CultLib/docs/runtime-parity-scope.md

Runtime Parity Scope

This is the claim CultLib can make without turning evidence into incense. Parity means the targeted runtimes speak the same wire language and expose similar developer-facing entrypoints for the roles they own. It does not mean every runtime clones the C# production server, LiteNetLib history, or hot-loop memory layout.

Objective

Cross-runtime parity has three layers:

• Wire parity: shared CultCache file/state contracts, schema-v0 MessagePack documents, transport profiles, and RUDP packets must cross runtime boundaries without translation folklore.
• Feature parity: each runtime must expose the CultCache/CultNet/CultMesh surfaces needed for its intended role, with unsupported production-server ownership called out plainly.
• Ergonomic parity: callers should find a branded CultMesh entrypoint, typed catalogs, discovery helpers, authority checks, stream surfaces, and transport helpers instead of assembling raw maps and channel strings.

SoA performance parity is deliberately not a cross-runtime requirement. C# owns the CPU-local SoA table and shared-memory streaming body path. Other runtimes may add native hot paths when their runtime role earns them, but they do not need to mimic Unity/C# memory layout to speak CultNet or participate in CultMesh.

Current Targeted Runtimes

Runtime	Role	Claimed parity	Not claimed
C#	Reference implementation and production game/server substrate	CultCache typed documents and SoA, CultNet schema-v0, LiteNetLib production path, shared transport profiles, shared RUDP socket transport, RUDP reconnect policy/controller and reconnect-loop helper, LiteNetLib client reconnect-controller adoption, CultMesh node/session/catalog/stream/simulation surfaces	No need to abandon LiteNetLib before the CultNet adapter fully owns production service adoption
Python	Package runtime, local daemon endpoint, raw interop peer, typed state participant	CultCache/CultNet/CultMesh package surface, schema catalogs, shard catalogs/logs, local TCP CultMesh server, session/prediction/simulation fact helpers, authority leases, streams, RUDP codec/session/socket transport, RUDP reconnect policy/controller and reconnect-loop helper, schema-v0 MessagePack over RUDP evidence, benchmark evidence against C# cache paths	Universal C# throughput, full C# daemon/server stack, and RUDP as the only public service pipe
TypeScript	Node/browser-adjacent projection and interop runtime	CultCache parity tests, CultNet schema-v0 peer, transport profiles, TCP-framed transport port, shared RUDP socket transport, RUDP reconnect policy/controller, RUDP reconnect-loop helper, local CultMesh node/catalog/authority/stream ergonomics	Full C# game session/server stack
Rust	Low-level cache/transport/runtime substrate	CultCache/CultNet interop lane, transport profiles, TCP-framed port, shared RUDP codec/session/socket transport, RUDP reconnect policy/controller and reconnect-loop helper, schema-v0 MessagePack over RUDP evidence, small CultMesh facade for peer cards, authority leases, RUDP endpoint parsing, and peer-card RUDP client construction	Full CultMesh game-session/server facade, stream catalog, or production game-session server
Kotlin	JVM/Android client substrate	Typed MessagePack cache, schema/shard catalogs, authority leases, stream catalog, branded CultMesh facade, RUDP client/server sugar, RUDP reconnect policy/controller and reconnect-loop helper, schema-v0 MessagePack over RUDP evidence	C# SoA store, full C# server daemon, or Unity hot-loop memory layout

Evidence Gates

• packages/cultnet-ts/test/interop/cultnet-interop.test.ts is the main live wire harness. It covers schema-v0 interop and RUDP exchange across C#, TypeScript, Rust, Python, and Kotlin, including loss, reordering, fragmentation, disconnect reason propagation, ping/pong, and schema-v0 MessagePack over RUDP for C#, Rust, Python, and Kotlin peers against TypeScript. Those RUDP schema-message tests also assert the advertised reconnectPolicy profile field from C#, Rust, Python, and Kotlin peers. Runtime-local tests cover the deterministic delay helper and reconnect controller in C#, TypeScript, Rust, Python, and Kotlin.
• packages/cultcache-py/PARITY.md is the Python-specific audit ledger. Its "Still Not Claimed" section is part of the contract, not an apology.
• docs/cultnet-transport-parity.md is the transport ownership map. It tracks the remaining work to lower older TCP/LiteNetLib/WebSocket bodies behind the shared transport port and expand RUDP adoption beyond the core proof.
• packages/cultmesh-kotlin/README.md records Kotlin's runtime role and ergonomic surface, including the explicit non-claim around C# SoA storage.

Remaining Work Before A Full Completion Claim

• Broaden service adoption so remaining daemon and production paths use the shared transport port consistently instead of keeping raw TCP/LiteNetLib/WebSocket ownership in individual bodies.
• Extend RUDP interop evidence through daemon/socket reconnect loops and the wider schema-message matrix. RUDP profiles now advertise the portable reconnect policy, runtime-local tests prove the shared controller across the targeted runtimes, and the C# LiteNetLib client plus C#/TypeScript/Rust/Python/Kotlin RUDP reconnect loops use that controller; broader service adoption remains a separate claim.
• Keep Kotlin ergonomic parity moving with Android/JVM-shaped APIs instead of backfilling C# server responsibilities it should not own.
• Keep performance claims evidence-bound: C# owns SoA; Python has benchmark comparison gates; other runtimes should advertise measured native hot paths only when those paths exist.