garmin_activity

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds valuable behavioral context beyond the annotations: the kinds of analysis performed (e.g., 'rep-by-rep fade', 'planned-vs-executed'), the selection fallback to the latest activity, and the addition of lap tables or HR/pace curves for 'splits' and 'full'. No contradictions exist.

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 compact sentences deliver all key information with no fluff. The first sentence front-loads the core purpose, the second covers selection logic, and the third explains detail levels. Every clause adds value and is appropriately sized for the complexity.

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 tool's moderate complexity and the presence of an output schema, the description covers purpose, selection modes, detail levels, and analytical insights. It is complete enough for an agent to select and invoke the tool correctly. The 'ONE session' phrasing also prevents confusion with the plural sibling garmin_activities.

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 only 25%, so the description must compensate, and it does extensively. It explains how activity_id, date, and sport interact in selection, and clarifies that omitting both activity_id and date returns the latest activity. It also gives meaning to the 'detail' parameter by specifying what 'splits' and 'full' add. This is well beyond the schema's bare parameter names.

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 opens with 'ONE session in depth,' clearly identifying the resource (a single Garmin activity/session) and the operation (retrieving detailed analysis). It distinguishes itself from the sibling tool 'garmin_activities' by explicitly focusing on one session rather than a list, and the phrases 'execution vs structure, rep-by-rep fade, decoupling, comparison to the closest past session, planned-vs-executed' specify the kind of depth provided.

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 explicit selection instructions: 'Select by activity_id, by date, or omit both for the latest — add sport for the latest of that sport.' It also explains when to use 'splits' and 'full' detail levels. However, it does not explicitly name alternatives or state when not to use this tool versus siblings, though the 'ONE session' wording implies the contrast with garmin_activities.

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