message-send

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 says an email is sent, with no mention of side effects, authentication requirements, delivery guarantees, or whether sending is reversible. This is comparable to a minimally described mutation tool with no safety context.

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, front-loaded sentence with no filler or redundancy. It immediately communicates the tool's function and earns its place without unnecessary elaboration.

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?

Even though an output schema exists and the input schema is well described, the one-sentence description does not address when to send a new message versus replying via message-respond, nor does it set expectations about delivery behavior. Given the sibling set and absent annotations, the context is incomplete for reliable tool selection and invocation.

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 input schema provides 100% coverage, including descriptions for all six parameters, comma-separated formatting for recipients, and the contentType enum. The description itself adds no parameter-specific meaning, so the baseline of 3 is appropriate.

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 states the specific action (send), the resource (email message), and the channel (Gmail), making the core purpose immediately clear. However, it does not explicitly distinguish this from sibling message-respond, which also involves composing an email, so it misses the final point for full sibling differentiation.

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?

No guidance is provided on when to use this tool versus alternatives. Sibling tools such as message-respond and message-search are present, but the description never mentions them or clarifies that message-send is for new outbound emails. This leaves the agent to infer the correct usage context.

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