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

Annotations already establish read-only, idempotent, non-destructive behavior. The description adds useful operational context by naming the exact status categories (active, revoked, terminated) and derived fields (deductibility, ruling date), so the agent knows what the response means without an output schema.

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 carry a complete definition: what the tool returns, the exact status semantics, and the intended audience. There is no filler or repetition of schema details.

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 single-parameter lookup with no output schema, the description explains the core return fields well. It does not specify behavior for unknown EINs or explicitly acknowledge the openWorldHint possibility of missing data, but the practical use case is sufficiently covered.

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 covers the single EIN parameter completely, including accepted formats with and without dashes. The description adds no new parameter-level semantics beyond reinforcing that the lookup is for one organization.

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 (look up current exempt-organization status) with a concrete resource (one organization by EIN) and enumerates the returned fields. It is clearly more specific than broad sibling searches, but it does not explicitly differentiate itself from sibling nonprofit detail/lookup tools by name.

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 use case is implied: check an organization's IRS standing before donating or granting money. However, the description never states when to choose this over sibling tools such as nonprofit_details or nonprofit_lookup_ein, nor any exclusions.

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