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

With no annotations provided, the description must disclose behavioral traits, yet it only states the high-level action. It does not mention whether the server runs in the background, whether it blocks execution, what happens on subsequent calls, or any side effects. The description is too terse to provide meaningful transparency beyond the obvious mutation implied by 'start'.

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 that immediately states the action and purpose. It is perfectly front-loaded, containing no filler, irrelevant details, or repetition. Every word earns its place, making this an exemplary model of conciseness.

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?

The tool has no output schema and no annotations, so the description must explain behavior and expected results. It does not mention return values, whether the server persists across requests, or the implications of optional parameters like port or receivingDomains. The description is a bare minimum and leaves critical behavioral questions unanswered for a tool that starts a long-running server.

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 schema fully documents all four parameters with clear descriptions, achieving 100% coverage. The tool description adds no parameter-specific meaning, relying entirely on the schema. Baseline of 3 is appropriate because the schema does the heavy lifting and the description offers no additional clarification or 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 a specific action ('Start') and a specific resource ('SMTP server'), along with the purpose ('to receive forwarded corporate emails'). This distinguishes it from sibling tools like stop_smtp_receiver and get_smtp_receiver_status, making the tool's function unmistakable.

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 provides no guidance on when to use this tool versus alternatives. It does not mention prerequisites, exclusions, or contrast with related tools such as stop_smtp_receiver or get_smtp_receiver_status. A user must infer the appropriate context from the tool name alone.

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