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

Annotations already declare readOnlyHint, openWorldHint, and idempotentHint, so the safety profile is covered. The description adds meaningful behavioral context by specifying the 'currently alive' filter and the 'when reviewed' condition for DOSE SCORE, which are not inferable from annotations or the empty input schema.

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?

One compact sentence front-loads the core scope—'Every tracked vendor that is currently alive'—and then lists the relevant returned fields with no filler or repetition.

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 zero-parameter read-only list tool with an output schema, the description is complete: it states the entity, the filter, and the key output attributes. No prerequisites, pagination details, or alternative routing are needed to invoke this 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?

The tool has zero parameters, and schema coverage is complete, so the baseline is 4. The description correctly focuses on output semantics rather than parameter details since there are none to explain.

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 clearly states the tool lists every tracked vendor that is currently alive, and enumerates the returned attributes (DOSE SCORE, liveness status, last-verified date, trust chips, canonical review URL). The noun 'vendor' and scope 'every tracked vendor' naturally distinguish it from siblings like search_compounds and get_compound, and from best_vendors_for.

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 tells what the tool returns but gives no explicit guidance on when to use it versus alternatives such as best_vendors_for. It does not mention exclusions or conditions, so an agent receives only implied context.

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