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

No annotations exist, so the description carries the full burden; it does disclose the key trait ('Read-only') and sketches the payload fields. It says nothing about authentication requirements, caching/rate limits, or whether the currency list is global versus workspace-specific — gaps that matter for a zero-parameter lookup.

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?

A single compact sentence, front-loaded with the primary payload and ending with the safety qualifier. Every clause earns its place, though the parenthetical field list could be integrated slightly more smoothly.

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 parameters and no output schema, the description must convey the return value, and it does: a currency list with code/symbol/name plus the account's billing currency. It stops short of stating the response shape (array vs object) or whether the account currency is a code or a full object, which is a minor residual gap.

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?

The tool takes zero parameters, so the baseline is 4; there is nothing the description could add about inputs and it does not waste words pretending otherwise.

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 (billing currencies Vendo supports) and adds the useful detail that the response includes code, symbol and name plus the account's own billing currency. It is distinguishable from billing-adjacent siblings like get_pricing, get_balance or get_subscription, though it never names them explicitly.

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?

Usage is only implied — an agent can infer it should call this when it needs currency codes or the workspace's billing currency. There is no statement of when to prefer get_pricing or get_balance instead, and no preconditions are given.

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