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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the description does not need to restate safety. It adds value by disclosing the constrained universe ('~50 strategic pairs are monitored') and the nature of the signal (co-mention volume and tone), which are behavioral facts beyond the schema. This is useful context without contradicting annotations.

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, no filler. The core purpose and example are front-loaded, and the monitored-pair count is a useful closing detail. Every word 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?

With an output schema present, return-value details are not the description's job. It supplies the key contextual facts: the pair scope, the monitored-set limitation, and the tone dimension. It could mention what happens for unmonitored pairs, but given openWorldHint=false and the existence of an output schema, this is a minor gap rather than a material omission.

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%, giving a baseline of 3. The description adds meaning by exemplifying the exact expected values ('a='cn', b='us'') and by signaling that only a limited set of pairs are valid ('~50 strategic pairs are monitored') – a domain constraint the schema alone does not reveal. This goes beyond the raw property descriptions.

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 states a concrete resource ('bilateral co-coverage signal') and exactly what it measures ('how much the world's press mentions the two countries together, and in what tone'), with a concrete example pair. This clearly distinguishes it from siblings like get_country (single country) and search_topics, so no ambiguity remains.

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?

The phrase 'for a monitored country pair' plus the explicit example (a='cn', b='us') gives clear context for when to call this tool. It does not explicitly name alternatives (e.g., get_country for single-country signals) or exclude conditions, but the monitored-pair scoping is strong implied guidance. This is more than vague, though slightly short of explicit alternative routing.

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