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

Annotations already declare readOnlyHint=false and destructiveHint=false, so the write-but-non-destructive profile is covered. The description adds one genuinely useful behavioral fact beyond annotations — that it returns the saved record with its SyncToken — which is meaningful since there is no output schema, but it omits permissions/required-field/error behavior.

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 short sentences, front-loaded with the action and the return contract. No filler, no restating the title.

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 two-parameter write tool with 100% schema coverage and annotations covering safety, the description is nearly sufficient: it names the resource, the platform, and the return shape (SyncToken) despite no output schema. It stops short of the 5 because it says nothing about required fields or failure behavior for a mutation.

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 both the 'entity' and 'company' parameters are already documented in the schema, including the PII restriction and the optional-company rule. The description adds no parameter-level meaning beyond that, which is the baseline 3 case.

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 ('Create an invoice') plus the system context ('in QuickBooks Online'), so an agent knows exactly what the tool does. However, it does not differentiate itself from the many sibling create_* tools (create_estimate, create_sales_receipt, create_credit_memo), which share the same shape and would be the plausible confusions.

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 when-to-use guidance and names no alternatives such as create_estimate, create_sales_receipt, or update_invoice. The agent is left to infer from the tool name alone whether this or a sibling is the right entry point.

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