Treat environment variables and configuration flags as a documented contract: the code must (1) read settings from the correct source with safe defaults, (2) make feature-flag behavior explicit (including what becomes a true no-op when disabled), and (3) validate any external runtime dependency that the integration relies on. Apply this standard: - Feature flags: if a toggle changes output structure, confirm the “disabled” behavior is intentional and harmless to the core payload. - Example pattern: ```python docs = {} if include_document_metadata: documents = DocumentService.get_by_ids([...]) docs = {d.id: DocMetadataService.get_document_metadata(d.id) or {} for d in documents} # When false, metadata loop should no-op; chunk title/url/content still come from chunks. ``` - Config/env parsing: use the intended settings/env source and add a default to avoid breaking existing deployments. - Example pattern: ```python secure = str(settings.MINIO.get("secure", False)).lower() == "true" client = Minio(host, access_key=..., secret_key=..., secure=secure) ``` - External dependency validation: if a library shells out (e.g., Java) or relies on host tools, detect and warn/fail early with the required version and where it must be installed. - Environment variable semantics: document assumptions about env-var behavior (e.g., `CUDA_VISIBLE_DEVICES` remapping makes device indices continuous within the process), and ensure the code aligns with those semantics. - Avoid config mistakes: keep imports consistent with the intended module (e.g., `DEBUG` from the correct settings namespace).