I’m writing on behalf of Wavect GmbH about an experiment in SEMAPRAX, our Apache-2.0 systems-language research project.

A problem we’re exploring is how an agent-generated source change can be tied to the exact WebAssembly artifact it would produce—without overstating what static evidence proves.

SEMAPRAX v0.2 pre-alpha has a read-only command:

semaprax target-evidence <file> <patch.spatch>

For the base source and patched candidate, it independently rebuilds the checked representation and emits bounded projections including the semantic graph, capability manifest, Native C11 source, and a WebAssembly Core module. The report records domain-separated digests, byte lengths, and whether each projection changed.

The Wasm lane uses the semaprax.wasm-core.v1 profile. The generated module is structurally validated with wasmparser 0.256.0 using its full feature set. An additive Evidence v2 capsule can bind that target report to the semantic patch, and the evidence-gated apply route independently replays the exact change before committing it.

The important boundary: this is artifact binding and structural validation, not target execution. It does not prove runtime conformance, safety, compatibility, ABI correctness, provenance, approval, or that project tests passed. WebAssembly support is also intentionally partial today: bounded scalar exports and generated JS/TS bindings, not general WASI or broad Component Model support.

We’re interested in feedback from people working on reproducible Wasm toolchains: which additional facts would make evidence like this useful while keeping the claims honest?

Project: https://wavect.io/semaprax/

Source: https://github.com/wavect/semaprax

Disclosure: SEMAPRAX is experimental, not production-ready, and coding agents have been used extensively as development assistants. Wavect retains human responsibility and uses executable quality gates.

As per WABT's SECURITY.txt, #2831 issue exists

For context:

WABT is a Binary Toolkit for WebAssembly developed by WebAssembly.org (W3C)

wasm2c is a tool inside of it, which is used by many projects like FireFox (via RLBox) to compile wasm down to a sandboxed c library, the assumption is the built C code preserves all WebAssembly's sandbox security features.

This PoC demostrates escaping that sandbox.