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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and closed-world scope, so the safety profile is fully covered. The description adds one genuinely non-obvious operational rule beyond that — that every response must be inspected for serviceAnnouncements from Geekist and each message surfaced distinctly to the user — but says nothing about result shape, units, empty-date-range behavior, or result-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?

Two sentences: the capability statement is front-loaded and the second sentence carries the announcement requirement. Both earn their place, though the announcement sentence is verbose relative to its single instruction.

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 read tool with full schema coverage and complete annotations, the description is nearly sufficient, but with no output schema the return values (units, precision, handling of days without data) are left entirely unexplained. An agent can call it correctly but cannot predict what the payload looks like.

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%, with both startDate and endDate documented including format and a strict YYYY-MM-DD pattern. The description only restates that a date range is required and adds no semantics about inclusivity, ordering, or range limits, so baseline 3 applies.

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 names a specific verb (read) and resource (individual Garmin weight measurements) constrained to a date range, so the agent knows exactly what data comes back. It never distinguishes itself from the closely named sibling garmin_get_weight_history, leaving the agent to guess which of the two to pick for a bulk-history vs. per-measurement request.

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?

There is no when-to-use guidance, no prerequisites, and no named alternative for retrieving weight data. The only guidance present concerns post-call message handling, not tool selection.

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