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

Annotations already declare readOnlyHint=true, and the description reinforces this with 'Read'. It adds the credential requirement ('Needs credentials') and the conditional invoice number behavior ('once one has been issued'), which are not in the annotations. This provides useful behavioral context beyond the schema.

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?

Two concise sentences with no filler. The primary purpose is front-loaded, and the credential note is a necessary caveat. Every word earns its place; nothing extraneous.

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?

The description covers the core functionality, the authentication requirement, and the conditional invoice inclusion. It does not describe the return format or error behavior, but with no output schema and a simple read operation, these are not critical. The tool is adequately described for an agent to invoke 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 description coverage is 100%, so each parameter (order, secret, clientId, accessToken) is already documented in the schema. The description does not add any additional meaning or clarify parameter usage beyond what the schema provides. It adheres to the baseline without adding value.

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 states a specific verb ('Read') and resource ('the order'), and explicitly enumerates the scope: offer, payments, and invoice number. This clearly distinguishes it from sibling tools like create_order, start_payment, and accept_offer, which are all mutations. The purpose is unambiguous.

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 makes it obvious this tool is for reading order status, and its read-only nature contrasts with the mutation siblings. However, it does not explicitly name alternatives or state when not to use it (e.g., 'use manifest for product details'). There is no exclusion guidance, so the usage context is implied rather than explicit.

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