Domain MONA Mail

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

Annotations already declare readOnly=true, idempotent=true, destructive=false, and openWorld=true, so the safety profile is covered structurally. The description adds only that results relate to verification status; it says nothing about pagination, ordering, or return shape. A 3 reflects a modest addition on top of full annotation coverage.

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 short bilingual clauses with no filler, and the domain/status scope is placed first. It is efficient, though the duplication across Vietnamese and English means half the text is a translation rather than new information.

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 list tool with no output schema, the definition is minimally adequate: it says what the domain listing shows (domains + verification status). Since no output schema exists, it could have clarified what the response contains (e.g. list of domains with status), which is the remaining gap.

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 takes zero parameters, so there is nothing for the description to disambiguate. Baseline 4 applies; the description's mention of verification status is a light domain hint rather than parameter guidance.

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 gives a concrete verb+resource framing (view/find domains and their verification status), which tells an agent this returns sender domains rather than adding, verifying, or configuring one. This distinguishes it reasonably from siblings like mail_domain_add, mail_domain_verify, and mail_domain_cloudflare, though it never explicitly says it lists all domains.

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 phrase 'Khi chọn địa chỉ gửi / Use to find verified sender domains' implies the usage context: consult this when you need a verified sender domain for sending mail. There is no explicit when-not or named alternative (e.g. mail_domain_add when you need to add one), so guidance is implied rather than spelled out.

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