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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds genuine value by disclosing the entity-resolution behavior ('Resolves all ids internally') and the mutual-exclusivity constraint ('provide only one'). No contradiction with annotations — a ratings query aligns with read-only.

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 and roughly 50 words with zero waste. The data scope is front-loaded, followed by id options and usage context. The final sentence ('this is the entity-resolution showcase') is mildly promotional but earns its place by signaling the tool's distinguishing capability.

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?

Moderate complexity with 5 optional params but a simple lookup purpose. With no output schema, the description adequately hints at return values by naming the rating sources. It covers what data comes back and how to invoke it. The only minor gap is not describing ranking position semantics or pagination, which is low-value for a ratings 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?

Schema coverage is 100%, so each parameter is already documented. The description adds value beyond the schema by clarifying the mutual exclusivity of query/id/imdb_id ('provide only one') and noting that id resolution happens internally, which helps the agent understand which parameter to supply. This exceeds the baseline of 3.

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 and resource ('Ratings for one film across sources') and enumerates the exact data returned (TMDB score, IMDb score/votes, Top 250 and Top 500 ranks). This clearly distinguishes it from siblings like movies_details, movies_reviews, and movies_search — an agent can tell what this tool returns without opening any 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?

Gives explicit usage context: 'Use for how is X rated everywhere questions' and explains the entity-resolution behavior. However, it does not name alternative siblings or state when NOT to use it (e.g., when to prefer movies_details for full metadata). Clear context but no exclusions.

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