list_accounts

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

Annotations indicate read-only, open world, idempotent, and non-destructive. The description adds that it connects via IMAP and verifies app passwords, which provides useful behavioral context beyond 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?

Two sentences, no filler, front-loaded with main purpose. Every sentence contributes value.

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 tool with no parameters and no output schema, the description adequately covers the purpose and a notable side-effect (password verification). Minor gap: no mention of potential latency or caching, but overall sufficient.

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 0 parameters with 100% schema coverage. The description adds meaning by specifying the output includes folders and message counts, which is helpful beyond the empty schema.

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 'List configured Yahoo accounts with their folders and message counts.' This is a specific verb+resource+scope, and it clearly distinguishes from sibling tools like search_messages or scan_mailbox.

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 for verifying app passwords ('so this also verifies that the app passwords work'), but does not provide explicit guidance on when to use vs alternatives or when not to use it.

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