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

Annotations only declare readOnlyHint=true, and the description adds real behavioral context: the return is a single FHIR bundle, and it can be a large document, which is a meaningful cost warning. It does not mention pagination even though a _count parameter exists, which is the one missing operational trait.

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?

Two compact sentences: capability plus contents first, then the routing rule and the endpoint reference. Every sentence earns its place; the trailing raw endpoint is mildly redundant but useful for agents mapping to the FHIR API.

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?

There is no output schema, and the description compensates by naming the return shape (FHIR bundle with enumerated resource types) and the size risk. Combined with the sibling routing guidance, an agent has enough to call this correctly; only paging behavior on the _count parameter is unaddressed.

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 100%, so patient_id and _count are already documented with range constraints in the schema. The description adds the underlying endpoint form GET /Patient/{id}/$everything, which reinforces patient_id semantics but adds nothing for _count. Baseline 3 applies when the schema carries the load.

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 (fetch) and resource (a patient's full record), then enumerates the concrete contents: conditions, medications, observations, encounters. It also names the sibling it is not (canvas_search) when you need a targeted resource, so an agent can distinguish it without opening any schema.

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?

Explicitly gives both the when ('the fastest way to answer a broad question about one person') and the when-not with the named alternative ('prefer canvas_search when you know which resource you need'), plus the reason (large document). Nothing is left to inference.

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