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

Goes well beyond the annotations by disclosing the success side effect (publishing unlocks), the four failure modes with their names, and that invalid_code carries attemptsRemaining. The idempotentHint is consistent with 'already_verified' being reported rather than an error of state corruption, but the description does not state whether retrying with the same code is safe or counts against attempts.

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?

Four short sentences, front-loaded with the action and the code source, then effect, then preconditions, then return/failure contract. Every clause carries information an agent needs; nothing is padding.

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?

With one required param, no output schema, and thin annotations, the description supplies the missing contract: the return shape { ok, verified, subdomain } and the enumerated failure codes. Nothing needed to invoke or interpret the call is absent.

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% and the single parameter is documented, so baseline is 3. The description adds real value: the code's provenance (emailed to the human) and the instruction to have the human read it aloud, which changes how the agent obtains the value.

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?

States a specific verb and resource: 'Finish account verification with the 6-digit code'. It is immediately distinguishable from sibling create_account (which starts the process) and from the page tools, and it names the unlock effect (publishing).

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?

Explicit preconditions: the code comes from the human, whom the agent must ask, and the call works either in the session where create_account ran or with an API key for an unverified account. The already_verified failure code also tells the agent when this tool is not applicable.

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