{"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[5350388a] Add pool-scoped voting: /vote?pool=<parent> picks pairs from children.\n\n- /vote now accepts an optional `pool` param (parent item path). When\n  provided without left/right, it picks the first unvoted pair from the\n  pool's children. When provided alongside left/right, it constrains\n  \"next pair\" navigation to siblings within the pool.\n- \"vote on children\" button appears on item pages with ≥2 children,\n  linking to /vote?pool=<item>.\n- Pool is threaded through VoteComparePost → success JS so in-page\n  morph after voting keeps the pool context for next-pair navigation.\n\nCo-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>\n\nSide A — unified diff (full patch):\ndiff --git a/server/src/api/ui_html.rs b/server/src/api/ui_html.rs\nindex 5faa642451d69555cb391974beb0ad22c9355c8c..b79efdb4d52bd445a67f38cbfd61d3507d2b3014 100644\n--- a/server/src/api/ui_html.rs\n+++ b/server/src/api/ui_html.rs\n@@ -193,6 +193,7 @@ async fn dispatch_ui_action(\n             ratio_right,\n             explanation,\n             next,\n+            pool,\n             form_action,\n         } => {\n             if form_action != \"/ui\" {\n@@ -239,6 +240,9 @@ async fn dispatch_ui_action(\n                         .into_response();\n                 }\n             };\n+            let pool_id = pool.as_deref().and_then(|p| {\n+                crate::path_types::ItemId::parse(p.trim()).map(|i| i.normalized_storage())\n+            });\n             let mut rl = ratio_left.trim().parse::<i32>().unwrap_or(0).max(0);\n             let mut rr = ratio_right.trim().parse::<i32>().unwrap_or(0).max(0);\n             if rl == 0 && rr == 0 {\n@@ -294,6 +298,7 @@ async fn dispatch_ui_action(\n                         &thread_tag,\n                         &left_id,\n                         &right_id,\n+                        pool_id.as_ref(),\n                         pid.as_str(),\n                         post_index,\n                     )\ndiff --git a/server/src/html/garden/pin.rs b/server/src/html/garden/pin.rs\nindex 5865cfdbc06aeb6555c97380e25591fae6b3d125..1820d7fe7ee167ecbf5ad5124f23b2ab92ffb01f 100644\n--- a/server/src/html/garden/pin.rs\n+++ b/server/src/html/garden/pin.rs\n@@ -79,7 +79,7 @@ pub(super) fn ont_pin_vote_controls(\n                         }\n                     }\n                 } @else {\n-                    a class=\"ont-vote-compare-btn\" href=(vote_compare_href(nav, pi, &current, None)) title=\"Compare and vote\" {\n+                    a class=\"ont-vote-compare-btn\" href=(vote_compare_href(nav, pi, &current, None, None)) title=\"Compare and vote\" {\n                         span class=\"ont-vote-glyph\" aria-hidden=\"true\" { \"⚖\" }\n                         span { \"vote\" }\n                     }\n@@ -121,7 +121,7 @@ pub(super) fn child_row_pin_or_vote(\n                         if nv == 1 { \"\" } else { \"s\" },\n                     );\n                     @let aria = format!(\"Vote; {} pairwise {}\", nv, if nv == 1 { \"vote\" } else { \"votes\" });\n-                    a class=\"ont-garden-vote-ico\" href=(vote_compare_href(nav, pi, row_item, None)) title=(tip) aria-label=(aria) {\n+                    a class=\"ont-garden-vote-ico\" href=(vote_compare_href(nav, pi, row_item, None, None)) title=(tip) aria-label=(aria) {\n                         span class=\"ont-garden-vote-glyph\" aria-hidden=\"true\" { \"⚖\" }\n                         span class=\"ont-garden-vote-count\" { (format!(\"{}\", nv)) }\n                     }\ndiff --git a/server/src/html/garden/render.rs b/server/src/html/garden/render.rs\nindex 5c3986ca36902f6c9019a4b5590f0b3b9d2cb4ff..bd8cbce059ee789de6e8dc9b6f69f54beee2f994 100644\n--- a/server/src/html/garden/render.rs\n+++ b/server/src/html/garden/render.rs\n@@ -29,6 +29,7 @@ use super::{\n     item::{child_depth_from_uri, item_code_label, item_display_path, item_href},\n     item_page::{build_item_page_view_model, sibling_nav_markup},\n     pin::{child_row_pin_or_vote, ont_pin_vote_controls, pinned_item_from_jar},\n+    vote::vote_pool_href,\n };\n \n pub(super) async fn render_scope_view(\n@@ -186,12 +187,21 @@ pub(super) async fn render_scope_view(\n             }\n \n             section class=\"ont-tab-panel ont-tab-panel-children\" {\n+                @let total_children = model.child_rankings.component_rankings\n+                    .iter().map(|c| c.ranked.len()).sum::<usize>()\n+                    + model.child_rankings.unranked_items.len();\n                 h3 {\n                     \"ranked child groups\"\n                     @if model.child_depth > 1 {\n                         \" \"\n                         span class=\"muted\" { (format!(\"(depth {})\", model.child_depth)) }\n                     }\n+                    @if total_children >= 2 {\n+                        \" \"\n+                        a class=\"ont-vote-children-btn\" href=(vote_pool_href(&nav, &model.item)) {\n+                            \"vote on children\"\n+                        }\n+                    }\n                 }\n                 @if model.child_rankings.component_rankings.is_empty() {\n                     p class=\"muted\" { \"no voted pairs yet in this scope\" }\ndiff --git a/server/src/html/garden/tests.rs b/server/src/html/garden/tests.rs\nindex 6900a6795bcde866a176722149d6378e5127b4c3..c2036fca7752aef63d260e36cfe9649f63b5c550 100644\n--- a/server/src/html/garden/tests.rs\n+++ b/server/src/html/garden/tests.rs\n@@ -105,7 +105,7 @@ fn suggest_next_vote_pair_prefers_unvoted_sibling_pair() {\n     let content = content_for_garden_view(&reduced, &ScopeId::Public);\n     let a = ItemId::parse(\"~/topic/a\").unwrap().normalized_storage();\n     let b = ItemId::parse(\"~/topic/b\").unwrap().normalized_storage();\n-    let next = suggest_next_vote_pair(content, &a, &b).expect(\"next sibling pair\");\n+    let next = suggest_next_vote_pair(content, &a, &b, None).expect(\"next sibling pair\");\n     assert_ne!(\n         canonical_edge_items(&next.0, &next.1),\n         canonical_edge_items(&a, &b)\ndiff --git a/server/src/html/garden/vote.rs b/server/src/html/garden/vote.rs\nindex 1d7fc8aa7436bfa9c1186dfd940a8d751ab7e088..2682cfcbd2f834b56459a02831aa225cffe67c58 100644\n--- a/server/src/html/garden/vote.rs\n+++ b/server/src/html/garden/vote.rs\n@@ -211,14 +211,15 @@ pub(crate) async fn vote_compare_post_success_js(\n     _thread_tag: &str,\n     left: &ItemId,\n     right: &ItemId,\n+    pool: Option<&ItemId>,\n     _post_id: &str,\n     _post_idx: Option<usize>,\n ) -> String {\n     let reduced = state.reduced.read().await;\n     let content = content_for_garden_view(&reduced, &nav.scope());\n     let edge_history = vote_edge_history_markup(content, left, right);\n-    let next_pair = suggest_next_vote_pair(content, left, right);\n-    let nav_markup = vote_compare_nav_markup(nav, next_pair.as_ref());\n+    let next_pair = suggest_next_vote_pair(content, left, right, pool);\n+    let nav_markup = vote_compare_nav_markup(nav, next_pair.as_ref(), pool);\n     drop(reduced);\n     JsBuilder::new()\n         .morph_inner_selector(\"#vote-edge-history-region\", edge_history)\n@@ -231,27 +232,39 @@ pub(super) fn vote_compare_href(\n     left: &ItemId,\n     right: &ItemId,\n     thread_override: Option<&str>,\n+    pool: Option<&ItemId>,\n ) -> String {\n     let left_q = urlencoding::encode(left.as_str());\n     let right_q = urlencoding::encode(right.as_str());\n-    let base = format!(\n+    let mut base = format!(\n         \"{}/vote?left={}&right={}\",\n         nav.room_path_prefix_for_vote_compare(),\n         left_q,\n         right_q\n     );\n     if let Some(t) = thread_override.filter(|s| !s.is_empty()) {\n-        format!(\"{}&thread={}\", base, urlencoding::encode(t))\n-    } else {\n-        base\n+        base = format!(\"{}&thread={}\", base, urlencoding::encode(t));\n+    }\n+    if let Some(p) = pool {\n+        base = format!(\"{}&pool={}\", base, urlencoding::encode(p.as_str()));\n     }\n+    base\n+}\n+\n+pub(super) fn vote_pool_href(nav: &ThreadNav, pool_item_str: &str) -> String {\n+    format!(\n+        \"{}/vote?pool={}\",\n+        nav.room_path_prefix_for_vote_compare(),\n+        urlencoding::encode(pool_item_str)\n+    )\n }\n \n fn vote_compare_nav_markup(\n     nav: &ThreadNav,\n     next_pair: Option<&(ItemId, ItemId)>,\n+    pool: Option<&ItemId>,\n ) -> maud::Markup {\n-    let next_pair_href = next_pair.map(|(nl, nr)| vote_compare_href(nav, nl, nr, None));\n+    let next_pair_href = next_pair.map(|(nl, nr)| vote_compare_href(nav, nl, nr, None, pool));\n     html! {\n         div class=\"vote-compare-nav\" {\n             @if let Some(href) = &next_pair_href {\n@@ -267,8 +280,15 @@ pub(super) fn suggest_next_vote_pair(\n     content: &ContentState,\n     current_left: &ItemId,\n     current_right: &ItemId,\n+    pool_parent: Option<&ItemId>,\n ) -> Option<(ItemId, ItemId)> {\n-    let pool: Vec<ItemId> = if current_left.parent().as_ref().map(|p| p.as_str())\n+    let pool: Vec<ItemId> = if let Some(parent) = pool_parent {\n+        content\n+            .item_children\n+            .get(parent)\n+            .map(|s| s.iter().cloned().collect())\n+            .unwrap_or_default()\n+    } else if current_left.parent().as_ref().map(|p| p.as_str())\n         == current_right.parent().as_ref().map(|p| p.as_str())\n     {\n         current_left\n@@ -322,10 +342,14 @@ pub(super) fn vote_compare_item_card(\n }\n #[derive(Debug, Deserialize)]\n pub struct VoteCompareQuery {\n-    pub left: String,\n-    pub right: String,\n+    #[serde(default)]\n+    pub left: Option<String>,\n+    #[serde(default)]\n+    pub right: Option<String>,\n     #[serde(default)]\n     pub thread: Option<String>,\n+    #[serde(default)]\n+    pub pool: Option<String>,\n }\n \n /// Public pairwise vote UI — `/vote?left=&right=&thread=`.\n@@ -376,17 +400,53 @@ async fn vote_compare_inner(\n     jar: CookieJar,\n     uri: Uri,\n ) -> axum::response::Response {\n-    let left = match ItemId::parse(q.left.trim()) {\n-        Some(i) => i.normalized_storage(),\n-        None => return (StatusCode::NOT_FOUND, \"bad left item\").into_response(),\n+    let pool_id: Option<ItemId> = match q.pool.as_deref() {\n+        Some(p) => match ItemId::parse(p.trim()) {\n+            Some(i) => Some(i.normalized_storage()),\n+            None => return (StatusCode::BAD_REQUEST, \"bad pool item\").into_response(),\n+        },\n+        None => None,\n     };\n-    let right = match ItemId::parse(q.right.trim()) {\n-        Some(i) => i.normalized_storage(),\n-        None => return (StatusCode::NOT_FOUND, \"bad right item\").into_response(),\n+\n+    let (left, right) = match (q.left.as_deref(), q.right.as_deref()) {\n+        (Some(l), Some(r)) => {\n+            let left = match ItemId::parse(l.trim()) {\n+                Some(i) => i.normalized_storage(),\n+                None => return (StatusCode::NOT_FOUND, \"bad left item\").into_response(),\n+            };\n+            let right = match ItemId::parse(r.trim()) {\n+                Some(i) => i.normalized_storage(),\n+                None => return (StatusCode::NOT_FOUND, \"bad right item\").into_response(),\n+            };\n+            if left == right {\n+                return (StatusCode::BAD_REQUEST, \"items must differ\").into_response();\n+            }\n+            (left, right)\n+        }\n+        (None, None) => {\n+            let Some(pool) = pool_id.as_ref() else {\n+                return (StatusCode::BAD_REQUEST, \"provide left+right or pool\").into_response();\n+            };\n+            let reduced = state.reduced.read().await;\n+            let content = content_for_garden_view(&reduced, &nav.scope());\n+            let children: Vec<ItemId> = content\n+                .item_children\n+                .get(pool)\n+                .map(|s| s.iter().cloned().collect())\n+                .unwrap_or_default();\n+            if children.len() < 2 {\n+                drop(reduced);\n+                return (StatusCode::BAD_REQUEST, \"pool has fewer than 2 children to compare\").into_response();\n+            }\n+            let pair = suggest_next_pair_in_pool(&content.ranking_group, &children, None);\n+            drop(reduced);\n+            match pair {\n+                Some(p) => p,\n+                None => return (StatusCode::BAD_REQUEST, \"no pairs available in pool\").into_response(),\n+            }\n+        }\n+        _ => return (StatusCode::BAD_REQUEST, \"provide both left and right, or just pool\").into_response(),\n     };\n-    if left == right {\n-        return (StatusCode::BAD_REQUEST, \"items must differ\").into_response();\n-    }\n \n     let reduced = state.reduced.read().await;\n     let content = content_for_garden_view(&reduced, &nav.scope());\n@@ -409,7 +469,7 @@ async fn vote_compare_inner(\n     let left_body = content.item_bodies.get(&left).cloned();\n     let right_body = content.item_bodies.get(&right).cloned();\n     let item_bodies_for_cards = content.item_bodies.clone();\n-    let next_pair = suggest_next_vote_pair(content, &left, &right);\n+    let next_pair = suggest_next_vote_pair(content, &left, &right, pool_id.as_ref());\n     drop(reduced);\n \n     let title = format!(\n@@ -432,6 +492,7 @@ async fn vote_compare_inner(\n         \"ratio_right\": {\"$form\": \"ratio_right\"},\n         \"explanation\": {\"$form\": \"explanation\"},\n         \"next\": next_path,\n+        \"pool\": pool_id.as_ref().map(|p| p.as_str()),\n         \"form_action\": \"/ui\",\n     }))\n     .expect(\"vote compare rpc json\");\n@@ -456,7 +517,7 @@ async fn vote_compare_inner(\n                 Some(&item_bodies_for_cards),\n             ))\n         }\n-        (vote_compare_nav_markup(&nav, next_pair.as_ref()))\n+        (vote_compare_nav_markup(&nav, next_pair.as_ref(), pool_id.as_ref()))\n         div id=\"vote-edge-history-region\" {\n             (edge_history)\n         }\ndiff --git a/server/src/html/ui_action.rs b/server/src/html/ui_action.rs\nindex dd5294202569454acf9f41b458718700bbf96f39..2589a2cc00bb7b18cd19ebcbb938083122d6921d 100644\n--- a/server/src/html/ui_action.rs\n+++ b/server/src/html/ui_action.rs\n@@ -50,6 +50,9 @@ pub enum HtmlUiAction {\n         explanation: String,\n         /// Same-origin path after successful post (JS redirect).\n         next: String,\n+        /// Pool parent item path, if the vote was initiated from a pool URL.\n+        #[serde(default)]\n+        pool: Option<String>,\n         #[serde(default = \"default_ui_form_action\")]\n         form_action: String,\n     },\n\n\nSide B — contributor: tommy-mor\nSide B — commit message:\n[3f35edab] progress\n\nSide B — unified diff (full patch):\ndiff --git a/server/src/api/mod.rs b/server/src/api/mod.rs\nindex a10ce662105cff8fad949c6b83f7035ce79bed18..a986f706ea4b261cbaf004c02b4cf84184b41371 100644\n--- a/server/src/api/mod.rs\n+++ b/server/src/api/mod.rs\n@@ -3,6 +3,7 @@ mod helpers;\n mod rpc;\n mod stream;\n mod validate;\n+mod ui_html;\n mod web_post;\n \n pub use auth::{\n@@ -33,6 +34,7 @@ pub use stream::{get_html_stream, get_stream};\n \n pub use validate::{normalize_room_and_thread, validate_ingest_document, ValidatedIngest};\n \n+pub use ui_html::post_ui_html;\n pub use web_post::{check_web_ingest, post_web_ingest, post_web_redact};\n \n #[cfg(test)]\ndiff --git a/server/src/api/ui_html.rs b/server/src/api/ui_html.rs\nnew file mode 100644\nindex 0000000000000000000000000000000000000000..2b40a72059981d558768f73d189b991f3448c257\n--- /dev/null\n+++ b/server/src/api/ui_html.rs\n@@ -0,0 +1,139 @@\n+//! Single `POST /ui` entry for browser [`crate::html::ui_action::HtmlUiAction`] (JSON in `__rpc__` + holes).\n+\n+use axum::{\n+    body::Body,\n+    extract::State,\n+    http::{header, HeaderMap, StatusCode},\n+    response::{IntoResponse, Response},\n+    Form,\n+};\n+use axum_extra::extract::cookie::CookieJar;\n+use std::collections::HashMap;\n+\n+use crate::{\n+    api::{\n+        auth::optional_principal,\n+        web_post::{run_check_web_ingest, run_post_web_ingest, run_post_web_redact, WebPostForm, WebRedactForm},\n+    },\n+    html::{\n+        fragment_public_new_thread_form, fragment_room_new_thread_form, login_to_post_hint_markup,\n+        parse_html_ui_from_form, user_can_post_room, user_can_view_room, HtmlUiAction, JsBuilder,\n+        ThreadNav,\n+    },\n+    state::AppState,\n+};\n+\n+pub async fn post_ui_html(\n+    State(state): State<AppState>,\n+    headers: HeaderMap,\n+    jar: CookieJar,\n+    Form(form): Form<HashMap<String, String>>,\n+) -> impl IntoResponse {\n+    let action = match parse_html_ui_from_form(&form) {\n+        Ok(a) => a,\n+        Err(e) => return ui_js_warn(&e.to_string()).into_response(),\n+    };\n+\n+    match action {\n+        HtmlUiAction::PostIngest {\n+            room,\n+            thread_tag,\n+            text,\n+            error_target,\n+            form_id,\n+        } => {\n+            run_post_web_ingest(\n+                &state,\n+                &headers,\n+                &jar,\n+                WebPostForm {\n+                    room,\n+                    thread_tag,\n+                    text,\n+                    error_target,\n+                    form_id,\n+                },\n+            )\n+            .await\n+        }\n+        HtmlUiAction::CheckIngest {\n+            room,\n+            thread_tag,\n+            text,\n+            error_target,\n+            form_id,\n+        } => {\n+            run_check_web_ingest(\n+                &state,\n+                &headers,\n+                &jar,\n+                WebPostForm {\n+                    room,\n+                    thread_tag,\n+                    text,\n+                    error_target,\n+                    form_id,\n+                },\n+            )\n+            .await\n+        }\n+        HtmlUiAction::RedactPost { post_id } => {\n+            run_post_web_redact(&state, &headers, &jar, WebRedactForm { post_id }).await\n+        }\n+        HtmlUiAction::ExpandPublicNewThreadForm => {\n+            let reduced = state.reduced.read().await;\n+            let user = optional_principal(&headers, &jar, &reduced);\n+            drop(reduced);\n+            let markup = if user.is_some() {\n+                fragment_public_new_thread_form(true)\n+            } else {\n+                login_to_post_hint_markup()\n+            };\n+            JsBuilder::new()\n+                .morph_selector(\"#public-new-thread-ui-slot\", markup)\n+                .into_response()\n+        }\n+        HtmlUiAction::ExpandRoomNewThreadForm { room_wire } => {\n+            let room_wire = room_wire.trim().to_string();\n+            if room_wire.is_empty() {\n+                return ui_js_warn(\"missing room\").into_response();\n+            }\n+            let reduced = state.reduced.read().await;\n+            let user = optional_principal(&headers, &jar, &reduced);\n+            if !reduced.rooms.contains(&room_wire) {\n+                drop(reduced);\n+                return ui_js_warn(\"room not found\").into_response();\n+            }\n+            if !user_can_view_room(&reduced, &room_wire, user.as_deref()) {\n+                drop(reduced);\n+                return ui_js_warn(\"forbidden\").into_response();\n+            }\n+            let can_post = user\n+                .as_ref()\n+                .map(|u| user_can_post_room(&reduced, &room_wire, u))\n+                .unwrap_or(false);\n+            drop(reduced);\n+            let Some(nav) = ThreadNav::from_room_id(&room_wire) else {\n+                return ui_js_warn(\"bad room\").into_response();\n+            };\n+            let markup = if can_post {\n+                fragment_room_new_thread_form(&nav, true)\n+            } else {\n+                login_to_post_hint_markup()\n+            };\n+            JsBuilder::new()\n+                .morph_selector(\"#room-new-thread-ui-slot\", markup)\n+                .into_response()\n+        }\n+    }\n+}\n+\n+fn ui_js_warn(msg: &str) -> Response {\n+    use crate::html::js_string_literal;\n+    let js = format!(\"console.warn({});\", js_string_literal(msg));\n+    Response::builder()\n+        .status(StatusCode::OK)\n+        .header(header::CONTENT_TYPE, \"text/javascript; charset=utf-8\")\n+        .body(Body::from(js))\n+        .unwrap()\n+}\ndiff --git a/server/src/api/web_post.rs b/server/src/api/web_post.rs\nindex a64010e382d3039821c836a5529adad0fe67cce5..265025f41ff1548d05b2d2d5d84202245388053f 100644\n--- a/server/src/api/web_post.rs\n+++ b/server/src/api/web_post.rs\n@@ -222,8 +222,18 @@ pub async fn post_web_redact(\n     jar: CookieJar,\n     Form(form): Form<WebRedactForm>,\n ) -> impl IntoResponse {\n+    run_post_web_redact(&state, &headers, &jar, form).await\n+}\n+\n+/// Shared with [`crate::api::ui_html::post_ui_html`].\n+pub(crate) async fn run_post_web_redact(\n+    state: &AppState,\n+    headers: &HeaderMap,\n+    jar: &CookieJar,\n+    form: WebRedactForm,\n+) -> Response {\n     let reduced = state.reduced.read().await;\n-    let Some(_username) = optional_principal(&headers, &jar, &reduced) else {\n+    let Some(_username) = optional_principal(headers, jar, &reduced) else {\n         drop(reduced);\n         return js_redirect(\"/login\").into_response();\n     };\n@@ -239,8 +249,8 @@ pub async fn post_web_redact(\n         return js_redirect(\"/login\").into_response();\n     };\n \n-    match rpc_post_redact(&state, &headers, form.post_id).await {\n-        Ok(RpcResult::RedactPostOk {}) => redact_success_response(&state).await.into_response(),\n+    match rpc_post_redact(state, headers, form.post_id).await {\n+        Ok(RpcResult::RedactPostOk {}) => redact_success_response(state).await.into_response(),\n         Ok(_) => (StatusCode::BAD_REQUEST, \"unexpected response\").into_response(),\n         Err((msg, hint)) => {\n             let detail = hint.as_deref().unwrap_or(\"\");\n@@ -255,8 +265,18 @@ pub async fn post_web_ingest(\n     jar: CookieJar,\n     Form(form): Form<WebPostForm>,\n ) -> impl IntoResponse {\n+    run_post_web_ingest(&state, &headers, &jar, form).await\n+}\n+\n+/// Shared with [`crate::api::ui_html::post_ui_html`] (`POST /ui`).\n+pub(crate) async fn run_post_web_ingest(\n+    state: &AppState,\n+    headers: &HeaderMap,\n+    jar: &CookieJar,\n+    form: WebPostForm,\n+) -> Response {\n     let reduced = state.reduced.read().await;\n-    let Some(_username) = optional_principal(&headers, &jar, &reduced) else {\n+    let Some(_username) = optional_principal(headers, jar, &reduced) else {\n         drop(reduced);\n         return js_redirect(\"/login\").into_response();\n     };\n@@ -282,8 +302,8 @@ pub async fn post_web_ingest(\n             .into_response();\n     }\n \n-    match rpc_post_with_bearer(&state, &bearer, room.clone(), thread_tag.clone(), text).await {\n-        Ok(RpcResult::PostOk { .. }) => post_success_response(&state, &form, &headers, &jar)\n+    match rpc_post_with_bearer(state, &bearer, room.clone(), thread_tag.clone(), text).await {\n+        Ok(RpcResult::PostOk { .. }) => post_success_response(state, &form, headers, jar)\n             .await\n             .into_response(),\n         Ok(_) => form_js_error(&form, \"unexpected response\", \"Post did not return PostOk.\").into_response(),\n@@ -297,8 +317,18 @@ pub async fn check_web_ingest(\n     jar: CookieJar,\n     Form(form): Form<WebPostForm>,\n ) -> impl IntoResponse {\n+    run_check_web_ingest(&state, &headers, &jar, form).await\n+}\n+\n+/// Shared with [`crate::api::ui_html::post_ui_html`] (`POST /ui`).\n+pub(crate) async fn run_check_web_ingest(\n+    state: &AppState,\n+    headers: &HeaderMap,\n+    jar: &CookieJar,\n+    form: WebPostForm,\n+) -> Response {\n     let reduced = state.reduced.read().await;\n-    let Some(_username) = optional_principal(&headers, &jar, &reduced) else {\n+    let Some(_username) = optional_principal(headers, jar, &reduced) else {\n         drop(reduced);\n         return js_redirect(\"/login\").into_response();\n     };\n@@ -324,7 +354,7 @@ pub async fn check_web_ingest(\n         return js_clear_errors(&form_error_target(&form)).into_response();\n     }\n \n-    match rpc_check_with_bearer(&state, &bearer, room, form.text.clone()).await {\n+    match rpc_check_with_bearer(state, &bearer, room, form.text.clone()).await {\n         Ok(RpcResult::CheckOk { .. }) => js_clear_errors(&form_error_target(&form)).into_response(),\n         Ok(_) => form_js_error(&form, \"unexpected response\", \"Check did not return CheckOk.\").into_response(),\n         Err((msg, hint)) => form_js_error(&form, &msg, hint.as_deref().unwrap_or(\"\")).into_response(),\ndiff --git a/server/src/form_template.rs b/server/src/form_template.rs\nnew file mode 100644\nindex 0000000000000000000000000000000000000000..3709c2c09a859da006e4af173413d5d235bc19be\n--- /dev/null\n+++ b/server/src/form_template.rs\n@@ -0,0 +1,142 @@\n+//! Plan2-style JSON templates with `{\"$form\": \"field_name\"}` holes, filled from\n+//! `application/x-www-form-urlencoded` (or any `String` → `String` map) **before**\n+//! deserializing into a typed struct.\n+//!\n+//! # Wire format\n+//!\n+//! Templates are **compact JSON** (`serde_json::to_string`): one line, no pretty\n+//! printing, strings escaped per JSON rules (`\\\"`, `\\n`, etc.). Embed that string\n+//! in HTML attributes or text nodes with normal HTML escaping (e.g. maud), not\n+//! bespoke encodings.\n+//!\n+//! # Power vs flat hidden fields\n+//!\n+//! A form is always a string→string map. You can fake depth with dotted keys (`a.b.c`),\n+//! but one structured blob (`__rpc__` = compact JSON) gives you nested objects,\n+//! arrays, and optional fields without inventing a new naming scheme each time.\n+//!\n+//! # Security\n+//!\n+//! Substitution runs **before** `serde` into your command type. It does not fix\n+//! authorization: if the client can replace the hidden `__rpc__` value, they can\n+//! change the command shape unless you validate (signed blob, server-side session\n+//! context, or treat the blob as hints only). Same threat model as any hidden field.\n+\n+use serde::Serialize;\n+use serde_json::Value;\n+use std::collections::HashMap;\n+\n+/// Serialize a value to compact JSON for a hidden `__rpc__` (or similar) field.\n+pub fn template_json_compact<T: Serialize>(v: &T) -> serde_json::Result<String> {\n+    serde_json::to_string(v)\n+}\n+\n+/// Recursively walk the JSON AST and replace `{\"$form\": \"key\"}` with the submitted\n+/// string for `key` (empty if missing). Other keys are unchanged.\n+pub fn substitute_form_vars(val: &mut Value, form_data: &HashMap<String, String>) {\n+    match val {\n+        Value::Object(map) => {\n+            if map.len() == 1 {\n+                if let Some(Value::String(field_name)) = map.get(\"$form\") {\n+                    let submitted = form_data\n+                        .get(field_name.as_str())\n+                        .map(|s| s.as_str())\n+                        .unwrap_or(\"\");\n+                    *val = Value::String(submitted.to_string());\n+                    return;\n+                }\n+            }\n+            for v in map.values_mut() {\n+                substitute_form_vars(v, form_data);\n+            }\n+        }\n+        Value::Array(arr) => {\n+            for v in arr.iter_mut() {\n+                substitute_form_vars(v, form_data);\n+            }\n+        }\n+        _ => {}\n+    }\n+}\n+\n+/// Parse JSON, apply [`substitute_form_vars`], return the mutated value.\n+pub fn fill_template_from_form(\n+    template_json: &str,\n+    form_data: &HashMap<String, String>,\n+) -> Result<Value, serde_json::Error> {\n+    let mut v: Value = serde_json::from_str(template_json)?;\n+    substitute_form_vars(&mut v, form_data);\n+    Ok(v)\n+}\n+\n+#[cfg(test)]\n+mod tests {\n+    use super::*;\n+    use serde::Deserialize;\n+\n+    #[derive(Debug, Deserialize, PartialEq, Eq)]\n+    struct Demo {\n+        room: String,\n+        thread_tag: String,\n+        nested: Nested,\n+    }\n+\n+    #[derive(Debug, Deserialize, PartialEq, Eq)]\n+    struct Nested {\n+        text: String,\n+    }\n+\n+    #[test]\n+    fn holes_become_strings() {\n+        let json = r#\"{\n+            \"room\": \"public\",\n+            \"thread_tag\": {\"$form\": \"tag\"},\n+            \"nested\": {\"text\": {\"$form\": \"body\"}}\n+        }\"#;\n+        let mut form = HashMap::new();\n+        form.insert(\"tag\".into(), \"foo\".into());\n+        form.insert(\"body\".into(), \"hello\\nworld\".into());\n+\n+        let v = fill_template_from_form(json, &form).unwrap();\n+        let d: Demo = serde_json::from_value(v).unwrap();\n+        assert_eq!(\n+            d,\n+            Demo {\n+                room: \"public\".into(),\n+                thread_tag: \"foo\".into(),\n+                nested: Nested {\n+                    text: \"hello\\nworld\".into(),\n+                },\n+            }\n+        );\n+    }\n+\n+    #[test]\n+    fn missing_form_key_is_empty_string() {\n+        let json = r#\"{\"x\": {\"$form\": \"nope\"}}\"#;\n+        let mut form = HashMap::new();\n+        form.insert(\"other\".into(), \"y\".into());\n+        let v = fill_template_from_form(json, &form).unwrap();\n+        assert_eq!(v[\"x\"], \"\");\n+    }\n+\n+    #[test]\n+    fn array_of_holes() {\n+        let json = r#\"{\"items\": [{\"$form\": \"a\"}, {\"$form\": \"b\"}]}\"#;\n+        let mut form = HashMap::new();\n+        form.insert(\"a\".into(), \"1\".into());\n+        form.insert(\"b\".into(), \"2\".into());\n+        let v = fill_template_from_form(json, &form).unwrap();\n+        assert_eq!(v[\"items\"], serde_json::json!([\"1\", \"2\"]));\n+    }\n+\n+    #[test]\n+    fn template_json_compact_escapes_and_single_line() {\n+        let s = template_json_compact(&serde_json::json!({\n+            \"x\": \"quote\\\"and\\nnewline\"\n+        }))\n+        .unwrap();\n+        assert!(!s.contains('\\n'));\n+        assert!(s.contains(\"\\\\\\\"\") || s.contains(\"\\\\n\"));\n+    }\n+}\ndiff --git a/server/src/html/forum.rs b/server/src/html/forum.rs\nindex f789e347dc136f8ffd356f4492f0bd76cea04bf0..b1c037f3dd93c7bb96d6624cab6019228432c501 100644\n--- a/server/src/html/forum.rs\n+++ b/server/src/html/forum.rs\n@@ -11,12 +11,15 @@ use crate::{\n     api::optional_principal,\n     canonical_path::{canonicalize_item, canonicalize_tag},\n     events::ThreadCapability,\n+    form_template::template_json_compact,\n     identity::parse_username,\n     reducer::{scope_from_room_wire, ReducerState, ScopeId},\n     state::AppState,\n     timeago,\n };\n \n+use super::ui_action::{HtmlUiAction, UI_RPC_FIELD};\n+\n use super::{\n     bc_segment, bc_threads, cli_panel, layout, now_ms, profile_href, recency_class,\n     render_linkified_with_embeds_in_scope, theme_from_jar, theme_next_from_uri, JsBuilder,\n@@ -289,7 +292,7 @@ fn rooms_for_user(reduced: &ReducerState, username: &str) -> Vec<String> {\n     v\n }\n \n-fn user_can_view_room(reduced: &ReducerState, room_id: &str, username: Option<&str>) -> bool {\n+pub(crate) fn user_can_view_room(reduced: &ReducerState, room_id: &str, username: Option<&str>) -> bool {\n     if !reduced.rooms.contains(room_id) {\n         return false;\n     }\n@@ -299,7 +302,7 @@ fn user_can_view_room(reduced: &ReducerState, room_id: &str, username: Option<&s\n     reduced.user_has_cap(room_id, u, ThreadCapability::View)\n }\n \n-fn user_can_post_room(reduced: &ReducerState, room_id: &str, username: &str) -> bool {\n+pub(crate) fn user_can_post_room(reduced: &ReducerState, room_id: &str, username: &str) -> bool {\n     reduced.user_has_cap(room_id, username, ThreadCapability::Post)\n }\n \n@@ -591,7 +594,6 @@ pub async fn home(\n     let nav = ThreadNav::public();\n     let reduced_read = state.reduced.read().await;\n     let strip = auth_strip(&headers, &jar, &reduced_read);\n-    let show_forms = user.is_some();\n     drop(reduced_read);\n \n     let page = layout(\n@@ -617,8 +619,14 @@ pub async fn home(\n                 }\n             }\n             p class=\"muted\" { \"dark = time-ordered · light = vote-ranked\" }\n+            div class=\"thread-feed-toolbar\" {\n+                form method=\"POST\" action=\"/ui\" {\n+                    input type=\"hidden\" name=(UI_RPC_FIELD) value=(expand_public_new_thread_rpc_value());\n+                    button type=\"submit\" class=\"section-add-btn\" { \"+\" }\n+                }\n+            }\n+            div id=\"public-new-thread-ui-slot\" {}\n             (render_thread_feed(Some(&nav), \"thread-feed\", &public_rows, now))\n-            (new_thread_form_public(show_forms))\n             (cli_panel(\"npx slugsocial public forum list\"))\n         },\n         None,\n@@ -901,7 +909,13 @@ pub async fn room_page(\n             h3 { \"threads\" }\n             (render_thread_feed(Some(&nav), \"room-thread-feed\", &rows, now))\n             @if show_new {\n-                (new_thread_form_for_room(&nav, show_new))\n+                div class=\"thread-feed-toolbar\" {\n+                    form method=\"POST\" action=\"/ui\" {\n+                        input type=\"hidden\" name=(UI_RPC_FIELD) value=(expand_room_new_thread_rpc_value(&nav));\n+                        button type=\"submit\" class=\"section-add-btn\" { \"+\" }\n+                    }\n+                }\n+                div id=\"room-new-thread-ui-slot\" {}\n             }\n             (cli_panel(&forum_cli))\n             (cli_panel(&garden_cli))\n@@ -945,6 +959,31 @@ fn new_thread_form_for_room(nav: &ThreadNav, show: bool) -> Markup {\n     }\n }\n \n+pub(crate) fn expand_public_new_thread_rpc_value() -> String {\n+    template_json_compact(&HtmlUiAction::ExpandPublicNewThreadForm).expect(\"static json\")\n+}\n+\n+pub(crate) fn expand_room_new_thread_rpc_value(nav: &ThreadNav) -> String {\n+    template_json_compact(&HtmlUiAction::ExpandRoomNewThreadForm {\n+        room_wire: nav.room_wire.clone(),\n+    })\n+    .expect(\"static json\")\n+}\n+\n+pub(crate) fn login_to_post_hint_markup() -> Markup {\n+    html! {\n+        p class=\"muted\" { \"log in to post\" }\n+    }\n+}\n+\n+pub(crate) fn fragment_public_new_thread_form(show: bool) -> Markup {\n+    new_thread_form_public(show)\n+}\n+\n+pub(crate) fn fragment_room_new_thread_form(nav: &ThreadNav, show: bool) -> Markup {\n+    new_thread_form_for_room(nav, show)\n+}\n+\n async fn thread_post_view_inner(\n     state: AppState,\n     tag: String,\ndiff --git a/server/src/html/mod.rs b/server/src/html/mod.rs\nindex 53041a0cf0b30e6f20749c92ecc15a4e9ac56e09..a4fd2dd60ac283f7eb9b2e64522501b21d1e27e9 100644\n--- a/server/src/html/mod.rs\n+++ b/server/src/html/mod.rs\n@@ -16,6 +16,7 @@ mod editor;\n mod forum;\n mod garden;\n mod search;\n+pub mod ui_action;\n use breadcrumb_path::OntologyPath;\n \n pub use auth::{auth_complete_page, auth_signed_in_fragment, choose_username_error_fragment, choose_username_page};\n@@ -27,9 +28,15 @@ pub use forum::{\n     thread_post_collapse_deleted, thread_post_expand, thread_post_expand_deleted, thread_post_view,\n     thread_view, ThreadNav,\n };\n+\n+pub(crate) use forum::{\n+    fragment_public_new_thread_form, fragment_room_new_thread_form, login_to_post_hint_markup,\n+    user_can_post_room, user_can_view_room,\n+};\n pub use garden::{garden_index, ontology_path, room_garden_index, room_ontology_path};\n pub use search::{search_page, search_results_fragment};\n pub use forum::user_profile_page;\n+pub use ui_action::{parse_html_ui_from_form, HtmlUiAction, HtmlUiParseError, UI_RPC_FIELD};\n \n /// Public profile URL path for a stored username (no `@`).\n pub(crate) fn profile_href(username: &str) -> String {\ndiff --git a/server/src/html/ui_action.rs b/server/src/html/ui_action.rs\nnew file mode 100644\nindex 0000000000000000000000000000000000000000..3bc69ecbb7e16a59d2d393b2d59f9cd3fedb12b1\n--- /dev/null\n+++ b/server/src/html/ui_action.rs\n@@ -0,0 +1,116 @@\n+//! Browser-only UI commands: JSON in hidden `__rpc__` plus hole fill ([`crate::form_template`]).\n+//! Not part of [`slug_types::RpcCommand`] (CLI / JSON API).\n+\n+use crate::form_template::fill_template_from_form;\n+use serde::{Deserialize, Serialize};\n+use serde_json::Value;\n+use std::collections::HashMap;\n+use thiserror::Error;\n+\n+/// Form field name for the compact JSON template (possibly with `{\"$form\":\"…\"}` holes).\n+pub const UI_RPC_FIELD: &str = \"__rpc__\";\n+\n+/// HTML form / fetch `POST /ui` payload after template fill and deserialization.\n+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]\n+#[serde(tag = \"action\", rename_all = \"snake_case\")]\n+pub enum HtmlUiAction {\n+    /// Same semantics as `POST /post` (forum ingest).\n+    PostIngest {\n+        room: String,\n+        thread_tag: String,\n+        text: String,\n+        #[serde(default)]\n+        error_target: Option<String>,\n+        #[serde(default)]\n+        form_id: Option<String>,\n+    },\n+    /// Same as `POST /post/check`.\n+    CheckIngest {\n+        room: String,\n+        thread_tag: String,\n+        text: String,\n+        #[serde(default)]\n+        error_target: Option<String>,\n+        #[serde(default)]\n+        form_id: Option<String>,\n+    },\n+    /// Same as `POST /post/redact`.\n+    RedactPost {\n+        post_id: String,\n+    },\n+    /// Morph `#public-new-thread-ui-slot` to the new-thread form (or login hint).\n+    ExpandPublicNewThreadForm,\n+    /// Morph `#room-new-thread-ui-slot` for the given room wire id.\n+    ExpandRoomNewThreadForm {\n+        room_wire: String,\n+    },\n+}\n+\n+#[derive(Debug, Error)]\n+pub enum HtmlUiParseError {\n+    #[error(\"missing __rpc__ field\")]\n+    MissingRpc,\n+    #[error(\"invalid template json: {0}\")]\n+    Template(serde_json::Error),\n+    #[error(\"invalid ui action: {0}\")]\n+    Action(serde_json::Error),\n+}\n+\n+/// Parse `__rpc__` JSON, apply `$form` holes from the rest of the form map, deserialize.\n+pub fn parse_html_ui_from_form(form: &HashMap<String, String>) -> Result<HtmlUiAction, HtmlUiParseError> {\n+    let template = form\n+        .get(UI_RPC_FIELD)\n+        .ok_or(HtmlUiParseError::MissingRpc)?;\n+    let mut hole_map = form.clone();\n+    hole_map.remove(UI_RPC_FIELD);\n+    let v: Value = fill_template_from_form(template, &hole_map).map_err(HtmlUiParseError::Template)?;\n+    serde_json::from_value(v).map_err(HtmlUiParseError::Action)\n+}\n+\n+#[cfg(test)]\n+mod tests {\n+    use super::*;\n+\n+    #[test]\n+    fn round_trip_post_ingest_with_holes() {\n+        let template = serde_json::json!({\n+            \"action\": \"post_ingest\",\n+            \"room\": \"public\",\n+            \"thread_tag\": {\"$form\": \"thread_tag\"},\n+            \"text\": {\"$form\": \"text\"},\n+            \"error_target\": \"e\",\n+            \"form_id\": \"f\",\n+        });\n+        let mut form = HashMap::new();\n+        form.insert(\n+            UI_RPC_FIELD.to_string(),\n+            serde_json::to_string(&template).unwrap(),\n+        );\n+        form.insert(\"thread_tag\".into(), \"x\".into());\n+        form.insert(\"text\".into(), \"body\".into());\n+\n+        let a = parse_html_ui_from_form(&form).unwrap();\n+        assert_eq!(\n+            a,\n+            HtmlUiAction::PostIngest {\n+                room: \"public\".into(),\n+                thread_tag: \"x\".into(),\n+                text: \"body\".into(),\n+                error_target: Some(\"e\".into()),\n+                form_id: Some(\"f\".into()),\n+            }\n+        );\n+    }\n+\n+    #[test]\n+    fn expand_public_unit_variant() {\n+        let template = serde_json::json!({ \"action\": \"expand_public_new_thread_form\" });\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::ExpandPublicNewThreadForm);\n+    }\n+}\ndiff --git a/server/src/lib.rs b/server/src/lib.rs\nindex b9d4b79791ba8dd3a3c26ff777943a2548092de5..5f5b6b0f01b29350c7415e5801ec5caa74f0b452 100644\n--- a/server/src/lib.rs\n+++ b/server/src/lib.rs\n@@ -3,6 +3,7 @@ pub mod paths;\n pub mod api;\n pub mod canonical_path;\n pub mod dsl;\n+pub mod form_template;\n pub mod html;\n pub mod event_log;\n pub mod events;\n@@ -33,6 +34,7 @@ pub fn create_app(state: AppState) -> Router {\n         .route(\"/post\", post(api::post_web_ingest))\n         .route(\"/post/redact\", post(api::post_web_redact))\n         .route(\"/post/check\", post(api::check_web_ingest))\n+        .route(\"/ui\", post(api::post_ui_html))\n         .route(\"/theme\", post(crate::html::post_theme))\n         .route(\"/sse\", get(api::get_html_stream))\n         .route(\"/stream\", get(api::get_stream))\n","role":"user"}],"model":"~x-ai/grok-latest"}