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

With no annotations provided, the description carries the full burden. It discloses that the code is sent to the existing email, is 6 digits, and replaces an expired or lost one, which is meaningful behavior. But it omits details about side effects (e.g., whether any existing valid code is invalidated), auth requirements, rate limits, and return 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 description is two short sentences with no filler. The core action is front-loaded, and the follow-up instruction is usefully appended without wasting space.

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?

While the tool's purpose and post-action are covered, it remains incomplete for actual invocation: the token parameter is entirely unexplained, and there is no output/return information. A low-parameter tool with no annotations and no output schema should clarify both input and result behavior; this description leaves a key input undefined.

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 has one parameter, 'token', with no description and 0% schema description coverage-still the description never mentions the token or whether it is required. The agent is left to guess what token value to supplyhol. This is a critical gap for invoking the tool correctly.

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 uses a specific verb ('Send') with a clear resource ('new 6-digit verify code to the email already on file') and explains the purpose: replacing an expired or lost code. It also differentiates itself by explicitly telling the agent to call verify_email afterward, so it is not confused with verification itself.

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 states the intended scenario: when the previous code is expired or lost/replaced. It gives a direct follow-up instruction ('Then call verify_email'), which helps an agent sequence the correct tool. However, it does not explicitly mention alternatives or situations where resending should be avoided.

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