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 genuinely new behavior: results are paginated one page per call and aggregate totals require summarize.all_pages. Missing auth/rate-limit notes, but the pagination contract is the key non-obvious trait and it is disclosed.

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?

Three short sentences, front-loaded with purpose, then the endpoint reference and the pagination caveat. The raw API URL is arguably filler since the operation name already conveys it, but nothing else is wasted.

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 an output schema present, return values need no explanation; annotations cover the safety profile; and the description supplies the two things structured fields cannot: the pagination model and the route to cross-page totals. Adequate for a zero-required-parameter read tool.

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%, so the schema documents Date, expand, fields, sortby and sortorder, while page/limit/offset are undocumented in both places. The description only illuminates the summarize.all_pages sub-parameter, leaving the paging parameters to be inferred from the 'one page per call' remark.

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 ('Retrieve a list of financial years') and pins the upstream endpoint (GET /3/financialyears), so an agent knows exactly what data comes back. It doesn't differentiate from siblings, but no sibling covers financial years, so the ambiguity risk is low.

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?

'One page per call; use summarize.all_pages for totals over every page' gives real guidance on how to get complete results versus paged results. However, there is no statement of when this tool is preferable to adjacent reporting tools (e.g. get_multi_year_overview, get_year_end_package) that also deal with fiscal periods.

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