Send newsletter

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

With no annotations provided, the description carries the burden of behavioral disclosure. It explicitly warns that the tool 'actually dispatches real emails' and advises user confirmation before calling. This effectively communicates the irreversible, side-effectful nature of the action, though it omits details such as return behavior or error conditions.

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 extremely compact: two sentences, front-loaded with the core action and immediately followed by a critical safety warning. Every sentence earns its place with no filler or repetition.

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 2-parameter tool with no output schema and no annotations, the description provides the essential safety context and invocation requirements. It could be more complete by describing what happens after sending or how to confirm success, but the core information needed to select and invoke the tool safely is present.

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 description mentions 'subject and HTML content,' which maps to the two required parameters, but adds no format, length, or content constraints beyond the schema. Since schema coverage is only 50% and the 'subject' property has no schema description, the description only partially compensates for the missing parameter context.

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 clearly states the verb ('Send'), the resource ('a newsletter campaign to all subscribers'), and the mechanism (site send-newsletter/Resend). It is easy to distinguish from sibling read-only tools like list_newsletter_sends or list_newsletter_subscribers.

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 when to use it: whenever the user wants to broadcast a newsletter to all subscribers. It includes an important usage precondition — confirm subject and HTML with the user before calling — but it does not explicitly contrast this with any alternative tool or state 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.