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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the description carries low burden. It adds minimal context by stating it returns 'a list of matching subject strings used to classify BHL holdings,' which is useful but largely duplicates what the output schema would convey. No contradictions with 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?

Three compact sentences with no wasted words: purpose first with examples, then return type, then downstream usage. Front-loaded with the core action and ends with actionable guidance.

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 single-parameter lookup tool with a full output schema, the description covers purpose, return behavior, and usage. It also points to the next logical step (bhl.literature.search). Nothing an agent needs to call it correctly 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%, and the schema already describes the 'subject' parameter with examples. The tool description repeats some examples and provides broader context (natural-history discipline), but does not add syntax or format details beyond what the schema provides. Baseline 3 applies given full schema coverage.

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 uses a specific verb ('Browse') and resource ('BHL subject index'), states the output (matching subject strings), and provides clear examples. It distinguishes itself from sibling tools like bhl.literature.search by focusing on discovering subject tags rather than searching publications directly.

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 explicitly tells the agent when to use this tool (to discover subject tags) and provides a direct alternative: 'Use the returned subjects as precise search terms in bhl.literature.search.' This gives clear routing guidance and implies when not to use it (when searching directly is sufficient).

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