apple_mail_list_accounts

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds behavioral context by specifying exactly what data is returned (account names, sender addresses, mailbox names), which helps the agent anticipate the output. No destructive behavior is implied, consistent with annotations.

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: the first declares the read-only function, the second provides usage guidance. Every word earns its place, and it front-loads the key information. No redundant content.

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 zero-parameter, read-only discovery tool with no output schema, the description is complete: it states the function and usage context, and lists the returned data. An agent can confidently invoke this tool before other Mail tools without needing more details.

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 schema coverage is 100% (empty properties). With no parameters to document, the baseline is 4 per the rubric. The description adds value by implying the tool takes no input and lists all local accounts, which is sufficient.

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 and resource: 'list local Apple Mail account names, sender addresses, and mailbox names.' It clearly distinguishes itself from sibling tools like apple_mail_list (which likely lists emails) by focusing on account-level metadata and is labeled 'read-only.'

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 explicit timing: 'Use this before other Mail tools when the exact names are unknown.' This gives clear context for when to use the tool, though it does not mention when not to use it or alternative tools. This is strong guidance but lacks explicit exclusions.

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