool,
+    },
+}
+
 #[derive(Subcommand, Debug)]
 enum IdentityCmd {
     /// Create agent delegate + pending session; output OAuth URL (exit immediately — do not poll here)
@@ -1252,6 +1270,43 @@ async fn main() -> Result<()> {
     match cmd {
         Command::Public { sub } => run_scoped(base, "public", sub).await?,
         Command::Private { room, sub } => run_scoped(base, &room, sub).await?,
+        Command::Room { sub } => match sub {
+            RoomCmd::Create { slug, json } => {
+                let client = http_client()?;
+                let bearer = effective_bearer().ok_or_else(|| {
+                    anyhow!(
+                        "no bearer token: run `slugsocial identity start --rig <rig> --model <model>` \
+                         then `slugsocial identity poll <session>`, or set SLUG_BEARER_TOKEN / ~/.config/slugsocial/token"
+                    )
+                })?;
+                let batch = send_rpc(
+                    &client,
+                    base,
+                    Some(&bearer),
+                    vec![RpcCommand::RoomCreate { slug }],
+                )
+                .await?;
+                match rpc_line_ok(&batch.results[0])? {
+                    RpcResult::RoomCreated { room_id } => {
+                        if json {
+                            println!(
+                                "{}",
+                                serde_json::to_string_pretty(&serde_json::json!({
+                                    "ok": true,
+                                    "room_id": room_id,
+                                }))?
+                            );
+                        } else {
+                            println!("{room_id}");
+                            println!();
+                            println!("Next: npx slugsocial private {room_id} forum post <TAG> --delegate '…' …");
+                            println!("      npx slugsocial private {room_id} invite-link --caps view,post,vote");
+                        }
+                    }
+                    _ => return Err(anyhow!("unexpected RPC result")),
+                }
+            }
+        },
 
         Command::Healthz { json } => {
             let client = http_client()?;
diff --git a/server/src/api/rpc.rs b/server/src/api/rpc.rs
index f6bbc3df71909a2da7403cd46fe4ea6ca130c692..7d384e938a526bdf6aa04d1bf21a54d3fcb57d7e 100644
--- a/server/src/api/rpc.rs
+++ b/server/src/api/rpc.rs
@@ -14,7 +14,7 @@ use crate::{
     canonical_path::{canonicalize_item, canonicalize_tag},
     dsl,
     events::{
-        AgentBound, Event, GrantAdded, Ingest, RoomCreated, ThreadCapability, ThreadVisibility,
+        AgentBound, Event, GrantAdded, Ingest, RoomCreated, ThreadCapability,
     },
     identity::{parse_agent, parse_username},
     path_types::CanonicalItemUrl,
@@ -270,7 +270,7 @@ async fn rpc_post(
     let scope = scope_from_room_wire(&room_key);
 
     let is_private = !matches!(scope, ScopeId::Public);
-    if is_private && !reduced.rooms.contains_key(&room_key) {
+    if is_private && !reduced.rooms.contains(&room_key) {
         drop(reduced);
         return Err(("unknown room".into(), Some(format!("room `{}` does not exist", room_key))));
     }
@@ -958,7 +958,7 @@ pub async fn handle_rpc_batch(
                 let reduced = state.reduced.read().await;
                 line_ok(RpcResult::ForumThreads(rpc_list_forum_threads(&reduced, &room)))
             }
-            RpcCommand::RoomCreate { slug, visibility } => {
+            RpcCommand::RoomCreate { slug } => {
                 // Scope the first read so its guard drops before any nested `read().await` / `write().await`.
                 // A guard from `match verify(..., &*state.reduced.read().await)` would otherwise live for the
                 // whole `match` and deadlock here (tokio::sync::RwLock is not reentrant).
@@ -975,53 +975,42 @@ pub async fn handle_rpc_batch(
                         } else if !slug.chars().all(|c| c.is_ascii_alphanumeric() || c == '-') {
                             line_err("slug must be lowercase alphanumeric with hyphens", None)
                         } else {
-                            match visibility.as_deref().unwrap_or("private") {
-                                "private" | "public" => {
-                                    let vis = if visibility.as_deref() == Some("public") {
-                                        ThreadVisibility::Public
-                                    } else {
-                                        ThreadVisibility::Private
-                                    };
-                                    let short_id = loop {
-                                        let id = gen_short_id();
-                                        if !state.reduced.read().await.rooms.contains_key(&format!("{id}/{slug}")) {
-                                            break id;
-                                        }
-                                    };
-                                    let room_id = format!("{short_id}/{slug}");
-                                    let ts = now_ms();
-                                    let tc_ev = Event::RoomCreated(RoomCreated {
-                                        ts,
-                                        room_id: room_id.clone(),
-                                        slug: slug.clone(),
-                                        owner: principal.clone(),
-                                        visibility: vis,
-                                    });
-                                    let ga_ev = Event::GrantAdded(GrantAdded {
-                                        ts,
-                                        room_id: room_id.clone(),
-                                        username: principal.clone(),
-                                        capabilities: vec![
-                                            ThreadCapability::View,
-                                            ThreadCapability::Post,
-                                            ThreadCapability::Vote,
-                                            ThreadCapability::AddItem,
-                                            ThreadCapability::Manage,
-                                        ],
-                                        granted_by: principal.clone(),
-                                    });
-                                    if let Err(e) = state.event_log.append(&tc_ev).await {
-                                        line_err(format!("{e}"), None)
-                                    } else if let Err(e) = state.event_log.append(&ga_ev).await {
-                                        line_err(format!("{e}"), None)
-                                    } else {
-                                        let mut r = state.reduced.write().await;
-                                        r.apply_event(tc_ev);
-                                        r.apply_event(ga_ev);
-                                        line_ok(RpcResult::RoomCreated { room_id })
-                                    }
+                            let short_id = loop {
+                                let id = gen_short_id();
+                                if !state.reduced.read().await.rooms.contains(&format!("{id}/{slug}")) {
+                                    break id;
                                 }
-                                other => line_err(format!("unknown visibility: {other}"), None),
+                            };
+                            let room_id = format!("{short_id}/{slug}");
+                            let ts = now_ms();
+                            let tc_ev = Event::RoomCreated(RoomCreated {
+                                ts,
+                                room_id: room_id.clone(),
+                                slug: slug.clone(),
+                                owner: principal.clone(),
+                            });
+                            let ga_ev = Event::GrantAdded(GrantAdded {
+                                ts,
+                                room_id: room_id.clone(),
+                                username: principal.clone(),
+                                capabilities: vec![
+                                    ThreadCapability::View,
+                                    ThreadCapability::Post,
+                                    ThreadCapability::Vote,
+                                    ThreadCapability::AddItem,
+                                    ThreadCapability::Manage,
+                                ],
+                                granted_by: principal.clone(),
+                            });
+                            if let Err(e) = state.event_log.append(&tc_ev).await {
+                                line_err(format!("{e}"), None)
+                            } else if let Err(e) = state.event_log.append(&ga_ev).await {
+                                line_err(format!("{e}"), None)
+                            } else {
+                                let mut r = state.reduced.write().await;
+                                r.apply_event(tc_ev);
+                                r.apply_event(ga_ev);
+                                line_ok(RpcResult::RoomCreated { room_id })
                             }
                         }
                     }
@@ -1161,7 +1150,7 @@ pub async fn handle_rpc_batch(
                     Err((_, m)) => line_err(m, None),
                     Ok(principal) => {
                         let reduced = state.reduced.read().await;
-                        if !reduced.rooms.contains_key(&room) {
+                        if !reduced.rooms.contains(&room) {
                             line_err("unknown room", None)
                         } else {
                             let can_audit = reduced.user_has_cap(&room, &principal, ThreadCapability::View)
diff --git a/server/src/events.rs b/server/src/events.rs
index 9e60f2c218f5c871a93e855e415dd984e3a017c5..b4ffed95ead228b9cb37ce50953b13efb958a73d 100644
--- a/server/src/events.rs
+++ b/server/src/events.rs
@@ -1,12 +1,5 @@
 use serde::{Deserialize, Serialize};
 
-#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq)]
-#[serde(rename_all = "snake_case")]
-pub enum ThreadVisibility {
-    Public,
-    Private,
-}
-
 #[derive(Debug, Clone, Copy, Hash, Serialize, Deserialize, PartialEq, Eq)]
 #[serde(rename_all = "snake_case")]
 pub enum ThreadCapability {
@@ -57,13 +50,13 @@ pub struct AgentBound {
     pub username: String,
 }
 
+/// Private space keyed as `shortid/slug`.
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
 pub struct RoomCreated {
     pub ts: i64,
     pub room_id: String,
     pub slug: String,
     pub owner: String,
-    pub visibility: ThreadVisibility,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
diff --git a/server/src/html/search.rs b/server/src/html/search.rs
index 9353cf229fbbd2cfbab5b89ba63ebe192042c91f..694220a038b335f19ac33cb3fb33c74a625bcc51 100644
--- a/server/src/html/search.rs
+++ b/server/src/html/search.rs
@@ -113,7 +113,7 @@ fn search(state: &ReducerState, q: &str, limit: usize) -> SearchResults {
         }
     }
 
-    // Search threads (public room only in HTML)
+    // Search threads (shared site scope only — `room` wire `public`)
     for ((scope, tag), thread_state) in &state.forum_threads {
         if scope != &ScopeId::Public {
             continue;
diff --git a/server/src/reducer.rs b/server/src/reducer.rs
index 5190d0a7ee3d545a786a68fef483322aafdce7f9..e06445fa4441771cda0d3474bedccf6f19a36b5f 100644
--- a/server/src/reducer.rs
+++ b/server/src/reducer.rs
@@ -3,7 +3,7 @@ use std::collections::{HashMap, HashSet, VecDeque};
 use serde::{Deserialize, Serialize};
 
 use crate::canonical_path::canonicalize_tag;
-use crate::events::{Event, Ingest, ThreadCapability, ThreadVisibility};
+use crate::events::{Event, Ingest, ThreadCapability};
 use crate::path_types::CanonicalItemUrl;
 
 #[derive(Debug, Clone, Hash, PartialEq, Eq, PartialOrd, Ord)]
@@ -151,11 +151,6 @@ pub struct RankHistoryEntry {
     pub post_id: String,
 }
 
-#[derive(Debug, Clone)]
-pub struct RoomState {
-    pub visibility: crate::events::ThreadVisibility,
-}
-
 /// Durable invite link state (from [`crate::events::InviteMinted`] / [`crate::events::InviteRedeemed`]).
 #[derive(Debug, Clone)]
 pub struct ActiveInviteState {
@@ -171,7 +166,6 @@ pub enum RoomTimelineKind {
     RoomCreated {
         owner: String,
         slug: String,
-        visibility: ThreadVisibility,
     },
     GrantAdded {
         username: String,
@@ -235,8 +229,8 @@ pub struct ReducerState {
     pub ingests_by_id: HashMap<String, Ingest>,
     /// (scope, thread_tag) → ingest ids, newest first.
     pub ingests_by_scope_thread: HashMap<(ScopeId, String), VecDeque<String>>,
-    /// Private (or public) room registry: room_id → visibility from [`RoomCreated`].
-    pub rooms: HashMap<String, RoomState>,
+    /// Private room ids (`shortid/slug`) known from [`RoomCreated`].
+    pub rooms: HashSet<String>,
     /// (scope, thread_tag) → last activity.
     pub forum_threads: HashMap<(ScopeId, String), ForumThreadState>,
     pub actor_last_post_ts: HashMap<String, i64>,
@@ -403,12 +397,7 @@ impl ReducerState {
                 self.agent_bindings.insert(ab.agent, ab.username);
             }
             Event::RoomCreated(rc) => {
-                self.rooms.insert(
-                    rc.room_id.clone(),
-                    RoomState {
-                        visibility: rc.visibility,
-                    },
-                );
+                self.rooms.insert(rc.room_id.clone());
                 self.room_timeline
                     .entry(rc.room_id.clone())
                     .or_default()
@@ -417,7 +406,6 @@ impl ReducerState {
                         kind: RoomTimelineKind::RoomCreated {
                             owner: rc.owner.clone(),
                             slug: rc.slug.clone(),
-                            visibility: rc.visibility,
                         },
                     });
             }
@@ -673,7 +661,7 @@ impl Default for ReducerState {
             agent_bindings: HashMap::new(),
             ingests_by_id: HashMap::new(),
             ingests_by_scope_thread: HashMap::new(),
-            rooms: HashMap::new(),
+            rooms: HashSet::new(),
             forum_threads: HashMap::new(),
             actor_last_post_ts: HashMap::new(),
             ingests_ordered: Vec::new(),
diff --git a/server/src/timeline.rs b/server/src/timeline.rs
index 251158943ab36d3015268e35f6bdd01c3f42ab3b..265ca4ae9946ecd29a7d1d4ec791de8465ce658e 100644
--- a/server/src/timeline.rs
+++ b/server/src/timeline.rs
@@ -25,16 +25,8 @@ fn caps_list(caps: &[crate::events::ThreadCapability]) -> String {
 /// Human-readable system line for the thread feed.
 pub fn format_room_timeline_entry(e: &RoomTimelineEntry) -> String {
     match &e.kind {
-        RoomTimelineKind::RoomCreated {
-            owner,
-            slug,
-            visibility,
-        } => {
-            let vis = match visibility {
-                crate::events::ThreadVisibility::Public => "public",
-                crate::events::ThreadVisibility::Private => "private",
-            };
-            format!("@{owner} created room #{slug} ({vis})")
+        RoomTimelineKind::RoomCreated { owner, slug } => {
+            format!("@{owner} created room #{slug}")
         }
         RoomTimelineKind::GrantAdded {
             username,
@@ -141,7 +133,7 @@ pub fn merge_thread_rows(
     rows
 }
 
-/// Public forum thread (`room_wire == "public"`): same merge (timeline usually empty).
+/// Shared-site thread view (`room_wire == "public"` on the wire). Same merge as private rooms; private-room timeline is unused here.
 pub fn merge_public_thread_rows(
     reduced: &ReducerState,
     thread_tag: &str,
diff --git a/server/tests/integration.rs b/server/tests/integration.rs
index b930120da09fe7d307f0411b84fb639fb8bd0b15..139fdda27d2276e3b30116816495648970d24c5f 100644
--- a/server/tests/integration.rs
+++ b/server/tests/integration.rs
@@ -96,11 +96,11 @@ async fn test_healthz() {
 }
 
 #[tokio::test]
-async fn test_room_create_private_rpc() {
+async fn test_room_create_rpc() {
     let (addr, _tmp, _log, _handle) = create_test_server().await;
     let client = reqwest::Client::new();
     let batch = serde_json::json!([{
-        "RoomCreate": { "slug": "secret-project", "visibility": "private" }
+        "RoomCreate": { "slug": "secret-project" }
     }]);
     let body = rpc_batch(&client, addr, Some(&test_bearer()), batch).await;
     let line = &body["results"][0];
diff --git a/test/grants.bb b/test/grants.bb
index 4ded5ce92576cdea653cce0ba8a751be4374731a..697e7d91545dd3ee96efde07fc8c3cf90f1a8056 100644
--- a/test/grants.bb
+++ b/test/grants.bb
@@ -82,7 +82,7 @@
            ;; Alice creates a private room.
            _ (println "\nalice creates private room…")
            create (rpc-batch! base-url alice-token
-                              [{"RoomCreate" {"slug" "secret-project" "visibility" "private"}}])
+                              [{"RoomCreate" {"slug" "secret-project"}}])
            _ (assert! (= 200 (:status create)) "room create HTTP 200")
            _ (assert! (rpc-line-ok? (:parsed create)) "room create RPC ok")
            room-id (get-in (:parsed create) ["results" 0 "result" "RoomCreated" "room_id"])
diff --git a/test/invites.bb b/test/invites.bb
index f72b1e630a6856174cdef11eb977e2f81b16e551..ca0fd6c858400671452c4ec59c490d05101dd0e4 100644
--- a/test/invites.bb
+++ b/test/invites.bb
@@ -86,7 +86,7 @@
 
            _ (println "\nalice creates private room…")
            create (rpc-batch! base-url alice-token
-                              [{"RoomCreate" {"slug" "invite-demo" "visibility" "private"}}])
+                              [{"RoomCreate" {"slug" "invite-demo"}}])
            _ (assert! (= 200 (:status create)) "room create HTTP 200")
            _ (assert! (rpc-line-ok? (:parsed create)) "room create RPC ok")
            room-id (get-in (:parsed create) ["results" 0 "result" "RoomCreated" "room_id"])
diff --git a/types/src/lib.rs b/types/src/lib.rs
index 98c66a00fd27803ef6f75b5ac478ff2eb762d771..bb8586f1734f77d95598a9294bdb0de2d55bf715 100644
--- a/types/src/lib.rs
+++ b/types/src/lib.rs
@@ -319,8 +319,6 @@ pub enum RpcCommand {
     },
     RoomCreate {
         slug: String,
-        #[serde(default, skip_serializing_if = "Option::is_none")]
-        visibility: Option<String>,
     },
     RoomGrant {
         room: String,


Side B — contributor: tommy-mor
Side B — commit message:
[88577c56] reconfigure

Side B — unified diff (full patch):
diff --git a/server/src/api/ui_html.rs b/server/src/api/ui_html.rs
index c4ab9d65c7b3cd42a5b4d093ba429993c101e9a8..82b2aa51d21ada1d0d849d3ddfc3a81e4241d861 100644
--- a/server/src/api/ui_html.rs
+++ b/server/src/api/ui_html.rs
@@ -9,7 +9,9 @@ use crate::{
     html::{js_string_literal, ranking_panel, JsBuilder},
     parser::parse_reddit_url,
     parser_render::navigate_panel,
-    state::AppState,
+    path_types::ItemId,
+    reddit::ensure_partial_tree,
+    state::{parse_item_param, AppState},
     ui_action::{parse_html_ui_from_form, HtmlUiAction},
 };
 
@@ -25,6 +27,10 @@ fn ui_js_warn(msg: &str) -> Response {
         .unwrap()
 }
 
+fn parent_from_scope(scope: &str) -> ItemId {
+    parse_item_param(scope)
+}
+
 pub async fn post_ui_html(
     State(state): State<AppState>,
     Form(form): Form<HashMap<String, String>>,
@@ -42,24 +48,36 @@ pub async fn post_ui_html(
             ratio_right,
             scope,
         } => {
+            let parent = parent_from_scope(&scope);
             if let Err(e) = state
-                .record_vote(&scope, &a, &b, ratio_left, ratio_right)
+                .record_vote(&parent, &a, &b, ratio_left, ratio_right)
                 .await
             {
                 return ui_js_warn(&e).into_response();
             }
-            let scope = crate::state::normalize_scope(&scope);
-            let groups = state.groups.read().await;
+            let tree = state.tree.read().await;
             let empty = crate::reducer::GroupState::new();
-            let group = groups.get(&scope).unwrap_or(&empty);
-            let panel = ranking_panel(&scope, group);
+            let group = tree
+                .get(&parent)
+                .map(|n| &n.local_ranking)
+                .unwrap_or(&empty);
+            let panel = ranking_panel(&parent, group);
             JsBuilder::new()
                 .morph_selector("#ranking-panel", panel)
                 .into_response()
         }
         HtmlUiAction::ParseQuery { query } => match parse_reddit_url(&query) {
-            Ok(subreddit) => {
-                let dest = format!("/?sub={subreddit}");
+            Ok(item) => {
+                {
+                    let mut tree = state.tree.write().await;
+                    ensure_partial_tree(&mut tree, &item);
+                }
+                let _ = state.ensure_node(&item).await;
+                let dest = if item.is_root() {
+                    "/".to_string()
+                } else {
+                    format!("/?item={}", item.as_str())
+                };
                 JsBuilder::new()
                     .raw(&format!(
                         "window.location.href={};",
diff --git a/server/src/events.rs b/server/src/events.rs
index a862370fc840ffe02184a11c578e18239cc9474d..ed5be6b13b9d46e838831d6ce0f96f569b401730 100644
--- a/server/src/events.rs
+++ b/server/src/events.rs
@@ -5,8 +5,8 @@ use serde::{Deserialize, Serialize};
 pub enum Event {
     /// Page view recorded (path → counter in views.json).
     ViewRecorded { path: String, ts: i64 },
-    /// Pairwise comparison vote (replayed into the scope's [`crate::reducer::GroupState`] on boot).
-    /// `scope` is the ranking subject (e.g. a subreddit); empty string is the default/global scope.
+    /// Pairwise comparison vote (replayed into the parent node's [`crate::reducer::GroupState`] on boot).
+    /// `scope` is the parent [`crate::path_types::ItemId`] string; empty string is the tree root.
     VoteRecorded {
         ts: i64,
         a: String,
@@ -16,4 +16,6 @@ pub enum Event {
         #[serde(default)]
         scope: String,
     },
+    /// Register a node path in the fractal tree (no external fetch).
+    NodeEnsured { id: String },
 }
diff --git a/server/src/html/mod.rs b/server/src/html/mod.rs
index 9650d333d29c4ac94ceb407aee3ee00399c7f40b..c973cb718ac74b95570dabea76e24459417790b9 100644
--- a/server/src/html/mod.rs
+++ b/server/src/html/mod.rs
@@ -12,9 +12,10 @@ use serde::Deserialize;
 use crate::{
     form_template::template_json_compact,
     parser_render::navigate_panel,
+    path_types::ItemId,
     ranking::{top_bottom, RankedItem},
-    reducer::GroupState,
-    state::{normalize_scope, AppState},
+    reducer::{GroupState, NodeState},
+    state::{parse_item_param, AppState},
     ui_action::UI_RPC_FIELD,
 };
 
@@ -216,6 +217,48 @@ fn layout(title: &str, body: Markup, views: u64, theme: &str, theme_next: &str)
     }
 }
 
+fn item_href(id: &ItemId) -> String {
+    if id.is_root() {
+        "/".to_string()
+    } else {
+        format!("/?item={}", id.as_str())
+    }
+}
+
+fn segment_label(seg: &str) -> &str {
+    seg
+}
+
+/// Generic breadcrumb trail from an [`ItemId`] path.
+pub fn breadcrumb_path(item: &ItemId) -> Markup {
+    html! {
+        nav class="breadcrumbs" aria-label="Breadcrumb" {
+            a href="/" { "Internet" }
+            @for path in item.breadcrumb_paths() {
+                @let seg = path.segments().last().map_or("", |v| *v);
+                span class="separator" { " / " }
+                a href=(item_href(&path)) { (segment_label(seg)) }
+            }
+        }
+    }
+}
+
+fn entity_panel(node: &NodeState) -> Markup {
+    html! {
+        @if let Some(data) = &node.data {
+            section id="entity-panel" class="demo-panel entity-card" {
+                h2 { (data.title) }
+                @if let Some(author) = &data.author {
+                    p class="muted small" { "by " (author) }
+                }
+                @if let Some(body) = &data.body_html {
+                    div class="entity-body" { (maud::PreEscaped(body)) }
+                }
+            }
+        }
+    }
+}
+
 fn rank_list(label: &str, items: &[RankedItem], start_rank: usize) -> Markup {
     html! {
         @if !items.is_empty() {
@@ -224,7 +267,9 @@ fn rank_list(label: &str, items: &[RankedItem], start_rank: usize) -> Markup {
                 @for (i, r) in items.iter().enumerate() {
                     li {
                         span class="rank-num" { (start_rank + i) ". " }
-                        strong { (r.item.as_str()) }
+                        a href=(item_href(&r.item)) {
+                            strong { (display_label(&r.item)) }
+                        }
                         span class="muted" {
                             " — "
                             ({ format!("{:.1}%", r.score * 100.0) })
@@ -236,23 +281,30 @@ fn rank_list(label: &str, items: &[RankedItem], start_rank: usize) -> Markup {
     }
 }
 
-pub fn ranking_panel(scope: &str, group: &GroupState) -> Markup {
+fn display_label(id: &ItemId) -> String {
+    id.segments()
+        .last()
+        .map_or("Internet", |v| *v)
+        .to_string()
+}
+
+pub fn ranking_panel(item: &ItemId, group: &GroupState) -> Markup {
     let total = group.idx_to_item.len();
     let (top, bottom) = top_bottom(group, 8);
     html! {
         section id="ranking-panel" class="demo-panel" {
             h2 {
                 "Ranking"
-                @if !scope.is_empty() {
-                    " — " span class="scope-name" { "r/" (scope) }
+                @if !item.is_root() {
+                    " — " span class="scope-name" { (item.as_str()) }
                 }
             }
             @if total == 0 {
                 p class="muted" {
-                    @if scope.is_empty() {
+                    @if item.is_root() {
                         "No votes yet — compare two items below."
                     } @else {
-                        "No votes yet for r/" (scope) " — compare two items below to start the ranking."
+                        "No votes yet for " (item.as_str()) " — compare two items below to start the ranking."
                     }
                 }
             } @else {
@@ -266,7 +318,8 @@ pub fn ranking_panel(scope: &str, group: &GroupState) -> Markup {
     }
 }
 
-pub fn vote_panel(scope: &str) -> Markup {
+pub fn vote_panel(parent: &ItemId) -> Markup {
+    let parent_str = parent.as_str();
     let rpc = template_json_compact(&serde_json::json!({
         "action": "record_vote",
         "a": {"$form": "item_a"},
@@ -280,16 +333,17 @@ pub fn vote_panel(scope: &str) -> Markup {
         section id="vote-panel" class="demo-panel" {
             h2 { "Compare" }
             p class="muted small" {
-                @if scope.is_empty() {
+                @if parent.is_root() {
                     "Left item wins at 2:1. Votes append to the JSONL log and update rank centrality."
                 } @else {
-                    "Ranking " span class="scope-name" { "r/" (scope) }
+                    "Ranking children of "
+                    span class="scope-name" { (parent_str) }
                     ". Left item wins at 2:1; each vote updates this ranking."
                 }
             }
             form method="post" action="/ui" id="vote-form" {
                 input type="hidden" name=(UI_RPC_FIELD) value=(rpc);
-                input type="hidden" name="scope" value=(scope);
+                input type="hidden" name="scope" value=(parent_str);
                 div class="vote-fields" {
                     label {
                         "Left (wins) "
@@ -329,17 +383,30 @@ pub async fn home(
     let views = state.views.get_views(&path);
     let theme = theme_from_jar(&jar);
     let theme_next = theme_next_from_uri(&uri);
-    let scope = normalize_scope(&query_param(&uri, "sub").unwrap_or_default());
 
-    let groups = state.groups.read().await;
-    let empty = GroupState::new();
-    let group = groups.get(&scope).unwrap_or(&empty);
+    let item_raw = query_param(&uri, "item")
+        .or_else(|| query_param(&uri, "sub").map(|sub| {
+            if sub.is_empty() {
+                String::new()
+            } else {
+                format!("reddit.com/r/{sub}")
+            }
+        }))
+        .unwrap_or_default();
+    let item = parse_item_param(&item_raw);
+
+    let tree = state.tree.read().await;
+    let empty_node = NodeState::default();
+    let node = tree.get(&item).unwrap_or(&empty_node);
+    let group = &node.local_ranking;
 
     let body = html! {
         h1 { "sorter2" }
+        (breadcrumb_path(&item))
         (navigate_panel("", None))
-        (vote_panel(&scope))
-        (ranking_panel(&scope, group))
+        (entity_panel(node))
+        (vote_panel(&item))
+        (ranking_panel(&item, group))
     };
     layout("sorter2", body, views, theme, &theme_next)
 }
diff --git a/server/src/journal.rs b/server/src/journal.rs
new file mode 100644
index 0000000000000000000000000000000000000000..b02ca025683621470ffdf8cd85cf9b85c56d024d
--- /dev/null
+++ b/server/src/journal.rs
@@ -0,0 +1,89 @@
+use std::sync::Arc;
+
+use tokio::sync::{mpsc, oneshot, RwLock};
+
+use crate::{
+    event_log::EventLog,
+    events::Event,
+    path_types::ItemId,
+    reducer::{GlobalTree, VoteData},
+};
+
+pub struct JournalCommand {
+    pub parent: ItemId,
+    pub vote: VoteData,
+    pub event: Event,
+    pub reply: oneshot::Sender<Result<(), String>>,
+}
+
+#[derive(Clone)]
+pub struct JournalClient {
+    tx: mpsc::Sender<JournalCommand>,
+}
+
+impl JournalClient {
+    pub fn spawn(tree: Arc<RwLock<GlobalTree>>, event_log: Arc<EventLog>) -> Self {
+        let (tx, rx) = mpsc::channel(64);
+        tokio::spawn(journal_worker(rx, tree, event_log));
+        Self { tx }
+    }
+
+    pub async fn record_vote(
+        &self,
+        parent: ItemId,
+        vote: VoteData,
+        event: Event,
+    ) -> Result<(), String> {
+        let (reply, rx) = oneshot::channel();
+        self.tx
+            .send(JournalCommand {
+                parent,
+                vote,
+                event,
+                reply,
+            })
+            .await
+            .map_err(|_| "journal worker stopped".to_string())?;
+        rx.await
+            .map_err(|_| "journal worker stopped".to_string())?
+    }
+}
+
+async fn journal_worker(
+    mut rx: mpsc::Receiver<JournalCommand>,
+    tree: Arc<RwLock<GlobalTree>>,
+    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 mut w = tree.write().await;
+            for cmd in &batch {
+                w.apply_vote(&cmd.parent, cmd.vote.clone());
+            }
+        }
+
+        for cmd in batch {
+            let _ = cmd.reply.send(Ok(()));
+        }
+    }
+}
diff --git a/server/src/lib.rs b/server/src/lib.rs
index de8bca48cbf689cad22337883e7791966e7c4919..14e7cfbc38feb5d07aff859b64bce6e2ec45cf91 100644
--- a/server/src/lib.rs
+++ b/server/src/lib.rs
@@ -7,8 +7,9 @@ pub mod parser;
 pub mod parser_render;
 pub mod path_types;
 pub mod ranking;
+pub mod reddit;
 pub mod reducer;
-pub mod settlement;
+pub mod journal;
 pub mod state;
 pub mod ui_action;
 pub mod views;
diff --git a/server/src/parser.rs b/server/src/parser.rs
index 50571a59f0d3ece1e2538f88e00ef46ec40ea545..51aa0e0f982546aab68bd5e1ca0cb726e88b3f50 100644
--- a/server/src/parser.rs
+++ b/server/src/parser.rs
@@ -1,47 +1,18 @@
-//! Extract a subreddit name from a pasted Reddit URL or path.
+//! Extract a canonical [`crate::path_types::ItemId`] from a pasted Reddit URL or path.
 
-pub fn parse_reddit_url(query: &str) -> Result<String, String> {
+use crate::path_types::ItemId;
+
+pub fn parse_reddit_url(query: &str) -> Result<ItemId, String> {
     let q = query.trim();
     if q.is_empty() {
         return Err("Paste a Reddit URL or r/subreddit path".into());
     }
 
-    if let Some(sub) = subreddit_after_prefix(q, "r/") {
-        return Ok(sub);
-    }
-
-    if let Some(sub) = subreddit_from_path_segment(q, "/r/") {
-        return Ok(sub);
+    if let Some(id) = ItemId::from_url(q) {
+        return Ok(id);
     }
 
-    Err("Could not find a subreddit in that URL".into())
-}
-
-fn subreddit_after_prefix(text: &str, prefix: &str) -> Option<String> {
-    let rest = text.strip_prefix(prefix)?;
-    let sub = rest.split(['/', '?', '#']).next()?.trim();
-    valid_subreddit(sub)
-}
-
-fn subreddit_from_path_segment(text: &str, needle: &str) -> Option<String> {
-    let idx = text.find(needle)?;
-    let rest = &text[idx + needle.len()..];
-    let sub = rest.split(['/', '?', '#']).next()?.trim();
-    valid_subreddit(sub)
-}
-
-fn valid_subreddit(name: &str) -> Option<String> {
-    if name.is_empty() {
-        return None;
-    }
-    if name
-        .chars()
-        .all(|c| c.is_ascii_alphanumeric() || c == '_')
-    {
-        Some(name.to_ascii_lowercase())
-    } else {
-        None
-    }
+    Err("Could not parse that Reddit URL".into())
 }
 
 #[cfg(test)]
@@ -50,34 +21,37 @@ mod tests {
 
     #[test]
     fn parses_short_path() {
-        assert_eq!(parse_reddit_url("r/rust").unwrap(), "rust");
-    }
-
-    #[test]
-    fn parses_path_with_trailing_slash() {
-        assert_eq!(parse_reddit_url("r/rust/").unwrap(), "rust");
+        assert_eq!(
+            parse_reddit_url("r/rust").unwrap().as_str(),
+            "reddit.com/r/rust"
+        );
     }
 
     #[test]
     fn parses_full_url() {
         assert_eq!(
-            parse_reddit_url("https://www.reddit.com/r/programming/hot").unwrap(),
-            "programming"
+            parse_reddit_url("https://www.reddit.com/r/programming/hot")
+                .unwrap()
+                .as_str(),
+            "reddit.com/r/programming"
         );
     }
 
     #[test]
-    fn parses_url_without_scheme() {
+    fn parses_post_url() {
+        let id = parse_reddit_url(
+            "https://old.reddit.com/r/AmItheAsshole/comments/1trnvdl/aita_for_cancelling/",
+        )
+        .unwrap();
         assert_eq!(
-            parse_reddit_url("reddit.com/r/AskReddit").unwrap(),
-            "askreddit"
+            id.as_str(),
+            "reddit.com/r/amitheasshole/comments/1trnvdl"
         );
     }
 
     #[test]
     fn rejects_empty() {
         assert!(parse_reddit_url("").is_err());
-        assert!(parse_reddit_url("   ").is_err());
     }
 
     #[test]
diff --git a/server/src/parser_render.rs b/server/src/parser_render.rs
index f2341afe21476b689a536137798d97277211a962..acf2e7403f4238291677ef0c79d5766302ea78cf 100644
--- a/server/src/parser_render.rs
+++ b/server/src/parser_render.rs
@@ -21,7 +21,7 @@ pub fn navigate_panel(query: &str, error: Option<&str>) -> Markup {
             p class="muted small" {
                 "Paste a Reddit URL or "
                 code { "r/subreddit" }
-                " path, then click Go to rank that subreddit."
+                " path. Breadcrumb links drill down the tree; rankings apply to each node's children."
             }
             form method="post" action="/ui" id="parser-form" {
                 textarea
diff --git a/server/src/path_types.rs b/server/src/path_types.rs
index 1cdc96a25b1954f11aaf955203e2b9907b578366..b5c41444f7bcd4d8d289ed3af464bc3f14d0df99 100644
--- a/server/src/path_types.rs
+++ b/server/src/path_types.rs
@@ -1,11 +1,13 @@
 use serde::{Deserialize, Serialize};
 use std::fmt;
 
-/// Stable item key for votes and rankings (opaque string for now).
-#[derive(Debug, Clone, Hash, PartialEq, Eq, PartialOrd, Ord, Serialize, Deserialize)]
+/// Canonical hierarchical identity for any URL/path in the fractal tree.
+#[derive(Debug, Clone, Hash, PartialEq, Eq, PartialOrd, Ord, Serialize, Deserialize, Default)]
 pub struct ItemId(String);
 
 impl ItemId {
+    /// Parse an already-canonical path (no URL normalization). Empty string is invalid here;
+    /// use [`Self::root`] for the tree root.
     pub fn parse(s: &str) -> Option<Self> {
         let t = s.trim();
         if t.is_empty() {
@@ -14,13 +16,170 @@ impl ItemId {
         Some(Self(t.to_string()))
     }
 
+    /// Build an opaque item key (legacy demo votes, non-URL items).
     pub fn opaque(s: impl Into<String>) -> Self {
         Self(s.into())
     }
 
+    /// Root of the internet tree (empty path).
+    pub fn root() -> Self {
+        Self(String::new())
+    }
+
+    pub fn is_root(&self) -> bool {
+        self.0.is_empty()
+    }
+
     pub fn as_str(&self) -> &str {
         &self.0
     }
+
+    /// Creates a canonical ID from a raw URL or path. Normalizes domains and
+    /// trims tracking query params.
+    pub fn from_url(raw_url: &str) -> Option<Self> {
+        Self::canonicalize(raw_url).map(Self)
+    }
+
+    /// Map legacy scope keys (`""`, `"rust"`) to fractal parent nodes.
+    pub fn from_legacy_scope(raw: &str) -> Self {
+        let s = raw.trim();
+        if s.is_empty() {
+            return Self::root();
+        }
+        Self(format!("reddit.com/r/{s}"))
+    }
+
+    /// Extract the parent, e.g. `reddit.com/r/aww/comments/1trnvdl` →
+    /// `reddit.com/r/aww`.
+    pub fn parent(&self) -> Option<Self> {
+        if self.0.is_empty() {
+            return None;
+        }
+
+        let parts: Vec<&str> = self.0.trim_end_matches('/').split('/').collect();
+        if parts.len() <= 1 {
+            return None;
+        }
+
+        if self.0.contains("/comments/") {
+            return Some(Self(parts[..parts.len().saturating_sub(2)].join("/")));
+        }
+
+        Some(Self(parts[..parts.len() - 1].join("/")))
+    }
+
+    pub fn segments(&self) -> Vec<&str> {
+        self.0.split('/').filter(|s| !s.is_empty()).collect()
+    }
+
+    /// Cumulative paths for breadcrumb rendering, e.g.
+    /// `reddit.com/r/movies` → `["reddit.com", "reddit.com/r", "reddit.com/r/movies"]`.
+    pub fn breadcrumb_paths(&self) -> Vec<ItemId> {
+        let segs = self.segments();
+        let mut paths = Vec::with_capacity(segs.len());
+        let mut current = String::new();
+        for seg in segs {
+            if current.is_empty() {
+                current = seg.to_string();
+            } else {
+                current.push('/');
+                current.push_str(seg);
+            }
+            paths.push(ItemId(current.clone()));
+        }
+        paths
+    }
+
+    fn canonicalize(raw: &str) -> Option<String> {
+        let s = raw.trim();
+        if s.is_empty() {
+            return None;
+        }
+
+        let owned = if let Some(rest) = s.strip_prefix("r/") {
+            format!("reddit.com/r/{rest}")
+        } else if let Some(rest) = s.strip_prefix("/r/") {
+            format!("reddit.com/r/{rest}")
+        } else {
+            s.to_string()
+        };
+
+        let (host_path, _query) = split_query(&owned);
+        let host_path = host_path.trim_end_matches('/');
+
+        let path = if host_path.contains("://") {
+            parse_url_host_path(host_path)?
+        } else if host_path.starts_with("reddit.com") || host_path.starts_with("www.reddit.com") {
+            normalize_reddit_host_path(host_path)
+        } else if host_path.contains('/') {
+            host_path.to_string()
+        } else {
+            return None;
+        };
+
+        Some(normalize_reddit_path(&path))
+    }
+}
+
+fn split_query(s: &str) -> (&str, Option<&str>) {
+    if let Some((path, q)) = s.split_once('?') {
+        (path, Some(q))
+    } else {
+        (s, None)
+    }
+}
+
+fn parse_url_host_path(url: &str) -> Option<String> {
+    let rest = url
+        .strip_prefix("https://")
+        .or_else(|| url.strip_prefix("http://"))
+        .unwrap_or(url);
+    let (host, path) = rest.split_once('/').unwrap_or((rest, ""));
+    let host = normalize_host(host);
+    if path.is_empty() {
+        Some(host)
+    } else {
+        Some(format!("{host}/{path}"))
+    }
+}
+
+fn normalize_host(host: &str) -> String {
+    let h = host
+        .strip_prefix("www.")
+        .unwrap_or(host)
+        .to_ascii_lowercase();
+    if h == "old.reddit.com" || h == "new.reddit.com" || h == "reddit.com" {
+        "reddit.com".to_string()
+    } else {
+        h
+    }
+}
+
+fn normalize_reddit_host_path(s: &str) -> String {
+    let (host, path) = s.split_once('/').unwrap_or((s, ""));
+    let host = normalize_host(host);
+    if path.is_empty() {
+        host
+    } else {
+        format!("{host}/{path}")
+    }
+}
+
+/// Lowercase subreddit segment, drop listing suffixes, drop title slug after post id.
+fn normalize_reddit_path(path: &str) -> String {
+    let mut parts: Vec<String> = path.split('/').map(str::to_string).collect();
+    if parts.len() >= 3 && parts[1] == "r" {
+        parts[2] = parts[2].to_ascii_lowercase();
+    }
+    if let Some(i) = parts.iter().position(|p| p == "comments") {
+        if parts.len() > i + 2 {
+            parts.truncate(i + 2);
+        }
+    } else if parts.len() > 3 && parts.get(1).map(|s| s.as_str()) == Some("r") {
+        // reddit.com/r/{sub}/hot → reddit.com/r/{sub}
+        parts.truncate(3);
+    }
+    parts.join("/")
 }
 
 impl fmt::Display for ItemId {
@@ -28,3 +187,69 @@ impl fmt::Display for ItemId {
         f.write_str(&self.0)
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn from_url_normalizes_reddit_domains() {
+        let id = ItemId::from_url(
+            "https://old.reddit.com/r/AmItheAsshole/comments/1trnvdl/aita_for_cancelling/",
+        )
+        .unwrap();
+        assert_eq!(
+            id.as_str(),
+            "reddit.com/r/amitheasshole/comments/1trnvdl"
+        );
+    }
+
+    #[test]
+    fn from_url_strips_query() {
+        let id = ItemId::from_url("https://www.reddit.com/r/rust/?sort=top").unwrap();
+        assert_eq!(id.as_str(), "reddit.com/r/rust");
+    }
+
+    #[test]
+    fn from_url_short_path() {
+        assert_eq!(
+            ItemId::from_url("r/rust").unwrap().as_str(),
+            "reddit.com/r/rust"
+        );
+    }
+
+    #[test]
+    fn parent_of_post_is_subreddit() {
+        let id = ItemId::parse("reddit.com/r/aww/comments/1trnvdl").unwrap();
+        assert_eq!(
+            id.parent().unwrap().as_str(),
+            "reddit.com/r/aww"
+        );
+    }
+
+    #[test]
+    fn parent_of_subreddit_is_r_segment() {
+        let id = ItemId::parse("reddit.com/r/movies").unwrap();
+        assert_eq!(id.parent().unwrap().as_str(), "reddit.com/r");
+    }
+
+    #[test]
+    fn breadcrumb_paths() {
+        let id = ItemId::parse("reddit.com/r/movies").unwrap();
+        let crumbs = id.breadcrumb_paths();
+        let paths: Vec<_> = crumbs.iter().map(|p| p.as_str()).collect();
+        assert_eq!(
+            paths,
+            vec!["reddit.com", "reddit.com/r", "reddit.com/r/movies"]
+        );
+    }
+
+    #[test]
+    fn legacy_scope_maps_to_reddit_sub() {
+        assert_eq!(
+            ItemId::from_legacy_scope("rust").as_str(),
+            "reddit.com/r/rust"
+        );
+        assert!(ItemId::from_legacy_scope("").is_root());
+    }
+}
diff --git a/server/src/reddit.rs b/server/src/reddit.rs
new file mode 100644
index 0000000000000000000000000000000000000000..d203dca09245daf869b3aa942898447700ae69fb
--- /dev/null
+++ b/server/src/reddit.rs
@@ -0,0 +1,21 @@
+//! Reddit API import (async, decoupled from UI request path).
+
+use crate::{
+    path_types::ItemId,
+    reducer::{EntityData, GlobalTree},
+};
+
+/// Bootstrap blank nodes along a URL path so breadcrumbs and voting work before fetch.
+pub fn ensure_partial_tree(tree: &mut GlobalTree, id: &ItemId) {
+    tree.ensure_path(id);
+}
+
+/// Placeholder for Reddit JSON import. Returns entity data when implemented.
+pub async fn fetch_reddit_entity(_id: &ItemId) -> Option<EntityData> {
+    None
+}
+
+/// Apply fetched entity data to a node (called from async worker).
+pub fn apply_entity(tree: &mut GlobalTree, id: &ItemId, data: EntityData) {
+    tree.set_entity_data(id, data);
+}
diff --git a/server/src/reducer.rs b/server/src/reducer.rs
index 8d28353e1f2a67e71b7d17a2041a0988150f3245..077f700bf00ddefe18ffd004bb5288bdc7c4adaf 100644
--- a/server/src/reducer.rs
+++ b/server/src/reducer.rs
@@ -115,6 +115,96 @@ impl GroupState {
     }
 }
 
+/// Structured data imported from Reddit or elsewhere.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct EntityData {
+    pub title: String,
+    pub author: Option<String>,
+    pub body_html: Option<String>,
+    pub thumb_url: Option<String>,
+}
+
+/// One node in the fractal tree: entity + ranked children.
+#[derive(Debug, Clone, Default)]
+pub struct NodeState {
+    pub id: ItemId,
+    pub data: Option<EntityData>,
+    pub children: HashSet<ItemId>,
+    pub local_ranking: GroupState,
+}
+
+impl NodeState {
+    fn new(id: ItemId) -> Self {
+        Self {
+            id,
+            ..Default::default()
+        }
+    }
+}
+
+/// Global fractal graph: every URL is both an item and a ranking scope for its children.
+#[derive(Default)]
+pub struct GlobalTree {
+    pub nodes: HashMap<ItemId, NodeState>,
+}
+
+impl GlobalTree {
+    pub fn new() -> Self {
+        let mut tree = Self::default();
+        tree.ensure_node(&ItemId::root());
+        tree
+    }
+
+    pub fn ensure_node(&mut self, id: &ItemId) -> &mut NodeState {
+        if !self.nodes.contains_key(id) {
+            self.nodes.insert(id.clone(), NodeState::new(id.clone()));
+        }
+        self.nodes.get_mut(id).expect("node just inserted")
+    }
+
+    /// Register a node and wire parent→child links along the canonical path.
+    pub fn ensure_path(&mut self, id: &ItemId) {
+        if id.is_root() {
+            self.ensure_node(id);
+            return;
+        }
+        self.ensure_node(&ItemId::root());
+        for path in id.breadcrumb_paths() {
+            self.ensure_node(&path);
+            if let Some(parent) = path.parent() {
+                self.ensure_node(&parent);
+                if let Some(p) = self.nodes.get_mut(&parent) {
+                    p.children.insert(path.clone());
+                }
+            } else if let Some(r) = self.nodes.get_mut(&ItemId::root()) {
+                r.children.insert(path.clone());
+            }
+        }
+    }
+
+    pub fn get(&self, id: &ItemId) -> Option<&NodeState> {
+        self.nodes.get(id)
+    }
+
+    pub fn apply_vote(&mut self, parent: &ItemId, vote: VoteData) {
+        self.ensure_path(parent);
+        self.ensure_path(&vote.a);
+        self.ensure_path(&vote.b);
+        if let Some(node) = self.nodes.get_mut(parent) {
+            node.children.insert(vote.a.clone());
+            node.children.insert(vote.b.clone());
+            node.local_ranking.apply_vote(vote);
+        }
+    }
+
+    pub fn set_entity_data(&mut self, id: &ItemId, data: EntityData) {
+        self.ensure_path(id);
+        if let Some(node) = self.nodes.get_mut(id) {
+            node.data = Some(data);
+        }
+    }
+}
+
 #[cfg(test)]
 mod from_recorded_tests {
     use super::*;
@@ -125,7 +215,20 @@ mod from_recorded_tests {
     }
 
     #[test]
-    fn rejects_empty() {
+    fn rejects_empty_pair() {
         assert!(VoteData::from_recorded(1, "", "b", 2, 1).is_none());
     }
+
+    #[test]
+    fn ensure_path_wires_children() {
+        let mut tree = GlobalTree::new();
+        let id = ItemId::parse("reddit.com/r/rust").unwrap();
+        tree.ensure_path(&id);
+        let root = tree.get(&ItemId::root()).unwrap();
+        assert!(root.children.contains(&ItemId::parse("reddit.com").unwrap()));
+        let reddit = tree.get(&ItemId::parse("reddit.com").unwrap()).unwrap();
+        assert!(reddit.children.contains(&ItemId::parse("reddit.com/r").unwrap()));
+        let sub = tree.get(&id).unwrap();
+        assert_eq!(sub.id, id);
+    }
 }
diff --git a/server/src/settlement.rs b/server/src/settlement.rs
deleted file mode 100644
index 7a44495512b7f788239b8aeefbbd0a83656eeac6..0000000000000000000000000000000000000000
--- a/server/src/settlement.rs
+++ /dev/null
@@ -1,94 +0,0 @@
-use std::collections::HashMap;
-use std::sync::Arc;
-
-use tokio::sync::{mpsc, oneshot, RwLock};
-
-use crate::{
-    event_log::EventLog,
-    events::Event,
-    reducer::{GroupState, VoteData},
-};
-
-/// Per-scope ranking state, keyed by scope (e.g. subreddit; "" is the default scope).
-pub type GroupMap = HashMap<String, GroupState>;
-
-pub struct SettlementCommand {
-    pub scope: String,
-    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(groups: Arc<RwLock<GroupMap>>, event_log: Arc<EventLog>) -> Self {
-        let (tx, rx) = mpsc::channel(64);
-        tokio::spawn(settlement_worker(rx, groups, event_log));
-        Self { tx }
-    }
-
-    pub async fn record_vote(
-        &self,
-        scope: String,
-        vote: VoteData,
-        event: Event,
-    ) -> Result<(), String> {
-        let (reply, rx) = oneshot::channel();
-        self.tx
-            .send(SettlementCommand {
-                scope,
-                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>,
-    groups: Arc<RwLock<GroupMap>>,
-    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 mut w = groups.write().await;
-            for cmd in &batch {
-                w.entry(cmd.scope.clone())
-                    .or_default()
-                    .apply_vote(cmd.vote.clone());
-            }
-        }
-
-        for cmd in batch {
-            let _ = cmd.reply.send(Ok(()));
-        }
-    }
-}
diff --git a/server/src/state.rs b/server/src/state.rs
index 2d9e5226057f8615897aac48bce947643a230fb4..cc1722f5a5bf4d415f2327ea585c488a15a75592 100644
--- a/server/src/state.rs
+++ b/server/src/state.rs
@@ -1,4 +1,3 @@
-use std::collections::HashMap;
 use std::sync::Arc;
 
 use tokio::sync::RwLock;
@@ -6,14 +5,22 @@ use tokio::sync::RwLock;
 use crate::{
     event_log::EventLog,
     events::Event,
-    reducer::VoteData,
-    settlement::{GroupMap, SettlementClient},
+    path_types::ItemId,
+    reducer::{GlobalTree, VoteData},
+    journal::JournalClient,
     views::ViewStore,
 };
 
-/// Normalize a raw ranking subject into a scope key: strip an optional `r/`
-/// prefix, keep only `[a-z0-9_]`, lowercase, and cap the length. Empty string
-/// is the default/global scope.
+/// Parse `?item=` query value into a canonical node id.
+pub fn parse_item_param(raw: &str) -> ItemId {
+    let s = raw.trim();
+    if s.is_empty() {
+        return ItemId::root();
+    }
+    ItemId::from_url(s).or_else(|| ItemId::parse(s)).unwrap_or_else(|| ItemId::opaque(s))
+}
+
+/// Legacy: normalize raw ranking subject into a scope key for old event replay.
 pub fn normalize_scope(raw: &str) -> String {
     let s = raw.trim();
     let s = s
@@ -27,6 +34,14 @@ pub fn normalize_scope(raw: &str) -> String {
         .collect()
 }
 
+fn parent_from_event_scope(scope: &str) -> ItemId {
+    if scope.contains('/') {
+        ItemId::parse(scope).unwrap_or_else(|| ItemId::from_legacy_scope(scope))
+    } else {
+        ItemId::from_legacy_scope(scope)
+    }
+}
+
 #[derive(Clone)]
 pub struct AppConfig {
     pub data_dir: String,
@@ -56,8 +71,8 @@ pub struct AppState {
     pub cfg: Arc<AppConfig>,
     pub event_log: Arc<EventLog>,
     pub views: ViewStore,
-    pub groups: Arc<RwLock<GroupMap>>,
-    settlement: SettlementClient,
+    pub tree: Arc<RwLock<GlobalTree>>,
+    journal: JournalClient,
 }
 
 impl AppState {
@@ -66,7 +81,7 @@ impl AppState {
         let views_path = format!("{}/views.json", cfg.data_dir);
         let views = ViewStore::new(&views_path);
 
-        let mut groups: GroupMap = HashMap::new();
+        let mut tree = GlobalTree::new();
         if let Ok((events, _)) = event_log.load_all().await {
             for ev in events {
                 match ev {
@@ -81,29 +96,45 @@ impl AppState {
                         if let Some(vote) =
                             VoteData::from_recorded(ts, &a, &b, ratio_left, ratio_right)
                         {
-                            groups.entry(scope).or_default().apply_vote(vote);
+                            let parent = parent_from_event_scope(&scope);
+                            tree.apply_vote(&parent, vote);
                         }
                     }
                     Event::ViewRecorded { .. } => {}
+                    Event::NodeEnsured { id } => {
+                        if let Some(parsed) = ItemId::parse(&id).or_else(|| ItemId::from_url(&id)) {
+                            tree.ensure_path(&parsed);
+                        }
+                    }
                 }
             }
         }
 
-        let groups = Arc::new(RwLock::new(groups));
-        let settlement = SettlementClient::spawn(groups.clone(), event_log.clone());
+        let tree = Arc::new(RwLock::new(tree));
+        let journal = JournalClient::spawn(tree.clone(), event_log.clone());
 
         Self {
             cfg: Arc::new(cfg),
             event_log,
             views,
-            groups,
-            settlement,
+            tree,
+            journal,
         }
     }
 
+    pub async fn ensure_node(&self, id: &ItemId) -> Result<(), String> {
+        let event = Event::NodeEnsured {
+            id: id.as_str().to_string(),
+        };
+        self.event_log.append(&event).await.map_err(|e| e.to_string())?;
+        let mut w = self.tree.write().await;
+        w.ensure_path(id);
+        Ok(())
+    }
+
     pub async fn record_vote(
         &self,
-        scope: &str,
+        parent: &ItemId,
         a: &str,
         b: &str,
         ratio_left: i32,
@@ -113,23 +144,24 @@ 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 scope = normalize_scope(scope);
         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,
-            scope: scope.clone(),
+            scope: parent.as_str().to_string(),
         };
 
-        self.settlement.record_vote(scope, vote, event).await
+        self.journal
+            .record_vote(parent.clone(), vote, event)
+            .await
     }
 }
 
 #[cfg(test)]
 mod tests {
-    use super::normalize_scope;
+    use super::{normalize_scope, parse_item_param};
 
     #[test]
     fn normalize_scope_strips_prefix_and_lowercases() {
@@ -138,4 +170,15 @@ mod tests {
         assert_eq!(normalize_scope("r/web_dev!!"), "web_dev");
         assert_eq!(normalize_scope(""), "");
     }
+
+    #[test]
+    fn parse_item_param_from_url() {
+        let id = parse_item_param("https://reddit.com/r/rust");
+        assert_eq!(id.as_str(), "reddit.com/r/rust");
+    }
+
+    #[test]
+    fn parse_item_param_empty_is_root() {
+        assert!(parse_item_param("").is_root());
+    }
 }
diff --git a/server/src/ui_action.rs b/server/src/ui_action.rs
index 0e030b3448b8e45acbe49d2de47ea26372445c54..d798874d1d94c0dfee59ec1ff703f9ee6ef432c0 100644
--- a/server/src/ui_action.rs
+++ b/server/src/ui_action.rs
@@ -18,7 +18,7 @@ pub enum HtmlUiAction {
         b: String,
         ratio_left: i32,
         ratio_right: i32,
-        /// Ranking subject (e.g. a subreddit). Empty string = default/global scope.
+        /// Parent node [`ItemId`] string; empty = tree root.
         #[serde(default)]
         scope: String,
     },
diff --git a/server/static/theme_default.css b/server/static/theme_default.css
index 6ad0ac712bbc840bedee60f613794de9385fbbd1..1bf8ac7a25207336c019f93cd4119bd0e06229f0 100644
--- a/server/static/theme_default.css
+++ b/server/static/theme_default.css
@@ -137,6 +137,38 @@ code {
   margin-top: 0.5rem;
 }
 
+.breadcrumbs {
+  font-size: 0.875rem;
+  margin-bottom: 1rem;
+  color: var(--muted);
+}
+
+.breadcrumbs a {
+  color: var(--accent);
+  text-decoration: none;
+}
+
+.breadcrumbs a:hover {
+  text-decoration: underline;
+}
+
+.breadcrumbs .separator {
+  color: var(--muted);
+}
+
+.rank-list a {
+  color: var(--accent);
+  text-decoration: none;
+}
+
+.rank-list a:hover {
+  text-decoration: underline;
+}
+
+.entity-card h2 {
+  margin-top: 0;
+}
+
 .scope-name {
   color: var(--accent);
   font-weight: 600;
diff --git a/server/tests/integration_ui.rs b/server/tests/integration_ui.rs
index afeeee24e32f2d7f1d852ca96ac799fac8bce665..f7ac9c26bf9f9277ad5f5708603224c095165fb8 100644
--- a/server/tests/integration_ui.rs
+++ b/server/tests/integration_ui.rs
@@ -2,7 +2,7 @@ use std::collections::HashMap;
 use std::net::SocketAddr;
 
 use axum::Router;
-use sorter2_server::{create_app, create_app_state, state::AppConfig, ui_action::UI_RPC_FIELD};
+use sorter2_server::{create_app, create_app_state, path_types::ItemId, state::AppConfig, ui_action::UI_RPC_FIELD};
 use tempfile::TempDir;
 use tokio::net::TcpListener;
 
@@ -63,9 +63,9 @@ async fn post_ui_record_vote_morphs_ranking_and_persists() {
         port: 0,
     };
     let state = create_app_state(cfg).await;
-    let groups = state.groups.read().await;
-    let group = groups.get("").expect("default scope group after replay");
-    let ranked = sorter2_server::ranking::ranked_items(group);
+    let tree = state.tree.read().await;
+    let root = tree.get(&ItemId::root()).expect("root node after replay");
+    let ranked = sorter2_server::ranking::ranked_items(&root.local_ranking);
     assert_eq!(ranked.len(), 2);
     assert_eq!(ranked[0].item.as_str(), "alpha");
 }
@@ -93,5 +93,5 @@ async fn post_ui_parse_query_redirects_to_subreddit() {
         .unwrap();
 
     assert!(body.contains("window.location.href"));
-    assert!(body.contains("/?sub=rust"));
+    assert!(body.contains("/?item=reddit.com/r/rust"));
 }