crates/adapters/postgres/src/feed.rs

@@ -141,6 +141,41 @@ impl FeedRepository for PgFeedRepository {
 
         Ok(Paginated { items: rows.into_iter().map(row_to_entry).collect(), total, page: page.page, per_page: page.per_page })
     }
+
+    async fn tag_feed(&self, tag_name: &str, page: &PageParams, _viewer_id: Option<&UserId>) -> Result<Paginated<FeedEntry>, DomainError> {
+        let total: i64 = sqlx::query_scalar(
+            "SELECT COUNT(*) FROM thoughts t
+             JOIN thought_tags tt ON tt.thought_id = t.id
+             JOIN tags tg ON tg.id = tt.tag_id
+             WHERE tg.name = $1 AND t.visibility = 'public'"
+        )
+        .bind(tag_name)
+        .fetch_one(&self.pool)
+        .await
+        .map_err(|e| DomainError::Internal(e.to_string()))?;
+
+        let sql = format!(
+            "{FEED_SELECT}
+             JOIN thought_tags tt ON tt.thought_id = t.id
+             JOIN tags tg ON tg.id = tt.tag_id
+             WHERE tg.name = $1 AND t.visibility = 'public'
+             ORDER BY t.created_at DESC LIMIT $2 OFFSET $3"
+        );
+        let rows = sqlx::query_as::<_, FeedRow>(&sql)
+            .bind(tag_name)
+            .bind(page.limit())
+            .bind(page.offset())
+            .fetch_all(&self.pool)
+            .await
+            .map_err(|e| DomainError::Internal(e.to_string()))?;
+
+        Ok(Paginated {
+            items: rows.into_iter().map(row_to_entry).collect(),
+            total,
+            page: page.page,
+            per_page: page.per_page,
+        })
+    }
 }
 
 #[cfg(test)]

crates/application/src/use_cases/feed.rs

@@ -2,10 +2,9 @@ use domain::{
     errors::DomainError,
     models::{
         feed::{FeedEntry, PageParams, Paginated, UserSummary},
-        thought::Thought,
         user::User,
     },
-    ports::{FeedRepository, FollowRepository, TagRepository, ThoughtRepository, UserRepository},
+    ports::{FeedRepository, FollowRepository, ThoughtRepository, UserRepository},
     value_objects::UserId,
 };
 
@@ -30,8 +29,8 @@ pub async fn get_following(follows: &dyn FollowRepository, user_id: &UserId, pag
     follows.list_following(user_id, &page).await
 }
 
-pub async fn get_by_tag(tags: &dyn TagRepository, tag_name: &str, page: PageParams) -> Result<Paginated<Thought>, DomainError> {
-    tags.list_thoughts_by_tag(tag_name, &page).await
+pub async fn get_by_tag(feed: &dyn FeedRepository, tag_name: &str, page: PageParams) -> Result<Paginated<FeedEntry>, DomainError> {
+    feed.tag_feed(tag_name, &page, None).await
 }
 
 pub async fn search(feed: &dyn FeedRepository, query: &str, page: PageParams, viewer_id: Option<&UserId>) -> Result<Paginated<FeedEntry>, DomainError> {

crates/domain/src/ports.rs

@@ -138,6 +138,7 @@ pub trait FeedRepository: Send + Sync {
     async fn home_feed(&self, following_ids: &[UserId], page: &PageParams, viewer_id: Option<&UserId>) -> Result<Paginated<FeedEntry>, DomainError>;
     async fn public_feed(&self, page: &PageParams, viewer_id: Option<&UserId>) -> Result<Paginated<FeedEntry>, DomainError>;
     async fn search(&self, query: &str, page: &PageParams, viewer_id: Option<&UserId>) -> Result<Paginated<FeedEntry>, DomainError>;
+    async fn tag_feed(&self, tag_name: &str, page: &PageParams, viewer_id: Option<&UserId>) -> Result<Paginated<FeedEntry>, DomainError>;
 }
 
 #[async_trait]

crates/domain/src/testing.rs

@@ -287,6 +287,9 @@ pub struct TestStore {
     async fn search(&self, _q: &str, _p: &PageParams, _v: Option<&UserId>) -> Result<Paginated<FeedEntry>, DomainError> {
         Ok(Paginated { items: vec![], total: 0, page: 1, per_page: 20 })
     }
+    async fn tag_feed(&self, _tag_name: &str, _page: &PageParams, _viewer_id: Option<&UserId>) -> Result<Paginated<FeedEntry>, DomainError> {
+        Ok(Paginated { items: vec![], total: 0, page: 1, per_page: 20 })
+    }
 }
 
 #[async_trait] impl SearchPort for TestStore {

crates/presentation/src/handlers/feed.rs

@@ -161,21 +161,12 @@ pub async fn tag_thoughts_handler(
     Query(q): Query<PaginationQuery>,
 ) -> Result<Json<serde_json::Value>, ApiError> {
     let page = PageParams { page: q.page(), per_page: q.per_page() };
-    let result = get_by_tag(&*s.tags, &tag_name, page).await?;
+    let result = get_by_tag(&*s.feed, &tag_name, page).await?;
     Ok(Json(serde_json::json!({
         "tag": tag_name,
         "total": result.total,
         "page": result.page,
         "per_page": result.per_page,
-        "items": result.items.iter().map(|t| serde_json::json!({
-            "id": t.id.as_uuid(),
-            "content": t.content.as_str(),
-            "in_reply_to_id": t.in_reply_to_id.as_ref().map(|id| id.as_uuid()),
-            "visibility": t.visibility.as_str(),
-            "content_warning": t.content_warning,
-            "sensitive": t.sensitive,
-            "created_at": t.created_at,
-            "updated_at": t.updated_at,
-        })).collect::<Vec<_>>()
+        "items": result.items.iter().map(to_thought_response).collect::<Vec<_>>(),
     })))
 }