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

Annotations already establish that this is read-only, idempotent, non-destructive, and closed-world. The description adds useful behavioral detail by enumerating what the explainer includes, which is valuable because there is no output schema. It does not describe not-found behavior, but the annotation coverage lowers the bar.

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, front-loaded with the core action and followed by the returned content. There is no filler or redundancy.

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 simple read-only lookup with a fully described two-parameter schema, the description covers the purpose and the returned content well enough. The main gaps are not-found behavior and explicit sibling differentiation, which are minor but real.

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 the slug and lang parameters are already documented. The description adds only that the lookup is 'by slug' and that the result is a full explainer; it does not add syntax, format, or semantic detail beyond the schema baseline.

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: returns the full explainer for a clinical condition by slug. The resource is clear enough to separate it from explain_marker, explain_panel, and explain_symptom, but it does not explicitly name those siblings or clarify the boundary.

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 the tool is used when an agent has a condition slug and needs the explainer, but it gives no explicit when-to-use guidance, no when-not-to-use guidance, and no alternatives. The schema mentions list_conditions for slug discovery, but that guidance is not in the description itself.

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