# fallow-cov-protocol
[](https://github.com/fallow-rs/fallow-cov-protocol/actions/workflows/ci.yml)
[](https://crates.io/crates/fallow-cov-protocol)
[](https://docs.rs/fallow-cov-protocol)
[](https://securityscorecard.dev/viewer/?uri=github.com/fallow-rs/fallow-cov-protocol)
[](#license)
Versioned JSON envelope types shared between the public [`fallow`](https://github.com/fallow-rs/fallow) CLI and the closed-source `fallow-cov` production-coverage sidecar.
## Why this crate exists
Fallow Runtime, the paid runtime intelligence layer for fallow, is a two-binary architecture. The open-source [`fallow`](https://github.com/fallow-rs/fallow) CLI handles static analysis and IO. A separate closed-source sidecar (`fallow-cov`) does V8-to-Istanbul normalization, three-state tracking, and combined scoring. Both sides marshal data through JSON on stdin/stdout. This crate is the single source of truth for that envelope so the two repositories cannot drift.
## Versioning
The `protocol_version` field is a full semver string. Consumers MUST reject mismatched majors and SHOULD forward-accept unknown fields and unknown enum variants (mapped to `Unknown` sentinel values).
## Status
Early access. Breaking changes until `1.0.0`.
## License
MIT OR Apache-2.0