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

Annotations already declare readOnlyHint, destructiveHint=false, so the safety profile is covered; the description adds genuinely new behavior context, namely that returned records are complete (SyncToken present) and that multiple known Ids can be resolved in a single call. It does not itself mention that inactive customers are excluded or that a page is capped/truncated, though that detail does live in the criteria parameter text.

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 sentences, front-loaded with the purpose, then the two operational facts an agent needs (complete records, batched Id lookup). No filler and nothing 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?

For a two-parameter read tool with a fully documented schema and no output schema, the description supplies what an agent needs to decide to use it: scope, completeness of results, and the bulk-Id pattern. Remaining details (filters, pagination, inactive handling) are thoroughly carried by the criteria schema text.

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 baseline is 3; the description still adds value by surfacing the 'Id IN' operator for bulk lookups, which is a non-obvious usage pattern for the criteria parameter. It does not add meaning for the company parameter, but the schema already handles that.

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 ('Search customer records in QuickBooks Online') and adds the key scope fact that results are full records carrying SyncToken. It implicitly distinguishes itself from get_customer ('no get is needed after') but never names nearby siblings such as get_customer or search_customer_types 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?

Gives a concrete usage pattern: use this to read several known Ids in one call via 'Id IN', and skip a follow-up get because the records are complete. It stops short of stating when NOT to use it (e.g., single-record fetches, or how to pick between this and the dedicated customer reports).

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