diff --git a/packages/core/src/connectors/capabilities/cookies-chrome.test.ts b/packages/core/src/connectors/capabilities/cookies-chrome.test.ts
index cb5c111..78e7163 100644
--- a/packages/core/src/connectors/capabilities/cookies-chrome.test.ts
+++ b/packages/core/src/connectors/capabilities/cookies-chrome.test.ts
@@ -1,7 +1,60 @@
 import { describe, it, expect } from 'vitest'
-import { makeChromeCookiesCapability } from './cookies-chrome.js'
+import { makeChromeCookiesCapability, getMatchingHostKeys } from './cookies-chrome.js'
 import { SyncError, SyncErrorCode } from '@spool/connector-sdk'
 
+describe('getMatchingHostKeys', () => {
+  it('matches host-only and same-host domain cookies', () => {
+    expect(getMatchingHostKeys('reddit.com')).toEqual([
+      'reddit.com',
+      '.reddit.com',
+    ])
+  })
+
+  it('matches parent domain cookies for subdomain requests', () => {
+    expect(getMatchingHostKeys('www.reddit.com')).toEqual([
+      'www.reddit.com',
+      '.www.reddit.com',
+      '.reddit.com',
+    ])
+  })
+
+  it('walks all parent labels for deep subdomains', () => {
+    expect(getMatchingHostKeys('a.b.example.co.uk')).toEqual([
+      'a.b.example.co.uk',
+      '.a.b.example.co.uk',
+      '.b.example.co.uk',
+      '.example.co.uk',
+      '.co.uk',
+    ])
+  })
+
+  it('does not walk into a bare TLD', () => {
+    const keys = getMatchingHostKeys('reddit.com')
+    expect(keys).not.toContain('.com')
+    expect(keys).not.toContain('com')
+  })
+
+  it('lower-cases the input host', () => {
+    expect(getMatchingHostKeys('WWW.Reddit.COM')).toEqual([
+      'www.reddit.com',
+      '.www.reddit.com',
+      '.reddit.com',
+    ])
+  })
+
+  it('strips a leading dot from the input', () => {
+    expect(getMatchingHostKeys('.reddit.com')).toEqual([
+      'reddit.com',
+      '.reddit.com',
+    ])
+  })
+
+  it('returns empty for single-label or empty hosts', () => {
+    expect(getMatchingHostKeys('localhost')).toEqual([])
+    expect(getMatchingHostKeys('')).toEqual([])
+  })
+})
+
 describe('makeChromeCookiesCapability', () => {
   it('returns a capability with a get method', () => {
     const cap = makeChromeCookiesCapability()
diff --git a/packages/core/src/connectors/capabilities/cookies-chrome.ts b/packages/core/src/connectors/capabilities/cookies-chrome.ts
index d3dc612..f7e6b1b 100644
--- a/packages/core/src/connectors/capabilities/cookies-chrome.ts
+++ b/packages/core/src/connectors/capabilities/cookies-chrome.ts
@@ -123,9 +123,33 @@ interface RawCookieFull {
   is_httponly: string
 }
 
-function queryAllCookiesForDomain(
+/**
+ * Enumerate every Chrome `host_key` value that should match a request to `host`
+ * per RFC 6265 §5.1.3. Chrome stores host-only cookies under the bare hostname
+ * and domain cookies under `.parent.example.com`; a request to `www.example.com`
+ * must see cookies at `www.example.com`, `.www.example.com`, and `.example.com`
+ * but not anything scoped to a sibling (`.other.example.com`) or a TLD alone.
+ */
+export function getMatchingHostKeys(host: string): string[] {
+  const normalized = host.toLowerCase().replace(/^\./, '')
+  if (!normalized || !normalized.includes('.')) return []
+
+  const keys = [normalized, `.${normalized}`]
+  let cur = normalized
+  while (true) {
+    const idx = cur.indexOf('.')
+    if (idx < 0) break
+    const parent = cur.substring(idx + 1)
+    if (!parent.includes('.')) break
+    keys.push(`.${parent}`)
+    cur = parent
+  }
+  return keys
+}
+
+function queryAllCookiesForHost(
   dbPath: string,
-  domain: string,
+  host: string,
 ): { cookies: RawCookieFull[]; dbVersion: number } {
   if (!existsSync(dbPath)) {
     throw new SyncError(
@@ -134,9 +158,12 @@ function queryAllCookiesForDomain(
     )
   }
 
-  const safeDomain = domain.replace(/'/g, "''")
+  const keys = getMatchingHostKeys(host)
+  if (keys.length === 0) return { cookies: [], dbVersion: 0 }
+
+  const quoted = keys.map(k => `'${k.replace(/'/g, "''")}'`).join(',')
   // Fetch cookies and DB version in one sqlite3 invocation to avoid double process spawn
-  const sql = `SELECT name, host_key, path, hex(encrypted_value) as encrypted_value_hex, value, expires_utc, is_secure, is_httponly, (SELECT value FROM meta WHERE key='version') as db_version FROM cookies WHERE host_key LIKE '%${safeDomain}';`
+  const sql = `SELECT name, host_key, path, hex(encrypted_value) as encrypted_value_hex, value, expires_utc, is_secure, is_httponly, (SELECT value FROM meta WHERE key='version') as db_version FROM cookies WHERE host_key IN (${quoted});`
 
   const output = runSqliteQuery(dbPath, sql)
 
@@ -190,8 +217,7 @@ export function makeChromeCookiesCapability(): CookiesCapability {
       const key = getMacOSChromeKey()
 
       const host = domainFromUrl(query.url)
-      const dotHost = host.startsWith('.') ? host : `.${host}`
-      const result = queryAllCookiesForDomain(dbPath, dotHost)
+      const result = queryAllCookiesForHost(dbPath, host)
 
       const cookies: Cookie[] = []
       for (const raw of result.cookies) {