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

Goes well beyond the readOnlyHint/openWorldHint annotations: it explains the data path (Google News public RSS index because apnews.com blocks automated clients), warns that links are Google News redirects rather than direct apnews.com URLs, limits scope to headlines with no article text, and discloses cost ($0.002 USDC per successful call, x402 on Base/Solana/Arc) with the key detail that failed calls are not charged. That pricing and link-format disclosure is exactly the context an agent cannot get from structured fields.

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?

A single dense but well-ordered passage that leads with what the tool returns, then source mechanics, then link caveats, then price. Every clause carries non-redundant information — nothing is repeated from the schema or annotations.

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?

All three parameters are optional with zero required inputs, and the description makes clear the tool works with no arguments (defaults apply). An output schema exists so return structure need not be described, and the payment model, link format, and content limits are all covered.

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%, so the schema already documents q, days, and limit with ranges and defaults. The description reinforces the semantics ('optionally matching search words', 'from the last 1-30 days', 'newest first') but adds no syntax, format, or edge-case guidance beyond what the schema already carries, so the baseline 3 applies.

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 pair plus the exact returned fields (headline, publisher, publish time, link), ordering (newest first), and scope (last 1-30 days). An agent can distinguish this from siblings like search_google_news or search_reuters_articles purely from the text, since it names AP News as the source site.

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?

Clear context is given for when this is appropriate: latest AP headlines from a bounded 1-30 day window, with an optional keyword filter. The line 'Headlines only, no article text' implicitly steers an agent toward a full-text extractor when body content is needed, but no sibling alternative is named explicitly and there are no stated exclusions.

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