feat(mark): add AI-generated one-sentence review titles

apps/mark/src-tauri/src/lib.rs

@@ -242,6 +242,7 @@ pub struct ReviewTimelineItem {
     pub scope: String,
     pub session_id: Option<String>,
     pub session_status: Option<String>,
+    pub title: Option<String>,
     pub comment_count: usize,
     pub created_at: i64,
     pub updated_at: i64,
@@ -1413,6 +1414,7 @@ fn build_branch_timeline(store: &Arc<Store>, branch_id: &str) -> Result<BranchTi
                 scope: r.scope.as_str().to_string(),
                 session_id,
                 session_status,
+                title: r.title,
                 comment_count,
                 created_at: r.created_at,
                 updated_at: r.updated_at,

apps/mark/src-tauri/src/session_commands.rs

@@ -1316,11 +1316,20 @@ fn review_timeline_entries(store: &Arc<Store>, branch_id: &str) -> Vec<TimelineE
             continue;
         }
         let short_sha = &review.commit_sha[..review.commit_sha.len().min(7)];
-        let mut content = format!(
-            "### Code Review of {} ({} scope)\n",
-            short_sha,
-            review.scope.as_str(),
-        );
+        let heading = match review.title.as_deref() {
+            Some(title) => format!(
+                "### {} — {} ({} scope)\n",
+                title,
+                short_sha,
+                review.scope.as_str(),
+            ),
+            None => format!(
+                "### Code Review of {} ({} scope)\n",
+                short_sha,
+                review.scope.as_str(),
+            ),
+        };
+        let mut content = heading;
 
         // Group comments by file path
         let mut by_path: std::collections::BTreeMap<&str, Vec<&crate::store::models::Comment>> =
@@ -1425,7 +1434,18 @@ Reserve `\"warning\"` and `\"issue\"` for genuine concerns.
 
 ## Output format
 
-Return your review as exactly one fenced JSON block with this structure:
+Your response must start directly with the review-title fenced block below — \
+do not output any preamble, commentary, or thinking before it.
+
+Provide a single-sentence title (max 15 words) that conveys your overall \
+confidence level in the changes. Do not describe what the changes do — instead focus on \
+how confident you are that they are correct and safe. Wrap it in a fenced block:
+
+```review-title
+Looks solid overall with one minor edge case worth checking
+```
+
+Then return your review comments as exactly one fenced JSON block:
 
 ```review-comments
 [
@@ -1445,10 +1465,12 @@ Return your review as exactly one fenced JSON block with this structure:
 ```
 
 Formatting requirements:
-- The opening fence line must be exactly: ```review-comments
-- The closing fence line must be exactly: ```
-- Put only the JSON array between the fences (no prose or markdown inside).
-- Do not wrap this block in any additional code fences.
+- The opening fence line for the title must be exactly: ```review-title
+- The opening fence line for comments must be exactly: ```review-comments
+- Each closing fence line must be exactly: ```
+- Put only plain text (no markdown) inside the review-title block.
+- Put only the JSON array inside the review-comments block (no prose or markdown).
+- Do not wrap these blocks in any additional code fences.
 
 Rules:
 - `span` uses 0-indexed line numbers from the \"after\" side of the diff (exclusive end).
@@ -1483,11 +1505,17 @@ mod tests {
             &BranchSessionType::Review,
         );
 
+        assert!(
+            prompt.contains("Then return your review comments as exactly one fenced JSON block:")
+        );
         assert!(prompt
-            .contains("Return your review as exactly one fenced JSON block with this structure:"));
-        assert!(prompt.contains("The opening fence line must be exactly: ```review-comments"));
-        assert!(prompt.contains("The closing fence line must be exactly: ```"));
+            .contains("The opening fence line for the title must be exactly: ```review-title"));
         assert!(prompt
-            .contains("Put only the JSON array between the fences (no prose or markdown inside)."));
+            .contains("The opening fence line for comments must be exactly: ```review-comments"));
+        assert!(prompt.contains("Each closing fence line must be exactly: ```"));
+        assert!(prompt.contains(
+            "Put only the JSON array inside the review-comments block (no prose or markdown)."
+        ));
+        assert!(prompt.contains("do not output any preamble, commentary, or thinking before it"));
     }
 }

apps/mark/src-tauri/src/session_runner.rs

@@ -518,17 +518,30 @@ fn run_post_completion_hooks(
         }
     }
 
-    // --- Review comment extraction ---
+    // --- Review comment and title extraction ---
     if let Ok(Some(review)) = store.get_review_by_session(session_id) {
-        if review.comments.is_empty() {
-            if let Ok(messages) = store.get_session_messages(session_id) {
-                let full_text: String = messages
-                    .iter()
-                    .filter(|m| m.role == MessageRole::Assistant)
-                    .map(|m| m.content.as_str())
-                    .collect::<Vec<_>>()
-                    .join("\n");
+        if let Ok(messages) = store.get_session_messages(session_id) {
+            let full_text: String = messages
+                .iter()
+                .filter(|m| m.role == MessageRole::Assistant)
+                .map(|m| m.content.as_str())
+                .collect::<Vec<_>>()
+                .join("\n");
+
+            // Extract and save review title (always attempt, even if comments exist)
+            if review.title.is_none() {
+                if let Some(title) = extract_review_title(&full_text) {
+                    log::info!("Session {session_id}: extracted review title: {title}");
+                    if let Err(e) = store.update_review_title(&review.id, &title) {
+                        log::error!("Failed to update review title: {e}");
+                    }
+                } else {
+                    log::warn!("Session {session_id}: review session completed but no review-title block found");
+                }
+            }
 
+            // Extract and save review comments
+            if review.comments.is_empty() {
                 let comments = extract_review_comments(&full_text);
                 if comments.is_empty() {
                     log::warn!("Session {session_id}: review session completed but no review-comments block found");
@@ -715,8 +728,9 @@ fn extract_review_comments(text: &str) -> Vec<Comment> {
     let marker_start = "```review-comments";
 
     let mut search_from = 0;
-    while let Some(start_pos) = text[search_from..].find(marker_start) {
-        let block_start = search_from + start_pos + marker_start.len();
+    while let Some(rel_pos) = find_opening_fence(&text[search_from..], marker_start) {
+        let start_pos = search_from + rel_pos;
+        let block_start = start_pos + marker_start.len();
         // Skip to the next line after the opening marker
         let json_start = match text[block_start..].find('\n') {
             Some(pos) => block_start + pos + 1,
@@ -768,6 +782,42 @@ fn extract_review_comments(text: &str) -> Vec<Comment> {
     comments
 }
 
+/// Extract the review title from assistant output.
+///
+/// Looks for a ```review-title fenced block and returns the trimmed text inside.
+/// The opening fence must appear at the start of a line to avoid matching the
+/// marker when it appears inside regular prose (e.g. the LLM discussing the
+/// extraction logic itself).
+fn extract_review_title(text: &str) -> Option<String> {
+    let marker = "```review-title";
+    let start_pos = find_opening_fence(text, marker)?;
+    let block_start = start_pos + marker.len();
+    let content_start = block_start + text[block_start..].find('\n')? + 1;
+    let end_pos = find_closing_fence(&text[content_start..])?;
+    let title = text[content_start..content_start + end_pos].trim();
+    if title.is_empty() {
+        None
+    } else {
+        Some(title.to_string())
+    }
+}
+
+/// Find an opening fence marker (e.g. ` ```review-title `) that appears at the
+/// start of a line (position 0 or immediately after `\n`).  Returns the byte
+/// offset of the marker within `text`, or `None` if no line-start match exists.
+fn find_opening_fence(text: &str, marker: &str) -> Option<usize> {
+    let mut pos = 0;
+    while pos < text.len() {
+        let candidate = text[pos..].find(marker)?;
+        let abs = pos + candidate;
+        if abs == 0 || text.as_bytes()[abs - 1] == b'\n' {
+            return Some(abs);
+        }
+        pos = abs + marker.len();
+    }
+    None
+}
+
 /// Find the closing ``` fence for a code block.
 ///
 /// A closing fence must appear at the start of a line (after a newline) and
@@ -888,6 +938,111 @@ mod tests {
         assert_eq!(find_closing_fence(text), Some(5));
     }
 
+    // ── extract_review_title ──────────────────────────────────────────
+
+    #[test]
+    fn extract_title_simple() {
+        let text = "Here is my review:\n\n```review-title\nSolid refactor with one edge case\n```\n\nAnd comments...";
+        assert_eq!(
+            extract_review_title(text),
+            Some("Solid refactor with one edge case".to_string())
+        );
+    }
+
+    #[test]
+    fn extract_title_trims_whitespace() {
+        let text = "```review-title\n  Clean changes, no concerns  \n```\n";
+        assert_eq!(
+            extract_review_title(text),
+            Some("Clean changes, no concerns".to_string())
+        );
+    }
+
+    #[test]
+    fn extract_title_none_when_missing() {
+        let text = "Just a normal message with no review title.";
+        assert_eq!(extract_review_title(text), None);
+    }
+
+    #[test]
+    fn extract_title_none_when_empty() {
+        let text = "```review-title\n\n```\n";
+        assert_eq!(extract_review_title(text), None);
+    }
+
+    #[test]
+    fn extract_title_with_review_comments() {
+        let text = r#"Here is my review:
+
+```review-title
+Risky changes to auth flow need closer look
+```
+
+```review-comments
+[
+  {
+    "path": "src/auth.rs",
+    "span": { "start": 10, "end": 15 },
+    "content": "Missing validation."
+  }
+]
+```
+"#;
+        assert_eq!(
+            extract_review_title(text),
+            Some("Risky changes to auth flow need closer look".to_string())
+        );
+    }
+
+    #[test]
+    fn extract_title_ignores_llm_preamble() {
+        let text = r#"I now have a complete picture of the changes. Let me produce the review.
+
+```review-title
+Clean, well-tested feature addition with good backward compatibility
+```
+
+```review-comments
+[
+  {
+    "path": "src/foo.rs",
+    "span": { "start": 10, "end": 15 },
+    "type": "suggestion",
+    "content": "Consider adding a test."
+  }
+]
+```
+"#;
+        assert_eq!(
+            extract_review_title(text),
+            Some(
+                "Clean, well-tested feature addition with good backward compatibility".to_string()
+            )
+        );
+    }
+
+    #[test]
+    fn extract_title_marker_mentioned_in_preamble() {
+        // The LLM discusses the ```review-title marker in its preamble before
+        // actually producing the fenced block.  The extractor must skip the
+        // mid-line mention and find the real opening fence.
+        let text = r#"Let me check whether `"```review-title"` would match inside `"```review-title-v2"`:
+I now have a complete picture. Let me produce the review.
+
+```review-title
+Solid changes with minor nit
+```
+
+```review-comments
+[]
+```
+"#;
+        assert_eq!(
+            extract_review_title(text),
+            Some("Solid changes with minor nit".to_string())
+        );
+    }
+
     // ── extract_review_comments ─────────────────────────────────────────
 
     #[test]

apps/mark/src-tauri/src/store/mod.rs

@@ -62,7 +62,7 @@ impl From<rusqlite::Error> for StoreError {
 ///
 /// Bump this whenever the schema changes.
 /// Many app versions may share the same schema version.
-pub const SCHEMA_VERSION: i64 = 17;
+pub const SCHEMA_VERSION: i64 = 18;
 
 /// Oldest schema version we can migrate forward from.
 ///
@@ -373,6 +373,7 @@ impl Store {
                 commit_sha      TEXT NOT NULL,
                 scope           TEXT NOT NULL,
                 session_id      TEXT,
+                title           TEXT,
                 created_at      INTEGER NOT NULL,
                 updated_at      INTEGER NOT NULL
             );
@@ -518,8 +519,13 @@ impl Store {
         }
 
         // v15→v16 and v16→v17 previously added a workstation_id column that
-        // has been removed. The migrations are no-ops now; SCHEMA_VERSION stays
-        // at 17 so existing databases are simply stamped forward.
+        // has been removed. The migrations are no-ops now.
+
+        if db_version < 18 {
+            // v17 → v18: add title column to reviews
+            conn.execute_batch("ALTER TABLE reviews ADD COLUMN title TEXT DEFAULT NULL;")
+                .ok(); // Ignore error if column already exists (fresh DB)
+        }
 
         // Stamp the current schema version so future opens skip applied migrations.
         conn.execute(

apps/mark/src-tauri/src/store/models.rs

@@ -822,6 +822,8 @@ pub struct Review {
     pub commit_sha: String,
     pub scope: ReviewScope,
     pub session_id: Option<String>,
+    /// AI-generated one-sentence title summarising the review's confidence.
+    pub title: Option<String>,
     /// Paths that have been marked as reviewed.
     pub reviewed: Vec<String>,
     /// Comments attached to specific locations.
@@ -841,6 +843,7 @@ impl Review {
             commit_sha: commit_sha.to_string(),
             scope,
             session_id: None,
+            title: None,
             reviewed: Vec::new(),
             comments: Vec::new(),
             reference_files: Vec::new(),