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

Annotations already declare readOnly/idempotent/non-destructive, and the description adds real behavioral value: the result is a fixed official set with release dates and lengths "where read from the official upload" — flagging that some fields may be missing. It doesn't discuss caching or freshness, but with annotations covering safety this is solid.

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, front-loaded with the usage trigger followed by the return contents. Slightly wordy parenthetical enumeration, but every clause carries information about what comes back.

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?

An output schema exists, so return shape is covered; the description usefully supplements it with the caveat about lengths. For a no-parameter read tool this is essentially complete, with only sibling routing 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?

Zero parameters, so the baseline of 4 applies. The description correctly implies a no-argument, fixed-set call and adds no misleading input expectations.

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 (retrieves the official GTA 6 trailers) and enumerates the exact items returned (Trailer 1, Trailer 2, An Extended Look, Launch Trailer), which implicitly separates it from news/facts siblings. It stops short of explicitly naming a contrasting sibling, so a 4 rather than 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?

"Use this when someone asks about the official GTA 6 trailers" gives a clear activation context. No when-not conditions or alternatives (e.g., get_latest_news for breaking items) are named, leaving routing between siblings partly to inference.

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