Tooling

Four more repositories sit beside the twenty-two-library roster. None of them is named in lib/mkGenLibs.nix’s formal arguments, and none publishes a gen-*.lib a framework composes with. They build the roster’s CI, exercise it as a consumer, or project its structure into other tools — support work the roster itself doesn’t do. See the roster for what does count as a library, and retirements for libraries that once did.

gen-harness

The CI harness the gen ecosystem’s test flakes are built from: mkCi and the flake module it imports give a library’s ci/flake.nix nix-unit wiring, treefmt with the tree-root invariant, a dev shell, pre-commit hooks, and the flake.tests / flake.testsError options every library uses to declare its own suite.

It declares no gen library input at all, and that is the whole reason it is a separate repository: a CI harness that itself depended on a roster member would have to be built and gated by the thing it exists to gate.

gen-demo

The acceptance corpus for the gen ecosystem. gen-demo is a consumer, not a library — it contains no library code of its own, takes the hub as its only input of note, and drives that hub the way a real framework does: through the published surface (flakeModules.default, flakeModules.genLibs), with no direct pin on any single gen-* member.

It belongs to no framework, no fleet, and no real machine. Nothing in it is a configuration anyone runs. It exists so that an integration error between landed components — something that works in each library’s own tests but not when composed — reads red somewhere, rather than surfacing for the first time in a real framework’s build.

gen-lsp

LSP/MCP projection tooling for the gen module stack. gen-lsp turns a fleet’s option, aspect, and gen-lib API surface into editor- and agent-facing artifacts: the option tree an LSP worker walks for hovers and completions, and a JSON-safe enumeration an MCP server hands to coding agents so they stop guessing at option paths and library signatures instead of reading them.

gen-differential

Comparison machinery for differential testing: a parameterized subject, a seam-routed identity control, a required claim on every comparison, an observable set per fixture, and a divergence register that asserts rather than mutes a disagreement. It is not scoped to one library — gen-merge’s own CI wires it in directly, as the module-system-core byte-parity harness described on CI and checks.

The rosterWhat does count as a library, and why.

RetirementsLibraries that left the roster, and gen-rebuild's unresolved status.

CI and checksWhere gen-differential's harness is wired into a gate.