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

Annotations and schema already disclose destructiveHint=true and the sparse-vs-full update semantics. The description adds genuine value by stating the SyncToken/concurrency prerequisite and the return payload ('saved record with its new SyncToken'), which is real behavioral context beyond structured fields. No contradiction with destructiveHint.

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, front-loaded with the action and the prerequisite, followed by the return value. Nothing wasted.

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 destructive mutation with nested entity params and no output schema, the description plus rich entity schema covers prerequisites and return shape. Slightly incomplete on when to prefer void/delete over update.

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 entity schema description already covers sparse, full-update clearing, line replacement, and restricted fields. The description restates the Id/SyncToken requirement, adding little beyond the schema. Baseline 3 for high 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+resource ('Update an existing bill payment') and names the domain (QuickBooks Online). Distinguishable from siblings like update_payment or update_bill by the resource, though it doesn't explicitly differentiate from void_bill_payment or delete_bill_payment.

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?

Implies usage via the SyncToken requirement and the note to fetch the BillPayment first, but never states when to use this vs void_bill_payment or delete_bill_payment, nor any exclusions. Usage context is implied rather than guided.

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