Readiness snapshot

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

Annotations already declare readOnly, idempotent, non-destructive, open-world, so the safety bar is low. The description goes further by disclosing the shape of the payload (one compact object), the comparison windows used (previous 7 days; 28-day weekly average for load; 3 days of activities), and the wake-up-date filing convention — all behaviors an agent could not infer from annotations.

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?

Front-loaded with the use case, then the payload inventory, then the date caveat — a sensible ordering with no filler sentences. The middle enumeration is dense but every clause carries distinct information; it is long only because the return payload is broad.

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?

There is no output schema, so the description must characterize return values, and it does so field-group by field-group with their comparison baselines. Combined with the date semantics, an agent has everything needed to call this correctly and interpret the result.

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?

With a single parameter at 100% schema coverage, the baseline is 3, but the description adds real meaning the schema cannot: sleep is keyed to the wake-up date, so 'today' retrieves last night. That resolves a genuinely ambiguous default, though it does not discuss time-zone edge cases beyond what the schema notes.

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 gives a concrete composite resource and enumerates its contents (sleep score/stages/HR/respiration, HRV vs baseline, resting HR, Body Battery, training load, recent activities). It also anchors the tool to the user questions it answers, which cleanly separates it from single-metric siblings like get_hrv, get_sleep, and get_body_battery.

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?

"Best first call for ..." is an explicit routing instruction with several example phrasings, plus a concrete date-selection rule ("use 'today' for last night"). It stops short of naming when to prefer the narrower sibling tools or when not to use this one, which keeps it just below a 5.

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