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

The description mentions a cost ($0.01), which is a behavioral trait. However, no annotations exist, and the description fails to disclose whether the tool is read-only, auth requirements, or any side effects. The cost is noted, but other important behaviors are omitted.

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 very concise (one sentence plus cost), which is efficient but at the expense of completeness. Every sentence serves a purpose, but additional details (e.g., output format, error cases) are missing, making it too sparse for a fully functional description.

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 has 2 parameters, no output schema, and no annotations, the description is inadequate. It does not explain the return value, how the api_key is used, or potential errors. The description is too minimal to be considered complete.

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 50% (holdings described, api_key not). The description adds no meaning beyond the schema; it does not describe the api_key parameter or provide any additional context for holdings. With low coverage, the description should compensate but does not.

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 action ('calculate') and the resource ('total portfolio value in USD'), and specifies the input format ('holdings JSON'). It implies a distinct functionality from siblings like 'get_portfolio_health' or 'get_price', though no explicit differentiation is provided.

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 given on when to use this tool versus alternatives. The description does not mention any prerequisites, context, or exclusions, leaving the agent to infer usage from the tool name and purpose alone.

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