List activities

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

Annotations already declare readOnlyHint/idempotentHint/non-destructive, so the safety profile is covered. The description adds real behavioral context beyond that: results are ordered newest-first and each row carries a fixed set of metrics, which tells the agent what a response looks like. Pagination defaults are left entirely to the schema.

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?

Two sentences, no filler. The return-shape and ordering information is front-loaded, and the routing hint to get_activity closes the description cleanly.

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 returned fields and ordering, and filtering is explained. Only paging behavior and result-size expectations are unaddressed in prose, though the schema covers them adequately.

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 coverage is 100%, so limit/offset/date bounds are fully documented and the baseline would be 3. The description adds meaning on the one weakly-specified parameter, activity_type, by giving concrete example values (running, cycling, lap_swimming, strength_training) even though no enum exists in the schema.

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 the specific resource (recorded activities), the ordering ('newest first'), and exactly which fields come back (type, start time, duration, distance, heart rate, power, pace, training effect). It also names the sibling it is not — 'Use get_activity for one activity in full' — so an agent can separate list vs. detail without opening either 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?

Gives clear usage context: filter by date range or activity type, and defer to get_activity when a single full record is needed. It does not cover when-not conditions such as aggregate/training-load queries (get_training_log) or per-day rollups (get_daily_summaries), which are plausible confusions among the siblings.

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