list_activities

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

With no annotations provided, the description carries the full burden and meets it well. It discloses ordering ('most recent first'), filtering semantics (including the nuanced behavior of sport filters revealing multisport legs), response format ('compact record'), and default/capped limit. This goes beyond basic expectations and fully informs the agent.

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 well-structured: a clear one-sentence summary followed by an 'Args' section. Every sentence provides valuable information, including the multisport edge case. It is detailed yet efficient, with no filler or 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?

Despite moderate complexity (4 optional params, no annotations), the description covers ordering, filtering, formatting, and a subtle multisport behavior. An output schema exists, so not detailing every return field is acceptable. The description is self-contained and sufficient for correct invocation.

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 input schema has 0% description coverage (no property descriptions), but the description compensates by explaining every parameter: ISO date format with example, sport filter options, default and max limit, and the 'until' boundary. It adds significant meaning beyond the raw 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?

The description opens with a specific verb+resource statement: 'List recorded activities, most recent first.' This clearly differentiates it from siblings like get_activity_detail or weekly_summary, and the mention of 'compact record' further highlights its listing focus.

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 gives useful context about filters and output format but does not explicitly state when to use it over alternatives (e.g., 'for a single activity's details, use get_activity_detail'). Usage is implied through the described behavior, but no exclusions or alternative guidance is provided.

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