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

Goes well beyond the readOnlyHint/openWorldHint annotations: discloses the exact pricing model (3 free calls/day across all tools, then $0.005 USDC via x402 or card credits), how payment is transmitted in-band via params._meta["x402/payment"], and the upstream data source (GDELT DOC 2.0). Those are operational facts 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?

Two dense sentences, no filler, with pricing and the payment mechanism front-loaded. The capability block is somewhat packed (language count, field list, data provider crammed into one clause), but every element is load-bearing for an agent deciding whether to call.

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 an output schema exists, return values needn't be explained, yet the description still summarizes them (title, URL, source domain, language, country, time). Combined with cost, data provenance, and sibling routing, nothing an agent needs before invoking it 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 100%, so the baseline is 3, but the description adds meaning the schema lacks: the timespan accepts a bounded range from 1h to 2 weeks, results favor recency (newest first), and the corpus spans 65+ languages. It doesn't explain the q syntax beyond what the schema says, so it stops short of a 5.

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 ('News search and monitor') with concrete scope: worldwide articles in 65+ languages, keyword match, time window, newest first. It explicitly separates itself from news_entity and news_sentiment by naming what each of those does instead.

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?

Contains an explicit 'When to use' clause that routes the agent: news-monitor for latest articles by keyword, news-entity for a 24h who-writes-about-X digest, news-sentiment for tone. Both alternatives are named with the condition that selects them.

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