External Invoices Get

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

Annotations already declare readOnly, idempotent, non-destructive and openWorld, so the safety profile is covered. The description adds genuinely new context: the required OAuth scope 'read_orders' and the 'unstable' API version warning, which is a real behavioral caveat an agent should know before depending on the response shape.

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 purpose sentence followed by endpoint, scope and version metadata – front-loaded and free of filler. The HTTP line is somewhat redundant with the tool name but is short and useful as a reference.

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-by-key endpoint with full schema coverage and rich annotations, the description covers purpose, scope and version stability. Return shape is not described, but with no output schema and a plain GET this is a minor gap rather than a blocking one.

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 parameter meaning is already carried by the schema. The description's phrase 'by fiscal key' corroborates the key parameter but adds no format or syntax detail beyond the schema's '44 digits' note; baseline 3 applies.

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 verb and resource ('Get an external invoice') and narrows the lookup to 'by fiscal key'. It implicitly separates itself from tiendanube_external_invoices_list by being a single-record fetch, but never names the sibling or states the distinction 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?

The required scope 'read_orders' and the HTTP path imply when the call is valid, but there is no explicit guidance on when to choose this over tiendanube_external_invoices_list or tiendanube_orders_invoices_list, nor any prerequisite or failure-mode note.

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