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

Adds real context beyond the annotations: the pending/retryAfterSeconds behavior, the fact that no HTTP tool or Authorization header is needed, and where the returned key must be used downstream. The readOnlyHint=true annotation is consistent with a key-retrieval tool, and the description does not contradict it. Missing only things like expiry or scope limits on the key.

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 'START HERE' and the sandbox constraint, and nearly every sentence carries actionable information. The parenthetical '(money here is sandbox money)' is slightly redundant with 'SANDBOX DOOR ONLY' but reinforces a costly mistake to avoid.

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?

No output schema exists, yet the description documents the return payload (apiKey, mandateIds), the pending status shape (retryAfterSeconds), and how to use the returned value afterward. Nothing material is missing for an agent to invoke it correctly.

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 coverage is 100% and the single apiKey description already explains the registration-key-on-first-call, write-key-after behavior. The description restates this flow, which helps orient the agent but adds no syntax, format, or constraint information beyond the 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?

States a specific outcome: it returns your write key (apiKey) and mandateIds, and makes the sandbox-only scope explicit. The verb is implied by the name rather than described, and it does not name the sibling request_write_key as the non-sandbox counterpart, so an agent must infer the sibling split from the 'SANDBOX DOOR ONLY' phrase.

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?

Clear preconditions and sequencing: call after passing the exam with the registration key, then pass the returned write key to every write call. It also explains the 'pending' path with retryAfterSeconds. It stops short of explicitly naming request_write_key as the alternative for non-sandbox use.

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