icu_get_pace_curves

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

Annotations already declare readOnly, non-destructive, idempotent, and open-world hints. The description adds value by explaining GAP normalization and sport type support, but does not contradict annotations. It does not provide further behavioral details (e.g., rate limits, auth needs) that are not already implied by annotations.

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 concise: 4 sentences in two short paragraphs. Every sentence adds value (purpose, sport types, usage context, GAP explanation). No redundant or filler content.

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 the existence of an output schema, the description adequately covers the tool's purpose, input parameters, and key features like GAP. It does not explain output structure, but that is acceptable. It could be slightly more specific about the exact durations returned, but overall it is complete enough.

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 input schema has 100% coverage with descriptions for all 4 parameters. The description adds context for 'use_gap' (explaining Grade Adjusted Pace for hills) and implies sport_type values, enhancing understanding beyond the schema. It does not describe 'days_back' or 'time_period' further, but schema handles them well.

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 gets pace curve data showing best efforts for various durations, with sport types (Run, Swim) and GAP normalization. It is specific about the resource and action, though it does not explicitly differentiate from siblings like 'get_best_efforts' or 'get_pace_histogram', which might overlap.

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 mentions the tool is 'useful for tracking running fitness and race predictions', providing some usage context. However, it does not state when to use this tool versus alternative pace-related tools (e.g., 'get_best_efforts' or 'get_pace_histogram'), nor does it include when-not-to-use guidance.

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