check_icd_for_major_illness_eligibility

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

Annotations already indicate readOnly, non-destructive, idempotent behavior. The description adds important real-world context: 'Reference only — confirmed eligibility still requires a formal application with supporting documentation per the official 重大傷病範圍及項目', which is beyond what annotations provide. 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 relatively concise (3-4 sentences) and front-loaded with the main purpose. Some minor redundancy in the 'Reference only' sentence, but overall efficient and well-structured.

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 simple lookup tool with no output schema, the description adequately describes the return values and the source (OPDSTAR). It provides sufficient context for an agent to understand the tool's purpose and limitations without extra 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 schema describes `icd_code` with examples and prefix-matching behavior. Schema coverage is 100%, so the description adds little beyond stating it's a single code. Baseline score of 3 is appropriate as the schema does the heavy lifting.

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 it is a reverse-lookup from ICD-10 code to major illness categories, including what is returned (category name, ICD pattern, copayment-exemption flag). It distinguishes itself from the sibling tool `lookup_major_illness` by specifying the opposite direction.

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?

Explicitly states when to use ('when an agent has a diagnosis and needs to flag major-illness applicability before claim submission') and when not to use ('Don't use to browse all categories — call lookup_major_illness instead'), providing clear guidance on alternatives.

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