What is a mod

A compiler mod is a type: Mod package in the dependency graph whose compiled AOT artifact exports SDK contract implementations—generators, analyzers, rewriters—not random scripts the CLI evals.

Not these things

Thing	Mod?
Rust proc-macro inside beskid_analysis	Host implementation detail
Language macro items	Language macros — parallel feature
User contract Disposable	Structural type contract—different namespace
meta { } blocks in old designs	Removed—Collector owns scope

Discovery

Manifest attachTo folklore is dead. During mod.load the host:

1. Resolves transitive Mod dependencies from CompilePlan
2. Loads AOT artifact for target triple + cache key
3. Reads mod.descriptor.json / export table
4. Schedules (contractId, typeId, entrySymbol) tuples

Duplicates → E1829 / E1851–E1870 before collect runs (Compiler Mod SDK — discovery).

Compiler never in Beskid

The reference compiler host is Rust-only. Mods extend compilation; they do not replace beskid_analysis.

Next

Mod SDK