Retrieve an invoice

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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=true, so the safety profile is fully covered. The description adds nothing on top — no mention of error behavior for missing IDs, required auth, or what the returned object contains.

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?

One short, front-loaded sentence with no filler, but the brevity comes at the cost of under-specification rather than efficient communication.

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?

This is a simple single-parameter read tool with rich annotations, so little is required, but with no output schema the description should at least hint at what the retrieved invoice contains or how a bad ID is handled. It provides none of that.

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% and there is a single required 'id' parameter, so the baseline is 3. However, the schema's phrasing 'The object's id' is generic and the description does not clarify that this must be an invoice ID rather than a customer or payment ID.

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 'Retrieve an invoice' merely restates the tool name and title with no added specificity. It does not distinguish this from sibling list_invoices or explain what 'retrieve' returns beyond a single invoice object.

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?

No guidance on when to use this versus list_invoices, retrieve_payment, or retrieve_receipt. The agent must infer that this is the single-object lookup counterpart to the list endpoints.

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