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

Annotations already declare readOnlyHint=true and openWorldHint=false, and the description goes beyond them with useful limits: it never returns the full list of reported grants, Form 990 filers expose only top 10 recipients and yearly totals, and no-application-info exists for 990 filers. It does not say what happens when the EIN has no profile (error vs. empty result), which would have earned a 5.

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 dense but front-loaded with the resource identity and follows with the 990-PF/990 split; every clause carries information. The first sentence is unusually long and packs the full return manifest, which slightly hurts scanability but not comprehension.

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?

No output schema exists, and the description compensates by enumerating returned fields and negative guarantees (no full grant list). With one parameter at full schema coverage and read-only annotations, the only meaningful omission is failure behavior for an EIN without a qualifying return.

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 EIN parameter is fully documented with a pattern and note that the dash is optional, so the schema carries the load. The description adds no EIN-specific guidance (e.g., where to source the EIN) beyond implying the lookup is on public-profile foundations.

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?

Names a specific verb/resource (a foundation's public GrantCue profile) and enumerates exactly what it returns: giving totals, median grant, giving by year, geography, 25 largest grants, plus how to apply for 990-PF filers. It is clearly distinguishable from get_grant, search_funders, and search_grants because it is a single-entity detail fetch keyed by EIN.

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?

Gives explicit coverage conditions (only foundations with a public profile, or funders with a Schedule I return, are found) and explains the 990-PF vs Form 990 branch, including that Form 990 never states whether applications are accepted. It stops short of stating the complementary workflow — e.g., use search_funders to obtain an EIN before calling this — so a small inference gap remains.

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