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

Annotations already cover readOnlyHint and openWorldHint, so the bar is lower, and the description still adds real value: it explains the email as an authorization gate ('stops anyone reading anyone else's order'), states the awaiting-payment return shape, and discloses an edge case (swept unpaid orders report as not found). It stops short of noting rate limits or pagination, so a 4 rather than a 5.

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 sentences, each doing distinct work: purpose, authorization requirement, and return behavior. Purpose is front-loaded and there is no filler or restatement of the name.

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?

There is no output schema, so the description must carry return-value context; it does so partially by describing the unpaid state and the not-found edge case. Coverage is good for a two-parameter read tool, though it does not describe the general paid/successful response shape.

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%, so the baseline is 3. The description goes further by explaining why email is required (security match against the billing email) rather than merely repeating that it is the billing email, adding meaning beyond the schema's own description text.

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 names a specific resource and the exact data it returns: 'Payment and fulfilment state for an order you created.' That is concrete and actionable. It does not, however, explicitly differentiate itself from the sibling get_client_order, leaving the agent to infer the distinction.

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 phrase 'for an order you created' and the required billing email imply the usage context (post-create lookup by the placing party). There is no explicit when-to-use or when-not-to-use guidance and no named alternative such as get_client_order, so the agent must infer the routing.

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