Tiers

Note

The tier classifier is not built yet (planned for milestone M1). This page describes what it will decide. No mod has a tier today.

Every mod Jarrow sees will get exactly one tier, decided by a classifier that scans the JAR without converting it. The result page will name the tier and the reasons, in order.

Tier	What it covers	Where it runs	Proof
A	Manifest, mappings, entrypoints, registries, resources, mixins, access wideners, and Fabric API calls covered by rule tables	Your browser (WebAssembly) or the CLI	Static checks, plus the harness in the nightly
B	Everything in A, plus API calls with no rule, event-model differences, networking, and rendering hooks the agent can port	A GitHub Actions job (JVM plus agent)	The full parity harness before the result is returned
Unsupported	Native libraries, coremod-style bytecode transformers, deep rendering pipelines, obfuscated or packed JARs, and mods whose license forbids modification	Nowhere	The page says so plainly and names the reason

In one sentence each

• Tier A covers what the rule tables translate mechanically, and it runs in your browser or the CLI.
• Tier B needs a deep conversion (decompile, rules, agent fixes, recompile) that runs in a GitHub Actions job and must pass the full parity harness before a result is returned.
• Unsupported means Jarrow will not convert the mod, and the reason is named.

What the classifier will look at

The manifest of the loader, native libraries (.so, .dll, .dylib), custom language adapters, use of Fabric Loader internals, bytecode transformer registration, signs of obfuscation, the Fabric API symbols the mod calls (matched against the rule tables), and the license.

A tier is not a result. A Tier A mod can still come out red if the harness finds a difference. Results are green, yellow or red, and only the harness sets them.