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

Annotations already declare readOnlyHint and openWorldHint, but the description adds genuine value beyond them: it discloses data provenance (schema.org structured data parsed from the film page) and that access is credential-free public data. It does not mention failure modes (invalid slug) or rate limits, so it is not fully complete.

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-loaded with the return payload, followed by provenance, the parameter example, and the sibling hand-off. Every sentence carries information and there is no filler.

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 single-parameter read tool with an output schema already defining the return shape, the description covers purpose, provenance, and an alternative tool. Nothing an agent needs to invoke 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 description coverage is 100%, so the schema already documents the single slug parameter, and the description's restatement ('Letterboxd film slug, e.g. parasite-2019') adds no syntax or format detail beyond it. Baseline 3 is appropriate when the schema does the heavy lifting.

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 Letterboxd film'), then enumerates the exact fields returned (synopsis, director, cast, genres, countries, languages, runtime, member rating). It also distinguishes itself from the reviews sibling, so an agent can tell it apart from letterboxd_film_reviews/rating_histogram 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?

Explicitly routes the agent to letterboxd_film_reviews for popular reviews, which is a concrete alternative and condition. However, it does not cover the other film-level siblings (letterboxd_film_similar, letterboxd_film_rating_histogram) nor contrast with the search tool, so routing is partial rather than complete.

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