Route a change through its owners

Identify the behavior and owner

Use the codebase orientation to trace the visible behavior. Do not begin at the first matching string if a contract, registry, shared model, or resident table owns the meaning.

Follow the matching route

Requested change	Developer documentation	Agent-specific completion rule
Wire message, field, command, or limit	Change the contract	Update the contract first; name both receiving directions and deliberate asymmetry
Host or Workshop module	Add a module	Update live registries, manifest, public module page, media slots, and inventory gate together
Host model or UI	Host architecture	Keep business behavior in the owning model and native-control work in adapters
PowerPC guest behavior	PowerPC architecture	Preserve console/wire parity and pump the wire through nested Toolbox loops
Resident plane or shared layout	Resident components	Change the shared header once, run native guards, and satisfy or explicitly defer the exact-source bake before checkpointing
Public docs or availability	Documentation and gates	Keep user, developer, and coding-agent audiences distinct; rederive every moved source

Verify proportionally

Run the smallest owning test while iterating, then the documented subsystem gate. Run scripts/test-all when the change crosses subsystems or is being prepared to land. If a required toolchain or machine is unavailable, report the skip as an unverified surface rather than converting it into success.