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 only states the intended effect ('send an email') but does not reveal whether the action is permanent, whether any record is created, what authentication or permissions are needed, or what happens after sending. For a mutating tool, this is a significant transparency gap.

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 a single, concise sentence with zero filler words. It is front-loaded and efficient, but it is perhaps too sparse to fully support tool selection.

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 3-parameter mutating tool with no annotations and no output schema, the description is insufficient. It lacks guidance on side effects, when to use the tool, and expected return values, making it difficult for an agent to invoke it safely and correctly in varied contexts.

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%, and the description adds no parameter-specific context. Although parameter names like 'contactId', 'subject', and 'htmlBody' are self-explanatory, the description does not explain any formatting requirements, precedence, or how the parameters relate to the email being sent.

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 action ('Send') and the resource ('an email') with a target ('to a contact'). It is a specific verb+resource combination, though it does not explicitly differentiate itself from the sibling tool 'send_message' or indicate how email differs from other messaging channels.

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?

There is no guidance on when to use this tool versus alternatives like 'send_message' or how to decide between email and other communication methods. No context, prerequisites, or exclusions are provided.

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