calendar_listList the calendars of the connected Google account: id, name, time zone, whether it is the primary one and whether you may add events to it. Pass an id as calendar to calendar_events and calendar_create_event; without one they use the primary calendar.
| Name | Required | Description | Default |
|---|---|---|---|
| account | No | Google account e-mail to read as, when you have several; an agent reads as the account connected to it. |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full disclosure burden. It usefully names the returned fields (including the event-write permission, which tells the agent whether downstream writes will succeed) and states the primary-calendar default behavior of sibling tools. It does not mention pagination, error behavior, or scope requirements, which keeps it short of 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?
Two sentences, zero filler, and front-loaded with the operation before the downstream usage hint. Every clause earns its place.
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 and no annotations, the description compensates well by enumerating the fields the list returns and explaining how the result feeds sibling tools. It stops short of covering ordering, pagination, or the empty-list case, but nothing essential to invoking it correctly is missing.
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 there is only one optional parameter, so the baseline is 3. The description reinforces the 'connected Google account' scope but adds no syntax or format detail beyond what the schema already documents.
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 ('List the calendars of the connected Google account') and immediately enumerates the returned fields (id, name, time zone, primary flag, event-write permission). This clearly distinguishes it from calendar_events and calendar_create_event, which operate on a single calendar.
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?
Explicitly explains the workflow: take an id from this list and pass it as `calendar` to calendar_events / calendar_create_event, noting those tools otherwise fall back to the primary calendar. It lacks an explicit 'when not to use this' clause (e.g., skip it if you already have the calendar id), but the intended context is unambiguous.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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