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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, and the description reinforces determinism ('No model: the same result every time'), which partly overlaps idempotentHint but still usefully tells the agent results are reproducible and rule-based. It also discloses coverage breadth (99 rules, 8 languages, 4 scripts) and that a routine level is returned when no rule fires, which is genuine behavioral context beyond the annotations.

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?

Front-loaded with the core purpose, then the usage paragraph with alternatives. Dense but every sentence carries information; the enumerated symptom categories are slightly list-heavy but justify the tool's scope.

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?

An output schema exists, so return-value details need not be repeated, and annotations carry the safety profile. The description covers purpose, determinism, input scope, when to use, when not to, and the two sibling alternatives, leaving nothing an agent needs in order to invoke it correctly.

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 coverage is 100% and the schema already documents all three parameters, so the baseline is 3. The description adds meaning by tying parameters to behavior: the eight languages/four scripts explain the lang enum's reach and the country parameter is framed as determining which emergency number is returned, which is more than the schema states.

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 (checks symptoms against 99 fixed warning-sign rules) plus the exact output domains (level, fired rules, warning text, emergency number). It also names the sibling tools it is not, so an agent can distinguish it without opening a 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 says when to use it ('when symptoms are described, first, to know if the child needs emergency care, a visit today or home care') and routes to two named alternatives with their own conditions (paediatric_question_with_sources for the explanation afterwards, oral_rehydration_plan for fluids without a danger sign). 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.