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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety and scope are covered. The description adds that the operation aggregates into tone-bucketed counts with representative stories rather than returning raw articles, which is useful. It offers no further behavioral context (rate limits, coverage caveats), so a 3 is appropriate.

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 sentences, zero waste. Purpose and output shape are front-loaded, with the sibling routing following. Every clause earns its place.

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-value detail is unnecessary, and annotations cover the safety profile. The description supplies the aggregation semantics and routing guidance, leaving only minor room (e.g., tone scale or bucketing range) that an agent might still infer.

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 every parameter (query, from, to, timespan, domain, country, language) is already documented, including the from/timespan mutual exclusion. The description adds no parameter-level meaning beyond that, so the baseline of 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 (Summarize) plus the resource (matching GDELT coverage) and the exact shape of the output (article counts grouped by integer tone, with representative stories). It also names the sibling tools it is not, so an agent can distinguish tone-distribution from search/timeline without opening schemas.

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?

Explicitly routes to alternatives: gdelt_search for inspecting matching articles and gdelt_timeline for tracking volume over time. This clearly implies the condition that selects this tool (analyzing tone/sentiment distribution), though it never spells out that condition directly.

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