get_activity_power_in_timezones

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It adds meaningful context by explaining the output format (time, watt thresholds, duration), the hard requirement of a power meter, and the FTP basis for zone calculation. It does not discuss error cases, but for a read-only data retrieval tool this is adequate.

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 compact and front-loaded: it states the core purpose in the first sentence, summarizes the return value, and gives prerequisites. Every sentence contributes useful information, and the parameter explanation is brief but sufficient.

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?

The tool is simple with one required parameter and no enums, and an output schema exists, so the description does not need to explain return fields. It covers prerequisites, output shape, and parameter meaning. Minor gaps like explicit error behavior or when not to use it prevent a perfect score.

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 0%, so the description must compensate for the schema's lack of parameter details. It does so by explaining that activity_id is 'ID of the activity to retrieve power zone data for,' which directly clarifies the only parameter's purpose.

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 uses a specific verb and resource: 'Get power distribution across training zones for an activity.' It clearly differentiates the tool from siblings by specifying it returns time spent in each power zone with watt thresholds and duration, making its purpose unmistakable.

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 gives clear context for when this tool is appropriate: it requires a power meter and uses FTP configured in Garmin Connect. It does not explicitly name alternatives or exclusion conditions, but the purpose and prerequisites effectively signal the intended use case.

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