The two tools perform inverse but clearly distinct operations: postal code to address versus address to postal code. An agent can unambiguously pick the correct tool based on the direction of the query.

Both names follow a verb_noun pattern (lookup_postal_code, search_address) in consistent snake_case. The verbs differ slightly (lookup vs search), but the convention is otherwise predictable and readable.

Two tools is thin, but the server's purpose (Japanese postal code lookup) is inherently narrow and both directions of the mapping are covered. It is borderline minimal rather than clearly well-scoped.

The core domain—bidirectional postal code/address resolution—is fully covered with no dead ends for the primary use case. Minor extras like batch lookup or input validation are absent but not essential.