ADR 0010: Artifacts as Project source, seeded from fixtures

• Status: Accepted. Updated 2026-10-10: more Workers bind ARTIFACTS; fork names; promotion moves main (ADR 0013).
• Date: 2026-10-08
• Decider: Project owner (cost cap: Linear HOM-192)

Context

Agents need a real codebase (AGENTS.md sections 29 and 54). Artifacts is Workers Paid only and in open beta. Billing starts 2026-10-14 with 10,000 operations and 1 GB-month included. The owner approved Artifacts within the included allowance.

Decision

• Terraform binds ARTIFACTS (namespace rhumbatron-projects-<env>) on the integration Worker. Provider 5.27 has no namespace resource. Artifacts creates a namespace on first use, so no adapter is needed. Repos are runtime data (section 2.1): one per Project, named by Project ID.
• Creating a Project queues project.provision on rhumbatron-integration. The integration Worker creates the repo and seeds a template commit with isomorphic-git over an in-memory file system (the binding has no write API, but Artifacts accepts git push protocol v1). Then it calls ProjectRootDO.assignSource. That method sets the canonical ref and tree for generation 0 once and records artifact.promoted in the same transaction.
• Templates live in fixtures/. scripts/build-fixtures.ts embeds them into *.fixture.gen.ts. The project cannot import its private GitHub repo, because Artifacts import accepts only public URLs. POST /v1/projects/:id/provision seeds an existing Project without source.
• The integration Worker mints push tokens per call with a 10-minute TTL. It never stores or logs them.

Cost

A seed is a handful of operations. Forks, clones, and pushes per Change are tens of operations. Stay far below 10,000 operations per month. Revisit before any automation that clones per wake.

Diagram

Repos in the namespace rhumbatron-projects-<env> (names from workers/integration/src/repo-names.ts).

flowchart TD
  fx["fixtures/ embedded as *.fixture.gen.ts"] --> prov["project.provision (integration Worker)<br/>isomorphic-git push, 10-minute token"]
  prov --> canon[("Canonical repo: Project ID, branch main")]
  prov --> root["ProjectRootDO.assignSource<br/>generation 0, artifact.promoted"]
  canon -- "fork per Task run (agents)" --> ws[("ws-RUN")]
  canon -- "fork per Candidate (integration)" --> cand[("cand-CANDIDATE")]
  ws -- "ChangeSet commits merged (--no-ff)" --> cand
  cand -- "promotion: fast-forward main (ADR 0013)" --> canon

Update (2026-10-10)

• ARTIFACTS is now bound on three Workers: integration (provision, Candidates, promotion), agents (Task Workspaces, ADR 0011), and indexer (reads canonical trees).
• Fork names: ws-<run> for a Task run and cand-<candidate> for a Candidate. Cleanup derives names from D1 row IDs and never lists the namespace.
• Promotion fast-forwards the canonical repo’s main after the compare-and-swap (ADR 0013).
• Read and write tokens are minted per call with a 600-second TTL.
• Prod has its own namespace, rhumbatron-projects-prod. Dev and prod share the 10,000 included operations per month (ADR 0017).