diff --git a/src/background/controllers/completions.js b/src/background/controllers/completions.js
index 613940f..c22ba83 100644
--- a/src/background/controllers/completions.js
+++ b/src/background/controllers/completions.js
@@ -13,6 +13,7 @@ export default class ContentMessageController {
     if (words.length === 1) {
       return this.completionsInteractor.queryConsoleCommand(name);
     }
+    let keywords = trimmed.slice(name.length).trimStart();
     switch (words[0]) {
     case 'o':
     case 'open':
@@ -20,22 +21,22 @@ export default class ContentMessageController {
     case 'tabopen':
     case 'w':
     case 'winopen':
-      break;
+      return this.completionsInteractor.queryOpen(name);
     case 'b':
     case 'buffer':
-      break;
-    case 'bd!':
-    case 'bdel!':
-    case 'bdelete!':
-    case 'bdeletes!':
-      break;
+      return this.completionsInteractor.queryBuffer(name, keywords);
     case 'bd':
     case 'bdel':
     case 'bdelete':
     case 'bdeletes':
-      break;
+      return this.completionsInteractor.queryBdelete(name, keywords);
+    case 'bd!':
+    case 'bdel!':
+    case 'bdelete!':
+    case 'bdeletes!':
+      return this.completionsInteractor.queryBdeleteForce(name, keywords);
     case 'set':
-      break;
+      return this.completionsInteractor.querySet(name, keywords);
     }
     return Promise.resolve(Completions.empty());
   }
diff --git a/src/background/repositories/completions.js b/src/background/repositories/completions.js
new file mode 100644
index 0000000..30ede05
--- /dev/null
+++ b/src/background/repositories/completions.js
@@ -0,0 +1,11 @@
+export default class CompletionsRepository {
+  async queryTabs(keywords, excludePinned) {
+    let tabs = await browser.tabs.query({ currentWindow: true });
+    return tabs.filter((t) => {
+      return t.url.toLowerCase().includes(keywords.toLowerCase()) ||
+        t.title && t.title.toLowerCase().includes(keywords.toLowerCase());
+    }).filter((t) => {
+      return !(excludePinned && t.pinned);
+    });
+  }
+}
diff --git a/src/background/usecases/completions.js b/src/background/usecases/completions.js
index fc1ff52..21049d2 100644
--- a/src/background/usecases/completions.js
+++ b/src/background/usecases/completions.js
@@ -22,19 +22,39 @@ export default class CompletionsInteractor {
     if (items.length === 0) {
       return Promise.resolve(Completions.empty());
     }
-    return Promise.resolve(new Completions(
-      [new CompletionGroup('Console Command', items)]
-    ));
+    return Promise.resolve(
+      new Completions([new CompletionGroup('Console Command', items)])
+    );
   }
 
-  async queryBdeleteCommand(name, force, args) {
-    let tabs = await this.completionRepository.queryTabs(args);
+  queryOpen() {
+    return Promise.resolve(Completions.empty());
+  }
+
+  queryBuffer(name, keywords) {
+    return this.queryTabs(name, true, keywords);
+  }
+
+  queryBdelete(name, keywords) {
+    return this.queryTabs(name, true, keywords);
+  }
+
+  queryBdeleteForce(name, keywords) {
+    return this.queryTabs(name, false, keywords);
+  }
+
+  querySet() {
+    return Promise.resolve(Completions.empty());
+  }
+
+  async queryTabs(name, excludePinned, args) {
+    let tabs = await this.completionRepository.queryTabs(args, excludePinned);
     let items = tabs.map(tab => new CompletionItem({
       caption: tab.title,
       content: name + ' ' + tab.title,
       url: tab.url,
       icon: tab.favIconUrl
     }));
-    return [new CompletionGroup('Buffers', items)];
+    return new Completions([new CompletionGroup('Buffers', items)]);
   }
 }