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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered and 'Read-only' is largely redundant. The value-add is the explicit limitation on what it does not do (no filing, no payment, no third-party day counts), which is modest but useful boundary context.

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 content is reasonably brief, but the opening clause is grammatically tangled and the vendor-specific asides ('EIN.LLC's qualified timing', 'another vendor's day count') sit awkwardly rather than front-loading the core answer. Not padded, but not clean either.

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?

An output schema exists, so return values need no explanation, and the description states what the answer covers (channels by SSN/ITIN and US location, plus timing). Given the low parameter complexity and existing annotations, it is close to sufficient, though the mapping of inputs to outcomes could be sharper.

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 0%, so the description carries the burden, and it does map both parameters conceptually ('whether the applicant has an SSN or ITIN', 'whether the principal business is in the United States'). However, this largely restates the self-documenting parameter names, and the yes/no/1/0/true/false enum forms are never addressed.

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 names a specific resource (IRS EIN application channels/route) and the inputs that select the answer (SSN/ITIN status, principal business in the US), so an agent can tell it is an explainer rather than an action. The phrasing is awkward – 'Read-only IRS EIN channels for whether...' – which slightly obscures the verb, but the intent is recoverable.

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?

No explicit when-to-use or sibling routing is given versus assess_formation, compare_states, or prepare_application. Negative scope statements ('does not file or take payment', 'does not state another vendor's day count') imply boundaries but don't state when this tool should be chosen over an alternative.

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