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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, destructiveHint=false, openWorldHint), so the description's main added value is operational: cost (0.008 USDC per call), p95 latency (600 ms), the GDELT data origin, and the hard 72-hour recency ceiling. Those extras are genuinely useful for planning a call. It does not add anything about result completeness, deduplication, or rate limits beyond cost, so it stays at solid-but-not-rich.

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?

Front-loads the return shape, then use/when-not, then cost and latency — a sensible priority order for an agent deciding whether to call. Three dense sentences, no filler, no repetition of the tool name or title.

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 the description is not obligated to explain return values (though it briefly does). Combined with 100% schema coverage, full annotations, and disclosed cost and latency — the three things an agent cannot get from structured fields — the definition is complete enough to call correctly without further discovery.

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 all five parameters including defaults, ranges and the enum. The description reinforces the recency cap and that `query` matches across headlines, people and organizations, but adds no syntax or format detail the schema lacks. Baseline 3 plus a small lift for tying the description's 72-hour rule to the `hours` parameter.

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 ('Returns ... recent news articles'), names the upstream source (GDELT), and enumerates the returned fields so the agent knows exactly what it gets. No sibling overlaps: the other tools are email, image, LLM, PDF, SEC, speech, wallet, weather and web tools, none of which return news.

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?

Explicit when-to-use ('news articles or headlines from the last 72 hours about a topic, company or person') and an explicit when-not list (full article text, paywalled sources, non-English coverage, news older than 72 hours). The 72-hour boundary is repeated and matches the hard maximum on the `hours` parameter, so the exclusion is enforceable rather than aspirational.

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