diff --git a/packages/core-shared/package.json b/packages/core-shared/package.json
index 7dbc7a3..7401b07 100644
--- a/packages/core-shared/package.json
+++ b/packages/core-shared/package.json
@@ -50,6 +50,7 @@
     "@sentry/react": { "optional": true }
   },
   "devDependencies": {
+    "@opentelemetry/context-async-hooks": "^1.28.0",
     "@repo/core-eslint": "workspace:*",
     "@repo/core-testing": "workspace:*",
     "@repo/core-typescript": "workspace:*",
diff --git a/packages/core-shared/src/instrumentation/otel/otel-tracer.test.ts b/packages/core-shared/src/instrumentation/otel/otel-tracer.test.ts
new file mode 100644
index 0000000..f20be99
--- /dev/null
+++ b/packages/core-shared/src/instrumentation/otel/otel-tracer.test.ts
@@ -0,0 +1,106 @@
+import { describe, it, expect, beforeEach, afterEach } from "vitest";
+import { context, trace } from "@opentelemetry/api";
+import { AsyncLocalStorageContextManager } from "@opentelemetry/context-async-hooks";
+import { BasicTracerProvider, InMemorySpanExporter, SimpleSpanProcessor } from "@opentelemetry/sdk-trace-base";
+import { OtelTracer } from "./otel-tracer";
+
+// Register the async context manager once for the entire test file.
+// This must be done before any OtelTracer is constructed.
+const ctxManager = new AsyncLocalStorageContextManager();
+ctxManager.enable();
+context.setGlobalContextManager(ctxManager);
+
+function setupProvider(): { exporter: InMemorySpanExporter; provider: BasicTracerProvider } {
+  const exporter = new InMemorySpanExporter();
+  const provider = new BasicTracerProvider({
+    spanProcessors: [new SimpleSpanProcessor(exporter)],
+  });
+  trace.setGlobalTracerProvider(provider);
+  return { exporter, provider };
+}
+
+describe("OtelTracer", () => {
+  let exporter: InMemorySpanExporter;
+  let provider: BasicTracerProvider;
+
+  beforeEach(() => {
+    ({ exporter, provider } = setupProvider());
+  });
+
+  afterEach(async () => {
+    await provider.shutdown();
+    trace.disable();
+  });
+
+  it("records span name and op attribute", async () => {
+    const tracer = new OtelTracer();
+    await tracer.startSpan({ name: "blog.getArticles", op: "use-case" }, async () => "value");
+    const spans = exporter.getFinishedSpans();
+    expect(spans).toHaveLength(1);
+    const [span] = spans;
+    expect(span!.name).toBe("blog.getArticles");
+    expect(span!.attributes["span.op"]).toBe("use-case");
+  });
+
+  it("records additional attributes, filtering out null values", async () => {
+    const tracer = new OtelTracer();
+    await tracer.startSpan(
+      {
+        name: "articles.findAll",
+        op: "repository",
+        attributes: { collection: "articles", limit: 10, tag: null },
+      },
+      async () => undefined,
+    );
+    const [span] = exporter.getFinishedSpans();
+    expect(span!.attributes["collection"]).toBe("articles");
+    expect(span!.attributes["limit"]).toBe(10);
+    expect(span!.attributes["tag"]).toBeUndefined();
+  });
+
+  it("nested spans — child span has parent span as its parent", async () => {
+    const tracer = new OtelTracer();
+    await tracer.startSpan({ name: "parent" }, async () => {
+      await tracer.startSpan({ name: "child" }, async () => "child-result");
+      return "parent-result";
+    });
+    const spans = exporter.getFinishedSpans();
+    expect(spans).toHaveLength(2);
+    const child = spans.find((s) => s.name === "child")!;
+    const parent = spans.find((s) => s.name === "parent")!;
+    // In sdk-trace-base@1.30.x the parent-child link is tracked via parentSpanId (string)
+    // Both spans are in the same trace
+    expect(child.spanContext().traceId).toBe(parent.spanContext().traceId);
+    // The child's parentSpanId should be the parent's span ID
+    expect(child.parentSpanId).toBe(parent.spanContext().spanId);
+  });
+
+  it("records exception and sets ERROR status on throw", async () => {
+    const tracer = new OtelTracer();
+    await expect(
+      tracer.startSpan({ name: "failing-op" }, async () => {
+        throw new Error("boom");
+      }),
+    ).rejects.toThrow("boom");
+
+    const [span] = exporter.getFinishedSpans();
+    expect(span!.status.code).toBe(2); // SpanStatusCode.ERROR = 2
+    const exceptionEvent = span!.events.find((e) => e.name === "exception");
+    expect(exceptionEvent).toBeDefined();
+    expect(exceptionEvent!.attributes!["exception.message"]).toBe("boom");
+  });
+
+  it("ISpan adapter: setAttribute ignores null; setStatus maps ok/error", async () => {
+    const tracer = new OtelTracer();
+    await tracer.startSpan({ name: "adapter-test" }, async (span) => {
+      span.setAttribute("key", "value");
+      span.setAttribute("nullable", null);
+      span.setStatus("ok");
+      return undefined;
+    });
+    const [span] = exporter.getFinishedSpans();
+    expect(span!.attributes["key"]).toBe("value");
+    expect(span!.attributes["nullable"]).toBeUndefined();
+    expect(span!.status.code).toBe(1); // SpanStatusCode.OK = 1
+  });
+});
diff --git a/packages/core-shared/src/instrumentation/otel/otel-tracer.ts b/packages/core-shared/src/instrumentation/otel/otel-tracer.ts
new file mode 100644
index 0000000..02e5b1a
--- /dev/null
+++ b/packages/core-shared/src/instrumentation/otel/otel-tracer.ts
@@ -0,0 +1,46 @@
+import { trace, SpanKind, SpanStatusCode } from "@opentelemetry/api";
+import type { ITracer, ISpan, SpanOpts } from "../tracer.interface";
+
+export class OtelTracer implements ITracer {
+  private readonly tracer = trace.getTracer("@repo/core-shared", "1.0.0");
+
+  async startSpan<T>(opts: SpanOpts, fn: (span: ISpan) => Promise<T>): Promise<T> {
+    const attributes: Record<string, string | number | boolean> = {
+      ...(opts.attributes
+        ? (Object.fromEntries(
+            Object.entries(opts.attributes).filter(([, v]) => v !== null),
+          ) as Record<string, string | number | boolean>)
+        : {}),
+      ...(opts.op ? { "span.op": opts.op } : {}),
+    };
+
+    return this.tracer.startActiveSpan(
+      opts.name,
+      { kind: SpanKind.INTERNAL, attributes },
+      async (otelSpan) => {
+        const adapter: ISpan = {
+          setAttribute(key, value) {
+            if (value !== null) {
+              otelSpan.setAttribute(key, value as string | number | boolean);
+            }
+          },
+          setStatus(status, message) {
+            otelSpan.setStatus({
+              code: status === "ok" ? SpanStatusCode.OK : SpanStatusCode.ERROR,
+              message,
+            });
+          },
+        };
+        try {
+          return await fn(adapter);
+        } catch (err) {
+          otelSpan.recordException(err as Error);
+          otelSpan.setStatus({ code: SpanStatusCode.ERROR });
+          throw err;
+        } finally {
+          otelSpan.end();
+        }
+      },
+    );
+  }
+}
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 5002d19..e400777 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -542,6 +542,9 @@ importers:
         specifier: ^3.24.0
         version: 3.25.76
     devDependencies:
+      '@opentelemetry/context-async-hooks':
+        specifier: ^1.28.0
+        version: 1.28.0(@opentelemetry/api@1.9.1)
       '@repo/core-eslint':
         specifier: workspace:*
         version: link:../core-eslint