Add workflow health monitoring runbook

.github/aw/runbooks/README.md

@@ -0,0 +1,32 @@
+# Agentic Workflow Runbooks
+
+This directory contains operational runbooks for managing and troubleshooting GitHub Agentic Workflows.
+
+## Available Runbooks
+
+- [**Workflow Health Monitoring**](workflow-health.md) - How to investigate and resolve workflow health issues, including missing-tool errors, authentication problems, and configuration failures.
+
+## Purpose
+
+Runbooks provide step-by-step procedures for:
+- Diagnosing workflow issues
+- Resolving common failure patterns
+- Applying learnings from incident response
+- Maintaining workflow reliability
+
+## How to Use Runbooks
+
+1. Identify the type of issue you're experiencing
+2. Open the relevant runbook
+3. Follow the investigation steps
+4. Apply the resolution procedure
+5. Verify the fix
+
+## Contributing
+
+When creating new runbooks:
+- Focus on actionable procedures
+- Include real-world examples and case studies
+- Document commands and configuration patterns
+- Reference related documentation
+- Follow the how-to guide format