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

readOnlyHint=true already covers the safety profile, and the description adds meaningful context beyond that: content may be a FHIR Binary JSON resource, XML C-CDA, or base64, and is returned as-is with raw text when not JSON. This return-shape disclosure is valuable, especially given there is no output schema.

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 tight sentences, front-loaded with the verb and resource, followed by the FHIR endpoint and then the return-format caveat. No sentence is redundant and nothing is buried.

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 single-parameter read tool with no output schema, the description supplies the essential missing piece: what the returned payload can look like (JSON, C-CDA XML, or base64, returned as-is). This makes the definition self-sufficient for correct invocation, short of explicit usage routing.

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?

With one parameter at 100% schema coverage, the schema already documents binary_id fully (including its origin in a DocumentReference). The description's 'by Binary id' adds no syntax or format detail beyond the schema, so the baseline 3 applies.

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?

States a specific verb (Retrieve) and resource (raw document content) keyed by Binary id, plus the underlying FHIR path GET /Binary/{id}. It is clearly distinct from the sibling list_documents operation, though it does not explicitly contrast itself with any sibling by name.

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 you need a Binary id, and the schema notes it comes from a DocumentReference, but it gives no explicit when-to-use guidance, no when-not conditions, and does not route the agent to or away from alternatives such as list_documents.

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