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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint=false and destructiveHint=false, so the safety profile is covered. The description adds genuinely new context by naming the data boundary (public educational data only, not private lab results) and noting it explains Vitals Vault coverage. No pagination or rate-limit detail, but the boundary disclosure is real added value.

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 with zero filler. The core action and searchable fields come first, and the scope boundary follows immediately, making it well front-loaded.

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 values need no explanation. For a two-parameter, read-only search tool with full annotation coverage, the description supplies everything an agent needs: what it searches, over what data, and what data is excluded.

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%, so the baseline is 3, but the description adds semantics the schema lacks: the query parameter accepts not just free text but also aliases and LOINC codes, which the schema's 'Search text such as ApoB or vitamin D' example does not convey. The limit parameter's default/max is fully covered by the schema.

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 gives a specific verb (searches) and resource (public educational biomarkers) and enumerates searchable fields (name, alias, LOINC, keyword). It also carves out the data scope ('private lab results are outside this tool's data boundary'), which implicitly differentiates it from siblings like get_biomarker or browse_biomarkers, but no sibling is named explicitly.

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 exclusion of private lab results functions as a when-not constraint, which is useful. However, no positive when-to-use guidance or named alternatives (e.g., browse_biomarkers for exploration, get_biomarker for a known ID) are provided, so selection among the many biomarker siblings 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.