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

Annotations already declare idempotentHint=true and destructiveHint=false. The description adds meaningful context: the user receives a 6-digit code by email, the email must match the earlier call, and a new API key is returned on success. No contradiction with annotations, though it stops short of detailing edge cases like invalid codes or key rotation.

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 compact and front-loaded. The first sentence states the purpose, the second provides the required trigger condition, and the Args section is clear and minimal. Every sentence contributes useful information without redundancy.

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 two-parameter verification tool with annotations and an output schema, the description covers the complete workflow: preconditions, exact inputs, and the success return value. No critical gaps are apparent, and the output schema handles return structure details.

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?

Although structured schema coverage is 0%, the description manually documents both parameters with clear semantics: 'email' is the address used in the discovery_login call, and 'code' is the 6-digit verification code from the email. This fully compensates for the schema's lack of descriptions and adds relationship context that the schema cannot convey.

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?

Description states the tool's core action: 'Complete login and receive a new API key.' It clearly distinguishes from sibling tools by specifying it is the follow-up to discovery_login when verification is required. The verb and resource are specific and unambiguous.

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?

Provides explicit when-to-use guidance: 'Call this after discovery_login returns {"status": "verification_required"}.' This clearly sequences the tool relative to discovery_login. It does not explicitly discuss when not to use it or alternatives, but the precondition is strong and actionable.

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