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

Annotations declare readOnlyHint=true and openWorldHint=true, so the agent knows it's a safe read from an open web source. The description adds useful output-field context (slug, topic, URL, last-modified date) but no pagination, rate limits, or result-count behavior. With annotations covering safety, a 3 is appropriate.

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?

Single dense sentence front-loads the resource then the filters then the return shape, followed by a short routing cue. Zero waste.

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?

Has an output schema, so it needn't explain return values, and the description names the output fields anyway. Covers filters, return shape, and sequencing. What's missing is pagination/limits and whether letter is case-sensitive – minor for a listing tool with an output schema.

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 0%, so parameters are undocumented in structured fields. The description compensates partially by listing example topic values (side-effects, dosage, interactions) and describing the letter as 'first letter of the slug', but neither is formalized as an enum or format spec, leaving ambiguity.

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 (dedicated drug guide pages) with filter facets, and names the sibling it must precede (goodrx_drug_guide). It's clear what the tool does, though it doesn't deeply differentiate from other GoodRx listing tools like goodrx_drugs or goodrx_conditions.

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 explicit sequencing guidance ('Use before goodrx_drug_guide') and describes filters. It doesn't state when NOT to use it or name alternatives for drug price info, but the routing cue is clear.

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