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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description accurately reflects a read-only retrieval and adds no contradictions, but it also offers no extra behavioral context such as failure behavior, return format, or interaction with connectionRef.

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?

The description is one short, front-loaded sentence with no filler or repetition. It states the core function immediately and does not waste the agent's attention on irrelevant details.

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 straightforward single-record get, the description is reasonably complete, especially with schema coverage at 100%. However, it omits mention that the tool requires company context via companyName and gives no indication of the return shape, which is more noticeable because there is no output schema.

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?

The input schema has 100% parameter descriptions, including id, companyName, and connectionRef. The description itself does not add semantic meaning beyond what the schema already provides, so the schema carries the full burden and the baseline of 3 is appropriate.

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 ('Gets') and a specific resource ('one BRC sales invoice') with an explicit lookup key ('by id'). This clearly distinguishes it from list, batch, create, update, and delete invoice tools without needing to open the schema.

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 gives no guidance about when to use this tool versus alternatives like brc_list_sales_invoices, brc_batch_sales_invoices, or brc_get_sales_entry. There are no stated conditions, exclusions, or references to sibling tools, so an agent has to infer the appropriate usage.

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