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

Annotations already establish readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds meaningful behavioral context beyond those annotations by explicitly confirming that it doesn't submit or start an application, and by clarifying that the tool returns a link rather than performing a transaction. 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 three sentences with a clear front-loaded 'Returns...' statement. The subsequent sentences add differentiation and usage context, so each sentence earns its place. It is concise without being terse, and well-organized for a quick agent read.

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?

With no output schema, the description fully enumerates what the tool returns: definition, cost, documents, IRS timeline, and application link. It also covers the limiting behavior and the exact queries that should trigger this tool. For a simple informational read-only tool with one optional parameter, nothing needed for correct invocation 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?

The schema description for the single 'socios' parameter is complete and self-explanatory: it states how many people need an ITIN and that it is used to quote the total. The tool description does not add detail about this parameter, but with 100% schema coverage, the structured field already carries the semantic burden.

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 opens with a specific verb ('Returns') and names a clear resource: information about ITIN, its cost, required documents, IRS processing time, and the application link. It also explicitly differentiates itself from application-creating tools by stating it does not submit or start an application, and the 'Use it when...' clause reinforces its distinct role among siblings.

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 description gives explicit use triggers: user asks about ITIN, tax ID, taxpayer number, or filing as a multimember LLC member. It also states a when-not condition ('does not submit or start an application'), though it does not name an alternative sibling tool to route to, so it stops short of a fully explicit alternatives mapping.

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