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

The annotations already declare destructiveHint=true and idempotentHint=false, so the description does not need to restate those. It adds useful context: confirmation is a hard requirement, an uncertain failure must not be retried (consistent with the non-idempotent hint), and responses may carry serviceAnnouncements that must be surfaced to the user. It does not state whether the deletion is permanent or recoverable.

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 destructive action and confirmation requirement are front-loaded in the first sentence, with the non-retry rule and the announcement-handling rule following as compact imperatives. All three sentences are actionable and there is no filler.

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 two-parameter destructive tool with no output schema, the description covers the safety-critical behavior: the confirmation gate, the non-idempotent failure case, and required handling of serviceAnnouncements in responses. The remaining gap is what a successful or failed deletion returns, though the annotation set already signals destructiveness.

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 coverage is 50%: activityId is documented in the schema, and confirmed is a const-true boolean that is mostly self-evident. The description adds that the confirmation must be explicit, which gives the confirmed flag meaning beyond its const value, but it does not describe ID format or sourcing because the schema already covers that.

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 and resource: 'Delete a specific activity.' This clearly separates it from siblings such as garmin_get_activity or garmin_update_activity. It does not explicitly name an alternative or contrast with garmin_delete_workout, but the resource noun 'activity' carries that distinction.

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 an explicit precondition ('only after explicit confirmation') and an explicit prohibition ('Do not retry an uncertain deletion'), which is real when-to-use/when-not guidance. It stops short of naming alternatives or describing the conditions under which a user might want to delete rather than update an activity.

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