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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds meaningful behavioral context: it merges similar + recommendations and deduplicates results, and stresses that only one identifier should be provided. These details go beyond the annotations and help set expectations.

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?

Three sentences, each earning its place: purpose, identifier constraint, and usage guidance with an explicit alternative. No fluff, and the critical info is front-loaded.

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 6-parameter tool with no output schema and annotations already covering safety, this description is complete. It covers what it does, when to use it, the identifier exclusivity rule, and what to avoid. An agent has everything needed to invoke it correctly without further digging.

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 all parameters are already documented. The description adds the crucial exclusivity constraint—provide only one of title, TMDB id, or IMDb id—which the schema only hints at in the query field. This is a high-value semantic addition that prevents misuse.

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 and resource: finds films/shows similar to a given one, with a clear distinction that it merges similar + recommendations and deduplicates. It also explicitly differentiates from genre browsing by naming movies_discover as the alternative, so an agent can tell it apart from 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?

Gives explicit when-to-use (e.g., 'like Whiplash what should I watch' questions) and when-not-to-use (genre browsing, with the explicit alternative movies_discover). This is unambiguous and routes the agent correctly.

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