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

readOnlyHint=true already tells the agent this is a safe read. The description adds that the call maps to GET /symptoms and that results can be narrowed by age, but says nothing about result size, pagination, or lookup semantics — which matters for a 'list all' endpoint. Some added value over annotations, but thin.

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 short sentences, with the purpose and scope front-loaded before the API note. No filler; the endpoint clause is marginal but short enough not to hurt readability.

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?

With no output schema, the description does not hint at the return shape (whether ids, names, or full records come back) nor at result limits for an unbounded 'list all'. Annotations cover safety, so the gap is moderate rather than severe, but the definition stops short of being fully self-sufficient.

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 the four parameters (age.value/age.unit, dev_mode, model_id, enable_triage_5) are fully self-documented and the baseline is 3. The description only restates the age filter and adds no semantics beyond the schema.

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 and resource ('List all symptoms in the Infermedica medical model') with a scope qualifier, which cleanly contrasts with the singular sibling infermedica_get_symptom. It does not, however, explicitly name that sibling or distinguish itself from the other list_* tools.

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 parenthetical '(optionally age-filtered)' implies when the age parameter matters, but there is no explicit when-to-use/when-not guidance and no pointer to infermedica_get_symptom for per-symptom detail. Usage is only inferable from the name and scope.

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