justwatch_discover

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

No annotations are provided, so the description carries the burden. It discloses allowed enums for 'type' and 'monetization_types', but doesn't discuss rate limits, pagination, or response format. It mentions 'Returns popular movies and shows' but doesn't specify whether it's a read-only operation or details of the output. With no annotations, a score of 3 is appropriate as it adds some behavior detail but misses key aspects like pagination.

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?

The description is concise, with three sentences that front-load the purpose and then add essential usage details. Every sentence adds value: the first states purpose, the second gives a use case, the third clarifies allowed enums. No fluff.

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 discovery tool with 10 optional parameters and no output schema, the description covers the primary filters and a use case, but doesn't explain response structure or pagination. However, given the schema covers parameters and the tool is fairly straightforward, it's mostly complete. The lack of output schema is not an issue since the description doesn't need to explain return values, but it could mention results are sorted by popularity.

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 the schema already documents each parameter. The description adds value by explaining how to combine 'providers' and 'production_countries' for chart use cases, which is beyond the schema. However, it doesn't clarify ambiguous parameters like 'country' vs 'language' or the format of year bounds. Baseline 3 is correct.

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 the tool discovers JustWatch titles, with a specific verb ('Discover') and resource ('JustWatch titles'), and details the filters it supports. It distinguishes itself from siblings like justwatch_title_by_id or justwatch_search by focusing on discovery with filters rather than specific title lookup.

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 clear context on when to use this tool (for discovery, especially for building charts like popular Korean titles on a service). It doesn't explicitly exclude alternatives, but its filter-focused nature implies it's for broad discovery rather than specific lookups. Sibling tools like justwatch_search may be for text search, but no explicit comparison is made.

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