Wardline
An embeddable guardrail evaluation library for Rust
open source · pre-alpha · Apache-2.0 / MIT · Aug 2026 — building
- ›Guards run inline in the request path — before an action is taken or an LLM response is released — and return a blocking verdict: allow, block, or modify.
- ›A library you call in-process, not a proxy you deploy: no separate service, no network hop, no async runtime.
- ›Guards are ordinary Rust implementing one trait, rather than entries in a YAML DSL, so a guard is testable like any other code.
- ›Fully synchronous by design — the core and built-in guards depend on nothing but std; the optional axum middleware is the single sanctioned async boundary.
- ›Four-crate workspace: core pipeline with panic isolation and a bounded audit trace, reference guards, an HTTP adapter, and an LLM wrapper.