Monorepo Boundaries

monorepo-boundaries

This skill records repository policy for Codex. Use repoctl as the authority for graph, ownership, affected analysis, task routing, and final hand-off verification, but keep repoctl out of the inner coding loop unless the graph or boundaries are changing.

When this fires

• A change touches imports, package manifests, workspace membership, generated code, proto ownership, IaC, deployment config, or multiple project roots.
• The user asks whether code should live in an app, framework, foundation service, proto root, or core infrastructure.
• A review includes app-to-app imports, framework internals, source proto edits, or production IaC.

Boundary model

• Apps may depend on framework facades and foundation clients, not on other apps.
• Framework internals are private. Consumers use the facade paths declared in project.yaml.
• Foundation services expose public clients and owned contracts; business apps do not import service internals.
• Source protos live under protos/. Generated code is consumer-local output.
• App IaC is colocated under the app; shared infrastructure lives under core-infra/.
• Generated files are build artifacts. Source changes happen in source roots, templates, or proto definitions.

Workflow

1. Classify the changed path:

   • apps/<name>/ - product or domain application.
   • frameworks/<name>/ - shared capability with public facade and private internals.
   • foundations/<name>/ - platform service plus public clients.
   • protos/ - source contracts owned by declared packages.
   • core-infra/ - shared infrastructure.
   • .agents/skills/, .codex/skills/, templates/, .github/ - repo-wide policy or tooling.

2. Read the nearest manifest when ownership is unclear:

   repoctl explain <project-name>
   

   If a path has no owning project and is not intentionally repo-wide, fix ownership before adding more files.

3. Check dependency direction:

   repoctl lint-boundaries --changed-file <path>
   

   Apps can call framework facades and foundation clients. Framework internals and service internals are not public API unless declared as facades or clients. Run repoctl graph validate before editing only when manifests, workspaces, task wiring, generated-code policy, or cross-project dependencies changed.

4. Choose the right home for new code:

   • Put product-specific behavior in an app.
   • Put reusable business capability behind a framework facade.
   • Put shared runtime/platform service ownership in a foundation service.
   • Put cross-cutting infrastructure in core-infra/.
   • Put contracts in protos/ and generated outputs under consumer workspaces.

5. Verify boundaries once at hand-off:

   repoctl affected --base origin/main --head HEAD --tasks check,test
   

   Run affected analysis once at hand-off to select the final verification surface. Do not pair every boundary check with graph validation.

Review checklist

• No app imports another app's internals.
• No app imports a framework internal package directly.
• No generated file is edited as the source of truth.
• Production IaC and deploy files have the owning team called out.
• Manifest changes include owners, tasks, workspaces, and AI editable/do-not-edit areas where relevant.
• Graph validation was run for structural boundary inputs, or the hand-off explains why the change was source-only.

Hand-off

Name the owning project, why the chosen directory is correct, which boundary checks ran, and any owner review required before merge.