diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
new file mode 100644
index 0000000..0b752eb
--- /dev/null
+++ b/.github/workflows/ci.yaml
@@ -0,0 +1,39 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+concurrency:
+  group: ci-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  ci:
+    runs-on: ubuntu-24.04
+    timeout-minutes: 10
+
+    steps:
+      - name: Check out source
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
+
+      - name: Set up Bun
+        uses: oven-sh/setup-bun@0c5077e51419868618aeaa5fe8019c62421857d6 # v2
+        with:
+          bun-version: latest
+
+      - name: Install dependencies
+        run: bun install --frozen-lockfile
+
+      - name: Check (lint + format)
+        run: bun run check
+
+      - name: Type check
+        run: bun run typecheck
+
+      - name: Test
+        run: bun run test
+
+      - name: Build
+        run: bun run build
diff --git a/src/client.ts b/src/client.ts
index 07c0fb2..42dcf72 100644
--- a/src/client.ts
+++ b/src/client.ts
@@ -154,7 +154,7 @@ export function loadConfig(pluginConfig?: PluginConfig): BraintrustConfig {
   let queueSize = defaults.queueSize
   if (process.env.BRAINTRUST_QUEUE_SIZE) {
     const parsed = parseInt(process.env.BRAINTRUST_QUEUE_SIZE, 10)
-    if (!isNaN(parsed) && parsed > 0) {
+    if (!Number.isNaN(parsed) && parsed > 0) {
       queueSize = parsed
     }
   }
diff --git a/src/event-processor.ts b/src/event-processor.ts
index 4fff721..a56dc4b 100644
--- a/src/event-processor.ts
+++ b/src/event-processor.ts
@@ -412,10 +412,9 @@ export class EventProcessor {
     // Guard: skip if state already exists (lazy-initialized when chat.message arrived
     // before session.created for API-created sessions).
     if (this.sessionStates.has(sessionKey)) {
-      this.log(
-        "Session state already exists (lazy-initialized), skipping session.created init",
-        { sessionKey },
-      )
+      this.log("Session state already exists (lazy-initialized), skipping session.created init", {
+        sessionKey,
+      })
       return
     }
 
diff --git a/src/span-queue.ts b/src/span-queue.ts
index 59e1307..5e3ba17 100644
--- a/src/span-queue.ts
+++ b/src/span-queue.ts
@@ -20,6 +20,7 @@ export class SpanQueue {
   private sink: SpanSink
   private log: LogFn
   private running = false
+  // biome-ignore lint/correctness/noUnusedPrivateClassMembers: intentionally held to prevent GC of background worker promise
   private workerPromise: Promise<void> | null = null
   // Notify the worker that a new item is available
   private notify: (() => void) | null = null
diff --git a/src/tracing.ts b/src/tracing.ts
index c9aecdc..237d19a 100644
--- a/src/tracing.ts
+++ b/src/tracing.ts
@@ -768,7 +768,9 @@ export function createTracingHooks(
         if (!state) {
           // session.created is not delivered to plugins for API-created sessions.
           // Initialize state lazily so API-created sessions are traced correctly.
-          log("No state found for session, initializing lazily (API-created session)", { sessionID })
+          log("No state found for session, initializing lazily (API-created session)", {
+            sessionID,
+          })
           const rootSpanId = generateUUID()
           const now = wallClock.now()
           state = {