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

Annotations already signal read-only and idempotent behavior. The description adds useful behavioral detail: content is ordered with trailers first, includes YouTube watch URLs, and accepts only one lookup key at a time.

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 compact sentences cover output content, ordering, URL format, identifier options, and the intended use case. 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?

Given the simple read-only nature, full schema coverage, and the description's explanation of what the response contains, an agent has enough context to select and invoke this tool correctly. The absence of an output schema is adequately compensated by the description of the returned video types and URLs.

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 100%, so the schema carries the parameter documentation burden. The description's 'title, TMDB id or IMDb id - provide only one' mostly restates what the query and imdb_id parameter descriptions already say, adding little new semantic value.

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 states a precise function: returning trailers, teasers, clips, and featurettes for a single movie or show, with YouTube watch URLs. It clearly separates this media-content tool from siblings like movies_artwork or movies_details.

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 explicitly gives the intended use case ('trailer for X' questions) and constrains input to one movie/show via exactly one identifier. It does not name alternatives or exclusions, so it stops short of a 5.

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