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

Annotations only declare readOnlyHint=true, so the description carries extra weight and does add real context: a hard 300-record ceiling and a $0.99 USDC charge per call via x402 on Base. Cost and result-cap disclosure are genuinely useful and go beyond the annotation. It does not explain pagination, batching, or what happens on a failed/aborted payment.

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 tight sentences: the payload scope and field list first, then the cap and price. Nothing is padded and the key constraint arrives early. The field enumeration is dense but appropriate for a data-feed tool.

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 correctly lists the returned fields, plus the record cap and payment model an agent needs before calling. Missing only edge behavior (what happens past 300 records, payment-failure handling, whether ntee filters the batch or is merely returned).

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 100%, so both parameters (state, ntee) are already documented with format examples. The description restates the state scoping and mentions NTEE as a returned field but adds no filtering syntax or semantics beyond the schema. 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?

Clear specific resource and scope: every organization in the newest monthly IRS batch for a single state, with the returned fields enumerated (EIN, name, city, ZIP, NTEE, subsection, ruling month, foundation type, financials). It does not explicitly distinguish itself from the sibling new_nonprofits_sample, so the fresh/sample split is left implicit even though the title says 'full'.

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 a clear selection condition for the high-volume case: 'Up to 300 records (use the 30-day feed for more).' That routes the agent to a broader alternative when the cap is insufficient. It stops short of naming any sibling tool or saying when the sample variant is preferable.

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