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

With all annotation hints set to false, the description carries the burden of explaining how the tool behaves. It adds meaningful non-obvious details: drafts count for nothing until finalized, currencies are never added together, and the grouping is by reason and by month. It could more explicitly state whether the call is side-effect-free, but the summary semantics are clear enough for safe 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?

Two sentences carry all the essential information with no filler. The core aggregation is front-loaded, and the two critical caveats—draft neglect and currency separation—are concise and immediately useful.

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 tool with only two optional date parameters and no output schema, the description provides the key semantics: what is totaled, how it is grouped, which documents are included, and how currencies are handled. It stops short of describing the exact response shape, but an agent has enough context to call and interpret the result correctly.

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?

The input schema already documents both parameters fully, including YYYY-MM-DD format and defaults. The description's 'optional issue-date period' only restates what the schema provides and adds no new parameter-level meaning, so the baseline score of 3 is appropriate.

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?

The description clearly states the resource (credit notes) and the operation (totals per currency, broken down by reason and month, over an optional issue-date period). This aggregation focus distinguishes it from sibling tools like credit_note_list, credit_note_get, and credit_note_create. The title reinforces the same message without relying on the tool name alone.

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 makes the useful context explicit: only finalized credit notes count, drafts are excluded, and currencies are never combined. It also signals that the date window is optional. It does not explicitly name an alternative tool for viewing individual credit notes, but the aggregate-versus-list distinction is strongly implied by the summary phrasing.

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