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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, so safety and idempotency are covered. The description adds behavioral context beyond these: it specifies the content of the response (release order, per-part runtime, total runtime, ratings, posters, streaming with region) and the edge-case behavior for standalone films. This adds meaningful value without contradicting the annotations.

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?

The description is three sentences long, front-loaded with the core purpose and immediately followed by input constraints and the use case. Every sentence adds value: the first defines the output, the second specifies input alternatives, and the third states the use case and edge case. No filler or redundant repetition of schema info.

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?

Given the tool has 6 parameters, no output schema, and is a read-only lookup, the description covers the essential aspects: what it returns (viewing order with runtime, ratings, posters, streaming), how to invoke it (with one of three identifiers), and the edge case (standalone films). It could be more explicit about the response structure or formatting, but for a query tool of this complexity, it is sufficiently complete. The annotations cover safety and idempotency, so the description doesn't need to repeat those.

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 each parameter is documented in the schema. The description adds critical usage semantics beyond the schema: it clarifies the mutual exclusivity of query, collection_id, and tmdb_id, and explains that 'query' resolves a collection from a film title. This enriches parameter understanding, especially the 'media' parameter which only matters with tmdb_id. The description compensates for any ambiguity in the schema.

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 states a specific purpose: providing franchise viewing order with runtime, ratings, posters, and streaming availability. It clearly distinguishes this from sibling tools like movies_details (single movie details) and movies_search (search) by explicitly targeting 'in what order do I watch X' questions. The verb-resource combination is precise and unambiguous.

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?

The description explicitly states the intended use case ('Use for "in what order do I watch X" questions') and specifies input constraints: 'provide only one of query, collection_id, tmdb_id'. It also covers the edge case of standalone films returning an empty result with an explanation. This gives an agent clear guidance on when to select this tool over alternatives.

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