list_available_calendars

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

Since annotations are absent, the description carries the full burden. It clearly indicates a read-only operation by using 'Lists' and discloses a useful output detail (CalDAV sync URLs). It does not hide side effects or require additional disclaimers for a simple list operation.

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 a single, well-structured sentence that front-loads the primary action. Every word adds value with no redundancy.

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?

This is a simple no-parameter tool with no output schema. The description adequately covers what the tool does and key return content. It is complete for its complexity and need.

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 parameters, and the input schema is trivially 100% covered because it is empty. The description does not need to explain parameters, and it adds a hint about the output ('including CalDAV sync URLs') which is relevant. Baseline for 0 params is 4.

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 uses a specific verb ('Lists') and clearly identifies the resource ('available calendars'), and adds a distinguishing detail ('including CalDAV sync URLs'). It is clearly distinct from sibling tools like list_events and list_channels, so there is no ambiguity.

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 implies usage: use this tool when you need to see available calendars. However, it does not explicitly provide context on when to choose this over alternatives, nor does it mention any exclusions or prerequisites. It is adequate but not explicit.

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