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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds valuable context beyond that by flagging the data as 'public' and 'user-contributed guide signals,' warning the agent about data provenance/quality. Return format is not described, but an output schema 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?

Three short sentences, scoping constraint and alternative routing front-loaded, zero filler. Every sentence earns its place.

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?

With an output schema carrying return values and annotations covering the safety profile, the description is nearly complete. It covers purpose, input rule, and alternative routing; the only minor gap is not noting possible absence of guide data for some titles.

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 the baseline is 3, but the description adds a genuine constraint not present in the schema: exactly one of id/url must be supplied. That mutex/one-of rule materially improves correct invocation.

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 (Fetch) and resource (IMDb parental-guide categories and severity signals for a title), and explicitly names the sibling imdb_title as the tool for general metadata. An agent can distinguish it from related imdb_title_* tools 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?

The description routes the agent to imdb_title for general metadata and states the input constraint ('pass exactly one title id or URL'). That is clear context for selection, though it does not state explicit when-not conditions (e.g., that parental guides may be absent for some titles).

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