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

Annotations already declare readOnlyHint=false, destructiveHint=false, and openWorldHint=false, so the write-but-non-destructive profile is covered. The description adds one genuinely useful behavioral fact beyond annotations: it returns the saved record including its SyncToken (relevant for subsequent update calls). It does not cover auth/connection requirements or whether the call is retry-safe.

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 tight sentences with zero filler; the core action is front-loaded and the return-value note is secondary. Nothing is wasted or buried.

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?

With no output schema, the description correctly picks up the slack by naming the returned record and SyncToken. However, for a tool whose sole required parameter is a free-form nested QBO object, it gives no hint about the minimum fields needed to construct a valid VendorCredit (e.g., vendor reference and amount/line items), leaving a meaningful gap.

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%: the 'entity' param is documented as a QBO API v3 VendorCredit object with an explicit data-privacy warning, and 'company' explains accepted identifiers. The description adds nothing beyond the schema, which is the baseline expectation at full coverage.

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 a vendor credit in QuickBooks Online') plus a second sentence on the return payload. The resource is unambiguous enough to separate it from the many other create_* siblings, but the description never explicitly distinguishes it from create_bill, create_purchase, or the update/delete vendor-credit siblings.

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?

No guidance on when to use this versus create_bill or create_purchase, no prerequisites (e.g., a vendor must already exist), and no note that search_vendor_credits/update_vendor_credit exist for other operations. The agent must infer all of this from the tool name alone.

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