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+# Copilot instructions
+
+This repository contains the Elastic APM Java agent.
+These instructions apply when reviewing pull requests.
+
+## Review priorities
+
+- Prioritize correctness, compatibility, and operational safety over style.
+- Focus findings on problems introduced or exposed by the pull request.
+- Explain the concrete failure scenario and user impact of each finding.
+- Prefer localized fixes over unrelated refactoring.
+
+## Compatibility and runtime behavior
+
+- Check compatibility of public APIs, configuration, and emitted telemetry.
+- Preserve supported Java versions and library or framework compatibility.
+- Check concurrent access, asynchronous context propagation, and lifecycle handling.
+- Check hot-path changes for unnecessary allocations, blocking, or contention.
+- Check resource cleanup and unbounded retention, including class-loader leaks.
+- Check error handling against existing failure-isolation and logging conventions.
+- Check that logs and telemetry do not expose credentials or sensitive data.
+
+## Tests and documentation
+
+- Look for focused regression tests for changed behavior and relevant edge cases.
+- Check that tests are deterministic and exercise observable behavior.
+- Check documentation when public behavior or configuration changes.
+- Follow existing project conventions without requesting unrelated formatting changes.
+
+## APM Java agent
+
+- Check that instrumentation failures do not escape into application code or change application behavior.
+- Check class-loading boundaries between agent and application code.
+- Check that instrumentation matches supported library versions without accidentally instrumenting unsupported versions.