Step-03: Add README for observability example with setup and instructions

Author: denis-domanskii

examples/code-agent/step-03-add-observability/README.md

@@ -0,0 +1,31 @@
+# Code Agent - Step 03: Add Observability
+
+> Code from the blog post: [TBA]()
+
+This example extends our Code Agent from Step 2 with OpenTelemetry observability through LangFuse.
+
+## Prerequisites
+
+- Java 17+
+- OpenAI API key
+
+## Setup
+
+```bash
+export OPENAI_API_KEY="your-openai-key"
+export LANGFUSE_HOST="https://cloud.langfuse.com"
+export LANGFUSE_PUBLIC_KEY="your-public-key"
+export LANGFUSE_SECRET_KEY="your-secret-key"
+```
+
+## Run
+
+Navigate to this example:
+```
+cd examples/code-agent/step-03-add-observability
+```
+
+Run the agent on any project:
+```
+./gradlew run --args="/absolute/path/to/project 'Task description'"
+```