The three tools have clearly distinct purposes: add_expense creates a record, list_expenses retrieves raw records, and summarize aggregates by category. There is no overlap or ambiguity between them.

All tools use lowercase snake_case and a verb-first pattern (add_, list_, summarize). The only minor inconsistency is that 'summarize' omits the explicit noun 'expenses' that the other two include, but it remains predictable and readable.

Three tools is a reasonable size for a focused expense tracker. It is slightly minimal but each tool serves a distinct core function (insert, query, aggregate), so the count feels appropriate rather than inadequate.

The surface covers basic recording, viewing, and summarizing expenses, but lacks update and delete operations, which are common expected capabilities in a data management domain. This is a notable gap that agents cannot easily work around.