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

Goes well beyond the annotations: discloses that a 6-digit code is emailed, that no account exists yet, that free-mail domains are refused, and that the response is indistinguishable whether or not the address is already registered (enumeration protection). None of this is derivable from the structured fields.

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?

Front-loaded with the action and key parameters, then the flow and constraints. Dense but every sentence carries information; only slight tightening possible across the multi-clause sentences.

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?

An output schema exists, so return values need no explanation; the description still supplies the crucial challenge_id/code handoff and the free-mail guard. Nothing an agent needs to call it correctly is missing.

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 50% and a nested body wrapper exists. The description names email/name as inputs and marks company as optional, partially compensating, but adds no format rules for the email or guidance on the `body`/`authorization` wrapper fields.

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+resource ('start registering a 4chems account') with the exact identifying fields (email, name, company) and names the follow-up tool verify_account_registration. Clearly separable from start_registration, start_inquiry, and start_device_login.

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 when-to-use (business email, anonymous, no account yet) and when-not (free-mail refused), with the alternative route named ('use the company address, or call start_inquiry'). The end-to-end sequence (start -> ask user for code -> verify) is stated.

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