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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds valuable context beyond annotations: the data source (NLM MedlinePlus Connect), public domain/no auth/unlimited free usage, and bilingual support. This complements annotations without contradiction.

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—three sentences—with the core action and output front-loaded, followed by practical examples and usage tips. Every sentence provides value: purpose, output, examples, optional parameter guidance, language support, and source/limitations. No fluff or redundancy.

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 low complexity (3 params, 1 required) and the presence of an output schema, the description covers all necessary aspects: what it does, what it returns, examples, optional parameter behavior, language options, and authentication/rate-limit context (unlimited free, no auth). An agent can select and invoke it correctly without gaps.

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 parameters are already documented. The description adds meaningful usage semantics: it clarifies that display_name improves match accuracy and that language=es enables Spanish responses, which goes beyond the schema's basic type/default descriptions. It reinforces the purpose of each parameter without redundancy.

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 'look up' with a specific resource ('SNOMED CT clinical concept') and describes the output ('MedlinePlus topic titles, URLs, and plain-language summaries'). It includes concrete examples and naturally distinguishes from sibling tools (icd10_lookup, icd9_lookup, rxnorm_lookup) by naming the SNOMED CT ontology, which the sibling names make obvious.

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 implicitly guides usage by specifying the input type (SNOMED CT) and gives practical advice ('Provide the optional display_name to improve match accuracy') and language support. It does not explicitly state 'do not use for ICD codes', but the sibling tool names and the clear ontology focus make the distinction obvious to an agent.

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