sendHtmlMail

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It states that email is sent and that CC, BCC, and attachments are supported, but it does not disclose authentication needs, immediate-delivery side effects, error behavior, rate limits, or whether sending is reversible.

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 and front-loads the core operation before the secondary use-case sentence. It is appropriately short, though 'Ideal for rich content emails' adds little beyond the first sentence.

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?

This is a six-parameter mutation tool with nested attachment objects and no output schema or annotations. The description is too thin for that complexity: it does not explain address formats, attachment payload expectations, SMTP/delivery behavior, or failure modes.

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?

Schema description coverage is 0% for six parameters. The description mentions recipients, CC, BCC, attachments, and HTML content, but it omits subject semantics, address formatting (especially whether CC/BCC accept multiple addresses), and attachment content encoding or contentType usage. It does not compensate for the complete lack of schema descriptions.

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 specific verb and resource: 'Send an HTML-formatted email' to a single recipient. It partially distinguishes from siblings by contrasting single-recipient sending with bulk mail and HTML content with simple mail, but it does not explicitly name sendSimpleMail or sendMail as alternatives.

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?

'Ideal for rich content emails' is a weak implied-use statement. There is no explicit guidance on when to choose this over sendMail or sendSimpleMail, no when-not guidance, and no prerequisites such as SMTP configuration or authentication.

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