AI sucks. AI is great. I think that AI simply doesn't know its place. SYNTH tries to solve this, creating a "novel" system of classifying whether a project is vibe coded and _receives_ AI generated…

Version: 1.0.0 Status: Draft for community adoption

SYNTH tries to answer one question about a repo in one line: how much of this code came from an AI and what does this project actually accept? It lives as a single file in the repo root plus a badge in the README if you want one.

SYNTH is a short answer to a question people keep asking anyway: how synthetic is this codebase and what's the project's stance on that?

SYNTH-0

means hand-made, no AI-generated code accepted. SYNTH-4

means the opposite end: prompt-directed, AI content welcome everywhere. Everything in between is just a declared position, and none of the levels judge quality, they're just an honest description of how the thing got built.

Each level covers two things at once: how the code came to exist and what the project will accept going forward.

This runs independently of the level above and it always has to be stated. If nothing was checked, say so, that's still useful information.

A declaration is just a level plus one or more assurance tags.

SYNTH-1 · REVIEWED · TESTED

— light AI help, well vetted. High trust.SYNTH-3 · REVIEWED · TESTED

— mostly AI-authored, but reviewed and tested. Moderate trust.SYNTH-4 · UNREVIEWED

— prompt-driven and unreviewed. Proceed carefully.

Note that SYNTH-3 · REVIEWED · TESTED

is more trustworthy than SYNTH-1 · UNREVIEWED

. More synthetic doesn't automatically mean less trustworthy, assurance is what actually separates them.

Colors run green to red across the levels (cause who doesn't like a cool badge?). Assurance is shown as text not color, since it's a separate axis and shouldn't be flattened into the same scale.

![synth](https://img.shields.io/badge/synth-SYNTH--3%20Co--authored-orange)
![assurance](https://img.shields.io/badge/assurance-REVIEWED%20%C2%B7%20TESTED-blue)
## AI disclosure

[![synth](https://img.shields.io/badge/synth-SYNTH--3%20Co--authored-orange)](./SYNTH)
[![assurance](https://img.shields.io/badge/assurance-REVIEWED%20%C2%B7%20TESTED-blue)](./SYNTH)

See the [SYNTH](./SYNTH) file for this project's AI-content policy and provenance.

This is the one thing a maintainer actually has to write and it's one line. Drop a file named SYNTH

(no extension) in the repo root, formatted like this:

<level> · <assurance tag> · <assurance tag> ...
SYNTH-3 · REVIEWED · TESTED

That's really all it takes. The level itself functions as the repo's AI-content policy (see the table in §2) and the tags say what's been checked, so anyone landing on the repo gets both the stance and the trust signal in a single glance.

If you want to note the tooling used or leave a short comment, add a second line starting with #

:

SYNTH-3 · REVIEWED · TESTED

The first line is the declaration and the only required part.

A repo doesn't have to be uniform. The root SYNTH

file states the dominant level and anything that deviates from it can be flagged with a one-line marker at the top of a file, or its own SYNTH

file in a subdirectory.

// synth: SYNTH-1 / REVIEWED
// synth: SYNTH-2 / TESTED

Dropping a SYNTH

file into a subdirectory overrides the root declaration but only for that subtree. Useful for something like a prototypes/

folder marked SYNTH-4 · EXPERIMENTAL

while the rest of the repo stays at SYNTH-1 · REVIEWED

.

A SYNTH declaration is a statement about provenance. It isn't a guarantee of safety or fitness for any particular purpose.

User responsibility: it's on the people using or consuming a repo to actually look at the declared level and assurance tags before they build on it or run it. A higher synthetic level (SYNTH-4

, say) or a missing assurance tag (UNREVIEWED

,EXPERIMENTAL

) is a signal of real risk, and if you choose to run or deploy the code anyway, that's on you.Maintainer disclaimers: SYNTH doesn't override the usual open-source license disclaimers. An MIT license, for instance, still hands you the code "AS IS," no warranty attached. Maintainers use SYNTH for transparency, not to take on legal liability for whatever an AI generated or however the code behaves.Model providers: the tools and model providers used to generate code aren't responsible for how that code gets declared, merged or used afterward, that responsibility stays with the repo.

A declaration states a fact from the contributor, it doesn't guarantee quality.

• You typed it yourself and AI only answered conceptual questions → SYNTH-0 - You wrote it, AI filled in completions and refactors you accepted line by line → SYNTH-1 - AI wrote some functions or modules and you read them and wired them in → SYNTH-2 - An agent wrote most of it from your direction and you reviewed the diff → SYNTH-3 - You prompted it, it committed, and you didn't really read it → SYNTH-4

If you're not sure which way to round, disclose more synthetic involvement rather than less, and reach for UNREVIEWED

or EXPERIMENTAL

instead of overclaiming assurance you don't actually have.

This spec follows semver. What each level means stays stable within a major version. The spec version (currently 1.0.0) lives in this document, not the one-line repo file, that way the repo's own declaration stays short.