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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds one genuinely useful caveat: offer links are returned only 'when JustWatch includes them in the search payload', signaling inconsistent return content. It does not mention rate limits, auth, or result pagination behavior beyond the schema's limit clamp.

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?

One front-loaded sentence with no padding; the core action comes first and the return caveat follows. Mentioning the 'public website GraphQL endpoint' is mildly implementation-flavored but not wasteful.

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 present, the description needn't explain return structure, and it does flag conditional offer availability. Still, for a tool with eight justwatch siblings, the absence of any routing or scoping guidance leaves a meaningful gap.

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 limit (default 10, clamped to 25), query, country, and language are all documented in the schema. The description adds nothing about parameter format or defaults, so the baseline 3 applies.

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 verb and resource ('Searches JustWatch titles') and describes the return payload, so the agent knows this is a title lookup. However, it does not differentiate itself from the many justwatch siblings (discover, popular, new, genre_titles, provider_titles, title), leaving ambiguity about when this search is preferred.

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?

There is no when-to-use guidance and no mention of alternatives, despite justwatch_discover, justwatch_popular, justwatch_new and justwatch_genre_titles being plausible substitutes. The agent must infer routing from the name alone.

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