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

Annotations already declare readOnly, idempotent, and closed-world, so the description's main added value is the access prerequisite: a connected account on Go or Pro. It also discloses that a chart is produced. It says nothing about behavior with sparse history, latency, or whether the analysis is cached/computed on demand.

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 verb, resource, and access caveat, then the output enumeration, then the usage sentence. The long output list is dense but each item helps the agent decide whether to call; only minor tightening is possible.

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?

With no output schema, the description compensates by enumerating the returned analysis fields, and it states the account prerequisite. It leaves open what is returned when there is little check-in data, but otherwise an agent has enough to call correctly.

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 fully documents the single 'days' parameter with range and default, so the baseline applies. The description adds no meaning beyond the schema — it does not say how the lookback window interacts with the reported trend or whether a minimum history is needed for trends to be meaningful.

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?

Names a specific verb ('Analyses') and resource ('the user's own Recalibrate check-in history') and enumerates the report's contents (wellbeing average, trend, flare days/severity, triggers, limits, what helps, day-of-week extremes, chart). The analytics scope separates it from log_daily_check_in and plan_paced_day, but it never states how it differs from create_my_doctor_report, which plausibly overlaps.

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?

Gives concrete trigger phrasings: asks about how they have been doing, what triggers their flares, or their patterns. That is a clear when-to-use signal, but there are no exclusions or named alternatives (e.g., when to prefer the doctor report or the nervous-system check instead).

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