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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds that offers are 'normalized' and that country/language affect results, which is useful, but says nothing about provider coverage, currency, or pagination 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?

Front-loads the purpose before the parameter notes and the sibling redirect, and is compact. It does repeat parameter details already present in the schema, which is mild redundancy but not severe.

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, return values needn't be explained, and annotations cover safety. Purpose, param defaults, and the sibling alternative are all present; only deeper behavioral traits (provider list, currency, rate limits) are 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 the schema already documents id, language, and countries. The description largely restates the schema's country and language text verbatim (defaults, examples) rather than adding new semantics, so baseline 3 applies.

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 (returns) and resource (normalized offers for a raw JustWatch episode id), scoped by country codes. It also names the sibling justwatch_title_offers, letting an agent distinguish episode offers from title offers without opening either 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?

Explicitly points to justwatch_title_offers as the alternative for title-level offers, giving clear context for choosing this episode-scoped tool. It stops short of stating an explicit when-not condition, so it falls 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.