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

Annotations already declare readOnly, openWorld, idempotent, and non-destructive. The description adds a valuable non-obvious behavior: 'Dates shift - present as a planning snapshot,' warning the agent that results are time-sensitive and approximate. This is useful context beyond the schema.

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?

Three short sentences: the core purpose, the usage examples, and the important caveat. Every sentence earns its place, and the most distinctive information is front-loaded in the first clause.

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 tool with 7 optional parameters, a fully documented schema, and strong annotations, the description covers the essential semantics: media types, date-window behavior, regional aspect, and the volatility caveat. Without an output schema, an agent might not know the response shape, but that is a minor gap given the strong schema and safety profile.

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%, and the schema already documents every parameter including defaults and the tv/movie behavior. The description mentions the date window and media split but adds little semantic detail beyond what the schema provides, so 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 identifies the resource: upcoming movies in theatres by region and shows currently on air, with an optional date window. It is immediately clear what the tool returns, though it never names or contrasts any sibling tool, so differentiation relies on the topic rather than explicit comparison.

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?

Explicit user-intent examples are given ('what comes out in December', 'what is in cinemas now'), making the intended use obvious. However, it does not mention when not to use this tool or point to alternatives like movies_discover or movies_trending.

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