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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and closed-world scope, so safety is covered. The description adds real domain behavior beyond that: it explains the IRC 6033(j) three-consecutive-missing-years revocation rule and names the date fields returned, which is substantive context an agent needs to interpret results. It stops short of describing response shape or behavior for orgs never granted exemption.

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, the core question front-loaded, with the parenthetical listing return fields and the second sentence supplying the legal rule that motivates the tool. No filler or repetition — every clause carries information.

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 and only one parameter, the description carries the burden of explaining returns, and it does so by naming revocation, posting and reinstatement dates plus missing-year flags. Minor gaps remain: no error/empty-result behavior and no note on what a clean status looks like.

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 coverage is 100% and the single parameter carries its own format guidance (9 digits, dash optional). The description adds no EIN-level detail beyond what the schema already provides, so baseline 3 applies.

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 subject: whether the IRS automatically revoked the organization's exemption, plus which of the last three ended accounting years have no return on file. The parenthetical enumerates returned data (revocation, posting, reinstatement dates), which clearly separates it from siblings like get_nonprofit_profile or search_nonprofits.

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?

Usage is implied by the domain phrasing — an agent can infer this is the tool for exemption-revocation questions — but the description never states when to prefer it over get_nonprofit_profile or search_nonprofits, nor any preconditions (e.g. needing a valid EIN already resolved). No exclusions or alternatives are named.

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