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

Annotations already establish read-only, idempotent, non-destructive behavior, and the description goes further by disclosing the health state enum (ok/limited/expiring/revoked/blocked) and the rule that non-ok connections carry a reconnectUrl to be handed to the owner verbatim. It does not discuss auth or rate limits, but adds genuine semantic context beyond the 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?

Roughly two sentences of dense, information-rich prose with no filler. It front-loads the resource but leads with a fragment rather than a verb, slightly weakening scannability.

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 correctly carries the burden of explaining return values and does so by spelling out the health object fields and enum states plus last error. Coverage is strong for a zero-parameter lister; only actor/permission context is absent.

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?

There are zero parameters and the empty schema leaves nothing to document, so the baseline is 4. The description adds no parameter meaning because none exist; no gap is created.

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 resource — connected calendar accounts — and enumerates the returned fields (label, health, last error), so an agent knows exactly what it retrieves. It never names a sibling like get_calendar_refs or list_calendars to distinguish scope, so it stays at 4 rather than 5.

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?

The description implies usage (inspect connection health, retrieve reconnectUrl when a connection is not ok) and even instructs to 'give it to the owner as returned,' which is a usage hint. It contains no explicit when-to-use-vs-alternative or exclusion guidance, leaving the agent to infer context.

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