Get Activity HR Zones

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

The description does not add behavioral details beyond the readOnlyHint and openWorldHint annotations. It does not mention potential errors, data format, or any side effects, which is acceptable for a read-only getter but not enriched.

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 a single, concise sentence that conveys the essential purpose without unnecessary words or complexity.

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 description gives a clear idea of the output (time per heart rate zone) but lacks details such as units, zone definitions, or any additional context. Given the simplicity of the tool, this is mostly sufficient, though a bit more specificity could enhance completeness.

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?

The schema already describes activityId as 'The unique activity identifier (required)'. The tool description does not add extra meaning to the parameter; it only reinforces that the data is tied to an activity.

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's function: retrieving time spent in each heart rate zone for an activity. It is specific and distinguishes it from other activity-related tools like get_heart_rate or get_activity_details.

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 indicates the tool is used for a specific activity (implied by 'during an activity' and the required activityId), but it does not explicitly compare it with alternatives or provide conditions for when to use it over others.

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