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

Annotations already declare the safety profile (readOnly=false, destructive=false, idempotent=false, openWorld=true), and the description adds genuinely new behavior: the API key is returned once and 'cannot be retrieved again', no email or human account is needed, and the wallet starts at zero EUR. The one-time-secret warning in particular prevents an unrecoverable agent mistake.

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?

Three compact sentences, front-loaded with the action and its outcome, then the sequencing, then the one-time key warning and the exclusion. No filler; each clause carries distinct information.

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?

There is no output schema, but the description still discloses the salient return value (the `mak_test_` key) and its irreversibility, along with the wallet starting balance. For a one-parameter creation tool, nothing an agent needs to call it safely 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 coverage is 100% and the single 'name' parameter is fully documented in-schema as a non-secret audit label. The description adds no further meaning about the parameter (e.g., its effect on the returned identity), so the baseline 3 applies.

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 and resource ('Create a NEW offline-sandbox machine identity') plus its immediate consequences (zero-EUR test wallet, one-time API key). The closing clause 'This does not create a live payment account' explicitly separates it from the live-payment siblings, so an agent can distinguish it without opening any schema.

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?

Gives an explicit prerequisite ordering — use before get_wallet, fund_wallet, set_wallet_limits, or sandbox purchases — which is exactly the routing an agent needs among these siblings. The negative case ('does not create a live payment account') is stated, though it doesn't name which sibling to use instead for live accounts.

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