get_channel_metrics

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

Annotations already mark the operation read-only, and the description adds useful behavior: default range, date format, and per-range caching. It does not cover rate limits, authentication, or return-shape details, but the read-only annotation lowers the burden.

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 compact sentences, front-loaded with the tool's purpose and immediately followed by the metrics and date constraints. Every sentence earns its place and there is no filler.

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 simple read-only metrics tool with three optional parameters, the description covers the key call context: metrics returned, default range, date format, and caching. The only notable omission is an explicit explanation of the refresh parameter, but the description still provides enough to invoke it 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?

With 0% schema description coverage, the description must carry parameter meaning; it does define date format and default range, and 'Cached per range' hints at caching semantics. It does not explicitly explain the refresh boolean or how start_date/end_date interact, leaving a gap.

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 names a specific resource ('Channel metrics from the YouTube Analytics API') and lists the measured fields, making the tool's function clear. It does not explicitly contrast with sibling tools, but the metric list and date-range scope distinguish it from get_channel_overview and list_videos.

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?

It gives clear context: metrics are for a date range, defaulting to the last 28 days, with dates formatted YYYY-MM-DD and results cached per range. It does not explicitly state when to prefer another sibling tool, but the intended use case is clear.

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