The manifest is the only file a biome MUST author. It declares the biome's identity, semver version, kernel-compatibility range, the set of contributions it ships, and any companion controllers or sidecar services. The kernel validates the manifest against BiomeManifestSchema in @xemahq/contracts/biome, computes the lockfile, and reconciles each contribution into the Object Registry. Manifests are immutable per version — to ship a change you publish a new version. The optional lifecycle block declares the five hook fields (onInstall, onUninstall, onUpgrade, onEnable, onDisable) that biome-host-api invokes at the corresponding BiomeLifecycle transitions. See the Manifest reference for every field and biome-host-api's OpenAPI spec for the publish / install surface. To run logic around an operation, see the hook plane.