List calendars

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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, so the safety profile is fully covered. The description adds that results span multiple connected accounts and include per-calendar access level, but says nothing about pagination, ordering, or permission failures beyond the annotation set; a 3 is fitting given the low bar annotations set.

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 tight sentences with no filler; the operational fact (what it returns and why it matters) is front-loaded right after the scope statement.

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 usefully discloses the returned fields (calendar id and access level), which is exactly what an agent needs before chaining into event tools. Minor gaps remain around result ordering/paging and whether calendars are grouped per account, so it is not perfect.

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 the single 'accounts' parameter is documented in the schema including its omission default ('every account you are permitted to read'). The description only restates 'one or more connected accounts' without adding format or filtering detail, so baseline 3 applies.

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') and clarifies scope ('on one or more connected accounts'), which cleanly separates it from siblings like list_accounts, list_events, and get_account. It also names the downstream value (the calendar id needed by the event tools), so an agent knows exactly what it gets back.

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 phrase 'returns the calendar id needed by the event tools' implies this is the prerequisite lookup before event operations, giving clear context for when to call it. There are no explicit exclusions or named alternative tools, so it stops short of a 5.

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