get_activity

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

Annotations already declare readOnlyHint and openWorldHint, lowering the bar. The description adds genuinely useful behavior beyond them: the failure mode ('Throws GarminError if Garmin returns nothing'), telling the agent to expect an exception rather than an empty summary.

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?

Two compact sentences, front-loaded with the core purpose and immediately followed by the exceptional behavior. Nothing extraneous.

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?

For a single-read tool with full annotation coverage and a fully documented parameter, this is nearly sufficient: purpose, scope, and error behavior are all present. Return-shape detail is only gestured at with 'summary', but there is no output schema requiring reconciliation.

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%, so the activityId parameter is already documented as a numeric id; baseline 3 applies. The description reinforces 'by id' but adds no format or constraint detail beyond what the schema provides.

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 ('get one activity') plus scope ('summary by id'), which meaningfully distinguishes it from the many sibling get_* tools like get_activity_details and get_activities. It stops short of naming those siblings explicitly, so differentiation relies on the reader inferring 'summary' vs 'details'.

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 'by id' framing implies a single-record lookup versus the list/chart siblings, giving an implied use case. However, it never states when to reach for this over get_activity_details or get_last_activity, and gives no prerequisites.

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