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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds substantive behavioral context beyond those annotations, especially the note about low-vote new releases rarely passing rating filterscarsionate why trending is the right selection. That extra reasoning is genuinely useful.

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 description is three short, purposeful sentences: purpose first, then positive usage guidance with a rationale, then an explicit do-not-use case with the correct sibling. Every sentence earns its place; there is no filler or repetition.

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 4-parameter, no-required-parameter tool with fully documented schemas and a clear read-only annotation set, the description covers everything needed to select and invoke it: what it returns, when to use it, and when to use something else. The lack of an output schema is not a gap for this straightforward retrieval endpoint.

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%, so all four parameters and their enums are already documented in structured form. The description reinforces the notion of time windows and media types but does not need to repeat parameter details; the baseline 3 applies since the schema does the heavy lifting.

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 uses a specific verb ('trending') and a clear resource scope ('movies, shows or people, today or this week'), immediately distinguishing it from list/ranking tools. It even names the sibling it is not meant for ('movies_compare_lists'), so an agent can separate it from other movie-list tools without further digging.

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 explicit positive triggers ('what is popular right now' and new-release questions), explains the rationale ('new titles have few votes, so they rarely pass rating filters'), and gives an explicit negative instruction with the alternative ('Do NOT use for all-time rankings (use movies_compare_lists)'). This is exactly the level of routing guidance an agent needs.

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