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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely new behavioral context: it is free, it is cached (i.e., fixed/stale data, not a fresh computation), and it reflects one specific real Base token rather than the caller's input. That 'cached' disclosure is the most useful thing here.

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?

One sentence, no filler, and the cost differentiator ("Free.") is front-loaded ahead of the explanation of what is returned. Every clause carries information.

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 does enough: it says what the payload is a sample of and why it exists. The one remaining gap is that it never says which token the sample covers or that the data is static, so an agent cannot tell whether the sample is representative of a specific verdict type.

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?

Zero parameters, so baseline is 4. The description implicitly reinforces this by framing the tool as returning a fixed example rather than something parameterized, leaving no ambiguity about why the schema is empty.

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?

States a specific resource (a cached example of the check_base_token response) and explicitly distinguishes it from the paid sibling by naming check_base_token and calling this an example of its output. An agent can tell instantly that this is a preview, not a live lookup.

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?

"To see the shape before paying" gives a clear condition for use: call this first to learn the response format, then move to the paid check_base_token. It does not mention when NOT to use it (e.g., when you need a verdict for an arbitrary token, use check_base_token or get_token_info instead), so it stops short of full routing guidance.

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