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

Annotations already cover the safety profile (readOnly, idempotent, openWorld, non-destructive), so the bar is lower. The description adds genuine behavioral value beyond them: it enumerates the possible outcomes (found, confirm with reason, not found in the named sources on a date, couldn't check) and warns that a not-found is not proof a work was never published.

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?

Four short sentences, front-loaded with the purpose before usage, input format, and outcome taxonomy. Every sentence earns its place with no padding.

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?

No output schema exists, so the description carries the return-value burden and does so by listing the four result states and their epistemic limit. It is essentially complete for a one-parameter read tool, though it could note what the 'confirm' reason contains or any source-coverage caveats.

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 there is a single parameter, so the schema already documents accepted identifier formats. The description's 'Give a DOI, an arXiv id or the reference as written' largely restates the schema, adding no new syntax or constraints.

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 and resource ('whether a reference resolves to a real work') that is clearly distinct from siblings like references_of (lists a work's references), what_cites, and retraction_listing. An agent can identify the tool's function without opening the schema.

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?

'Use when an answer is about to cite a paper' gives a concrete triggering context, which is stronger than implied usage. It does not explicitly name when to prefer a sibling or state exclusions, so it falls short of a 5.

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