The source tree separates proof protocol, backend capabilities, frontend
semantics, backend-specific integrations, and command-line products. Each
package's package.contract.json (where present) defines its public Zig
module, dependencies, and focused CI command. The repository guide
describes product availability and supported workflows; a package compiling
successfully does not by itself qualify a complete proving product.
| Layer | Responsibility | Package guides |
|---|---|---|
| Protocol and proof engine | Backend-independent protocol, proof wire formats, backend contracts, and proving APIs | Core, backend contracts, prover API, prover engine, proof wire, recursion wire |
| Compute backends | CPU, Metal, and resident CUDA implementations | CPU, Metal, CUDA |
| Frontends | Trace semantics, statements, and backend-neutral AIR | Cairo, circuit recursion, RISC-V, SM83 |
| Cairo integrations | Backend-specific Cairo proving | CPU, Metal, CUDA |
| Circuit recursion integrations | Backend-specific circuit proving and aggregation | CPU, Metal, CUDA |
| RISC-V integrations | Backend-specific RISC-V proving | CPU, Metal, CUDA |
| SM83 integrations | Backend-specific SM83 proving | CPU, Metal |
| Native and service packages | Native examples, Native CUDA adaptation, persistent artifacts, and Metal sessions | Examples, Native CUDA, artifact store, Metal session |
| Recursion products | User-facing leaf wrap, fold, and verification commands | CPU, Metal |
Run documented commands from the repository root unless a guide says
otherwise. For an owner-local test, use the exact ci.command in that
package's contract. Hardware qualification, historical measurements, and
release status are distinct: consult the linked receipt for a measured result
and the repository product matrix for current availability.
Ordinary *_test.zig files live in a subsystem's tests/ directory.
Standalone test roots remain at package roots where Zig's module-root import
rules require them. See Contributing before
moving a test or changing a package boundary.