garmin_brief

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

Annotations already mark readOnlyHint and destructiveHint, so the bar is lower. The description adds useful output context (verdict, alerts, yesterday's activity_id, planned workout). However, the claim 'Zero arguments' is factually wrong since the schema includes an optional date parameter, which undermines transparency.

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 compact, front-loaded, and free of fluff. The 'Zero arguments' inaccuracy is a minor blemish, but overall it earns its place.

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 the presence of an output schema and strong annotations, the description covers what the tool does, when to use it, and how it differs from siblings. The only notable gap is the misleading argument count, but the core functionality is sufficiently complete for a read-only brief.

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?

The schema alone covers the date parameter with 100% coverage and a clear description. But the tool description's false 'Zero arguments' statement actively misleads the agent about parameter usage, so the description detracts from rather than adds to parameter understanding.

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 clearly states what the tool does: provides a fused daily brief for today's readiness and training status. It differentiates from siblings by explicitly directing to garmin_activity for a single session and garmin_activities for browsing.

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 explicitly instructs 'Call FIRST for anything about TODAY' and gives clear alternatives: 'One session → garmin_activity; browsing → garmin_activities.' This is textbook when-to-use guidance.

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