read_fhir_resource

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

With no annotations provided, the description carries the full burden. It discloses the tool reads resources (non-destructive) and mentions error handling ('or an error message'), but lacks details on authentication needs, rate limits, or server-specific behaviors beyond the Zus headers example. It adds some context but is incomplete for a mutation-free read operation.

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 well-structured with a clear purpose statement, parameter explanations, and return information. It uses bullet-like formatting under 'Args:' and 'Returns:' for readability. Some minor verbosity exists (e.g., repeating 'FHIR' could be trimmed), but overall it's efficient and front-loaded.

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 has an output schema (returns JSON), the description needn't detail return values. It covers the core purpose, parameters, and a key usage note (Zus headers). For a read operation with no annotations, it provides adequate context, though it could benefit from more behavioral details like error types or access requirements.

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 0%, so the description must compensate. It explains all three parameters: 'resource_type' with examples ('Patient', 'Observation'), 'resource_id' as the target ID, and 'custom_headers' with a specific use case for Zus servers. This adds meaningful semantics beyond the bare schema, though it doesn't cover all possible header formats or constraints.

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 ('Read a FHIR resource') with the target ('by type and ID from the FHIR server'), distinguishing it from sibling tools like 'search_fhir_resources' (which searches) and 'write_fhir_resource' (which writes). The verb+resource combination is precise and unambiguous.

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 implies usage for retrieving specific resources by type and ID, but does not explicitly state when to use this versus alternatives like 'search_fhir_resources' for broader queries or 'get_patient_zus_upid' for patient-specific IDs. No exclusions or prerequisites are mentioned, leaving usage context somewhat open-ended.

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