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

Annotations already declare readOnly, idempotent and closed-world, so safety is covered. The description adds genuinely new behavior: a paid call at $0.001 USDC via x402 on Base mainnet, which an agent must know before invoking. It stops short of describing the shape of the returned record.

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 resource and the two operating modes; the ten-bank enumeration is long but earns its place by signaling exact coverage. The pricing clause is placed last, which is appropriate. Slight redundancy between 'for EFT payments' and 'completing payment details'.

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?

For a one-parameter, no-output-schema lookup tool this is nearly complete: it names the domain, the banks, the two modes and the cost. The only real omission is what a lookup returns (bank name, universal code, or both), which an agent must discover by calling.

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 parameter is already documented as an optional bank name or code. The description adds the key semantic the schema omits: that omitting the parameter yields the full list ('list all'), which tells the agent how to use the default case.

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 resource (South African universal branch codes) and an explicit verb pair ('Look up one bank or list all'), then enumerates the covered banks. No sibling tool covers branch codes, so an agent can route to it unambiguously.

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?

Gives a concrete use context: EFT payments and debit orders, and 'completing South African bank payment details'. It does not name exclusions or alternatives, but no sibling overlaps this domain, so the gap is small.

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