get_pace_curves

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

Annotations already declare readOnlyHint and openWorldHint, and the description reinforces with 'Read-only, one API call' while adding real behavioral detail: default 90-day curve, return contents (best time + pace + setting activity), units (min/km, min/100 m for Swim/OpenWaterSwim), and that missing distances are reported as not available.

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?

Front-loaded with the use case, then dense factual sentences about returns, defaults, and cross-references. No filler; every clause carries information an agent needs.

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?

With no output schema, the description carries the return-value burden and does so (time, pace, units, missing-distance handling, optional GAP). It also cross-references the HR sibling and the underlying method guide, leaving nothing essential missing for a 7-param, all-optional tool.

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 all seven parameters are documented in the schema itself. The description restates the same facts (gradient-adjusted pace, ~90-day default, pace units) without adding syntax or constraints beyond the schema, so the baseline 3 applies.

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?

States a specific noun+scope ('best times per distance over one or more periods') with concrete use cases (PBs, comparing periods, progress). It differentiates toward get_hr_curves for the HR side, but does not address the more ambiguous overlaps with get_best_efforts and compare_best_efforts in the sibling list.

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?

'Use for...' explicitly frames the scenario, and 'HR side: get_hr_curves' points to the correct alternative when the athlete's heart-rate curves are wanted. No explicit when-not-to-use guidance, but the context is clear enough to route correctly.

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