available_markets

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

No annotations are provided, so the description carries the full burden. It is a simple read operation with no parameters, but the description does not mention any behavioral traits such as data freshness, error handling, or whether the list is comprehensive. However, given the simplicity, the lack of behavioral detail is acceptable but could be improved.

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 a single sentence with no wasted words. It is front-loaded with the key information. For a simple tool, this is appropriately concise.

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?

The tool has no parameters and an output schema exists, so the description does not need to detail return values. However, it could be more complete by explaining that the output is a list of market identifiers or names, or indicating that this is a prerequisite for other market-based queries. The example helps but is minimal.

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 schema description coverage is 100% (empty schema). The description does not add parameter information, which is acceptable since there are none. Baseline 4 is appropriate.

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 'List available markets (e.g., 'S&P 500')' clearly states the action (list) and the resource (markets). It provides an example, making the purpose understandable. However, it does not explicitly differentiate from sibling tools like 'available_regions' or 'available_tickers', but the context implies it is for markets specifically.

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?

No guidance is provided on when to use this tool versus alternatives. The sibling tools list many ticker-specific tools, but the description does not indicate that this tool should be used to discover market options before querying other tools that require a market parameter.

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