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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. Beyond that the description discloses two useful behavioral traits: a hard result cap of 18 and the fact that book_id does not measurably affect output, which is genuine caller-relevant context rather than a restatement of annotations.

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 sentences, no filler, with the payload description and the cap front-loaded before the parameter caveat. Every clause carries information an agent needs to call the tool correctly.

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 an output schema present, return values need not be explained, yet the description still summarizes them briefly. Combined with the annotations and the required-parameter workaround, an agent has enough to call this correctly; only the lack of sibling routing guidance keeps it from a 5.

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 the baseline is 3. The description's note that book_id is inert largely duplicates the schema's own wording ('required by ReelShort but not observed to change the result'), and the language parameter is not mentioned at all, so it adds little beyond the structured data.

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 opens with a specific verb and resource ('List ReelShort's curated New Release titles'), states a concrete cap of 18 items, and enumerates the fields returned. It is distinguishable from reelshort_search or reelshort_tag_books, though it never explicitly contrasts itself with reelshort_home or reelshort_shelf, which are the most plausible confusable siblings.

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 real invocation guidance for the required parameter ('pass any known title id, for example from reelshort_movie'), which resolves the main practical hurdle. It does not, however, say when an agent should prefer this tool over reelshort_home, reelshort_search, or reelshort_shelf, so the when-to-use decision is only implied by the 'New Release' framing.

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