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

Annotations already declare readOnlyHint and openWorld, so safety is covered. The description adds genuinely useful behavior beyond the structured fields: the mutual-exclusivity constraint ('pass exactly one title id or title URL') and that results are 'public' episode rows, plus the limit cap. It does not describe pagination, but the output schema carries return shape.

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 tight sentences, no waste, front-loaded with the core action and scope, then constraints, then sibling routing. Every clause earns its place.

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 and annotations covering safety, the description needs only to convey action, scope, input constraints, and routing — all of which it does. Nothing an agent needs to call the tool 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 description coverage is 100%, so baseline would be 3. The description adds value the schema does not: the exactly-one-of rule between id and url, what 'season' actually selects ('an upstream season'), and the limit default/cap. That elevates it above baseline.

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 (List) and resource (IMDb episode rows) scoped to a series, and explicitly names the sibling tools it is not (imdb_title, imdb_title_credits). An agent can distinguish it from the many imdb_* siblings 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?

Names two alternatives with the condition that selects each ('Use imdb_title for series metadata or imdb_title_credits for cast and crew'), giving clear routing. It lacks an explicit when-not-to-use beyond those alternatives, so it stops short of full 5-level guidance.

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