Derive aerobic decoupling and GAP for one activity

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

With no annotations provided, the description carries full behavioral burden and does so well: it discloses read-only behavior, states derived values never overwrite provider-supplied values, and explains null return conditions with caveats. This gives an agent confidence about side effects and edge cases.

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 dense but efficient: it front-loads the core computation, explains the metric formulas in parentheses, then moves to edge-case behavior, side-effect safety, and prerequisite. Every sentence contributes information, with no filler or repetition.

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 there is no output schema, the description covers return edge cases, side-effect safety, data requirements, and a prerequisite. It does not describe the shape of a successful return or clarify the optional includeGap behavior, but the overall call context is sufficiently composed for an agent to proceed.

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. It adds the useful fact that athleteId comes from list_athletes and clarifies the data source, but it never explicitly introduces the activityId parameter and many of its details are qualitative. The optional includeGap parameter is entirely unexplained, leaving a meaningful 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 verb ('derive') and resource ('one activity'), and specifies the metrics: aerobic decoupling with sport-specific formulas and grade-adjusted pace. It is clearly distinguishable from sibling tools that read series, analyze trends, or manage syncs.

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 states a clear prerequisite ('Requires athleteId from list_athletes') and implies this is the tool for deriving decoupling/GAP from stored samples for a single activity. It does not explicitly mention when NOT to use it or name alternatives, but the context is clear enough for correct selection.

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