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

With no annotations, the description carries the full burden of behavioral disclosure. It transparently explains temporary MX redirection, starting or reusing the SMTP receiver, forwarding of all inbound mail, and automatic teardown after ttl_minutes. This is unusually complete for a state-changing tool, covering the main side effects and safety-relevant behavior.

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 entire operation—MX change, receiver behavior, forwarding, and teardown—is conveyed in a single dense sentence with no filler. It is front-loaded with the verb and resource, and every clause adds necessary detail.

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 multi-step state-changing tool with no output schema or annotations, this description covers the main workflow, prerequisites (via the schema), and teardown behavior. It could mention expected return values or failure modes, but the combination of tool description and rich schema descriptions is nearly complete for the tool's complexity.

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 coverage is 100%, so the baseline is 3. The description adds workflow-level meaning by explaining that domain and forward_to work together to relay *@domain mail, and connects ttl_minutes to auto-teardown. real_mx_target is not repeated in the description but is fully described in the schema, so the added context beyond the schema justifies a 4.

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 a specific action ('Begin a domain-verification window') and details the exact mechanism: set MX to verify.setip.io, start/reuse the SMTP receiver on :25, and forward inbound mail to forward_to. This clearly distinguishes it from siblings like start_smtp_receiver (which only starts a receiver) and stop_domain_verification.

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 clearly implies the use case (obtaining email verification codes from providers) and mentions auto-teardown, but it does not explicitly state when not to use the tool or name sibling alternatives. The prerequisite that the domain must be a POC owned in setipio-api appears only in the parameter schema, not in the tool description. Clear context but no exclusions makes this a 4.

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