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

With no annotations, the description carries the full burden. It discloses success behavior (returns API keys) and mentions subscription activation for paid tools, but does not describe error cases (e.g., invalid code, expired code) or state changes, which limits transparency.

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 concise with 4 sentences plus Args and Examples. It front-loads the core purpose. The subscription mention is slightly tangential but not overly verbose. Overall efficient 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?

Given the presence of an output schema, the description needn't detail return structure. It covers the workflow clearly: after registration, verify with code to get API keys. It lacks error handling details but is sufficient for a straightforward verification tool.

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%, but the description explicitly defines both parameters: 'email: The email you registered with' and 'code: The 6-digit verification code from your email.' This adds essential meaning beyond the bare schema.

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 verifies email and returns API keys. It distinguishes itself from the sibling tool mcp_register by explicitly mentioning 'after calling mcp_register', making the purpose and context 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?

The description provides clear context on when to use (after mcp_register, check email for code) and includes an example. However, it does not explicitly mention when not to use or alternatives, missing some usage boundaries.

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