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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the bar is lower, and the description adds real context beyond them: it discloses that the response is shaped by what 'the plan allows to read' and which entry kinds are loggable. It does not discuss caching, freshness, or auth requirements, which keeps it below a 5.

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?

A single compact sentence listing exactly the returned settings, with no filler or repetition. It is slightly fragmental — no leading verb phrase — but the information density is high and front-loaded.

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 carries the burden of describing return contents and does so by enumerating the fields. For a zero-parameter read tool this is nearly complete; only the exact structure of the response (e.g., how plan permissions are represented) is left unspecified.

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 tool takes zero parameters, so there is nothing for the description to disambiguate; the baseline of 4 applies. Schema coverage is 100% and the empty object schema is unambiguous.

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 enumerates the specific data the tool returns — glucose unit, target range, time zone, local time, loggable entry kinds, and plan read permissions — so an agent can infer it retrieves account/diary configuration. It stops short of naming a verb ("get"/"retrieve") or distinguishing itself from siblings like get_stats or get_entries, leaving the separation implicit.

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 explicit when-to-use statement or named alternative. Usage is only implied by the content: an agent would reasonably call this to learn units, target range, or local time before logging or interpreting glucose data. That inference is easy but not stated.

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