Get Available Bank Details

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

Goes well beyond the readOnly/idempotent annotations by disclosing that no API key is required ('Public'), which annotations cannot express, and by describing the response payload structure (label, key, regex, items). For a read-only lookup, that covers the behavioral burden fully.

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?

Three dense sentences, front-loaded with the purpose, then the use case, then the payload/validation detail. Nothing is repeated from the schema or annotations and no sentence is 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?

With no output schema, the description must describe the return payload and it does so precisely, plus it supplies the missing parameter documentation and auth context. An agent has everything needed to call it correctly.

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 0%, so the description carries the load: it explains that `rail` selects the payout rail and directs the agent to GET /v1/available/rails for valid values, which the bare enum cannot convey. It stops short of explaining the semantic difference between enum values (wire vs ach vs pix).

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?

States a specific verb and resource ('Returns the fields a bank account needs for a payout rail') and immediately scopes it to the pre-creation validation use case. It is clearly distinguished from sibling GetV1AvailableRails, which it names as the source for valid rail values.

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?

Explicitly says when to call it ('so a recipient form can collect and validate them before calling create bank account') and names the companion endpoint for obtaining the required `rail` input. Both the when and the prerequisite lookup are spelled out.

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