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

Annotations already declare readOnlyHint=true, so safety is covered; the description adds genuinely new behavioral context by promising the full field set plus line items in the response. It does not say what happens when the id is unknown (error vs empty) or whether related records are expanded, which keeps it from 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?

Two sentences, zero waste, with the resource and payload description front-loaded ahead of the parameter hint. Nothing is repeated from the schema or annotations.

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 one-parameter read with no output schema, the description covers resource, payload shape, and id sourcing, which is most of what an agent needs. Missing only failure behavior and a clearer statement of what "all its fields" contains.

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% and the schema already documents the numeric id and the code:ABC form, so the baseline would be 3. The description adds a sourcing hint the schema lacks — that ids come from the list tool — which is real value for an agent picking an 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?

States a specific verb and resource ("Get one received invoice") and explicitly scopes the payload ("all its fields and its line items"). The singular "one" cleanly separates it from the sibling abraflexi_list_received_invoices without needing to name it.

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?

Tells the agent where the id comes from ("from the list"), implicitly routing to abraflexi_list_received_invoices. It gives no explicit when-not guidance or mention of a bulk-fetch alternative, so it stops just short of a full routing statement.

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