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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false. The description adds substantial context: it enumerates the returned data (due date or TBD, source metadata, explicit submission-status limits, handoffs), emphasizes it is 'free read-only', lists prohibited actions, and notes invalid NPIs are handled as invalid results. There is no contradiction with annotations.

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 three sentences: the first states purpose, the second lists outputs, and the third lists limitations. Every sentence provides distinct value with no redundancy. It is front-loaded with the core action and remains appropriately sized for the tool's complexity.

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 fully explains what the tool returns (matching enrollment, due date/TBD, source metadata, limits, handoffs). It also covers the read-only nature, free access, and prohibitions. The schema's invalid NPI behavior complements the description. This is complete enough for an agent to invoke the tool 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?

The only parameter 'npis' has comprehensive schema description coverage (format, bounds 1-100, uniqueness, invalid-digit handling). The description adds no new parameter-level information beyond echoing 'up to 100 NPIs'. Baseline 3 is appropriate since the schema carries the semantic burden.

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 the specific verb 'Check' and the resource 'current public CMS Medicare Revalidation List'. It enumerates distinct outputs (matching enrollment, due date/TBD, source metadata, submission-status limits, handoffs), clearly distinguishing it from sibling tools like 'get_medicare_revalidation_automation_offer' and 'get_medicare_roster_watch_offer', which focus on offers/previews.

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?

It does not explicitly name alternative tools, but it clearly states the tool's scope and limitations ('cannot open PECOS, submit a revalidation, start a paid run, open checkout, or purchase anything'), effectively telling the agent when not to use it. This provides clear context for decision-making without naming siblings.

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