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

Beyond the annotations (readOnly=false, openWorld=true, destructive=false), the description discloses required permissions (firm owner or Manage invoices access right), the confirmation policy ('confirm each call'), that it reaches other people, and the API-key requirement. It also states the return contents (invoice ID and total). This is rich behavioral context.

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 first sentence ('Create an invoice... and send it to the client') and second sentence ('Creates an invoice from line items and sends it') largely duplicate each other, wasting space. The access-rights and confirmation details are useful but the front-loading is diluted by the redundancy.

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 mutation tool with no output schema, the description covers the key operational facts: required access rights, confirmation requirements, no-draft behavior, and the return values. It is nearly complete, with only minor gaps around failure/edge behavior.

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 all four parameters are already documented in the schema. The description reinforces that items are line items and that the total is their sum, but adds no syntax or format detail beyond the schema. 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?

The description states a specific verb and resource ('Create an invoice for an account from line items and send it to the client') and clarifies the create-and-send-in-one-step behavior. It distinguishes the operation from a draft flow, though it never names a sibling to route against, so it falls just short of the top mark.

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?

'as the Create button does in TaxDome, so there is no draft step' gives clear context that this is an immediate, non-draft issuance. There is no explicit when-not or alternative-tool routing, but there is no competing invoice-creation sibling, so the guidance is effectively complete.

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