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

Goes well beyond the annotations (readOnlyHint=false, openWorldHint=true, destructiveHint=false) by disclosing the asynchronous payment flow, the fact that the API key is shown exactly once, and the polling contract on status_url. These are exactly the non-obvious behavioral traits an agent cannot infer from 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?

Dense but front-loaded: the core action and the checkout_url/status_url workflow come first, with parameter constraints packed into a compact tail. It reads as a run-on of several concerns, but nearly every clause carries information an agent needs.

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, so the description must carry the return contract, and it does: checkout_url for the human, status_url to poll, and the one-time API key reveal. Combined with currency enumeration hints, an agent has everything needed to drive the flow end to end.

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?

With only 50% schema coverage, the description compensates by giving concrete allowed values (topup 10/25/50, monthly 50/100/250, USD/EUR/CHF) and guidance to omit category and level to let the server choose. It still leaves 'level' and the category/level interaction only partially explained, so it falls short of fully covering the schema gap.

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 ('Creates a card checkout (Stripe) for a new broker account') and even maps it to the underlying REST endpoint POST /api/v1/broker/accounts. An agent immediately understands this is account provisioning via payment, not a generic account mutation, which distinguishes it from the read-only siblings (chat, get_balance, list_models).

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 clear operational context: hand checkout_url to a human, then poll status_url until 200 to retrieve the one-time API key. It does not name alternatives or state when-not to use it, but no sibling tool overlaps this provisioning role, so the omission is minor.

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