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

Annotations already establish read-only, idempotent, and non-destructive behavior. The description adds meaningful context beyond annotations by specifying the return payload (match status, IRS code/reason, last-checked date) and the synchronous sub-5-second execution model. No contradiction with annotations exists.

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?

The description is compact and front-loaded: purpose comes first, followed by return values, latency, and a concrete invocation example. Every sentence earns its place, and the example helps an agent quickly understand how to format the call without bloating the description.

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 moderate-complexity read-only tool with fully documented parameters, the description covers what the tool does, what it returns, its latency, and how to invoke it. It lacks an explicit alternative-routing note, but the absence of an output schema is mitigated by listing the key return fields.

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 already documents tin, businessName, and _apiKey well. The description reinforces that businessName is the legal name on file with the IRS and provides a complete example call, but it doesn't add substantial new semantic information beyond the schema.

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?

The description states a specific action ('Verify'), a specific resource ('business TIN/EIN against IRS records'), and the exact success criterion ('9-digit EIN matches the legal business name on file with the IRS'). This clearly distinguishes it from sibling tools like cobalt_business_search, which performs broader lookups rather than targeted IRS verification.

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?

The intended use is implied clearly: use this when you need to confirm a business TIN/EIN against IRS records and obtain a match status. However, it does not explicitly state when not to use it or name alternatives such as cobalt_business_search for broader business data needs.

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