Create customer

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

Goes well beyond the annotations: readOnlyHint=false and idempotentHint=false are already present, but the description adds that it adds exactly one Customer and changes nothing else, explains the non-idempotent behavior with QuickBooks' specific duplicate error, and discloses the success/error return shape. No contradiction with annotations.

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?

Four sentences, each earning its place: purpose, usage precondition, write-scope and idempotency, and return/error behavior. The most decision-relevant information is front-loaded.

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?

The definition covers what the tool does, when to use it, what to check first, its side effects, its idempotency trap, and its return shape. With annotations and a full output schema also present, nothing an agent needs to invoke and interpret this tool correctly is missing.

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 every field already has a description, so the baseline is 3. The description adds meaningful extra semantics by highlighting that display_name must be unique and that duplicates trigger error 6240, plus clarifying the return payload includes Id and SyncToken, which helps an agent interpret the result.

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 customer in the connected QuickBooks Online company." It also distinguishes itself from sibling tools by framing its role as a prerequisite to invoicing and by explicitly warning against duplicating records that search_customers would find.

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?

Explicitly says when to use the tool (before invoicing someone not on file) and gives a required precondition (run search_customers first to avoid creating duplicates). It also clarifies a non-obvious constraint by stating the operation is not idempotent and the duplicate will be rejected with error 6240.

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