# Checked capability and component artifacts

`mkCaminoArtifacts` is the fresh package builder. It regenerates candidate
bindings, typechecks the entry's dependency closure, bundles declared targets,
generates a process service when requested, and emits content manifests and
receipts. It has no migration step or package-defined shell hooks.

```nix
# Inside a per-system flake output:
quixosPackages.checkedArtifacts =
  { buildContract, sourceDigest, generator, core, sharedRuntime, typescript, packageRevisionId, ... }:
  helpers.mkCaminoArtifacts {
    inherit pkgs buildContract sourceDigest core sharedRuntime typescript packageRevisionId;
    protocol = generator;
    src = ./.;
    portable = {
      entry = "src/portable.ts";
      bindingOutput = "src/gen/qx.ts";
      registryExport = "registry";
      targets = [ "browser" "server" ];
    };
  };
```

`buildContract` is a canonical, source-free capability slice. `sourceDigest`
records the exact selected package source in the final installation manifest;
it does not enter the reusable compilation group. Ordinary source dependencies,
SDKs and React props companions remain explicit Nix inputs. Raw QX and resource
lock files enter through the checked contract and evaluated recipe, and are
excluded from the implementation source tree. The `plan` argument on the low-level
helper is a composition convenience for fixtures; it is projected before building.
Package recipes receive the contract directly and can be checked without a workspace.

Inside `checkedArtifacts = context: ...`, the package helpers expose
`camino.packageSet { inherit nixpkgs system context; }` as the usual package set
selection. It shares the workspace composition's evaluated Nixpkgs when the
source content, system, and default import arguments match. Pass ordinary Nixpkgs
arguments such as `config` or `overlays` to use a separate import. A direct
`import nixpkgs { inherit system; }` also works, with additional evaluation cost.
The implementation groups depend on the complete execution compiler bundle and
JavaScript build drivers by content; unrelated checker CLI and publication
metadata changes do not enter those inputs.

The handler entry exports `registry = createRegistry(handlers)` from the generated
bindings. One registry contains many exports. The builder always supplies a server
implementation for the generated process service. A service-only package instead
omits `portable` and supplies `service.entry`, an ordinary JavaScript process entry
using the versioned stdin/stdout protocol. Custom services own their lifecycle and
may hold external resources. This first helper supports JavaScript custom service
entries; other languages can emit the same checked artifact contract independently.

Additional portable source dependencies can be provided as a locked `nodeModules` directory.
The workspace supplies the exact SDK and compiler; packages cannot replace those
with their own versions. Authored source symlinks and non-bundled portable imports
other than the SDK and server Node builtins are rejected. This is build closure
checking, not a purity proof or security sandbox.

The core/Automerge bundle and Replicache bundle are built once. Browser modules
import the core through a content-addressed gateway URL, independent of package
identity. Each manifest covers the shared bytes it uses. The gateway retains its
workspace authentication and explicit file registry; it never interprets an HTTP
path as a Nix store path. Applications cannot import Replicache through the SDK.

`checked-artifacts.nix` evaluates a package's `checkedArtifacts` output without
activation. During the checked Nix build, `loadCheckedArtifactWorld` verifies manifest bytes, the selected
generator identity, and exact regenerated binding sources. Receipts are consistency
evidence from a trusted Nix build, not cryptographic attestations of remote builds.
The build stores the checked plan, kernel/query programs, their digests and original
compiler provenance in its immutable candidate output. Runtime loading validates
that output's identities, artifact contents and supported runtime contracts. It
does not regenerate bindings or programs with the currently running compiler.
Nix owns rebuilding and cache reuse when a toolchain input changes.

The root `camino-artifact-builds` check exercises actual reader/service outputs,
module and process execution, browser shared imports, rejection recovery, and
altered receipt rejection at the build boundary. The managed workspace host loads
the resulting checked candidate before activation. No adapter pretends this ABI
works in the old server dispatcher.

Component packages add `components = { inherit (react) sdk runtime; entries; }`.
The ordinary execution candidate checker supplies the selected React build inputs
when the package declares components. Each entry maps a component ID to
`{ entry = "src/card.tsx"; export = "Card"; }`. See the
[React SDK](../camino-react/README.md) for bindings and hooks. CSS is emitted as a
checked artifact; local image/font imports are inlined. The helper rejects
undeclared external assets and substituted React/client dependencies.
Component-only packages produce no backend service.

`camino-component-artifacts` checks bad subject/SDK/dependency/asset inputs and
proves that a component-only edit preserves a mixed package's service digest.
Run `nix run .#camino-component-source-qualification` from the monorepo to
materialize separate retained Git resources and compile an ordinary Nix candidate.
This is a source/build qualification harness; it does not deploy a workspace.