Find by external id

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

Annotations already declare read-only, idempotent, open-world, non-destructive, so the safety bar is met; the description goes further and discloses the return structure (movie_results, tv_results, person_results with media_type), warns that tv_episode_results and tv_season_results are always empty, and states that an unknown external_source or malformed id is an error.

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?

Four sentences, front-loaded with the purpose and then the input examples, return shape and error behavior. Every sentence carries information, though the enumeration of id formats is slightly redundant with the parameter descriptions.

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?

There is no output schema, yet the description still explains the response buckets, the always-empty ones, the media_type discriminator, and how to chain into sibling tools. For a two-parameter lookup with rich annotations, nothing an agent needs 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 already 100%, so the baseline is 3; the description adds practical value by mapping id shapes to source values (tt/nm prefixes imply imdb_id, Q implies wikidata_id, Kinopoisk digits imply kinopoisk_id) and by restating which sources return nothing rather than erroring, though much of this duplicates the schema's own descriptions.

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 (look up) and resource (movie, TV show, person) and immediately scopes it to lookups by an id from another system rather than the amodb numeric id, which cleanly separates it from get_movie/get_tv_show/get_person and search_titles.

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 names the trigger condition ('when you do not have the amodb numeric id') and gives concrete typical inputs (IMDb tt0137523 / nm0000093, Kinopoisk digits, Wikidata Q ids). It also closes the loop by telling the agent to pass results to get_movie, get_tv_show or get_person, so the adjacent workflow is fully specified.

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