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

Annotations already declare readOnly, idempotent, non-destructive and openWorld, so the safety profile is covered. The description adds genuinely useful context beyond them: the $0.002 USDC per-call cost via x402, which is a real behavioral consideration for an agent deciding whether to spend. It does not mention rate limits or result-set freshness lag.

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?

Two short sentences, with the substantive purpose front-loaded and the cost disclosure second. Nothing is padded and the title is not restated verbatim beyond what is needed to identify the category.

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 simple read-only browse tool with an output schema and a fully documented single parameter, the description covers purpose and the cost/payment model. The only real gap is the absence of any routing hint against the many sibling arxiv__recent-* and arxiv__recent tools.

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?

There is one optional parameter and schema description coverage is 100% ('Results, max 50 (default 25)'), so the schema fully documents limit including its cap and default. The description contributes nothing additional about the parameter, which is the expected baseline when the schema does the work.

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 (newest submissions) and resource (arXiv cs.AI), so the agent knows exactly what it returns. However, it never explains how it differs from the sibling arxiv__recent (which presumably takes a category) or why the cs.AI-specific variant exists alongside arxiv__search; the distinction rests entirely on the tool name.

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?

Recency ('newest') implies a browse-what's-new use case versus arxiv__search for topical lookup, but this is inferred rather than stated. There is no explicit when-to-use, no exclusion, and no mention of the near-identical arxiv__recent sibling that would let an agent pick correctly.

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