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

Annotations already declare readOnlyHint=true, so the description only needs to add context beyond that. It adds the detail that the invoice number is included once issued, which is useful. However, it doesn't disclose auth requirements or error handling, but for a simple read operation this is acceptable.

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, concise sentence that front-loads the action ('Read') and specifies the resource and an additional detail (invoice number). There is zero waste, and all information is essential.

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 simple read tool with a readOnlyHint annotation, the description covers the main purpose and mentions the invoice number. However, it omits response format, error behavior, and authentication specifics, which could be relevant for correct invocation but are not critical for basic usage.

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 only 50% (order and accessToken lack descriptions), and the tool description provides no parameter explanations at all. It fails to compensate for the missing schema descriptions, leaving agents to infer the meaning of 'order' and why accessToken is required.

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 the tool reads the current state of an order and its payments, including the invoice number once issued. This specific verb+resource structure distinguishes it from write-oriented siblings like create_order and start_payment, making selection straightforward.

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 provides clear context that this tool is for reading order status, which implicitly separates it from creation or payment tools. While it doesn't explicitly name alternatives or exclusion conditions, the purpose is unambiguous given the sibling names, so it's adequate.

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