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

Annotations already declare readOnlyHint=true, so the read-only nature is covered. The description adds context about the data returned (status, weather, etc.) and the full scope of 16 passes, which is useful behavioral context beyond the annotation. However, there is no disclosure of rate limits, authentication needs, or any side effects, and the description does not go beyond what the annotation plus its own purpose statement already communicate.

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 three sentences with no waste. The first sentence states purpose and data fields, the second lists the passes, and the third gives usage examples. It is front-loaded with the core function and efficiently structured.

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?

With zero parameters, a read-only hint, and an output schema present, the description covers everything an agent needs to call this tool: what it returns, the full scope of passes, and typical use cases. There is no missing information for correct invocation.

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 accepts zero parameters, and the schema coverage is 100% (there is nothing to document). The description properly indicates the tool needs no input and focuses on the output scope. Per the rubric, a 0-parameter tool receives a baseline of 4, and the description does not need to add 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 ('Returns') and a precise resource ('current road conditions for all Washington State mountain passes'), and lists the data fields it provides (status, weather, road condition, traction laws, temperature, elevation). It also mentions all 16 passes by name, clearly distinguishing this tool from siblings that handle ferries, borders, and cameras.

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 gives explicit use cases: 'Use for "is the pass open?", traction law status, or winter driving planning.' This provides clear context for when to call the tool. However, it does not explicitly mention alternatives or when not to use it, though the sibling differentiation is implicit given the highly specific scope.

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