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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the safety profile is covered structurally. The description adds genuinely useful behavioral context beyond those annotations: the corpus is offline and baked at package-build time, so the call reports exactly what release is in the running server — a key caveat for an agent relying on currency. The ICD-10-CM/PCS vs. base ICD disambiguation also prevents a conceptual misapplication. 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 efficient at roughly 65 words and front-loads the primary function in the first sentence. The middle sentence's enumeration of each code system and release type adds specificity but is slightly verbose relative to the first sentence's summary. The closing ICD disambiguation earns its place. Every sentence contributes, though the second sentence could be tightened.

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 zero-parameter, read-only inventory tool with an output schema present, the description is complete: it tells the agent what will be returned (release identifiers, effective dates, code counts), why it matters operationally (validate releases before acting on results), and the key build-time constraint. Since the output schema already documents the return shape, the description does not need to restate it. Nothing an agent needs to call this correctly is missing.

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?

This tool has zero parameters (schema shows an empty object with additionalProperties=false), so there is no parameter ambiguity to resolve. Per the rubric's baseline for zero-parameter tools, a 4 is appropriate — the description correctly handles the parameter-free case and needs no compensating detail.

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 states a specific verb ('List') and a well-defined resource ('bundled US medical code systems') with explicit content detail (release identifiers, effective dates, code counts). It clearly distinguishes itself from its siblings (browse/check/get/map/search) by identifying its job as cataloging the available systems rather than operating on codes. The clarification that ICD-10-CM/PCS are US clinical modifications rather than the ICD-10/11 base adds important disambiguation.

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 gives explicit when-to-use guidance: 'Confirms which ICD-10-CM fiscal year, ICD-10-PCS fiscal year, HCPCS Level II release, and RxNorm normalized set are active before acting on any decode, search, or crosswalk result.' This clearly tells an agent to call this before trusting results from sibling operations. It does not explicitly name alternatives or state when not to use it, but for a zero-parameter inventory tool the usage context is clear enough.

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