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

Annotations already declare readOnlyHint and idempotentHint, so the safety profile is covered. The description adds that results are ordered 'best first' and that paging uses offset, but these are also stated in the schema (sort default, offset description). It discloses no auth needs, rate limits, or result-size behavior beyond that.

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?

Two tight sentences with the routing cue front-loaded ahead of the capability summary. The parenthetical inventory is a little dense but every clause maps to a real capability; nothing is padded.

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 a 100% documented schema, full annotations, and an output schema covering return shape, the description only needs to establish entry point and filtering scope, which it does. The remaining gap is the absence of any sibling routing, which matters given how many adjacent tools exist.

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 100%, including an enum for sort and enumerated examples for form, mood, theme and collection, so the baseline is 3. The description only restates the filterable dimensions and offset paging, adding no format, combination or precedence guidance beyond the schema.

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 ('Shows ... an index of poems') and adds scope detail: it returns shelf-level facets (collections, themes, moods, forms, with counts) as well as the poem index. The 'Start here' opener signals it is the entry-point browse tool. It never names search_poems or random_poem, so differentiation from siblings is implied rather than stated.

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?

'Start here' is a genuine usage cue and the filter/paging sentence tells the agent how to narrow results. However, with seven siblings including search_poems and random_poem, no alternative is named and no when-not-to-use condition is given. Usage is implied rather than routed.

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