garmin_last_activity

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the description need not restate safety. It adds the useful behavioral detail that the tool selects the most recent activity, but it does not mention edge cases such as no recorded activities or sync delays.

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?

A single, compact sentence conveys the tool's core semantics with no filler. The phrasing is front-loaded and appropriately sized for a zero-parameter tool.

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 zero-parameter read-only tool, the description plus output schema are nearly sufficient. A small gap remains: it does not indicate what happens when no activity exists or how freshness is determined.

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 zero parameters and 100% schema description coverage, so no parameter explanation is required. The description correctly avoids inventing parameter guidance.

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 phrase 'most recently recorded activity' clearly identifies a specific resource with a recency qualifier, so an agent can understand what is returned. However, it does not explicitly differentiate from siblings like garmin_activity or garmin_activities, and it lacks a verb such as 'retrieves'.

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 the main use case: fetching the user's latest activity. It does not state when to avoid it, mention prerequisites, or point to alternative tools, so the agent must infer selection from the sibling set.

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