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

Annotations declare readOnlyHint=true, and the description adds meaningful behavioral context: rates are time-banded, change dynamically, and results are paged with a notice reporting the next offset. This goes beyond the annotation safety profile. However, it does not mention error handling or rate limits, but given read-only and output schema exists, the added value is solid.

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 compact (three sentences) and front-loads the primary purpose. The paging explanation is useful, but the 'stateRoute' sentence is tangential and could mislead since it does not appear in the parameter list. Overall efficient, but not perfectly focused.

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 read-only paginated tool with an output schema, the description covers core usage: what data it returns, dynamic nature, and how paging works. It does not explicitly state that repeated calls may be needed to fetch all toll rates, but the notice about next offset implies it. The output schema covers return structure, so no missing critical info.

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 100%, so limit and offset are already described in the schema. The description mentions paging, but the schema already covers defaults and bounds. The odd mention of 'stateRoute' is not a parameter and could confuse, adding no semantic value for the parameters. Baseline of 3 is appropriate.

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 tool returns current dynamic toll rates, names the specific WA express lanes and tolled facilities (SR 99, SR 167, I-405, SR 509, SR 520 Bridge). This distinguishes it from siblings like ferry or border tools, which are unrelated. The verb 'returns' and resource are explicit.

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 implies when to use it (when toll rate data is needed) and provides practical paging guidance. It does not explicitly exclude alternative tools or state when not to use it, but given the distinct sibling types (ferries, passes, cameras), the context is clear enough. No misleading guidance.

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