Instruction file imported from Hemavathi15sg/perltonode (.github/instructions/enterprise-modernization.instructions.md). Copyright stays with the author.

Enterprise Modernization Coding Standards

• Preserve existing business behavior before improving structure.
• Explain intended behavior preservation and migration risk before modifying code.
• Prefer incremental changes that can coexist with legacy code.
• Keep business logic separate from transport, framework, persistence, and infrastructure code.
• Maintain compatibility with existing API contracts unless a versioned migration path is provided.
• Validate input at trust boundaries.
• Use parameterized queries or safe data access abstractions; never introduce SQL injection risk.
• Do not hardcode secrets, credentials, tokens, connection strings, certificates, or environment-specific values.
• Use secure authentication and authorization patterns appropriate to the target platform.
• Avoid unsafe deserialization and validate untrusted payloads.
• Protect sessions with secure cookie, expiration, and fixation controls where applicable.
• Add structured logging for important business and operational events; avoid logging sensitive data.
• Include unit tests, integration tests, regression tests, edge case checks, and behavioral parity checks where applicable.
• Include rollback or coexistence notes for risky changes.
• Follow existing repository conventions for formatting, dependency injection, tests, naming, and project structure.
• Avoid unrelated refactors during migration work.