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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds genuinely useful behavioral scope: it aggregates "all synced and logged sessions" (not just logged ones) and defines the week boundary ("weeks start Monday"), which the annotations cannot convey.

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 dense but front-loaded sentence delivers the data content first and the usage trigger last, with no filler. Every enumerated metric and the week-boundary parenthetical earns its place by describing what an agent will actually get back.

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?

With no output schema, the description usefully enumerates the return payload (per-session metrics plus weekly and current-week totals) and the aggregation scope, so an agent can call it correctly with zero required params. Minor gaps remain: no mention of units beyond km/mi or of behavior when no sessions exist in the window.

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 single parameter has 100% schema description coverage including default (28) and max (365), so the schema does the work. The description adds no syntax or interpretation for `days` beyond what is already structured; baseline 3 applies.

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 resource (running/riding/walking volume) and enumerates the exact metrics returned: per-session distance, moving time, pace, heart rate, plus weekly totals. This is clearly distinguishable from siblings like get_recent_runs (individual runs) and get_workout_stats (broader workout stats) without opening any 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?

"Use for mileage, volume and pace questions" gives an explicit positive trigger that maps to the metric set. However, it names no alternatives and gives no exclusions (e.g., when to prefer get_recent_runs or get_workout_stats), so routing between overlapping siblings is still partly left to inference.

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