get_availability

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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is well-covered. The description adds useful context about what buying power includes (cash for stocks/derivatives, with/without margin), but it does not disclose any additional behavioral traits (e.g., data freshness, rate limits, or authorization requirements) beyond what annotations already imply. This matches the calibration example of get_calls where the description adds some value but not rich behavioral context.

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 long with no fluff. The first sentence immediately states the purpose and scope, while the second gives actionable usage guidance. Every word earns its place, and it is front-loaded with the most critical information.

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?

For a zero-parameter tool with rich annotations (read-only, idempotent, non-destructive) and an output schema present, the description sufficiently explains what the tool does and when to use it. It clarifies the distinction from a sibling tool and provides the exact use case. There are no missing prerequisites, side effects, or return-formats to explain since the output schema covers return values.

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, so the schema carries no parameter semantics (coverage is trivially 100%). The baseline for 0 parameters is 4, and the description adds meaning to the tool's output ('buying power' and its components) which indirectly clarifies what the tool returns. No parameter information is needed, and the description does not confuse with parameter details.

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 specific verb ('Get') and resource ('buying power') and clarifies scope ('cash available for stocks and derivatives, with and without margin'). It also distinguishes itself from sibling get_account_balance by naming it and providing the exact use case ('how much can I invest'), satisfying sibling differentiation.

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 explicitly says 'Use this rather than get_account_balance when the question is "how much can I invest"'. This provides clear when-to-use guidance and names the alternative, which is exactly the kind of directive expected for a 5 on this dimension.

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