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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint. The description adds valuable context: arXiv's official API, the one-request-per-3-seconds pacing, caching for instant repeats, and the $0.001 cost per call (10 free/day). This goes beyond the annotations and informs the agent about operational constraints.

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 and front-loaded with the core purpose, then adds essential details (syntax, rate limit, caching, price) in logical order. No redundant sentences; every clause earns its place.

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?

Given the tool's moderate complexity (3 params, no output schema), the description covers the return content (abstracts, authors, dates, PDF links), the query language, the API source, and the operational policies (rate limit, caching, cost). Nothing an agent needs to decide whether to use it or construct a valid query 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 coverage is only 33% (only query has a description), but the description compensates by explaining the query syntax (ti:, au:, abs:, cat:cs.AI, AND/OR) and mentioning the sort options (newest or most relevant). This adds meaning beyond the bare parameter names, even though it does not detail the limit 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?

States a specific verb+resource: 'Search arXiv research papers' with clear scoping to keywords, author, or category, and mentions the output includes abstracts, authors, dates, and PDF links. It clearly distinguishes itself from sibling search tools like book_search or web_read by targeting the arXiv corpus.

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 explains what the tool does and mentions the arXiv syntax and rate limit, but does not explicitly say when to use it versus alternatives or when not to use it. It implies usage via the topic, but lacks an explicit exclusion or routing to other tools.

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