garmin_get_trends

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

Annotations already disclose read-only, idempotent, non-destructive behavior. The description adds meaningful context that the tool operates on locally cached data, which implies the results may be stale until a sync occurs—beyond what annotations say. This helps the agent set expectations about data freshness.

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?

One clean, front-loaded sentence with no filler. It efficiently conveys the core operation and data source.

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 simple read-only tool with an output schema and strong annotations, the description is adequate but incomplete: it lacks usage differentiation, parameter documentation, and any note on date range handling. The 'locally cached' detail is valuable, but overall the agent gets minimal orientation beyond the tool name.

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 has 0% description coverage for the two parameters. The description does not mention start_date or end_date, nor does it explain expected formats (e.g., ISO 8601) or relationships between them. Param names are self-explanatory, but the description adds no semantic value beyond what the schema field names already hint at.

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 ('calculate') and resource ('trends from locally cached daily summaries'). It clearly distinguishes the tool from siblings like garmin_get_day or garmin_compare_periods by highlighting the 'locally cached' source and trend-focused scope.

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?

No explicit guidance on when to use this tool vs alternatives such as garmin_compare_periods or garmin_recent_overview. The description implies a trend calculation use case but does not state prerequisites (e.g., needing a recent sync) or exclusions. Agents must infer when selection is appropriate.

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