A compatibility adapter is justified when the old and target calls have the same meaning and a bounded transition period reduces release risk; semantic changes should remain explicit and require migrated callers.
Check whether the meaning is actually equivalent
An adapter is attractive because it can keep old prompts or programs running while the runtime changes. That value disappears when the adapter hides a semantic break. If the old tool accepted a customer name and the new tool requires a verified customer identifier, inventing or guessing the identifier would change the action rather than translate it.
The map should compare authorization, defaults, units, side effects, error behavior, and return meaning as well as field names. Direct renames and representation changes may support an adapter. A split action, removed capability, stronger permission check, or changed business rule usually requires an explicit caller migration and a clear failure for old requests.
Constrain the adapter as temporary infrastructure
Semantic Versioning treats incompatible public API changes as major-version changes, which is a useful signal even when the tool surface is internal. A versioned registry can advertise the target contract while a bounded adapter accepts known old calls. Every adapted request should log the old version, translated request, target result, and caller identity so remaining usage is measurable.
The adapter needs an owner, removal condition, and final supported date set by the buyer. It should accept only enumerated old shapes and reject unknown combinations instead of becoming a permissive compatibility layer. Deprecation messages should identify the target tool and field mapping without exposing private system details.
Test both acceptance and removal
Tests must prove the old call reaches the same accepted effect through the adapter and that migrated callers use the target contract directly. They should also prove that semantic breaks fail as designed. Before removal, production-shaped traces or canary records should show that no approved caller still depends on the old path.
Reality Contact, LLC can implement and instrument the adapter within the migration scope. The buyer decides whether two operations are semantically equivalent, sets the deprecation period, communicates with internal callers, and authorizes removal. The service does not preserve an old behavior that conflicts with current permissions or product policy.
Where the service stops
Reality Contact, LLC implements and tests the migration, but does not invent target semantics, weaken authorization, approve external side effects, select production traffic, or retire a contract without buyer approval. The buyer approves the target semantics and caller set, runs the accepted canary scenarios, and retires the old contract only after compatibility and rollback gates pass. This is software migration and technical testing, and it does not replace legal, security, privacy, compliance, or professional advice. The buyer owns tool semantics, credentials, permissions, caller communication, canary authorization, production release, and contract retirement.
Sources: Semantic Versioning specification.