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

Annotations already cover the safety profile (readOnlyHint=true, idempotentHint=true, destructiveHint=false), lowering the bar. The description adds useful output context — 'curated interactions with severity, description, and management guidance' — which partially compensates for the absence of an output schema. It does not disclose edge-case behavior (unknown drug names, single-drug input, rate limits), but this is a simple read-only lookup.

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 purpose is front-loaded in the first sentence, followed by output format and input forms, closing with two illustrative examples. The second sentence is long but earned — it demonstrates both accepted input formats. No wasted words.

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 2-parameter read-only tool with 100% schema coverage, the description is nearly complete: it states input formats, output contents, and usage pattern. The only minor gaps are edge-case behaviors (e.g., unknown drug handling), which are not critical for a simple query tool.

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%, so the schema already documents both parameters with examples. The description largely repeats this information (comma-separated names or IDs) and adds only marginal value by showing the full invocation with _apiKey inline. Baseline 3 is appropriate since the schema carries the load.

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 a specific verb and resource: 'Check drug-drug interactions among a set of drugs' and 'Returns curated interactions with severity, description, and management guidance.' This clearly distinguishes it from its domain siblings (drugbank_drug for single-drug info, drugbank_drug_names for name lookups) without needing to open 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?

The description conveys when to use it: 'among a set of drugs' implies multi-drug checks, and the examples demonstrate concrete invocation patterns with names and DrugBank IDs. It does not explicitly name alternatives or give exclusion criteria, but the context is clear enough for an agent to route to it.

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