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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering safety and idempotency. The description adds useful content details (returns indication, MoA, dosages, adverse effects) and an example, but does not disclose any error behavior, rate limits, or authentication nuances beyond the schema's API key note. It adds some value without contradicting annotations.

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 description is two sentences: the first states purpose, the second provides an example. It is front-loaded and free of fluff. The example is somewhat redundant with the schema example, but it does not hurt. It could be slightly tighter, but it is appropriately sized.

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 tool with no output schema and no nested objects, the description covers what the tool returns and how to call it. It does not describe the exact return structure, but listing the content areas (indication, MoA, dosages, adverse effects) is sufficient. The prerequisite to resolve names is also noted in the schema. No critical information is missing.

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%, with both id and _apiKey fully described (including format, example, and the note to resolve names first). The description adds no additional parameter meaning beyond the example call. Since the schema carries the full semantic load, a baseline 3 is appropriate.

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 verb 'Returns' and the resource 'a single DrugBank drug', then enumerates the specific content (indication, mechanism of action, dosages, adverse effects). This precisely distinguishes it from siblings like drugbank_drug_names (name resolution) and drugbank_ddi (interactions).

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 provides clear context: use for a single drug's monograph. The id parameter description explicitly says 'Resolve names first via drugbank_drug_names', giving a workflow hint. However, it does not explicitly exclude alternatives like drugbank_ddi or state when not to use it, so it lacks full when-not guidance.

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