Get trailers & videos

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

Annotations already provide readOnlyHint=true and openWorldHint=true. The description adds significant behavioral context: it lists the types of videos included, mentions that YouTube entries include a watch URL, and crucially discloses the language restriction with a live example (29 vs 2 results). This goes beyond the annotations and fully informs the agent about the tool's behavior.

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 consists of two concise sentences. The first sentence states the main purpose and key feature (YouTube watch URL). The second provides usage guidance and a critical behavioral note. Every part earns its place, and it is front-loaded with the most important information.

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 complexity of the tool (two parameters with clear schema, an output schema exists for return values), the description covers all necessary aspects: what videos are returned, where to get the id, and the language limitation. It is fully informative for an agent to use the tool correctly.

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?

The input schema has 100% coverage, so the baseline is 3. The description adds minimal extra meaning to the parameters: it mentions that the id comes from search tools, but the schema already describes id and media_type sufficiently. The language caveat is not a parameter. Thus, the description adds some context but doesn't significantly enhance parameter understanding 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?

The description clearly states the verb "List" and the resource "trailers, teasers and clips for a movie or TV show" and distinguishes the tool from siblings by noting that YouTube entries include a watch URL. It also directs where to get the required id from search_movies/search_tv, making the purpose specific and distinct from other listing tools.

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?

The description gives explicit context on when to use: after obtaining an id from search_movies/search_tv. It also warns about the language limitation (no per-call override) with a concrete example. While it doesn't explicitly list exclusions or alternatives, the provided context is sufficient for an agent to understand the appropriate usage.

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