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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so safety is covered. The description adds valuable context beyond annotations: it is a fixed fictional sample EMR, requires no account or API key, and returns data normalized from FHIR R4 Observation. This gives the agent an accurate behavioral model without contradicting 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 tightly written sentences, with the core purpose front-loaded and no filler. Every sentence adds distinct value: what is returned, the auth/sample context, and the sibling alternative.

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 tool with an output schema and comprehensive annotations, the description covers purpose, scope, data source, authentication, and routing to the appropriate sibling. Nothing needed for correct invocation 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, so there is nothing for the description to explain beyond the data scope, which it does by listing vital sign categories. Per the baseline for zero-parameter tools, this is sufficient.

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 names a specific verb ('get'), a specific resource ('vital signs'), and enumerates the measures (blood pressure, heart rate, weight). It also explicitly contrasts itself with get_demo_health_record, so an agent can distinguish this tool from its siblings immediately.

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 states when to use this tool ('only the vital signs') and explicitly directs the agent to call get_demo_health_record when vitals are needed alongside other categories, preventing unnecessary multiple calls. This is clear usage guidance with a named alternative.

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