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

Annotations already declare readOnly, idempotent, and non-destructive, so the safety profile is covered. The description adds substantial behavioral context: the dataset excludes markets other Western aggregators miss, gives examples of hidden markets, explains legal-recognition phasing and venue-level retail caps, and clarifies that the tool returns coverage along with reasons. This goes well beyond the 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?

The description is front-loaded with purpose and ends with a clear usage instruction and omit-country reminder. However, the middle section contains lengthy country-specific facts (Japan's ¥1tn consortium chain, Korea's 2027 legal recognition, India's lack of stablecoins) that are illustrative but not necessary for an agent to select and invoke the tool correctly.

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 the lightweight 2-parameter schema, 100% parameter coverage, an output schema, and annotations covering safety, the description is complete enough. It explains what the tool reveals, why it matters, when to call it, and how to request all markets by omitting country. Nothing needed to invoke it correctly 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 description coverage is 100%, and both country and readable_only are already well documented in the input schema, so the baseline is 3. The description reinforces the omit-country behavior and gives country examples, but it does not add meaningful semantic detail for readable_only beyond what the schema already states.

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 opening phrase 'Which countries this dataset can see into, which it cannot, and why' clearly identifies a specific verb, resource, and unique scope. It distinguishes the tool from a 'general search', but does not explicitly name or contrast sibling tools like get_market_stats or compare_tokenized_access, so sibling differentiation is only implicit.

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 description gives strong when-to-use guidance: 'Call this before stating what a market holds, or before quoting any total as if it were the world.' It also says the tool should answer country-tokenization questions 'rather than from a general search.' However, it does not name specific sibling tools or state when not to use this tool in favor of one of them.

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