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

readOnlyHint=true already establishes this is a safe read, so the bar is lower. The description does add genuine context annotations don't carry: that each list's provenance is reported ('whether each list has been checked against the official text'), which tells the agent about data freshness/reliability. It stops short of describing scope, coverage, or refresh cadence.

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 front-loaded sentence that opens with the scoping condition ('which rules are in force right now') before listing contents. No filler, though the dense comma-list of returned fields reads slightly like an inventory rather than prose.

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 no parameters and no output schema, the description carries the burden of conveying the return payload, and it does so by naming the four things returned. It does not describe the response shape or format, but for a simple zero-arg status read that is a minor gap.

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 takes zero parameters, so per the rubric the baseline is 4. Nothing in the schema needs additional explanation and the description correctly spends no effort on arguments.

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 names the specific resource (Canada/US border rules currently in force) and enumerates the payload it covers: tariff measures, rates, start dates, and verification status. It is clearly distinguishable from border_quote and door_cost_estimate, though it never explicitly contrasts itself with siblings and is framed as a content list rather than a verb+resource action.

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 phrase 'in force right now' implies the temporal use case (current-state lookups) but there is no explicit when-to-use guidance, no exclusions, and no mention of the sibling tools. Usage is only implied.

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