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README.md

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+## Architecture note
+
+The environment is implemented as a FastAPI application that exposes the
+OpenEnv-spec endpoints (`/reset`, `/step`, `/state`, `/tasks`, `/health`,
+`/metadata`, `/schema`) directly, rather than extending `openenv.Environment`
+as a Python class. Both implementations are spec-compliant — they expose
+the same JSON-over-HTTP interface — but the FastAPI-direct approach gave
+us finer control over the multi-component reward function and Pydantic
+validation during the time-boxed hackathon build.
+
+The client (`client.py`) does extend `openenv.EnvClient` and provides the
+standard Gym-style typed interface, so any code that uses an `EnvClient`
+to talk to this Space will work without modification.
+
 ## Compliance checklist
 
 - ✅ Built on **OpenEnv** (latest release, `openenv-core>=0.2.0`)