activities

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds the ordering guarantee ('newest first'), which is genuine behavioral context not in the schema, but says nothing about pagination, default limit of 10, or how many records are returned when the range is large.

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 ordering fact is front-loaded, which is good, but the bulk of the text is a long enumeration of return fields that largely duplicates the existing output schema. The one genuinely useful sentence about activity_type is buried at the end.

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 an output schema present, the metric enumeration is redundant, and the real gaps — date format for start/end and limit semantics — are left open. An agent can probably call it with defaults, but any date-bounded query is guesswork.

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 0%, so the description carries the full burden, yet it explains only activity_type (with concrete example keys). start and end are undocumented strings with no expected format (ISO date? epoch?), and limit's default of 10 and any cap are unaddressed.

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 states clearly that this returns a list of activities ordered newest first, with an explicit roster of the metrics included and an activity_type filter. It never clarifies how it differs from the sibling 'activity' (singular) or from 'daily'/'training_load', so an agent must infer which one to pick.

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?

Usage is only implied: an agent can infer this is the tool for browsing many activities, and the activity_type example ('running, cycling, virtual_ride') suggests filtering by sport. There is no explicit when-to-use vs. 'activity' for a single record, no guidance on combining start/end with limit, and no exclusions.

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