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. The description still adds real behavioral value beyond that: the mutual exclusivity of the two mutually exclusive inputs ('exactly one') and the fact that the response bundles episode data with parent series/season and video metadata, so the caller knows they get a combined payload. It does not mention auth or rate limits, but for a read-only fetch that is a minor omission.

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 short sentences, each earning its place: purpose/scope first, the exactly-one constraint second, and the sibling routing third. Front-loaded and waste-free.

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, the description needn't detail return values, and it still sketches the payload. For a read-only fetch with two well-documented params, the scope, input constraint, and sibling alternative are all covered — nothing needed to call it correctly is missing.

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 baseline is 3, but the description adds genuine meaning: it clarifies the exactly-one-of relationship between path and url, and it shows the path shape ('/tv/.../s.../e...'). That is more than the schema's per-field text and helps the agent construct a valid input.

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 + resource ('Fetch a Rotten Tomatoes TV episode's metadata, scorecard, parent series and season, and public video metadata'), enumerating exactly what comes back. It explicitly names the sibling rottentomatoes_season as the season-level alternative, so an agent can distinguish it without opening a schema.

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 states the input constraint ('Pass exactly one episode path ... or absolute URL') and names the alternative to use for season-level data ('Use rottentomatoes_season'). The selection condition versus the sibling is spelled out explicitly, leaving nothing to inference.

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