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

Annotations only declare readOnlyHint and openWorldHint; the description adds substantial context beyond them: no API key required, latest-items-only freshness, and a pay-per-call model ($0.002 USDC via x402 on Base, Solana or Arc) with the important detail that failed calls are not charged. That payment behavior is exactly the kind of side effect an agent must know before invoking.

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 purpose and scope come first, followed by sibling disambiguation and then the pricing disclosure, so the important material is front-loaded. The sibling enumeration is verbose, but each item carries routing value rather than filler.

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?

With annotations, an output schema and fully described parameters already supplied, the description covers the remaining agent-critical facts: cost, no auth, and freshness. Only minor gaps remain, such as whether results are paginated or how many items the feed typically holds.

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 100%, so both parameters are already documented, and the baseline of 3 applies. The description's 'keyword filter on title/summary/categories' adds some meaning about where the match occurs, but it slightly diverges from the schema's 'title or summary' and says nothing about the limit range beyond 'latest items only'.

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 names the specific resource (Semafor articles), its source (public RSS feed) and the filter behavior (keyword on title/summary/categories), which is enough to separate it from the dozens of other news-search siblings. It is a sentence fragment without an explicit verb, but the retrieval action is unambiguous.

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?

It explicitly routes the agent away from this tool for adjacent needs by naming search_al_jazeera_articles and search_bbc_news_articles with the condition that selects them. It also implies a scope limit with 'Latest items only', though it never states the negative case directly (e.g., no historical archive or full-text body search).

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