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

Annotations already establish the safe read-only, non-destructive, closed-world profile, so the description need not restate safety. It does add genuinely non-obvious behavioral context: the one-call-per-period contract and the prohibition on repeating identical periods, which prevents over-calling. It does not describe pagination or response size, but with an output schema present that gap is small.

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?

Three sentences, front-loaded with the user-facing purpose before the return contract and the call discipline. Every sentence carries operative information; nothing is redundant or decorative.

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?

An output schema exists, so return-value detail is unnecessary, and the description covers the two things the schema cannot: what the summary contains and how many times to call it. Complete for a zero-required-parameter read tool.

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 100% and the schema itself already explains the period window and the muscle_group id-vs-name trap, so the schema carries the parameter burden. The description only references 'last_7d' and 'last_30d' as examples, adding no syntax or semantics beyond the enum. Baseline 3 is appropriate.

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 with concrete scope: totals, volume, weekday frequency, and streak over a rolling period, and clarifies it returns one summary per period. The call-discipline sentences ('never call once per day, workout, exercise, set, or muscle group') implicitly separate it from the per-entity siblings like get_workout and get_recent_workouts, so an agent can route correctly without opening a schema.

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?

Explicit when-to-use rules: call exactly once per distinct requested period, exactly two calls for a 7-day/30-day comparison, and explicit never-call-per-entity exclusions. Alternatives and anti-patterns are both named, leaving nothing to inference.

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