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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is clear. The description adds useful content about what data is included for runs, rides, and swims, but it does not add operational details like permissions, rate limits, or error behavior. Because an output schema exists, much of the return-content disclosure is already covered structurally.

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 front-loaded with the core purpose and then efficiently itemizes the data available by activity type. It is somewhat detailed for a read-only single-record tool, but the structure is clear and every section is relevant.

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 one required parameter, a read-only annotation profile, and an output schema, the description is largely complete about what the tool returns. The main gap is the lack of parameter format guidance and explicit usage guidance versus get_activities.

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 needs to compensate for the single parameter. It only says 'activity_id: The activity's id,' which restates the parameter name and does not clarify the anyOf integer-or-string type, expected format, or examples.

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 a specific resource and scope: one activity in detail, with lap/split data plus type-specific metrics for runs, rides, and swims. The singular, detailed framing distinguishes it clearly from the sibling list tool get_activities without needing to name it.

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 phrase 'One activity in detail' implies it should be used when detailed data for a single activity is needed, but it gives no explicit when/when-not guidance or direct alternative. It does not tell the agent to use get_activities for listing versus this tool for detail.

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