Interoperability and dynamic-control evidence
GAOS is the simulation authority in every native integration below. Networking, accounts, matchmaking, storage, rendering, and external trust remain product responsibilities. Run the built-in runReferenceHostConformance() and the product adapter through runHostConformance() before claiming compatibility; each gaos.host-conformance.v1 report names the runtime, adapter version, every fixture, and the pass/fail result.
Authoritative hosts
| Platform | Classification and authority | Runtime and cryptography | Persistence and evidence |
|---|---|---|---|
| Nakama | Direct host. One authoritative TypeScript match invokes SessionHostDriver; clients never reduce game state. | Nakama's TypeScript runtime must provide the SDK's ES2022 features and Ed25519 WebCrypto, or a product-supplied signer/verifier adapter. Do not assume Node built-ins. | Persist the committed transition, seat-control checkpoint, and outbox before publish. The match process finalizes evidence in-process when its runtime supports the complete stack. |
| Colyseus | Direct host. The room owns transport and connection membership; one GAOS session owns simulation. | Node.js 20.3+ and WebCrypto support the complete evidence stack. Colyseus schema state is a projection, not a second reducer. | A product storage adapter durably commits transition/checkpoint/outbox state. The room may finalize evidence in-process after durable commit. |
| Node.js HTTP/WebSocket | Direct reference host. HTTP creates and repairs sessions; WebSocket carries commands, receipts, snapshots, and patches; SessionHostDriver is authoritative. | Node.js 20.3+; WebCrypto Ed25519 executes signature v1/v2 and external-attestation verification. Enforce product payload and backpressure limits at the socket edge. | Store committed transition, checkpoint, and publish outbox atomically. Retry publish from the durable outbox; keep replay and benchmark bundles in product object storage. |
| Photon Fusion | Transport/orchestration layer. Fusion forwards ordered command envelopes and seat scopes to one headless GAOS server or sidecar. It must not simulate the same match independently. | Fusion transports opaque JSON/binary payloads; the GAOS process performs canonical hashing and cryptography. Product code propagates controller id, epoch, transition revision, and submission id. | The GAOS process owns durable evidence. Use ordered delivery, idempotent submission ids, bounded payloads/backpressure, and snapshot repair after reconnect. |
| Photon Quantum | Alternate simulation core unless GAOS is explicitly selected as the sole simulation core. | Option 1 uses a non-simulating transport and native GAOS evidence. Option 2 uses Quantum confirmed inputs, pinned simulation identity, frame digests, and final results. | Option 2 emits an explicitly external artifact format and an external-verifier result. It must never claim that a GAOS reducer replayed the run. Quantum or product infrastructure owns its evidence durability. |
The reference lifecycle is create, control, ingest, advance, snapshot, and terminate. A host acknowledges only after durable commit. Byte-identical retries return the durable result; conflicting reuse is rejected. Reconnect binds a new connection to the active controller and logical seat scopes without creating an epoch. A patch without its base triggers snapshot repair.
Rendering engines
| Engine | Authority boundary | Projection and reconnect |
|---|---|---|
| Unity | The C# client decodes GAOS observations. GameObjects, Animator state, camera, and input are presentation only. Unity must not run a competing authoritative reducer. | Map stable entity ids to GameObjects. Apply durable state before animation. Feed product cue types through the PresentationCueClient algorithm, acknowledge each cue, and request replay or a snapshot on repair. |
| Godot | GDScript or C# decodes the same fixture over WebSocket. Nodes/scenes are projections; GAOS remains authoritative. | Map stable ids to Nodes. Preserve unknown optional fields. Mirror PresentationCueClient sequence/idempotency state for scene, video, particle, and emergency-stop cues; replace the durable projection when retention requires a snapshot. |
| Unreal Engine | C++ decodes GAOS messages and projects entities into Actors/UObjects. Native replication may distribute the projection but must not become a second simulation authority. | Reconcile durable snapshots by stable ID. Mirror PresentationCueClient before emitting Blueprint effects so retries are idempotent and reconnect gaps are repaired. |
The executable examples live under examples/clients. The release test compiles and runs TypeScript/Node, C#/.NET, C++17, and GDScript/Godot against fixtures/ecosystem/presentation-client-v1.golden.json. The fixture includes an unknown optional field so integrations can verify compatible minor-field preservation. These examples intentionally do not prescribe a UI, art, camera, animation, or input framework.
The separate gaos.presentation-cue.v1 lane carries ephemeral product effects without turning a renderer into an authority. The TypeScript host and client implementations define ordering, acknowledgement, bounded replay, snapshot repair, and emergency interruption; native engines mirror that small state machine around their own product-defined cue handlers.
Dynamic controller evidence
gaos.submission.ed25519.v2 starts a distinct command chain for every logical seat epoch. Its genesis binds the session, seat, epoch key, transition digest, previous epoch digest, and the last authenticated prior chain head when available. A voluntary gaos.controller-handoff.v2 is signed by both outgoing and incoming keys. Abrupt replacement is recorded as host-policy; it is never presented as controller consent.
verifyDynamicControlEvidenceV2() rehydrates and validates the full seat-control history, resolves every command at its exact transition revision, checks checkpointed epoch genesis/final heads and periodic signatures, requires a voluntary handoff to name the exact computed outgoing head, identifies host-policy epochs, and reports unsigned or incomplete tails. The v2 golden vectors are shared with the Python SDK. Existing replay v1.0–v1.3 and gaos.submission.ed25519.v1 retain their original interpretation.
External attestations are verified only against caller-supplied ExternalTrustPolicy and ExternalTrustResolver values. Embedded keys and certificate chains are evidence, never trust anchors. Private keys stay behind product-supplied signer callbacks.