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

With no annotations provided, the description carries the full burden of behavioral disclosure. It states the tool returns a 'comprehensive list of countries' but does not mention the output format (e.g., country names, codes, objects), alphabetical ordering, or potential pagination. This is not misleading but adds minimal context beyond the tool name.

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 two sentences. The first sentence is direct and front-loaded with the core purpose. The second sentence adds context about filtering/analyzing stock symbols, but is somewhat generic and could be trimmed. Overall, it is concise and readable without excessive verbosity.

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 tool's simplicity (no parameters, no output schema), the description covers the basic purpose. However, it lacks any detail about the return structure—whether the result is a list of strings, objects with country codes, or something else. Since the description must compensate for the missing output schema, this gap prevents a higher score.

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?

The tool has zero parameters, and the schema coverage is 100% (an empty properties object). According to the rubric, a baseline of 4 is appropriate for no-parameter tools. The description does not need to add parameter semantics since there are none.

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 clearly states the tool's function: 'Access a comprehensive list of countries where stock symbols are available.' This uses a specific verb ('Access') and resource ('list of countries'), and is distinct from sibling tools like getAvailableExchanges or getAvailableIndustries. The mention of filtering by country of origin or primary market further clarifies its domain.

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 implies the use case: 'enables users to filter and analyze stock symbols based on the country of origin or the primary market.' However, it does not explicitly state when to use this tool versus alternatives like getAvailableExchanges or getAvailableSectors. No exclusions or alternative references are provided, so guidance is only implicit.

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