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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is well covered. The description adds valuable context beyond annotations: it explains the code type distinction (stem vs extension), the coverage scope (55,000+ codes), and the no-auth/public domain nature. It doesn't mention pagination or rate limits, but the 'unlimited free' statement covers the rate limit concern. The description is consistent 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 compact and front-loaded with the core purpose. The first sentence states the action and resource, the second explains the return value, and the third covers scope and use cases. The final sentence about auth is useful but could be considered slightly extraneous. Overall, every sentence earns its place, though the use case list is a bit long.

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 search tool with 2 parameters, 100% schema coverage, and an output schema, the description is quite complete. It covers what the tool does, what it returns, its scope, and its access model. The only minor gap is not explicitly distinguishing from icd11.disease.lookup and icd11.disease.autocomplete, but the description's clarity about searching by clinical term makes this a minor issue. The output schema exists, so return values don't need to be explained in the description.

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?

Schema description coverage is 100%, so the schema already documents both parameters (terms and max_results) with examples and constraints. The description adds the clinical context for the terms parameter and the code type distinction, but doesn't add significant meaning beyond the schema. Baseline 3 is appropriate since 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 states a specific verb ('Search'), a specific resource ('ICD-11 disease classification'), and the exact purpose ('for diagnosis codes by clinical term'). It also distinguishes itself from siblings by explaining what it returns (codes with titles and code type) and explicitly mentions coverage of all 55,000+ ICD-11 codes. This clearly differentiates it from the sibling tools like icd11.disease.lookup and icd11.disease.autocomplete.

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 provides clear use cases ('clinical coding, medical record classification, disease surveillance, and health informatics') and states the input type ('clinical term'). It doesn't explicitly say when NOT to use this tool versus the sibling icd11.disease.lookup or icd11.disease.autocomplete, but the context of searching by clinical term is clear enough. The sibling list shows related tools, but the description doesn't explicitly route to them.

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