diff --git a/src-tauri/src/ai_chat.rs b/src-tauri/src/ai_chat.rs
index 9770e4e3..a3903f61 100644
--- a/src-tauri/src/ai_chat.rs
+++ b/src-tauri/src/ai_chat.rs
@@ -184,8 +184,12 @@ mod tests {
         assert_eq!(extract_response_text(&resp), "");
     }
 
+    // Mutex to serialize env-var tests and avoid race conditions in parallel test runs
+    static ENV_MUTEX: std::sync::Mutex<()> = std::sync::Mutex::new(());
+
     #[test]
     fn test_get_api_key_missing() {
+        let _guard = ENV_MUTEX.lock().unwrap();
         // Temporarily clear the env var
         let prev = std::env::var("ANTHROPIC_API_KEY").ok();
         unsafe {
@@ -206,6 +210,7 @@ mod tests {
 
     #[test]
     fn test_get_api_key_present() {
+        let _guard = ENV_MUTEX.lock().unwrap();
         let prev = std::env::var("ANTHROPIC_API_KEY").ok();
         unsafe {
             std::env::set_var("ANTHROPIC_API_KEY", "sk-test-key-123");
diff --git a/src/components/Editor.test.tsx b/src/components/Editor.test.tsx
index c97e6068..a28258ad 100644
--- a/src/components/Editor.test.tsx
+++ b/src/components/Editor.test.tsx
@@ -22,14 +22,19 @@ vi.mock('@blocknote/core', () => ({
   filterSuggestionItems: vi.fn(() => []),
 }))
 
+// eslint-disable-next-line @typescript-eslint/no-explicit-any -- mock
+const mockFilterSuggestionItems = vi.fn((...args: any[]) => args[0] ?? [])
 vi.mock('@blocknote/core/extensions', () => ({
-  filterSuggestionItems: vi.fn(() => []),
+  filterSuggestionItems: (...args: unknown[]) => mockFilterSuggestionItems(...args),
 }))
 
+// eslint-disable-next-line @typescript-eslint/no-explicit-any -- mock
+let capturedGetItems: ((query: string) => Promise<any[]>) | null = null
 vi.mock('@blocknote/react', () => ({
   createReactInlineContentSpec: () => ({ render: () => null }),
   useCreateBlockNote: () => mockEditor,
-  SuggestionMenuController: () => null,
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any -- mock
+  SuggestionMenuController: (props: any) => { capturedGetItems = props.getItems; return null },
 }))
 
 vi.mock('@blocknote/mantine', () => ({
@@ -268,3 +273,78 @@ describe('Editor', () => {
     mockEditor.insertBlocks.mockClear()
   })
 })
+
+describe('wikilink autocomplete', () => {
+  const entries: VaultEntry[] = [
+    { ...mockEntry, title: 'Alpha Project', filename: 'alpha.md', aliases: ['al'] },
+    { ...mockEntry, title: 'Beta Review', filename: 'beta.md', path: '/vault/beta.md', aliases: [] },
+    { ...mockEntry, title: 'Gamma Notes', filename: 'gamma.md', path: '/vault/gamma.md', aliases: ['gam'] },
+  ]
+
+  function renderWithEntries() {
+    capturedGetItems = null
+    mockFilterSuggestionItems.mockClear()
+    render(
+      <Editor
+        {...defaultProps}
+        tabs={[mockTab]}
+        activeTabPath={mockEntry.path}
+        entries={entries}
+      />
+    )
+  }
+
+  it('returns empty array for query shorter than 2 characters', async () => {
+    renderWithEntries()
+    expect(capturedGetItems).toBeTruthy()
+    expect(await capturedGetItems!('')).toEqual([])
+    expect(await capturedGetItems!('a')).toEqual([])
+    // filterSuggestionItems should NOT be called for short queries
+    expect(mockFilterSuggestionItems).not.toHaveBeenCalled()
+  })
+
+  it('returns items for query of 2+ characters', async () => {
+    renderWithEntries()
+    const items = await capturedGetItems!('Al')
+    expect(items.length).toBeGreaterThan(0)
+    expect(mockFilterSuggestionItems).toHaveBeenCalled()
+  })
+
+  it('limits results to MAX_RESULTS (20)', async () => {
+    // Create many entries that will all match
+    const manyEntries = Array.from({ length: 50 }, (_, i) => ({
+      ...mockEntry,
+      title: `Match Item ${i}`,
+      filename: `match-${i}.md`,
+      path: `/vault/match-${i}.md`,
+      aliases: [],
+    }))
+
+    capturedGetItems = null
+    mockFilterSuggestionItems.mockImplementation((items: unknown[]) => items)
+    render(
+      <Editor
+        {...defaultProps}
+        tabs={[mockTab]}
+        activeTabPath={mockEntry.path}
+        entries={manyEntries}
+      />
+    )
+
+    const items = await capturedGetItems!('Match')
+    expect(items.length).toBeLessThanOrEqual(20)
+    mockFilterSuggestionItems.mockImplementation((items: unknown[]) => items)
+  })
+
+  it('each item has onItemClick that inserts wikilink', async () => {
+    renderWithEntries()
+    mockEditor.insertInlineContent.mockClear()
+    const items = await capturedGetItems!('Alpha')
+    expect(items.length).toBeGreaterThan(0)
+    items[0].onItemClick()
+    expect(mockEditor.insertInlineContent).toHaveBeenCalledWith([
+      { type: 'wikilink', props: { target: 'Alpha Project' } },
+      ' ',
+    ])
+  })
+})
diff --git a/src/components/Editor.tsx b/src/components/Editor.tsx
index 12c9745c..9d219063 100644
--- a/src/components/Editor.tsx
+++ b/src/components/Editor.tsx
@@ -14,6 +14,7 @@ import { TabBar } from './TabBar'
 import { BreadcrumbBar } from './BreadcrumbBar'
 import { useEditorTheme } from '../hooks/useTheme'
 import { splitFrontmatter, preProcessWikilinks, injectWikilinks, restoreWikilinksInBlocks, countWords } from '../utils/wikilinks'
+import { preFilterWikilinks, MAX_RESULTS, MIN_QUERY_LENGTH } from '../utils/wikilinkSuggestions'
 import { resolveWikilinkColor as resolveColor } from '../utils/wikilinkColors'
 import './Editor.css'
 import './EditorTheme.css'
@@ -141,7 +142,10 @@ function SingleEditorView({ editor, entries, onNavigateWikilink, onChange }: { e
   )
 
   const getWikilinkItems = useCallback(async (query: string) => {
-    const items = baseItems.map(item => ({
+    if (query.length < MIN_QUERY_LENGTH) return []
+
+    const candidates = preFilterWikilinks(baseItems, query)
+    const items = candidates.map(item => ({
       ...item,
       onItemClick: () => {
         editor.insertInlineContent([
@@ -153,7 +157,7 @@ function SingleEditorView({ editor, entries, onNavigateWikilink, onChange }: { e
         ])
       },
     }))
-    return filterSuggestionItems(items, query)
+    return filterSuggestionItems(items, query).slice(0, MAX_RESULTS)
   }, [baseItems, editor])
 
   return (
diff --git a/src/hooks/useCommitFlow.ts b/src/hooks/useCommitFlow.ts
index e4d66ba2..3cb3c1f1 100644
--- a/src/hooks/useCommitFlow.ts
+++ b/src/hooks/useCommitFlow.ts
@@ -1,7 +1,7 @@
 import { useCallback, useState } from 'react'
 
 interface CommitFlowConfig {
-  savePending: () => Promise<void>
+  savePending: () => Promise<void | boolean>
   loadModifiedFiles: () => Promise<void>
   commitAndPush: (message: string) => Promise<string>
   setToastMessage: (msg: string | null) => void
diff --git a/src/utils/wikilinkSuggestions.test.ts b/src/utils/wikilinkSuggestions.test.ts
new file mode 100644
index 00000000..3b1ead17
--- /dev/null
+++ b/src/utils/wikilinkSuggestions.test.ts
@@ -0,0 +1,98 @@
+import { describe, it, expect } from 'vitest'
+import { preFilterWikilinks, MIN_QUERY_LENGTH, MAX_RESULTS, type WikilinkBaseItem } from './wikilinkSuggestions'
+
+function makeItem(title: string, aliases: string[] = [], group = 'Note'): WikilinkBaseItem {
+  return { title, aliases, group, entryTitle: title }
+}
+
+describe('preFilterWikilinks', () => {
+  const items: WikilinkBaseItem[] = [
+    makeItem('Build Laputa App', ['laputa-app'], 'Project'),
+    makeItem('Quarterly Review', ['q1-review'], 'Responsibility'),
+    makeItem('TypeScript Tips', ['ts-tips']),
+    makeItem('Café Notes', ['café']),
+    makeItem('React Hooks Deep-Dive', ['react-hooks']),
+  ]
+
+  it('returns empty for query shorter than MIN_QUERY_LENGTH', () => {
+    expect(preFilterWikilinks(items, '')).toEqual([])
+    expect(preFilterWikilinks(items, 'a')).toEqual([])
+  })
+
+  it('returns matches for query of exactly MIN_QUERY_LENGTH', () => {
+    const result = preFilterWikilinks(items, 'la')
+    expect(result.length).toBeGreaterThan(0)
+    expect(result.some(r => r.title === 'Build Laputa App')).toBe(true)
+  })
+
+  it('matches on title (case-insensitive)', () => {
+    const result = preFilterWikilinks(items, 'quarterly')
+    expect(result).toHaveLength(1)
+    expect(result[0].title).toBe('Quarterly Review')
+  })
+
+  it('matches on aliases', () => {
+    const result = preFilterWikilinks(items, 'ts-tip')
+    expect(result).toHaveLength(1)
+    expect(result[0].title).toBe('TypeScript Tips')
+  })
+
+  it('matches on group', () => {
+    const result = preFilterWikilinks(items, 'Project')
+    expect(result).toHaveLength(1)
+    expect(result[0].title).toBe('Build Laputa App')
+  })
+
+  it('handles accented characters', () => {
+    const result = preFilterWikilinks(items, 'café')
+    expect(result).toHaveLength(1)
+    expect(result[0].title).toBe('Café Notes')
+  })
+
+  it('handles hyphens in query', () => {
+    const result = preFilterWikilinks(items, 'deep-di')
+    expect(result).toHaveLength(1)
+    expect(result[0].title).toBe('React Hooks Deep-Dive')
+  })
+
+  it('returns empty when nothing matches', () => {
+    expect(preFilterWikilinks(items, 'zzzzz')).toEqual([])
+  })
+
+  it('returns all matches when multiple items match', () => {
+    // Both "Build Laputa App" and "React Hooks Deep-Dive" contain 'e'
+    // but query must be >= 2 chars, so use a longer shared substring
+    const result = preFilterWikilinks(items, 'No') // "Note" group + "Café Notes"
+    expect(result.length).toBeGreaterThan(1)
+  })
+
+  it('handles empty items array', () => {
+    expect(preFilterWikilinks([], 'test')).toEqual([])
+  })
+})
+
+describe('constants', () => {
+  it('MIN_QUERY_LENGTH is 2', () => {
+    expect(MIN_QUERY_LENGTH).toBe(2)
+  })
+
+  it('MAX_RESULTS is 20', () => {
+    expect(MAX_RESULTS).toBe(20)
+  })
+})
+
+describe('preFilterWikilinks with large dataset', () => {
+  const largeItems: WikilinkBaseItem[] = Array.from({ length: 10000 }, (_, i) =>
+    makeItem(`Note ${i}`, [`alias-${i}`], i % 3 === 0 ? 'Project' : 'Note')
+  )
+
+  it('handles 10000+ items without throwing', () => {
+    const result = preFilterWikilinks(largeItems, 'Note 50')
+    expect(result.length).toBeGreaterThan(0)
+    expect(result.length).toBeLessThan(largeItems.length)
+  })
+
+  it('short query on large dataset returns empty', () => {
+    expect(preFilterWikilinks(largeItems, 'N')).toEqual([])
+  })
+})
diff --git a/src/utils/wikilinkSuggestions.ts b/src/utils/wikilinkSuggestions.ts
new file mode 100644
index 00000000..5acedb85
--- /dev/null
+++ b/src/utils/wikilinkSuggestions.ts
@@ -0,0 +1,29 @@
+export const MIN_QUERY_LENGTH = 2
+export const MAX_RESULTS = 20
+
+export interface WikilinkBaseItem {
+  title: string
+  aliases: string[]
+  group: string
+  entryTitle: string
+}
+
+/**
+ * Pre-filter wikilink suggestion candidates using case-insensitive substring
+ * matching on title, aliases, and group. This avoids creating expensive
+ * onItemClick closures for thousands of entries that won't match anyway.
+ *
+ * Returns [] when query is shorter than MIN_QUERY_LENGTH.
+ */
+export function preFilterWikilinks<T extends WikilinkBaseItem>(
+  items: T[],
+  query: string,
+): T[] {
+  if (query.length < MIN_QUERY_LENGTH) return []
+  const lowerQuery = query.toLowerCase()
+  return items.filter(item =>
+    item.title.toLowerCase().includes(lowerQuery) ||
+    item.aliases.some(a => a.toLowerCase().includes(lowerQuery)) ||
+    item.group.toLowerCase().includes(lowerQuery)
+  )
+}