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

Annotations already declare readOnly, idempotent, and non-destructive behavior. The description adds valuable context beyond that: the data is FinchNode's fixed fictional sample, no account or API key is needed, and the data is normalized from FHIR R4 Immunization. This is meaningful behavioral context without contradicting the 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?

Three sentences, each earning its place: the first states the core purpose, the second adds data-source and auth context, and the third gives routing guidance to an alternative. Information is front-loaded and there is no filler.

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?

With zero parameters, a read-only annotation set, and an output schema present, the description covers all necessary operational context: what data to expect, that no credentials are needed, and how to get a broader dataset. Nothing an agent needs to invoke it 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?

The tool has zero parameters and the schema covers 100% of them trivially, so the baseline is 4. There is nothing for the description to add about parameters, and it correctly does not invent any.

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 ('get') and resource ('immunizations'), and narrows scope with 'only' and 'Vaccination history, normalized from FHIR R4 Immunization.' It also signals how this tool differs from the sibling get_demo_* tools by directing combined requests to get_demo_health_record.

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?

It explicitly says when to use this tool (to get only immunizations from the sample EMR) and when not to (when immunizations are needed alongside other categories, call get_demo_health_record once). It even warns against calling several tools unnecessarily, which is direct usage guidance.

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