list_activities

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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds the 'completed' qualifier and 'activity summaries' scope, which is useful, but it does not disclose potential pagination, ordering, or other behavioral traits. This matches the level of moderate added context seen in the calibration example.

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 two sentences plus an Args list, with no fluff. Purpose, usage, alternative, and parameters are all front-loaded. Every element earns its place.

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?

The tool has an output schema, annotations, and clear sibling context. The description provides purpose, usage guidance, alternative tools, and parameter documentation, making it fully contextual for an agent.

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 100%, with parameter descriptions identical to the Args section. The description adds no meaning beyond the schema—it simply restates the same date formats and athlete_id default. Baseline 3 is appropriate.

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+scope: 'List completed workout activities within a date range.' It clearly distinguishes from sibling tools like get_activity by stating it retrieves summaries rather than detailed streams.

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?

Explicit usage guidance: 'Use when retrieving activity summaries across a date range.' It directly names the alternative for detailed data: 'To fetch detailed power/HR streams or intervals for a single activity, use get_activity.' This provides both when-to-use and when-not-to-use.

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