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

Annotations already declare readOnlyHint=true, so the agent knows this is a safe read operation. The description adds useful behavioral context about the computation basis ('current listing prices plus the key price') and exclusions ('Cases whose contents are not sufficiently priced are excluded'). This goes beyond the annotations, but it doesn't cover other behavioral aspects like rate limits or authentication. A 3 is appropriate.

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?

Three sentences, front-loaded with the core action, then details on entries and exclusions. Every sentence earns its place without redundancy.

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 no output schema, the description explains what each entry contains (price, expected value, return in basis points, chance of profitable opening), which is essential. It also notes exclusions. However, it could mention if there are any parameters or if the ranking is always complete, but for a parameterless read-only tool, it's quite 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?

There are no parameters (0 params), so the baseline is 4. The description doesn't need to explain parameters, and it correctly doesn't invent any. It provides no parameter information because none exist.

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 ('Rank'), resource ('Counter-Strike 2 cases'), and metric ('expected return on opening'), clearly distinguishing it from sibling tools like get_armory_roi or browse_cases.

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?

It implicitly defines usage by describing the ranking and what data each entry contains, but doesn't explicitly state when to use this tool versus alternatives like browse_cases or get_armory_roi. However, the narrow focus on ROI ranking provides clear context.

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