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

With no annotations, the description must carry the full burden. It states the core function but does not disclose whether the tool executes a purchase, returns a schedule, or has side effects. The phrase 'buy this endpoint' is ambiguous and not elaborated. Score 2.

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?

A single sentence with no filler, front-loading the purpose. Score 5.

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 tool with no annotations, no output schema, and an ambiguous 'buy' action, the description leaves critical gaps about behavior and return values. The simplicity of the schema does not compensate for the missing context. Score 2.

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 schema has one parameter (duration_hours) with no description in the schema, and the description does not mention it. The parameter name and constraints are self-evident, but the description adds no value in explaining how it relates to the window. Score 2.

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 uses the verb 'schedule' and identifies the resource as 'a contiguous operating window at the lowest average electricity price,' which clearly conveys the tool's function. However, it does not explicitly distinguish it from similar sibling tools like flexibility_window, so a 4 is appropriate.

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 mentions the target user ('Flexible-load agents') and the context ('lowest average electricity price'), implying when to use it, but it does not provide explicit guidance on alternatives or exclusions. A score of 3 reflects that the usage is implied rather than explicit.

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