list_addressbooks

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

No annotations are present, so the description must stand alone. It clearly frames the tool as a read-only listing operation ('List all available') and indicates the return payload includes address book URLs. This is sufficient for a zero-parameter list tool.

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 sentences, first states action and scope, second states purpose. No filler or redundant elaboration.

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 listing tool with no output schema, the description covers what it returns (URLs) and why. It does not detail pagination or error behavior, but that is not critical for a simple list operation.

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 accepts zero parameters, so there is nothing to document. The description's mention of address book URLs is the only meaningful data-related context, and nothing is missing.

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 action 'List' on a clear resource 'address books' with a source 'CardDAV server'. Distinguishes from siblings like list_contacts and list_calendars by targeting the address book collection itself.

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?

Explicitly tells the agent to use this to fetch address book URLs needed for other contact operations, establishing when to call it (before operations requiring address book identifiers). Does not explicitly contrast with alternatives like addressbook_query, but the prerequisite role is clear.

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