Get stats for part of an activity

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds the segment-range scoping and metric details, which are useful, but does not disclose additional behavioral traits such as limits, errors, or dependencies. This is acceptable but not exceptional given the annotation coverage.

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?

Two short sentences with no filler. The core action and resource appear first, followed by a useful example and a clear use case. Every sentence earns its place.

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 tool with three well-documented parameters, an output schema, and read-only/idempotent annotations, the description provides sufficient context: what metrics are returned, how the segment is specified, and when it is useful. Nothing critical is missing.

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 coverage is 100%, so a baseline of 3 applies. However, the description's example 'from 10:00 to 20:00' adds a concrete illustration of how start and end values are expressed in the 'm:ss' format, going slightly beyond the schema's dry description.

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 ('Get') and clearly names the resource: stats for a selected part of an activity, listing pace, heart rate, cadence, and intensity. The example 'from 10:00 to 20:00' distinguishes this from whole-activity tools like get_activity and from time-series tools like get_activity_streams.

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 explicitly suggests when to use the tool: 'Use it to compare the first and second half or a climb.' This provides a clear usage context, though it does not explicitly name alternatives or state when not to use it, so it falls short of a full 5.

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