[creatifcoding]

Complete Cosmo home. tmnl consumes. Not a stub. Cluster is @gbg/cluster; Cosmo home is @gbg/nexus. Rebased onto feat/mantis-biomemetics-lab after PR 109. Same PR. Mergeable for the operator.

What this is

• Cosmo filenames: graph.yaml (version: 1, subgraphs[]), config.yaml (execution_config.file + events.providers.nats), Federation v2 SDL at fixtures/fixture-demo.graphql, compose script wgc router compose -i graph.yaml -o router.json.
• wgc@0.130.1 is a real, pinned dependency (tmnl already has wgc; current npm is 0.130.1).
• Tests run composition. npm install, npm run typecheck, and npm test from packages/nexus. .github/workflows/nexus-ci.yml runs those three. No deploy job.
• Sibling package shape: private, "type": "module", vitest, tsc --noEmit, project.json, own lock. Excluded from the root workspace (!packages/nexus) alongside !packages/cluster.
• src/index.ts exports compose helpers and types.

Router image: ghcr.io/wundergraph/cosmo/router. Default listen: 3002. Execution file name is router.json everywhere.

What compose actually emits

Command:

wgc router compose -i graph.yaml -o router.json

CLI:

Router execution config successfully written to "router.json".

router.json keys from wgc@0.130.1 / @wundergraph/composition@0.63.3:

Key	What it is
compatibilityVersion	"1:0.63.3"
engineConfig.graphqlSchema	Federated SDL: Query.fixtureHealth, FixtureDemo { id, label }
engineConfig.datasourceConfigurations	One GRAPHQL datasource; federation enabled; serviceSdl is the fixture file
engineConfig.stringStorage	Upstream schema blob keyed by hash
subgraphs	[{ id, name: "fixture-demo", routingUrl: "http://localhost:4001/graphql" }]
featureFlagConfigs	{}
version	Placeholder UUID (00000000-0000-0000-0000-000000000000) — no control plane

The fixture subgraph is named fixture-demo on purpose. No catalog, specimen, procurement, GPS, or taxon types.

tmnl consumes. Leftover Pepr stays in tmnl.

• @gbg/nexus is mapped in tsconfig.base.json and packages/tmnl/tsconfig.json.
• Leftover Pepr cosmo-operator stays at packages/tmnl/src/infra/graph. Not copied. INFRA_DIR is not peeled this cut.
• Cluster-create in packages/tmnl/nix/modules/k8s.nix remains a helper path, not Cosmo's home.

After PR 109

Root package.json workspaces exclude both !packages/cluster and !packages/nexus. tsconfig.base.json maps both @gbg/cluster and @gbg/nexus. Nexus is not a second home inside cluster files.

Ship

Ship when CI is green on the lab branch. User corrects after the fact.

Stop is only: paid cloud, deploy that leaves this machine, a second NATS, a second catalog source of truth, a second API group. Wallet still stops paid cloud and alchemy deploy that leaves this machine.

Catalog stays Postgres off-cluster. One NATS: packages/tmnl/nix/modules/nats/values.yaml.

Docs opened

• https://cosmo-docs.wundergraph.com/cli/router/compose.md
• https://cosmo-docs.wundergraph.com/tutorial/from-zero-to-federation-in-5-steps-using-cosmo.md
• https://cosmo-docs.wundergraph.com/tutorial/mastering-local-development-for-graphql-federation.md
• https://github.com/wundergraph/cosmo-demo (graph.localhost.yaml + wgc router compose + ghcr.io/wundergraph/cosmo/router)
• https://cosmo-docs.wundergraph.com/router/cosmo-streams/nats.md (events.providers.nats)
• Leftover tmnl CRDs: listen 3002, execution file /config/router.json