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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds the dependency on a prior movies_search id and the warning not to guess IDs, but does not disclose much beyond the annotations. No contradiction exists.

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?

Two sentences carry both the tool's purpose and its key prerequisite. The content list is front-loaded, and the usage warning is concise. No filler or redundant phrasing.

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?

Even with no output schema, the description enumerates the major return fields (plot, genres, ratings, cast, director, trailer, awards, IMDb id, poster) and states the required precursor action. This is sufficient for an agent to select and call the tool correctly. Minor gaps like response format or pagination are not critical for a single-item details tool.

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?

The input schema already provides 100% coverage, describing id as 'Numeric TMDB id from movies_search (required)', media as 'movie or tv', and language as ISO language for plot/tagline. The description reinforces the id-source rule but does not add new parameter semantics beyond the schema. Baseline 3 is appropriate.

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 clearly states this tool returns 'Full details for one movie or TV show' and enumerates specific content: plot, genres, ratings, cast, director, trailer, awards, IMDb id, poster. This distinguishes it from sibling tools like movies_ratings or movies_artwork by positioning it as the comprehensive details endpoint.

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 provides explicit usage context: 'Use after movies_search gave you an id' and warns 'Do NOT guess ids - search first.' This is strong guidance on when to call the tool)Skip. It does not explicitly name alternatives for edge cases like ratings-only lookups, so it misses the 'when-not/alternatives' part of a 5.

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