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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false. The description adds cardinality ('single customer') and retrieval by Id, but does not disclose error behavior, company scoping, or return format.

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?

One concise sentence that front-loads the purpose. The trailing usage clause is slightly cryptic but does not waste space.

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 simple get-by-Id tool with full schema coverage and annotations covering safety, the description is largely sufficient. It omits explicit alternative guidance and company parameter behavior, but these are minor for this tool's complexity.

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 the schema fully documents both parameters. The description mentions Id retrieval but adds no syntax or format details beyond the schema, and does not address the optional company parameter.

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 (Get), resource (customer), and scope (single, by Id) from QuickBooks Online. Distinguishes from search and write operations implicitly, but does not name the sibling tool search_customers explicitly.

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?

Offers a usage condition ('when no search or write answer already holds it'), implying the tool should be used only when the customer isn't already available from a search or write. However, it does not explicitly name the alternative tool (search_customers) or clarify when to search versus fetch by Id.

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