list_activities

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

With no annotations provided, the description carries full burden for behavioral disclosure. It describes the tool as listing activities, which is a read operation, and does not mention destructive actions or side effects. It adds context on the default limit and optional sport filter, but it does not disclose response pagination or latency implications. However, given the output schema exists, the return format is inferred.

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 description is concise and well-structured, with a clear introductory sentence followed by parameter documentation in a bullet-point style (Args section). Every sentence serves a purpose: the first defines the tool, the second guides usage, and the Args section provides parameter details without redundancy.

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 has 3 parameters (all optional), an output schema, and no nested objects, the description is complete enough. It covers all parameters, usage context, and a clear purpose. The output schema likely documents return fields, so this need not be in the description.

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 description adds significant meaning beyond the input schema, which has 0% schema description coverage and only provides types and defaults. It explains the period parameter with examples like 'last 30 days' and a date range format, details the sport parameter with a list of valid values, and clarifies the limit parameter's default and purpose. This fully compensates for the lack of schema descriptions.

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 clearly states the tool lists recorded activities with specific examples (runs, rides, swims, walks) and a period filter. It distinguishes itself from sibling tools by explicitly noting 'Use this to find an activity before asking for its details,' which sets it apart from tools like get_activity_details or get_last_activity.

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?

The description provides explicit guidance on when to use this tool: 'Use this to find an activity before asking for its details.' This implies it is a precursor to other activity-related tools, and it effectively excludes usage for getting detailed data, sleep, heart rate, etc., which are covered by sibling tools.

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