calendar_list_calendarsLists calendars in the user's Google Calendar list, including primary, so you can retrieve calendar IDs and choose where to read or add events.
List calendars on the user's calendar list, including 'primary'.
| Name | Required | Description | Default |
|---|---|---|---|
| page_token | No | ||
| max_results | No |
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly, idempotent, non-destructive, openWorld, so the safety profile is fully covered. The description adds the useful content detail that 'primary' is included, but says nothing about pagination (page_token), result caps, or ordering—notable for a list tool that defaults to 50 items.
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 with zero waste. It is appropriately terse, though that terseness comes at the cost of the pagination information an agent needs.
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?
An output schema exists, so return-value documentation is not required, and annotations cover the safety profile. However, an agent still lacks any indication of how to page through results or cap them, which is material for a list endpoint with a default page size.
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 0% for both parameters, so the description carries the full burden—yet it explains neither page_token (continuation semantics) nor max_results (default 50, upper bound). With two undocumented params, the description fails to compensate for the coverage gap.
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?
Specific verb+resource: lists calendars from the user's calendar list, and explicitly notes 'primary' is included. Clearly distinct from siblings like calendar_list_events and calendar_get_event, though it never names or contrasts them directly.
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?
No when-to-use guidance, no prerequisites, and no mention of alternatives. The agent must infer that this is the discovery step to obtain calendar IDs before calling calendar_list_events or calendar_query_freebusy.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.