Views by country

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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, destructiveHint=false. The description adds context beyond annotations: countries are returned as ISO codes, results are ranked, and it can be scoped to a single video. No contradiction with annotations. It does not mention pagination, but annotations cover the safety profile.

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 three sentences, front-loaded with the primary action, and contains no redundant or filler wording. It efficiently conveys purpose, output format, optional scoping, and use case.

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?

Given the rich schema (100% coverage), comprehensive annotations, and absence of output schema, the description is complete enough. It covers the tool's purpose, output format (ISO codes), ranked results, optional video scoping, and a practical use case. No critical information is missing for an agent to select and invoke the tool correctly.

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 all parameters. The description adds minimal parameter context—'Optionally scope to a single video' paraphrases video_id, and 'ranked' relates to max_results—but does not significantly expand on the schema's detailed parameter descriptions. 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 states it 'break[s] views and watch time down by viewer country, ranked.' It specifies the resource (geographic breakdown) and action, and mentions output format (ISO 3166-1 alpha-2). This distinguishes it from sibling tools like yt_traffic_sources or yt_top_videos by focusing on country-level data.

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 a concrete use case: 'Useful for deciding where an audience actually is before making scheduling, language, or sponsorship calls.' It implies when to use this tool but does not explicitly name alternatives or state when not to use it. Clear context, but no exclusions mentioned.

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