Shachi SDK — Interface Design Specifications

Date: 2026-02-25 Source: SPECTRE capability audit (Simulant) + KOS API survey Status: DRAFT — for MjF review before implementation Companion: internal/SHACHI_SDK_PRESCRIPTION.md (architecture), this doc (interfaces)

These 8 specs define game-facing APIs for Shachi. Each is grounded in what KOS provides today, what the Simulant audit revealed as the right shape, and what SPECTRE’s Kamui/PVR2 analysis says about hardware reality.

Design principles: - C99 (not C++). Shachi is a C SDK on KOS. - Thin wrappers where KOS is already good. New code only where KOS has gaps. - Every struct and function prefixed sh_ (Shachi namespace). - PVR2-native first. GL-abstraction is explicitly rejected.


Spec 1: VMU Interface (shachi/vmu.h)