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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so safety is covered. The description adds genuinely useful context beyond the annotations: the $0.002 USDC cost per call via x402, which alerts the agent that invoking this tool incurs a payment. It stops short of describing pagination or result volume behavior.

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 zero waste. The purpose is front-loaded, and the cost constraint follows immediately. Nothing is redundant or 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?

An output schema exists, so return values need not be explained, and annotations cover the safety profile. The description adds the critical payment note. It could be slightly more complete by clarifying ordering (newest-first) or relationship to the general arxiv__recent tool, but nothing essential 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 description coverage is 100% with a single 'limit' parameter (max 50, default 25) fully documented in the schema. The description adds no parameter detail beyond that, so the baseline of 3 is appropriate.

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 ('newest arXiv submissions in q-bio (Quantitative Biology)') and names the exact category, which distinguishes it from sibling category tools like arxiv__recent-cs-ai or arxiv__recent-stat-ml. An agent can pick the right category feed 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?

The category scope implies when this tool is appropriate, but there is no explicit guidance on when to choose it over arxiv__recent (the general feed) or arxiv__search. No exclusions or alternatives are named, so selection relies on inference.

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