download_activity_fit

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

With no annotations, the description carries the full burden. It discloses key behaviors: the tool saves the original FIT file as a ZIP and returns the file path. However, it does not elaborate on failure modes or auth requirements, which would add further transparency.

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?

Three concise sentences with no fluff. The main action is front-loaded and every sentence adds relevant information: file type, saving behavior, return value, and data 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?

For a single-parameter download tool with an output schema, the description covers purpose, side effect, and return value. It is nearly complete, though a note about when to prefer this format over sibling download tools would improve completeness.

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 one parameter, activity_id, has no schema description, and schema coverage is 0%. The phrase 'for a specific activity' provides minimal semantic context for the parameter, but it does not specify where the ID comes from or how it should be formatted. The description partially compensates for the coverage gap but does not fully document the parameter.

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 and resource: 'Download a FIT file for a specific activity.' It also distinguishes from siblings like download_activity_gpx/tcx/csv by emphasizing the raw sensor data contained in a FIT file.

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 implies usage for obtaining raw Garmin sensor data, but it does not explicitly say when to choose FIT over GPX/TCX/KML/CSV or mention any exclusions. The guidance is implicit rather than explicit.

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