AGENTS.md

Logger backend instructions

Each logger backend must honor the common ILogger lifecycle contract while remaining independently usable through loggers.hpp.

• log() must become a no-op after shutdown and must not access backend state after the logger's worker or callback resources are released.
• Serialize backend-specific writes with the backend mutex/executor only; do not hold the global Logger registry lock while invoking user callbacks or doing I/O.
• Snapshot callback/subscriber lists before invocation. Callbacks may remove themselves, add another callback, throw, or call back into the logger.
• Keep synchronous and asynchronous modes behaviorally equivalent for ordering, error reporting, and shutdown. Test both modes when changing dispatch.
• Optional backends must remain behind their feature macros and must include only the dependency umbrella supplied by CMake.
• File and MDBX backends own durable resources. Close/commit them before destruction and report failures through the configured error callback without allowing callback exceptions to escape a noexcept path.

Update the backend-specific documentation and tests with any lifecycle or configuration change. Do not duplicate serialization or retry logic when a shared helper already owns that behavior.