Cite from an ISBN

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

Annotations already declare readOnlyHint=true and openWorldHint=true; the description usefully confirms the external source ('Open Library'), which is consistent with openWorldHint. It does not disclose what happens on an invalid/unknown ISBN, rate limits, or lookup failures — behavioral gaps that matter for a network-dependent tool.

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: purpose first, then inputs, then a concrete example. Every sentence carries information and nothing is padded.

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?

With no output schema, the description adequately signals the return ('format the book citation' in a given style) and names the data source. Missing only edge-case behavior for unresolvable ISBNs or unsupported styles, which would round it out.

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 coverage is 100%, so both parameters are already documented, and the description largely restates them. Notably it lists only apa7, mla9, chicago-ad and ieee while the schema also accepts harvard, a small inconsistency that could mislead on valid values; the dash-tolerance note is repeated from the schema.

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+resource pair: 'Look up an ISBN on Open Library and format the book citation' in four named styles. The ISBN focus implicitly separates it from the DOI/URL siblings, but it never names those alternatives, so sibling differentiation is left to inference.

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 'Inputs: isbn ... and style ...' line plus the worked example prompt ('Cite ISBN 978-0-262-03384-8 in MLA 9') give a clear picture of when and how to call it. No exclusions are stated — nothing tells the agent to use cite_from_doi or cite_from_url instead when it holds a DOI or URL rather than an ISBN.

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