netfishing/docs/decisions/0001-host-authority.md

ADR 0001: Host-authoritative shared state

Status: accepted

Context

NETfishing supports private hosts, open hosts, and joined clients. Catches, currency, owned items, jobs, mail, drawings, profiles, and moderation affect state that cannot safely trust a client's local presentation.

Decision

The host validates requests against registered peers and host-owned context, then performs the authoritative mutation. Clients receive results and replicated presentation state. Client evidence is bounded and reconstructed where possible; it is not treated as authority.

Private single-player uses the same host path. Presentation-only state does not add RPCs or persistence.

Consequences

• Shared behavior is consistent across private, open-host, and joined-client modes.
• Tests must cover local-host and paired host/client paths.
• Stable protocol payloads and rejection cleanup require explicit handling.
• UI activation cannot be used as proof that a server-side mutation succeeded.