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

Annotations already declare readOnly, idempotent, openWorld, and non-destructive behavior. The description adds valuable context that it's the reverse direction from references, clarifying the semantic direction of the operation. However, it doesn't mention potential output format or edge cases (e.g., no citations found), but the output schema likely covers return structure.

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 compact but rich, using multiple example phrasings to convey the same concept. It's slightly longer than minimal but every part adds value, including the usage guidance. The front-loaded examples make the purpose immediately clear.

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 tool with an output schema, the description covers purpose, usage, and direction. It fully explains what the tool does and when to use it, making it complete within its context.

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?

The input schema only specifies 'doi' as a string without further description (0% coverage). The description compensates by repeatedly using 'DOI' in examples and clarifying that the tool operates on a given DOI. This makes the parameter's meaning clear, though it doesn't explicitly state it's a single string parameter.

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 tool's function: it returns DOIs that cite a given DOI (incoming citations). It uses explicit verbs like 'cites' and 'reference' and provides example queries. It distinguishes itself from the sibling 'references' tool by noting it's the reverse direction.

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 gives explicit usage scenarios: 'Use for impact analysis, follow-on research discovery, "is this paper influential" questions.' It also contrasts with references, making it clear when to use this tool vs. the alternative.

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