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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered structurally. The description adds the return shape (slug, topic, URL, last-modified date) and that filters are optional, but since an output schema exists this is largely redundant and no pagination/limit behavior is disclosed.

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?

A single front-loaded sentence with zero wasted framing; the scope, filters, and returns are all packed efficiently. Slightly dense with a semicolon clause, but every element 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?

For a simple two-parameter listing tool with full schema coverage and an output schema, the description covers purpose, filters, return fields, and sibling sequencing. Nothing critical is missing, though usage depth is modest.

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% and both parameters are documented there, so the schema does the heavy lifting. The description restates the topic values and letter semantics but adds no syntax or meaning beyond the schema, matching the baseline 3.

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 (List) and resource (GoodRx's dedicated drug guide pages) with scope, and explicitly names the sibling it relates to (goodrx_drug_guide) with a sequencing rule. An agent can distinguish it from goodrx_drug_guide and goodrx_drugs without opening schemas.

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?

Gives a clear ordering rule: 'Use before goodrx_drug_guide.' Also describes the optional filters. It does not, however, state when NOT to use it or name alternative lookups like goodrx_drug_info/drug_options, so guidance is contextual but not exhaustive.

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