get_balance

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

There are no annotations, so the description carries the full burden of behavioral disclosure. 'Get' implies a read operation and suggests the tool does not modify data, but the description does not state that explicitly. It also doesn't clarify what kind of balance is returned, in what units or currency, or whether pending transactions are included.

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 a single clear sentence with no filler or irrelevant details. It is front-loaded and concise, though it could have packed in more useful guidance about behavior or return value without becoming bloated.

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 tool is simple with one well-documented required parameter, so the description is minimally adequate for invocation. However, with no output schema and no annotations, the description should say more about what 'balance' means (available/current/cleared), the units/currency, and that account_id is likely obtained from list_accounts. These gaps prevent it from being complete.

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 schema already describes account_id as 'The Monzo account ID to inspect'. The tool description adds no additional parameter context, but because the schema fully documents the only parameter, the baseline of 3 is appropriate.

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 clear verb ('Get') and a specific resource ('the balance for a Monzo account'), so an agent can tell this is a read-only balance lookup rather than a transaction or account listing tool. It is not maximally detailed because it doesn't clarify whether this is the available, current, or cleared balance, nor does it explicitly differentiate from siblings, but the core purpose is unambiguous.

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 description gives no guidance about when to use this tool instead of siblings like list_accounts or list_transactions. It also doesn't mention that account_id comes from list_accounts or any prerequisite/context. The intended usage is only implied by the tool name and description, not stated.

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