Cap'n Proto Schemas

AMP leverages Cap'n Proto for all match-related data. Cap'n Proto is a "zero-copy" serialization format that is significantly faster than JSON or Protobuf, making it ideal for high-frequency game telemetry.

Base Schema: match.capnp

The core data structures for every match are defined in match.capnp.

@0xabcdef1234567890;

struct InputFrame {
  tick @0 :UInt64;
  playerId @1 :UInt32;
  inputData @2 :Data; # Opaque game-specific bits
}

struct MatchAssignment {
  matchId @0 :Text;
  verifierEndpoint @1 :Text;
  playerCapabilities @2 :List(Text);
}

struct MatchTranscript {
  config @0 :MatchConfig;
  frames @1 :List(InputFrame);
  events @2 :List(GameEvent);
}

Why Cap'n Proto?

1. Zero-Copy: Data is structured in memory exactly as it appears on the wire. No expensive encode/decode steps.
2. Performance: Millions of messages per second on standard hardware.
3. Schema Evolution: Add new fields to your game events without breaking existing verifiers or clients.

Versioning Strategy

AMP uses Canonical Schemas for the core protocol, but allows developers to define Extended Schemas for their specific game logic.

• v1.x (Current): Focuses on basic state hashing and RT_HASH_AGREE.
• v2.x (Roadmap): Will introduce nested capability handles for complex multi-stage tournaments.

Compiling Schemas

The AMP SDK includes a helper script to generate bindings for all supported languages (C++, C#, Go, Python, Rust):

./amp-sdk/generate_bindings.sh

This will populate the amp-sdk/<lang>/generated directories with the appropriate source files.

If you are adding custom .capnp files, you can compile them individually using the capnpc tool:

capnpc -oc++ my_game_events.capnp
capnpc -ocsharp my_game_events.capnp
capnpc -ogo my_game_events.capnp