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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description adds genuinely new behavioral context by disclosing the returned content (meaning, causes, lab work-up, urgent-evaluation criteria) and the side-car slug arrays that enable graph traversal. Missing: behavior for an unknown slug or translation fallback.

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 tight sentences: the action and scope come first, then the payload contents and the graph-following hint. No filler and no repetition of the title.

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 usefully enumerates the explainer's sections, which is exactly the burden it must carry. For a two-parameter read tool that is close to sufficient; only error/edge behavior (unknown slug, language fallback) is left unstated.

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 both slug and the lang enum are already documented, including slug discovery guidance. The description only restates 'by slug' and adds no format or normalization detail beyond the schema. There is a minor inconsistency worth noting: the schema points to list_markers/list_conditions for slug discovery, while this is a symptom tool (list_symptoms exists).

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: 'Return the full triage explainer for a single symptom by slug', and enumerates the sections returned. It is clearly a per-symptom detail lookup, distinct from the list_* siblings, though it never names the alternative tools by contrast (only as downstream graph hops).

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 'for a single symptom by slug', and the second sentence gives forward guidance on following related marker/condition arrays into mediora__explain_marker / explain_condition. There is no explicit statement of when to use this instead of mediora__list_symptoms or lookup_marker, and no prerequisites or exclusions.

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