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

Annotations already declare readOnlyHint=true, idempotentHint=true, and no destructive actions. The description adds valuable behavioral context: the source (NIH ODS), content scope (~45 topics), and the two reading levels with their output characteristics (plain-language vs. clinical with references). It does not contradict 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?

The description is information-dense with no wasted sentences. It front-loads the core purpose (what kind of fact sheet), then covers source, levels, topic coverage, and alternative routing. Each sentence serves a distinct function and earns its place.

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?

Despite having no output schema, the description sufficiently conveys what the returned fact sheet contains (function, efficacy, safety, interactions, references for professional level) and how to disambiguate from siblings. An agent has everything needed to select and invoke the tool 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 description coverage is 100%: both 'name' and 'level' are fully documented in the schema, including the default for 'level'. The description repeats the reading-level distinction but adds no new parameter details beyond examples like Ashwagandha and Vitamin D, which already exist in the schema's examples. Baseline 3 is appropriate because the schema carries the parameter burden.

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 the specific action (retrieve an NIH fact sheet for a vitamin, mineral, or supplement), the resource (NIH ODS fact sheet), and the content areas (function, efficacy, safety, interactions). It explicitly distinguishes from the sibling 'supplement_factsheets' (full list) and 'herb_at_a_glance' (herbs not on the list), leaving no ambiguity about scope.

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 provides explicit routing rules: 'call supplement_factsheets to see the full list' and 'For popular herbs NOT on that list ... use herb_at_a_glance instead.' This tells an agent exactly when to pick this tool over closely related siblings.

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