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 covered. The description adds useful signal that the payload is deep (nested entries, sets, cardio, wearable metrics), which hints at a heavier response than a list call, but says nothing about not-found behavior or payload size limits.

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?

A single front-loaded sentence with no filler; every clause names a component of the returned payload.

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, the description needn't spell out return values, and for a one-parameter read getter this is close to sufficient. The only gap is routing guidance versus the list and activity siblings.

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?

Only one parameter exists and the schema provides zero description coverage for session_id. The description never mentions the identifier at all, though the name is largely self-explanatory, leaving the agent to infer it must be an existing session's ID.

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 (get) and resource (one session) and enumerates the nested payload (entries, sets, cardio, wearable metrics). 'One session' implicitly distinguishes it from the plural get_sessions sibling, though the sibling is never named.

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 singular scope implies this is the detail-fetch tool rather than the list tool, but the description never states when to use it over get_sessions or get_activities, nor any prerequisites. Usage is only inferable from the wording.

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