get_capabilities

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It effectively describes the tool's purpose and constraints (e.g., it's for metadata discovery, not resource fetching), but lacks details on potential errors, rate limits, or authentication requirements. However, it adds significant context beyond basic functionality.

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 front-loaded with the core purpose, followed by usage rules and exclusions in two concise sentences. Every sentence earns its place by providing essential guidance without redundancy, making it highly 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?

Given the tool's complexity (metadata discovery for FHIR operations) and lack of annotations or output schema, the description is largely complete. It explains the tool's role and constraints clearly, though it could benefit from mentioning what the output includes (e.g., search parameters, operations) or error handling, which would enhance completeness.

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 input schema has 100% description coverage, clearly documenting the single required parameter 'type' with examples. The description adds no additional parameter-specific information beyond what the schema provides, such as format details or constraints, so it meets the baseline for high schema coverage.

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 specific action ('Retrieves metadata') and resource ('FHIR resource type'), distinguishing it from sibling tools like 'read' or 'search' that fetch actual resources. It explicitly contrasts with those operations by stating 'Do not use this tool to fetch actual resources.'

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 explicit guidance on when to use this tool ('MUST always be invoked before performing any resource operation') and when not to use it ('Do not use this tool to fetch actual resources'). It implicitly positions this as a prerequisite for other operations like search, read, create, update, or delete, offering clear alternatives.

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