calendar_list_calendars

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

With no annotations and no output schema, the description carries the behavioral burden and largely meets it by disclosing the return fields (name, note_id, title, timezone, colour, event count) and implying a non-mutating read via 'List'. It omits auth requirements, pagination, and cost characteristics, which are minor for a zero-parameter listing.

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?

Front-loaded with the action, then the payload, then the call-to-action. The 'Start here' sentence and the closing clause about names being how the user refers to calendars overlap somewhat, but the text is short and each sentence is nearly load-bearing.

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?

No output schema exists, so the description's enumeration of return fields is exactly the right compensation, and the identifier hand-off to other tools is explained. Nothing essential is missing for a zero-parameter, read-only list; only secondary details like pagination are 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?

The tool takes no parameters, so the baseline is 4; the description goes slightly beyond by explaining that the returned `name` is the `calendar_name` identifier consumed by sibling tools, which is useful cross-tool semantics rather than schema restatement.

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 this server exposes') and enumerates the returned fields, so an agent can immediately distinguish this discovery tool from the event CRUD siblings. The purpose is unmistakable.

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?

'Start here' gives explicit sequencing guidance, and the note that calendar names are what the other tools accept tells the agent how to chain this call into siblings. It does not name exclusions or alternatives, but for a single list-calendars tool that would be artificial.

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