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

Annotations already cover readOnlyHint/destructiveHint/openWorldHint, so 'Read-only' in the description is redundant. The genuinely additive content is semantic: what a null user_id row means (unassigned candidacies) and how to read conversion safely — useful context that annotations could not convey. Pagination, ordering, and date-range defaults remain undisclosed.

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?

The metric list is front-loaded and the two caveats follow logically. The 'three applications and one hire is 33%' aside is slightly editorial but earns its place as a concrete caution against misreading the output.

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 no output schema, the description does solid work enumerating the returned fields and the meaning of the null bucket. However, for a time-windowed report it leaves the two date parameters completely undefined, so an agent cannot confidently bound the query.

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?

Both parameters (since, until) have 0% schema description coverage, and the description says nothing about them — no format, no defaults, no open-ended range behavior. With 0% coverage the description was required to compensate and does not, so it falls below the baseline 3.

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 names a specific resource (per-recruiter report) and enumerates the exact metrics returned: applications handled, hired, rejected, still active, conversion, median days to hire. An agent can tell it apart from hr_funnel_report or hr_source_report by the per-recruiter grouping, 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?

It gives interpretation guidance rather than selection guidance: the null user_id bucket is flagged as 'usually the more actionable row', and it warns against comparing conversion across dissimilar volumes. There is no explicit statement of when to pick this report over the many adjacent hr_*_report siblings.

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