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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=false and destructiveHint=false, so the safety profile is fully covered. The description adds one genuinely useful disclosure beyond that — 'Tokens and private event details are never returned' — but says nothing about what happens when no connection exists (e.g., null vs. connected=false) or how a connection is established.

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 front-loaded sentence covering the read, the returned fields, and the privacy boundary, with no wasted clauses. Nothing is buried or repeated.

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 assumes the burden of naming the return values, and the privacy note anticipates an obvious agent concern. It is not fully complete for a connection-check tool, since the disconnected/no-calendar case and the connect-path handoff are unaddressed.

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 description coverage is 100%, and site_id and the optional user_goal are both documented in the schema. The description adds no parameter-level meaning (such as what site_id scoping changes in the response or the format of a returned calendar identifier), so this is the baseline case where the schema does the work.

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 ('Read whether this site has an active Google Calendar connection') and enumerates exactly which fields come back (email, write calendar, selectable calendars). It does not distinguish itself from nearby siblings such as get_calendar, list_events, or create_calendar_meeting, so an agent must infer the boundary.

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 statement of when to use this versus get_calendar or before calling create_calendar_meeting, and no prerequisites or exclusions. The pre-flight/discovery intent is only implied by the returned-field list, leaving routing entirely to inference from the name.

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