feat: auto-rename untitled notes + Rust title resolution tests

- Add auto_rename_untitled Rust command: one-shot rename of untitled-*
  files based on H1 heading, with collision handling (-2, -3)
- Wire auto-rename into frontend save flow (useAppSave.ts)
- Update Rust tests: extract_title now uses H1 > frontmatter > filename
- Add extract_h1_title tests

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

demo-vault-v2/career-tracks-depend-on-company-shape.md

@@ -1,5 +1,4 @@
 ---
-title: Untitled note 360
 type: Note
 status: Active
 ---

demo-vault-v2/renamed-title-xyz.md

@@ -1,5 +1,4 @@
 ---
-title: Untitled note 345
 type: Note
 status: Active
 ---

demo-vault-v2/responsive-rename-test-renamed.md

@@ -0,0 +1,7 @@
+---
+type: Project
+status: Active
+---
+
+
+Appended by raw editor test

demo-vault-v2/responsive-rename-test.md

@@ -1,4 +0,0 @@
----
-type: Note
-status: Active
----

demo-vault-v2/untitled-note-1775473969.md

@@ -0,0 +1,7 @@
+---
+type: Note
+status: Active
+---
+[[2024-03|March 2024]]
+
+[[2024-03|March 2024]]

demo-vault-v2/untitled-project-1775473964.md

@@ -0,0 +1,15 @@
+---
+type: Project
+status: Active
+---
+
+## Objective
+
+
+
+## Key Results
+
+
+
+## Notes
+

src-tauri/src/commands/vault.rs

@@ -45,6 +45,16 @@ pub fn rename_note(
     vault::rename_note(&vault_path, &old_path, &new_title, old_title.as_deref())
 }
 
+#[tauri::command]
+pub fn auto_rename_untitled(
+    vault_path: String,
+    note_path: String,
+) -> Result<Option<RenameResult>, String> {
+    let vault_path = expand_tilde(&vault_path);
+    let note_path = expand_tilde(&note_path);
+    vault::auto_rename_untitled(&vault_path, &note_path)
+}
+
 #[tauri::command]
 pub fn detect_renames(vault_path: String) -> Result<Vec<DetectedRename>, String> {
     let vault_path = expand_tilde(&vault_path);

src-tauri/src/lib.rs

@@ -119,6 +119,7 @@ pub fn run() {
             commands::update_frontmatter,
             commands::delete_frontmatter_property,
             commands::rename_note,
+            commands::auto_rename_untitled,
             commands::detect_renames,
             commands::update_wikilinks_for_renames,
             commands::get_file_history,

src-tauri/src/vault/getting_started.rs

@@ -539,8 +539,8 @@ mod tests {
         create_getting_started_vault(vault_path.to_str().unwrap()).unwrap();
 
         let entry = crate::vault::parse_md_file(&vault_path.join("AGENTS.md"), None).unwrap();
-        // No frontmatter title → derived from filename slug (H1 is body content)
-        assert_eq!(entry.title, "AGENTS");
+        // H1 is now the primary title source
+        assert_eq!(entry.title, "AGENTS.md \u{2014} Vault Instructions for AI Agents");
         // Config files have no frontmatter type field — type is None
         assert_eq!(entry.is_a, None);
     }

src-tauri/src/vault/mod.rs

@@ -20,7 +20,8 @@ pub use getting_started::{create_getting_started_vault, default_vault_path, vaul
 pub use image::{copy_image_to_vault, save_image};
 pub use migration::migrate_is_a_to_type;
 pub use rename::{
-    detect_renames, rename_note, update_wikilinks_for_renames, DetectedRename, RenameResult,
+    auto_rename_untitled, detect_renames, rename_note, update_wikilinks_for_renames,
+    DetectedRename, RenameResult,
 };
 pub use title_sync::{sync_title_on_open, SyncAction};
 pub use trash::{batch_delete_notes, delete_note};

src-tauri/src/vault/mod_tests.rs

@@ -94,8 +94,8 @@ fn test_parse_empty_frontmatter() {
         "just-a-title.md",
         "---\n---\n# Just a Title\n\nNo frontmatter fields.",
     );
-    // No title in frontmatter → derived from filename slug (H1 is body content)
-    assert_eq!(entry.title, "Just A Title");
+    // H1 is now the primary title source
+    assert_eq!(entry.title, "Just a Title");
     assert!(entry.aliases.is_empty());
 
     assert!(entry.belongs_to.is_empty());

src-tauri/src/vault/parsing.rs

@@ -341,29 +341,65 @@ mod tests {
         assert_eq!(slug_to_title("a--b"), "A B");
     }
 
+    // --- extract_h1_title tests ---
+
+    #[test]
+    fn test_extract_h1_title_basic() {
+        assert_eq!(extract_h1_title("# Hello World\n\nBody."), Some("Hello World".to_string()));
+    }
+
+    #[test]
+    fn test_extract_h1_title_after_frontmatter() {
+        let content = "---\ntype: Note\n---\n# My Note\n\nBody.";
+        assert_eq!(extract_h1_title(content), Some("My Note".to_string()));
+    }
+
+    #[test]
+    fn test_extract_h1_title_with_empty_lines_before() {
+        let content = "---\ntype: Note\n---\n\n# Spaced Title\n\nBody.";
+        assert_eq!(extract_h1_title(content), Some("Spaced Title".to_string()));
+    }
+
+    #[test]
+    fn test_extract_h1_title_none_when_no_h1() {
+        assert_eq!(extract_h1_title("Just body text."), None);
+    }
+
+    #[test]
+    fn test_extract_h1_title_none_when_h1_not_first() {
+        assert_eq!(extract_h1_title("Some text\n# Not first\n"), None);
+    }
+
     // --- extract_title tests ---
 
     #[test]
-    fn test_extract_title_from_frontmatter() {
+    fn test_extract_title_h1_takes_priority_over_frontmatter() {
         assert_eq!(
-            extract_title(Some("My Great Note"), "", "my-great-note.md"),
-            "My Great Note"
+            extract_title(Some("FM Title"), "---\ntitle: FM Title\n---\n# H1 Title\n\nBody.", "note.md"),
+            "H1 Title"
         );
     }
 
     #[test]
-    fn test_extract_title_ignores_h1_uses_filename() {
-        // H1 is body content, not a title source
+    fn test_extract_title_h1_when_no_frontmatter_title() {
         assert_eq!(
             extract_title(None, "# Hello World\n\nBody text.", "some-file.md"),
-            "Some File"
+            "Hello World"
         );
     }
 
     #[test]
-    fn test_extract_title_ignores_h1_after_frontmatter() {
+    fn test_extract_title_h1_after_frontmatter() {
         let content = "---\nIs A: Note\n---\n# My Note\n\nBody.";
-        assert_eq!(extract_title(None, content, "fallback.md"), "Fallback");
+        assert_eq!(extract_title(None, content, "fallback.md"), "My Note");
+    }
+
+    #[test]
+    fn test_extract_title_frontmatter_when_no_h1() {
+        assert_eq!(
+            extract_title(Some("My Great Note"), "Just body text.", "my-great-note.md"),
+            "My Great Note"
+        );
     }
 
     #[test]
@@ -375,11 +411,10 @@ mod tests {
     }
 
     #[test]
-    fn test_extract_title_empty_fm_falls_back_to_filename() {
-        // Empty frontmatter title falls back to filename, not H1
+    fn test_extract_title_h1_wins_over_empty_frontmatter() {
         assert_eq!(
             extract_title(Some(""), "# From H1\n", "empty-h1.md"),
-            "Empty H1"
+            "From H1"
         );
     }
 

src-tauri/src/vault/rename.rs

@@ -251,6 +251,42 @@ pub fn rename_note(
     })
 }
 
+/// Check if a filename matches the untitled pattern (e.g. "untitled-note-1234567890.md").
+fn is_untitled_filename(filename: &str) -> bool {
+    let stem = filename.strip_suffix(".md").unwrap_or(filename);
+    // Match: untitled-note-{digits} or untitled-{type}-{digits}
+    stem.starts_with("untitled-") && stem.rsplit('-').next().is_some_and(|s| s.chars().all(|c| c.is_ascii_digit()))
+}
+
+/// Auto-rename an untitled note based on its H1 heading.
+/// Returns `Some(RenameResult)` if renamed, `None` if conditions not met.
+/// This is a ONE-SHOT rename: only fires for untitled-* files with an H1.
+pub fn auto_rename_untitled(
+    vault_path: &str,
+    note_path: &str,
+) -> Result<Option<RenameResult>, String> {
+    let path = Path::new(note_path);
+    let filename = path
+        .file_name()
+        .map(|f| f.to_string_lossy().to_string())
+        .unwrap_or_default();
+
+    if !is_untitled_filename(&filename) {
+        return Ok(None);
+    }
+
+    let content = fs::read_to_string(path)
+        .map_err(|e| format!("Failed to read {}: {}", note_path, e))?;
+
+    let h1_title = match super::parsing::extract_h1_title(&content) {
+        Some(t) => t,
+        None => return Ok(None),
+    };
+
+    let result = rename_note(vault_path, note_path, &h1_title, None)?;
+    Ok(Some(result))
+}
+
 /// A detected rename: old path → new path (both relative to vault root).
 #[derive(Debug, Serialize, Deserialize, Clone)]
 pub struct DetectedRename {

src/hooks/useAppSave.ts

@@ -1,7 +1,9 @@
 import { useCallback, useEffect, useRef } from 'react'
+import { invoke } from '@tauri-apps/api/core'
 import { useEditorSaveWithLinks } from './useEditorSaveWithLinks'
 import { needsRenameOnSave } from './useNoteRename'
 import { flushEditorContent } from '../utils/autoSave'
+import { isTauri } from '../mock-tauri'
 import type { VaultEntry } from '../types'
 
 interface TabState {
@@ -55,7 +57,27 @@ export function useAppSave({
   const onNotePersisted = useCallback((path: string) => {
     clearUnsaved(path)
     if (path.endsWith('.yml')) reloadViews?.()
-  }, [clearUnsaved, reloadViews])
+    // Auto-rename untitled notes when they have an H1 heading
+    const filename = path.split('/').pop() ?? ''
+    const stem = filename.replace(/\.md$/, '')
+    if (isTauri() && stem.startsWith('untitled-') && /\d+$/.test(stem)) {
+      invoke<{ new_path: string; updated_files: number } | null>('auto_rename_untitled', {
+        vaultPath: resolvedPath,
+        notePath: path,
+      }).then((result) => {
+        if (result) {
+          // Re-read the renamed file content and entry, then replace
+          Promise.all([
+            invoke<VaultEntry>('reload_vault_entry', { path: result.new_path }),
+            invoke<string>('get_note_content', { path: result.new_path }),
+          ]).then(([newEntry, newContent]) => {
+            replaceEntry(path, { ...newEntry, path: result.new_path }, newContent)
+            loadModifiedFiles()
+          }).catch(() => { /* ignore reload failure */ })
+        }
+      }).catch(() => { /* auto-rename is best-effort */ })
+    }
+  }, [clearUnsaved, reloadViews, resolvedPath, replaceEntry, loadModifiedFiles])
 
   const { handleSave: handleSaveRaw, handleContentChange, savePendingForPath, savePending } = useEditorSaveWithLinks({
     updateEntry, setTabs, setToastMessage, onAfterSave, onNotePersisted,