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

readOnlyHint=true already tells the agent this is a safe read, so the burden is lower. The description adds the raw endpoint (GET /symptoms/{id}), which confirms read semantics but nothing about authentication, rate limits, or error behavior for an invalid id.

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 zero waste. The core action is front-loaded, and the endpoint reference is a compact, useful piece of context rather than padding.

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?

Low-complexity single-resource fetch where annotations cover safety and the schema fully covers inputs. No output schema exists, so the shape of the returned symptom is undocumented anywhere, but the tool's simplicity keeps this a minor gap.

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 all four parameters (id, age, dev_mode, model_id) are already documented in the schema with examples and header mapping. The description adds no syntax or meaning beyond that, 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?

The description states a specific verb and resource: 'Get a single symptom by its id', which lets an agent distinguish it from infermedica_list_symptoms without opening either schema. It stops short of naming the sibling it contrasts with, so 4 rather than 5.

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?

Usage is implied by 'by its id' — an agent infers this is the tool for a known symptom identifier, not for discovery. No explicit when-to-use, when-not-to-use, or pointer to infermedica_list_symptoms or infermedica_search_concepts for lookup by name.

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