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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds no behavioral context beyond the one-liner: no note on whether the catalog is static/complete, caching, rate limits, or what the country default of US implies. With annotations doing the heavy lifting, this is a minimal addition.

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?

A single front-loaded sentence with zero filler; the resource and scoping constraint come first. It is efficient, though almost too terse to be maximally useful.

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?

An output schema exists so return values need not be explained, and annotations cover safety. For a one-parameter read tool this is minimally adequate, but the absence of any usage or caveat context leaves a gap given the 25+ justwatch siblings the agent must route among.

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% with a single optional parameter documented as a two-letter ISO code defaulting to US. The description only echoes 'for a country' and adds no syntax or edge-case detail. Baseline 3 is appropriate when the schema fully documents the parameter.

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 (Returns) and resource (JustWatch provider catalog) scoped to a country, which is more specific than a bare name restatement. It does not explicitly contrast with near siblings like justwatch_provider_titles or justwatch_monetization_titles, but the phrase 'provider catalog' is distinct enough to separate it from those.

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, no prerequisite (e.g. needing a country code for accurate results), and no mention of alternatives such as justwatch_provider_titles for a provider's titles. The agent must infer the context entirely.

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