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

The readOnlyHint annotation already signals a safe read operation. The description adds meaningful context beyond that: it specifies the HTTP method and path, notes that accountId comes from configured credentials, and states the return type (JSON array). This gives the agent a good understanding of the tool's behavior without needing to inspect the API.

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?

The description is two sentences, with the core purpose and usage intent front-loaded, followed by the API endpoint and return format. Every word contributes value; there is no redundancy or filler.

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?

For a parameterless, read-only tool, the description covers the essential details: what it lists, why it is used, the endpoint, and the return type. It does not specify the exact fields in the returned array (e.g., 'calendarId', 'name'), but the stated purpose strongly implies the array contains the needed calendarId. This is adequate but could be slightly more explicit.

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 has zero input parameters, and the description appropriately clarifies that accountId is taken from configured credentials rather than being an input. With no parameters to document, the baseline of 4 applies and the description does not need further elaboration.

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?

The description clearly states the action ('List'), the resource ('accounts/calendars'), and the purpose ('find the calendarId for a team member'). It also identifies the API endpoint, leaving no ambiguity about what the tool does or how it differs from sibling tools like list_team_members.

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 description provides a clear use case: to retrieve available accounts/calendars when you need to find a calendarId for a team member. It does not explicitly mention alternative tools or when not to use it, but the stated purpose gives sufficient context for an agent to decide.

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