{"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[1531154d] dequeue -> vec\n\nSide A — unified diff (full patch):\ndiff --git a/server/src/projection_apply.rs b/server/src/projection_apply.rs\nindex 9c8990a8af927f35d3344c8d0872a516aba56b86..ad404bacb8bcdd5ae0e682cff97f974fd44528ea 100644\n--- a/server/src/projection_apply.rs\n+++ b/server/src/projection_apply.rs\n@@ -6,8 +6,6 @@\n //! batch as the (non-idempotent) edge merges guarantees exactly-once application\n //! across replay.\n \n-use std::collections::BTreeSet;\n-\n use crate::{\n     event_log::EventLogError,\n     events::{Event, EventRecord},\n@@ -44,7 +42,6 @@ pub fn apply_records(\n \n     let db = projection_store.db();\n     let mut batch = db.batch();\n-    let mut vote_parents: BTreeSet<ItemId> = BTreeSet::new();\n     let mut last_seq = 0u64;\n \n     for record in records {\n@@ -70,7 +67,6 @@ pub fn apply_records(\n                     *ts,\n                 )\n                 .map_err(|e| EventLogError::Apply(e.to_string()))?;\n-                vote_parents.insert(parent);\n             }\n             Event::NodeEnsured { id } => {\n                 let parsed = parse_event_id(id)?;\n@@ -85,11 +81,5 @@ pub fn apply_records(\n         .commit_with(durable::Durability::DisableWal)\n         .map_err(|e| EventLogError::Apply(e.to_string()))?;\n \n-    for parent in vote_parents {\n-        projection_store\n-            .trim_recent_votes(&parent)\n-            .map_err(|e| EventLogError::Apply(e.to_string()))?;\n-    }\n-\n     Ok(())\n }\ndiff --git a/server/src/projection_store.rs b/server/src/projection_store.rs\nindex 8576d671f351004426207894ac35594ddb0f70cf..9a8953d010029d3639dc3987687554bab8b7663e 100644\n--- a/server/src/projection_store.rs\n+++ b/server/src/projection_store.rs\n@@ -18,7 +18,7 @@ use crate::{\n \n const PROJECTION_CURSOR_KEY: &str = \"cursor\";\n const PROJECTION_SCHEMA_KEY: &str = \"schema_version\";\n-const PROJECTION_SCHEMA_VERSION: u64 = 3;\n+const PROJECTION_SCHEMA_VERSION: u64 = 4;\n \n #[derive(Debug, thiserror::Error)]\n pub enum ProjectionStoreError {\n@@ -142,16 +142,6 @@ impl ProjectionStore {\n         Ok(tree)\n     }\n \n-    /// Cap a node's recent-vote window after applying votes (best-effort, blind).\n-    pub(crate) fn trim_recent_votes(&self, parent: &ItemId) -> Result<(), ProjectionStoreError> {\n-        node(parent).recent_votes().truncate_back(\n-            &self.db,\n-            crate::storage_schema::RECENT_VOTES_CAP,\n-            Durability::DisableWal,\n-        )?;\n-        Ok(())\n-    }\n-\n     /// Cache Reddit display content outside the event log (must be evicted per policy).\n     pub fn put_ephemeral_content(\n         &self,\ndiff --git a/server/src/reducer.rs b/server/src/reducer.rs\nindex 0c75c85150bb9e5f578bbadf58b3e43f8a80be4b..759918b8c0eb8f8bf1ed0911d8877adaa55c8ea6 100644\n--- a/server/src/reducer.rs\n+++ b/server/src/reducer.rs\n@@ -1,4 +1,4 @@\n-use std::collections::{HashMap, HashSet, VecDeque};\n+use std::collections::{HashMap, HashSet};\n \n use serde::{Deserialize, Serialize};\n \n@@ -52,7 +52,7 @@ pub struct GroupState {\n     pub idx_to_item: Vec<ItemId>,\n     pub edges: HashMap<(usize, usize), f64>,\n     pub voted_pairs: HashSet<(usize, usize)>,\n-    pub recent_votes: VecDeque<VoteData>,\n+    pub recent_votes: Vec<VoteData>,\n }\n \n impl GroupState {\n@@ -62,7 +62,7 @@ impl GroupState {\n             idx_to_item: Vec::new(),\n             edges: HashMap::new(),\n             voted_pairs: HashSet::new(),\n-            recent_votes: VecDeque::with_capacity(200),\n+            recent_votes: Vec::new(),\n         }\n     }\n \n@@ -111,10 +111,7 @@ impl GroupState {\n         self.add_edge_weight(b_idx, a_idx, w_a);\n         self.add_edge_weight(a_idx, b_idx, w_b);\n \n-        self.recent_votes.push_front(vote);\n-        while self.recent_votes.len() > 200 {\n-            self.recent_votes.pop_back();\n-        }\n+        self.recent_votes.push(vote);\n     }\n }\n \ndiff --git a/server/src/storage_dto.rs b/server/src/storage_dto.rs\nindex 9dfb13c53efe4389277625a6ab3bfc18f566a453..3fd6db5cb909ac4896bd8a3ecace796de5f08781 100644\n--- a/server/src/storage_dto.rs\n+++ b/server/src/storage_dto.rs\n@@ -39,7 +39,7 @@ pub struct StoredEntityDataV1 {\n     pub link_url: Option<String>,\n }\n \n-/// One vote stored in a node's `recent_votes` deque.\n+/// One vote stored in a node's `recent_votes` list.\n #[derive(Debug, Clone, Serialize, Deserialize)]\n pub struct StoredVoteV1 {\n     pub version: u32,\ndiff --git a/server/src/storage_schema.rs b/server/src/storage_schema.rs\nindex bd26e665e084b95b10fdfff091c31e8dc84d07b8..5d2bb1d56927fb61c7c6d2d8602bd6882327f862 100644\n--- a/server/src/storage_schema.rs\n+++ b/server/src/storage_schema.rs\n@@ -2,13 +2,13 @@\n //! durable collections instead of one blob per node.\n //!\n //! A vote updates a handful of keys: a few edge-weight merges, a voted-pair flag,\n-//! a recent-vote deque push, and child-link set entries. The in-memory\n+//! a recent-vote list append, and child-link set entries. The in-memory\n //! [`crate::reducer::GroupState`] is reconstructed from these keys on read for\n //! rank-centrality.\n \n use std::collections::{BTreeSet, HashMap, HashSet};\n \n-use durable::{Batch, Db, Deque, Durable, Leaf, Map, Sum};\n+use durable::{Batch, Db, Durable, Leaf, List, Map, Sum};\n \n use crate::{\n     path_types::ItemId,\n@@ -38,8 +38,8 @@ pub struct NodeSchema {\n     pub edges: Map<EdgeKey, Sum<f64>>,\n     /// Voted pairs `(min, max) -> true`.\n     pub voted_pairs: Map<PairKey, Leaf<bool>>,\n-    /// Recent votes, newest at the front (capped on write).\n-    pub recent_votes: Deque<Leaf<StoredVoteV1>>,\n+    /// Recent votes, append-only oldest-first (cap applied on read).\n+    pub recent_votes: List<Leaf<StoredVoteV1>>,\n     /// When ephemeral Reddit display content was last fetched (ms); absent after eviction.\n     pub fetched_at: Leaf<i64>,\n }\n@@ -55,7 +55,7 @@ pub struct Store {\n     pub view_meta: Map<String, Leaf<u64>>,\n }\n \n-/// Cap on the per-node recent-vote window (matches the in-memory reducer).\n+/// Max recent votes returned when loading a node (query-time cap only).\n pub const RECENT_VOTES_CAP: u64 = 200;\n \n fn id_key(id: &ItemId) -> String {\n@@ -148,11 +148,14 @@ fn build_group_state(\n         }\n     }\n \n-    // Deque is front=newest; in-memory VecDeque is also front=newest.\n-    let mut recent_votes = std::collections::VecDeque::new();\n-    for stored in np.recent_votes().iter(db)? {\n-        recent_votes.push_back(decode_vote(stored).map_err(durable::Error::Deserialize)?);\n-    }\n+    // List is index order (oldest first); keep the newest RECENT_VOTES_CAP entries.\n+    let stored = np.recent_votes().iter(db)?;\n+    let cap = RECENT_VOTES_CAP as usize;\n+    let start = stored.len().saturating_sub(cap);\n+    let recent_votes = stored[start..]\n+        .iter()\n+        .map(|s| decode_vote(s.clone()).map_err(durable::Error::Deserialize))\n+        .collect::<Result<Vec<_>, _>>()?;\n \n     Ok(GroupState {\n         item_to_idx,\n@@ -248,7 +251,7 @@ pub fn vote_writes(\n     };\n     batch.write(pnode.voted_pairs().key(&(lo, hi)).set(&true));\n \n-    // Recent votes (newest at front).\n+    // Recent votes (append-only; cap on read).\n     let stored = encode_vote(&VoteData {\n         ts,\n         a: a_id,\n@@ -260,7 +263,7 @@ pub fn vote_writes(\n         delegate: None,\n         thread_tag: \"default\".to_string(),\n     });\n-    batch.push_front(&pnode.recent_votes(), &stored)?;\n+    batch.push(&pnode.recent_votes(), &stored)?;\n     Ok(())\n }\n \n@@ -314,6 +317,35 @@ mod tests {\n         assert!(load_node_state(&db, &parent).unwrap().is_none());\n     }\n \n+    #[test]\n+    fn load_caps_recent_votes_at_query_time() {\n+        let dir = tempfile::tempdir().unwrap();\n+        let db = Db::open(dir.path()).unwrap();\n+        let parent = ItemId::root();\n+\n+        let mut batch = db.batch();\n+        for i in 0..RECENT_VOTES_CAP + 10 {\n+            vote_writes(&mut batch, &parent, \"alpha\", \"beta\", 1, 0, i as i64).unwrap();\n+        }\n+        batch.commit().unwrap();\n+\n+        assert_eq!(\n+            node(&parent).recent_votes().len(&db).unwrap(),\n+            RECENT_VOTES_CAP + 10\n+        );\n+\n+        let node_state = load_node_state(&db, &parent).unwrap().unwrap();\n+        assert_eq!(node_state.local_ranking.recent_votes.len(), RECENT_VOTES_CAP as usize);\n+        assert_eq!(\n+            node_state.local_ranking.recent_votes.first().map(|v| v.ts),\n+            Some(10)\n+        );\n+        assert_eq!(\n+            node_state.local_ranking.recent_votes.last().map(|v| v.ts),\n+            Some(RECENT_VOTES_CAP as i64 + 9)\n+        );\n+    }\n+\n     #[test]\n     fn missing_node_is_none() {\n         let dir = tempfile::tempdir().unwrap();\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":"openai/gpt-chat-latest"}