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

readOnlyHint=true already tells the agent this is a safe read, so the description's marginal burden is low, but it still adds nothing beyond the annotations and schema: no ordering, no pagination semantics (default limit 20, offset paging), and no indication of how multiple filters combine (AND vs OR) or how date ranges behave.

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 tight sentence with the resource front-loaded and the filter dimensions trailing. Nothing is wasted, though it is arguably under-specified rather than optimally economical.

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?

For a 9-parameter, no-required-argument list tool with no output schema, the description covers filter intent but omits pagination behavior, result ordering, and how it relates to the overlapping search_expenses sibling. Adequate as a minimum viable definition, but with clear gaps.

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 coverage is 67%, and the description's filter list (date, merchant, category, account, text) roughly mirrors the documented parameters. It adds no meaning beyond the schema descriptions and says nothing about the undocumented limit, offset, or transactionType parameters.

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 and resource ("List expenses") and enumerates the filter dimensions, so an agent immediately knows what the tool returns. It does not, however, distinguish this from the sibling search_expenses, which appears to serve an overlapping purpose.

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?

There is no guidance on when to use this versus search_expenses or get_expense_detail, nor any mention of prerequisites or exclusion conditions. The word "optional" is the only usage signal, which an agent could already infer from the all-optional schema.

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