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

With no annotations, the description carries the full behavioral burden. It discloses a trial quota per signed wallet, but says nothing about what the tool computes, whether it is a safe read-only calculation, what formula it applies, or what result format to expect.

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 definition is short, but its lead sentence is redundant and does not front-load useful information. The trial note is concise and behavioral, but the overall structure leaves the core operation entirely unexplained.

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 three-parameter physics calculation with no annotations, no output schema, and no parameter descriptions, the description is inadequate. It gives neither the formula nor the meaning of any input, so an agent lacks what it needs to invoke the tool correctly.

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 schema has three parameters with 0% description coverage, and the description does not explain waveSpeed, sourceVelocity, or sourceFrequency at all. An agent cannot tell whether these are numeric strings, units, or how they relate to the Doppler formula.

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 is essentially a tautology: "Doppler Frequency: Frequency of doppler" restates the tool name without specifying the computation, such as observed frequency from wave speed and source velocity. It also does not distinguish this tool from nearby siblings like x402-frequency or x402-wave-speed.

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?

There is no guidance on when to use this tool, what inputs are appropriate, or how it differs from alternatives. The only contextual note is a free-trial quota, which does not help an agent choose between this and related frequency or wave-speed tools.

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