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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint false, but the description adds substantial behavioral specifics: it lists exactly what will be returned (matching enrollments, due date or TBD, source metadata, submission-status limits, monitoring and automation handoffs), and explicitly states limitations ('free read-only tool cannot open PECOS, submit a revalidation, start a paid run, open checkout, or purchase anything'). This exceeds what annotations provide and gives rich transparency.

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 description is exactly two sentences, front-loaded with the core purpose. Every clause adds meaning—limits, return contents, negative boundaries—and there is no filler or duplication of schema/annotation data.

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, read-only checklist tool, the description is complete. It explains the input limit (100 NPIs), the output structure (returns matching enrollments, due date/TBD, source metadata, submission-status limits, handoffs), and limitations. Since there is no output schema, the description compensates by detailing return contents.

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 already covers 100% of the parameter meaning with a detailed description of the 'npis' array, including constraints and invalid NPI handling. The tool description adds context about the CMS list but does not materially enhance the schema's parameter semantics. Baseline 3 is appropriate.

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 opens with a specific verb and resource: 'Check up to 100 NPIs against the current public CMS Medicare Revalidation List.' This clearly states the tool's function and scope, distinguishing it from sibling tools like 'get_medicare_revalidation_automation_offer' or 'get_pending_medicare_behavioral_health_preview', which are about offers/previews rather than the actual check.

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 description conveys the primary use case (checking NPIs against the CMS list) and what the tool cannot do (open PECOS, submit revalidation, purchase). However, it does not explicitly mention when to prefer this tool over its siblings or provide exclusions. The context is clear, but without explicit comparisons, it falls just short of a 5.

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