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

Annotations already establish readOnly/idempotent/non-destructive, so the safety profile is covered. The description adds genuinely new behavioral context that annotations cannot express: the tool is free, requires no payment, has no x402 challenge, and has an HTTP GET equivalent. It stops short of describing what the response actually contains (text spec vs. structured parameters).

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 free/no-payment message is stated twice — once as the 'FREE:' prefix and again in a long parenthetical ('no payment required: call directly without payment (no x402 challenge; this tool is free)') — which is redundant. The core subject (what the formula is) is buried mid-sentence after the pricing hook rather than front-loaded. The HTTP URL is also duplicated information rather than added value.

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 and no output schema, the description carries the full burden of explaining what comes back, and it only says 'formula and parameters' without indicating the shape, units, or whether the returned parameters are machine-usable values. It is adequate to decide whether to call it, but not to know what to expect from the response.

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 there is nothing for the description to disambiguate. The baseline for a no-parameter tool applies, and the description correctly implies it is called with no 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 a concrete resource: the published cost-to-fake formula and its parameters (versioned as cost-to-fake/v1) underlying the Reputation-Integrity Verdict. That is specific enough to distinguish it from an action tool. It does not, however, contrast itself with the sibling tools reputation_check and reputation_attest, so sibling differentiation is left implicit.

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?

Usage is only implied: 'anyone can recompute a verdict from the 402 Open Book's public record' suggests this is for independent verification, and 'FREE' signals cost. There is no explicit when-to-use statement, no when-not-to-use, and no routing to reputation_check or reputation_attest.

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