ADR-0015: Platform support order

• Status: Accepted
• Date: 2026-07-15

Context

Process, port, IPC, PTY, notification, launcher, and packaging behavior differs substantially by operating system. Attempting simultaneous parity would slow the product and spread conditionals through domains.

Decision

Implement and validate macOS first, Linux second, and Windows/WSL third. Platform-specific behavior lives behind capability interfaces and OS adapter packages. Domain and application packages remain platform-neutral.

Consequences

Early releases may have explicitly documented platform gaps. Cross-platform contracts are designed early but adapters are implemented in roadmap order. Unsupported capability is a typed, explainable state rather than silent failure.