garmin_activity_trackpoints

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

No annotations, so the description carries the full burden: it discloses the ~1/sec sampling rate, resulting volume (a 1-hour activity ~3600 points), pagination mechanics, and that the response includes total_count. This is strong disclosure of size/performance traits, though it says nothing about auth requirements or rate limits.

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 payload contents, then behavior, then use-case routing. Four short sentences, each earning its place; only minor redundancy between the field list and the 'best for' examples.

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?

An output schema exists, so return values need not be restated, and the description covers everything else an agent needs: what is returned, how large it gets, how to page, and when to pick a lighter sibling.

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 explains limit/offset as the paging mechanism but gives no format, defaults (500/0), bounds, or meaning for activity_id beyond the implicit name. Partial but not full compensation for the coverage 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?

States a specific verb+resource ('GPS trackpoints for an activity') and enumerates the fields returned (lat/lon, altitude, distance, speed, HR, cadence, power, temperature) in chronological order. It distinguishes itself from garmin_activity_detail without the agent needing to open either schema.

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?

Provides an explicit 'Best for:' list (elevation profile, HR drift, GPS track inspection, pacing, climb segmentation) and names the alternative with the condition that selects it ('For aggregate stats ... prefer garmin_activity_detail — much smaller output'). When-to-use and when-to-use-something-else are both covered.

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