Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered. The description adds genuine behavioural detail beyond that: ordering semantics ('newest first, or biggest first'), pagination ('Pages of up to 200: pass nextCursor back as cursor'), and the minor-unit convention for amounts — all useful for correct invocation.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

A single dense paragraph that front-loads purpose and ordering before filters, pagination, and unit conventions. Every clause carries information, though the run-on construction packs date/period/unit rules tightly enough that it reads more like a spec note than a description.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With 11 parameters, no required fields, and no output schema, the description supplies the essentials an agent needs: sort meaning, filter axes, pagination protocol, and numeric/date encoding. It is complete enough to call correctly; only the lack of explicit param-name-to-concept mapping leaves a small gap.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is only 9%, so the description must carry the load, and it largely does: it explains amount units (45000 = 450.00), date format and time zone, that a month is a budget period YYYY-MM, and what sort's two values mean. It stops short of explicitly mapping every param name (memberId, accountIds, categoryIds, limit are only alluded to as 'member', 'accounts', 'categories', 'pages of up to 200').

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb+resource with its domain shape: 'Entries (expenses, income, transfers) newest first, or biggest first.' An agent can immediately distinguish this listing tool from get_transaction, add_transaction, and the other list_* siblings without opening any schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description enumerates filter axes (month/dates, type, note text, accounts, categories, member), which implies when the tool is useful, but it never names an alternative or states when NOT to use it (e.g., use get_transaction for a single entry). Usage is inferable rather than explicit.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.