get_activity

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

Annotations already cover safety (readOnly, idempotent, non-destructive, openWorld), so the bar is lower, and the description still adds real context: no GPS/location data is returned, setting either include flag yields an explicit unsupported error, results are paginated, and laps are not guaranteed. It does not mention auth requirements or rate limits, which keeps it below a 5.

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?

Four short sentences with no filler, and the core purpose is front-loaded. The opening clause 'not guaranteed laps' is cryptic out of context, but every sentence carries information the agent needs.

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, return shape need not be described, and the description covers the important behavioral gaps: unsupported flags, absent location data, and pagination continuation. The remaining gap is page-size/offset semantics for split_limit and split_offset, which neither schema nor description explains.

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 must carry parameter meaning and it only partly does: it defines activity_id's format (positive decimal string) and the failure behavior of include_gps/include_samples, and implies split_offset via the next_offset instruction. split_limit and split_offset's own semantics (max page size 100, offset bounds) are never explained in prose.

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 a specific verb and resource: retrieves an activity summary plus one page of split summaries, and flags that laps are not guaranteed. The 'feature/group split summaries' phrasing is jargon-heavy, but combined with the tool name and sibling set (list_activities, get_sleep, get_hrv, get_daily_summary) an agent can still tell what this returns and how it differs from a listing tool.

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?

It gives concrete usage constraints for the include flags (samples/GPS unsupported in v1, will error) and tells the agent to follow pagination.next_offset — genuinely useful invocation guidance. However it never states when to choose get_activity over list_activities or get_daily_summary, so the sibling routing is left to inference.

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