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

Annotations already declare readOnly/openWorld, and the description goes well beyond them: it discloses the pricing model ($0.002 USDC per successful call via x402 on Base/Solana/Arc), that failed calls are not charged, the 20-record cap per call, and a data-coverage limitation (no hospital affiliations). This is exactly the cost/auth/scope context an agent needs before paying for a call.

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?

One dense but well-ordered block: dataset and fields first, then the coverage caveat, then the result cap and price. No filler sentences; every clause carries information an agent needs.

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 an output schema present, return values need no explanation. Scope, lookup key, result cap, coverage gap, and cost are all covered, leaving nothing an agent must know to invoke it correctly.

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 all three parameters are documented in the schema itself. The description only restates that last name is the key and state is optional, and reiterates the 20-record ceiling — no format or interpretation value 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?

States the specific dataset (CMS Medicare Doctors and Clinicians file) and enumerates the fields returned, then explicitly rules out hospital affiliations — which distinguishes it from siblings like hospitallink_cms_ratings and npi_provider_registry. An agent can tell exactly what record type this returns.

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 lookup shape ('by last name and optional state') is implied as the usage pattern, and the caveat that hospital affiliations are absent hints at when not to use it. But it never names the alternative tool for affiliations, nor states prerequisites beyond the payment note.

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