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

With no annotations, the description carries the full burden. It discloses the 10-minute expiry and the instruction not to retry, which is valuable. However, it does not mention the effect of a successful confirmation (e.g., whether it invalidates the code or triggers recovery) or any side effects, leaving some behavioral gaps.

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?

Two sentences with no filler. The purpose is front-loaded, and the usage guidance is placed immediately after. Every clause adds value, making it exceptionally concise and well-structured.

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 tool with 2 parameters and no output schema, the description covers the essential context: purpose, prerequisite, expiry, and fallback. The only gap is the unexplained token parameter and lack of success/failure details, but these are minor given the tool's simplicity. It is almost complete.

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 description coverage is 0%, so the description must compensate. It explains the 'code' parameter (6-digit format, purpose) but does not mention the optional 'token' parameter at all. Since token is optional, it is less critical, but its absence leaves the agent guessing about its role, so the compensation is only partial.

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 the tool's purpose: confirming a 6-digit code sent to the agent email, and ties it to email recovery. It distinguishes itself from resend_email_code by naming it as an alternative, making it easy for an agent to select the right tool.

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 explicitly says when to use this tool (required before email recovery) and when not to (if code expired or never arrived, call resend_email_code). It also warns against retrying old codes, providing clear conditional routing.

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