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

With no annotations, the description carries full behavioral disclosure. It reveals the tool is a 'docent' that explains the model and points to a live source, but deliberately does NOT return a tax rate. It also notes the actual fee is reported at transaction time. This is transparent about the tool's non-numeric, informational behavior.

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 four sentences, tightly packed with essential information. It front-loads the main purpose, explains the key conceptual point (per-Authority, no network-wide number), states what the tool does, and gives the alternative. No wasted words.

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 the tool's simplicity (no parameters), the presence of an output schema, and the explanation of the model and alternatives, the description is complete. It covers what the tool does, what it doesn't do, and where to get exact data. The output schema handles return structure details.

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 has zero parameters, so the baseline is 4. The description does not need to add parameter semantics since there are none. It clearly frames the tool as a conceptual explainer, which is sufficient for a parameterless tool.

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's purpose: 'Explain how Tollbooth certification taxation works.' It uses a specific verb ('Explain') and resource ('Tollbooth certification taxation'), and explicitly distinguishes itself from returning a numeric rate, which differentiates it from any hypothetical rate-returning sibling.

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 provides explicit usage guidance: it tells the agent when to use this tool (to understand the taxation model) and when not to (for exact figures). It names the alternative: 'query the relevant Authority's check_price for certify_credits.' This is a clear when/when-not distinction with an alternative tool.

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