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

Annotations only declare readOnlyHint=false, destructiveHint=false and openWorldHint=false, so they do not explain the asynchronous payment flow. The description adds genuinely useful behavior the annotations omit: it returns a payment_url that requires human action outside the agent, and the deposit stays pending until polled via get_deposit. It does not mention auth requirements, amount limits, or expiry of the checkout session.

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?

Two sentences, zero filler, and the primary action plus the essential follow-up behavior are both front-loaded. Every clause carries information the agent needs to complete the flow.

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, and the description compensates by naming the returned payment_url and the session_id used for polling, which is the most important missing piece. Combined with annotations covering the write/safety profile, this is nearly complete; only the undocumented currency and provider parameters keep it from a 5.

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 only 33% — amount is documented in the schema, but currency and provider have no descriptions anywhere. With low coverage the description is expected to compensate, yet it says nothing about these parameters, so an agent must guess whether currency is an ISO code and what provider values are accepted.

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 ('Start a card deposit into your wallet') and immediately names the related tool get_deposit for the follow-up flow. An agent can tell this begins a payment session rather than being a query or a withdrawal. The only minor gap is that it never contrasts itself with the sibling topup_wallet.

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?

It gives clear operational context: a human must complete payment on Stripe Checkout, and the agent should poll get_deposit with the session_id until status is completed. That is real usage guidance for a multi-step flow. It stops short of stating when to prefer this over topup_wallet or which sibling handles the non-card case, so it is not a full when/when-not/alternatives answer.

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