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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the description's job is to add behavioral substance — it does, disclosing that the output is counts and summed pipeline amount and that the date bounds apply to creation date specifically, which is a non-obvious filter semantic. It does not mention empty-group handling or result ordering.

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 front-loaded sentence that names the metrics and the grouping axis first, then the optional filter. Nothing here is filler.

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 and full parameter documentation, the description needs only to frame what is computed and how filtering works, which it does. Only edge-case behavior (groups with zero opportunities, ordering, whether ungrouped totals are available) is left unaddressed.

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 100%, so the baseline is 3; both date parameters are already documented as YYYY-MM-DD creation-date bounds and group_by is documented in the schema. The description's 'creation-date bounds' phrasing reinforces the filter semantics but adds little beyond what the schema already says.

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 (aggregate) plus the resource, the two metrics produced (opportunity counts and pipeline amount), and the grouping dimensions. It is clearly distinguishable in kind from list-opportunities-tool, though no sibling is named explicitly.

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 word 'aggregate' plus 'by stage or company' implies this is the roll-up path rather than the row-listing path, but there is no explicit 'use this instead of list-opportunities-tool when you want totals' statement and no exclusions. Usage is inferable, not stated.

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