MetaCrate is a test-driven, clean native Rust reimplementation of LibreMetaverse. LibreMetaverse is a behavioral and API reference only: the finished project must not load, host, bind to, invoke, or ship the .NET implementation. The current stage is a compiling structural shell: crate boundaries mirror the .NET library projects, public C# type names have Rust declarations, every upstream NUnit invocation has a traceable catalog entry, and every sample/tool project has a Rust binary target. Types, StructuredData, Imaging, PrimMesher, both rendering adapters, and the main assembly's packet/message/asset/primitive wire-data, core runtime/networking, avatar-facing manager, world/social/service manager, RLV, LSL tools, Utilities, Vivox, and WebRTC slices now have complete callable, failure-only signatures. The independent downstream fixture compiles every cataloged type and member with zero exclusions; semantic Rust test translations are the next stage.

Pending NUnit cases are inventory only, not generated fake tests. A case counts as translated only when an explicit Rust test body calls the mapped API and retains the upstream identity and body hash.

The source snapshot, compatibility rules, dependency research, and ordered implementation plan are in RUSTREWRITE.md.

The authoritative compiled .NET surface is checked in as api/public-api.json. Every type and member has a reviewed Rust destination in api/RUST-TYPES.tsv and api/RUST-MAPPING.tsv; api/README.md documents deterministic regeneration and validation. All API crates expose the same typed Error for fallible unimplemented members; infallible shims use libremetaverse_types::unimplemented_api! so placeholders cannot look like successful behavior.

cargo build --workspace
cargo test --workspace --no-run
python3 tools/generate_rust_mapping.py --check
python3 tools/generate_api_shims.py --check
python3 tools/check_test_parity.py

tests/upstream-tests.json is the machine-readable NUnit parity catalog. Translated tests live in hand-written Rust files with the parity-case marker documented in tests/PARITY.md; python3 tools/generate_surface.py --check verifies the catalog against the pinned adjacent LibreMetaverse checkout without overwriting those files.

Running cargo test --workspace is intentionally red during the shim stage.