List subjects

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

Annotations already declare readOnly, idempotent and non-destructive, so the safety profile is covered. The description adds real behavioral context beyond them: the result set is capped at ten subjects, index documents are excluded from counts, and band narrows the counted population. Return format/ordering is not described.

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 terse sentences, front-loaded with what the tool returns, then the parameter effect, then the counting exclusion. No filler and nothing repeated from structured fields.

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 simple read-only list tool with one optional enum parameter and no output schema, the description covers result size, count semantics, and an important exclusion. It is nearly complete, with only minor gaps such as ordering or what counts as a subject.

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 0% for the single 'band' parameter, so the description must compensate, and it does explain that band limits which items are counted. However it never explains the enum values (little/young/emerging/adult) or defaults, so the semantics are only partially covered.

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+resource ('List subjects') with item counts and a ten-item cap, which is concrete enough for an agent to know what it returns. It does not distinguish itself from nearby siblings like list_age_bands or list_by_age_band, so it falls 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?

The only usage instruction is about the band parameter ('Pass band to count only items in that age band'), which is parameter behavior rather than tool-selection guidance. No when-to-use, when-not-to-use, or alternative (e.g. list_by_age_band) is named.

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