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

Annotations only declare readOnly=false, openWorld=false, and destructive=false. The description adds substantial behavioral context beyond that: payment methods, credential keys, chargeback risk for cards versus stablecoins, and daily deposit limit accounting.

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?

The paragraph is front-loaded with the core action, then proceeds through the payment mechanics in logically ordered sentences. Every sentence conveys necessary information about a complex flow, with no filler.

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?

The description thoroughly explains the two-step payment handshake, credential locations, and risk/limit behavior, which is essential for this complex tool. However, with no output schema, it does not describe the successful return payload or resulting state, leaving a gap an agent might need.

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 50%: amount is already documented in the schema with its range and decimal rules, while currency has only an enum and no description. The description merely restates 'amount in USD' and never mentions the currency parameter, so it fails to compensate for the undocumented parameter.

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?

The description gives a specific verb (add money) and resource (wallet), and scopes it to self-payment with no human or browser. It does not explicitly distinguish this tool from the sibling start_deposit, so sibling differentiation is incomplete.

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 details the exact call sequence: first call returns payment required, then pay and call again with the credential in _meta. It does not name alternative tools or say when not to use this flow, so it stops short of full routing guidance.

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