billy_get_bank_account

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

No annotations are provided, so the description carries the full burden. It declares the tool as READ-ONLY, indicating no side effects. It also mentions a limitation regarding listing. However, it does not cover authentication, rate limits, or error handling, which are minor gaps for a simple fetch operation.

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 consists of two concise sentences. The first sentence states the action and read-only nature. The second provides context about listing limitations and an alternative. Every sentence is efficient and adds value.

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 one required parameter, no output schema, and no annotations, the description covers the essential purpose, read-only behavior, and listing limitation. It references an alternative for the default account. It could potentially mention the output structure, but it's not critical for a simple fetch tool.

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?

There is only one parameter (id, required) with 0% schema description coverage. The description adds 'by id', which is already implied by the tool name and schema. It does not specify format, length, or any additional constraints, offering minimal added value beyond the schema.

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 clearly states 'Fetch one bank account by id', specifying the verb (fetch), resource (bank account), and method (by id). It distinguishes from listing all bank accounts, which is not supported, and mentions an alternative for the default account.

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 explicitly states 'READ-ONLY' and notes that Billy v2 does not support listing all bank accounts, advising to look up the default via billy_whoami. This provides clear when-to-use, when-not, and an alternative tool.

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