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

Annotations already declare the tool as read-only, idempotent, non-destructive, and open-world. The description adds value by specifying exactly what data is returned (covered indications, limitations, effective dates, benefit category, revision text), providing behavioral context beyond the annotations. It is consistent with annotations and does not contradict them.

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 a single, concise sentence that front-loads the action and resource, then lists the return content. Every word adds value; there is no redundancy or fluff. It is well-structured for quick reading.

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?

Given the tool's simplicity (2 parameters, one required), the annotations, the presence of an output schema, and the description's clear enumeration of returned fields, the description provides complete context. An agent can understand the tool's purpose, inputs, and outputs without additional information.

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 input schema covers 100% of parameters (document_id and version) with descriptions. The description restates that retrieval is by document ID and optional version, but adds no new information beyond what the schema already provides. Per guidelines, when schema coverage is high, a score of 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 clearly states the verb 'Retrieve' and the specific resource 'Medicare National Coverage Determination'. It specifies the retrieval by document ID and optional version, and lists the included content areas. This clearly distinguishes it from sibling tools like medicare_ncd_search (which searches) and medicare_lcd_detail (which retrieves a different type of determination).

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 implies that the tool is used after obtaining a document ID from medicare_ncd_search, and mentions optional versioning. However, it does not explicitly state when to use this tool versus alternatives (e.g., for LCD determinations, use medicare_lcd_detail), nor does it provide any when-not-to-use guidance. Given the many sibling tools, more explicit usage context would be helpful.

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