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

Annotations already establish readOnly/idempotent/non-destructive/closed-world, so the bar is lower; the description still adds real behavior beyond them: grouping splits results separately by source and currency with overlap exclusions, and results are aggregate rather than paginated. It does not describe limits on result size or empty-result behavior.

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 dense sentences with no filler, but the middle sentence stacks grouping and currency/overlap clauses into one run-on, and the routing caveats are buried at the end rather than front-loaded. Readable and compact, but structure could be cleaner.

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?

No output schema and 9 mostly-undocumented parameters mean the description carries a lot of weight. It explains aggregation semantics well but omits result shape on the return end and leaves limit/body/body_id/supplier_id undefined, so an agent could still invoke it incorrectly.

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 11% across 9 parameters, so the description must compensate. It covers the filterable dimensions (supplier, buyer/department, year, source) and the group_by values implicitly, but leaves limit, body, body_id, and supplier_id unexplained and doesn't clarify that 'buyer' maps to the department parameter.

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 the resource (aggregated totals/rankings) and its scope (full-record, filtered by supplier/buyer/year/source, grouped by several dimensions). It also names a sibling it is not (get_department) and excludes paginated-search sums, so an agent can place it. The vague phrase 'full-record totals' and the conflation of 'totals or rankings' into one tool keep it short of a 5.

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?

Gives two explicit routing rules: use get_department for program spending, and awards are not payments. It also signals the aggregate-only scope via 'no paginated-search sums'. It stops short of a full when-to-use statement (e.g. when to choose a ranking vs a total, or currency handling).

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