Check Balance

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

No annotations are provided, so the description carries full responsibility for behavioral disclosure. It does reveal the auth requirement and that arguments are optional in OAuth mode. However, it does not explicitly state that this is a read-only, non-destructive operation (though 'check' implies it), nor does it mention rate limits or potential errors. There is a clear gap in side-effect disclosure.

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 description is two sentences, front-loaded with the core purpose and followed by the key operational nuance. Every word earns its place, with no fluff or redundancy. It is appropriately sized for a tool with two optional parameters.

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?

Given the low complexity (two optional params, no output schema, no annotations), the description covers the essential aspects: what the tool does and how authentication works. It does not describe the return value in detail, but 'check balances' implicitly conveys the result. Minor gaps remain around explicit read-only assurance and what happens on invalid credentials, but these are not critical for correct invocation.

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%, so the baseline is 3. The description adds the conditional context that api_key is only needed without OAuth, but the schema already states 'Not needed over OAuth'. No extra meaning is added for the chain parameter. The description does not compensate beyond the schema's existing parameter descriptions.

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 states a specific action ('Check') on a specific resource ('a linked wallet's stablecoin balances and remaining agent spending allowance'). This clearly differentiates it from siblings like transaction_history or pay_bill. An agent can immediately understand the tool's function 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?

The purpose sentence implies when to use the tool (to check balances/allowance), but there is no explicit mention of alternatives or when not to use it. The auth guidance ('Works with no arguments once authorized via OAuth; otherwise pass the api_key') is operational rather than usage-selection guidance. No sibling is named as a substitute.

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