balance

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so the safety profile is covered. The description adds value beyond them by restating the critical constraint in domain terms ('Spends no money, never pays') and sketching the returned contents, though it omits auth/permission requirements and any caveats on the different identity modes.

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 the read-only framing, then the contents, then the usage triggers — a sensible order with no filler. The opening sentence is heavy with parenthetical nesting, which costs some readability but every clause carries 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?

No output schema exists, yet the description enumerates the returned fields (identity, USDC deposit address, balance, spend limits, vIBAN balances and pay-in details) well enough to set expectations. Missing pieces are minor: error behavior and what the 'agent' selector changes in the response.

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 optional 'agent' parameter is fully described there, so baseline 3 applies. The description gestures at the identity modes (stored ArisPay agent, delegated, PAYAGENT_PRIVATE_KEY-derived) but never ties them to the 'agent' argument or explains what happens when it is omitted.

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?

Specific verb+resource: 'shows where the money is', enumerated as the active payment identity, USDC deposit address, on-chain balance, spend-mandate limits, and bank accounts (vIBANs) with balances and pay-in details. An agent can distinguish this reporting tool from pay, history, and inspect without opening the 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?

Explicit selection guidance: 'Select this to tell the human where their money is and how to add more, to confirm a deposit landed, or when a payment fails.' Three concrete triggering scenarios leave nothing to inference and route the agent away from payment tools.

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