FAQ

Isn’t this just tests? No — see the 2×2 in What is Surface?. A test asserts that behavior matches an expectation written in code; Surface asserts that prose still matches the code it describes. Different expectation, different failure mode, and they drift apart exactly when someone updates one and forgets the other.

Why not just put doc comments next to the code? Co-located comments still rot silently — nothing gates them. Surface is the gate; your prose can live wherever you like, but the seal is what’s enforced in CI.

Does it slow CI down? No. It parses and hashes a handful of spans — I/O-bound, not compute-bound. No model, no network, no API key.

Will editing a string literal trip the gate? By default, yes. Literal values are part of the hashed logic, so changing a string — even user-facing copy — inside an anchored span fires a divergence. “Cosmetic” means whitespace, comments, and consistent renames, not “edits that feel unimportant.” If copy churn re-opens a claim too often, you have two options: anchor a narrower symbol, or set ignore_literals: true on that claim to exclude string-literal content from its hash (logic edits are still caught). See Authoring hubs.

What languages? TypeScript, JavaScript/JSX, Rust, Python, and Go today, via bundled tree-sitter grammars. More are a build-time addition to the binary, never a runtime dependency.

What does a green check actually promise? That nothing you anchored has changed since it was last verified — not that your docs are true, and nothing at all about code you didn’t anchor. See What Surface does NOT do.