list_account_addresses

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

With no annotations provided, the description carries the full burden. It clearly states the return format (dict mapping account name to list of addresses, with accounts having no addresses mapping to []). While it implies a read-only operation, it could explicitly note the lack of side effects or auth requirements.

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 concise at 3 paragraphs: purpose, use case, return format. No redundant information, and sentences are well-structured and front-loaded.

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?

Given the simplicity (no parameters, output schema exists, many siblings), the description covers the necessary aspects. It could be slightly more complete by specifying whether it lists all accounts or only configured ones, but it is sufficient for its intended use.

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?

There are no parameters, so schema coverage is 100%. The description adds no parameter-specific information, but the baseline for 0 parameters is 4. It does provide context about the output, which indirectly helps understand the tool's usage.

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 explicitly states the verb 'list' and the resource 'configured email addresses for each Mail account'. It distinguishes itself from sibling tools like list_accounts by specifying the mapping from account name to addresses, and provides a concrete use case.

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 gives a specific scenario ('handy when an integration needs to know which inbox a message landed in by address rather than by Mail.app's display name'), which helps the agent decide when to use it. However, it does not explicitly state when not to use or mention alternatives.

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