List activities

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

Annotations already declare the safe read-only, idempotent, non-destructive profile, so the description adds the ordering guarantee ('newest first') and the summary field set that comes back. It does not spell out paging behavior beyond the schema's offset, but the ordering and content disclosure are meaningful additions.

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?

The scope sentence is front-loaded, followed by two compact examples and one routing hint; every sentence carries information an agent needs to call the tool or find the sibling. Nothing is redundant with the schema.

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?

Six optional parameters, a 100% description-covered schema and annotations that cover the safety profile mean the description only needed to add ordering, output shape and sibling routing — which it does. With no output schema, listing the returned fields compensates well.

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?

With 100% schema description coverage the baseline is 3, but the description goes beyond the schema by showing how parameters combine for a realistic query (start_date + activity_type, limit=5). It gives practical meaning to activity_type and start_date rather than restating their definitions.

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 first sentence names a specific verb ('List') and resource ('recorded activities'), states ordering ('newest first'), and enumerates the key returned fields (distance, time, pace, heart rate, training effect, training load). This clearly distinguishes it from garmin_get_activity (single activity) and garmin_get_activity_splits.

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?

It gives worked examples that map natural-language requests ('my runs this month', 'last 5 activities') to concrete parameter values, and explicitly routes the agent to garmin_get_activity_splits when per-km splits are wanted. The alternative tool and the condition selecting it are both named.

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