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

No annotations are provided, so the description carries the full burden, and it discloses nothing about output shape, edge cases (short input, window larger than data), or whether the call is a pure computation. The free-trial/payment note is pricing metadata rather than behavioral disclosure.

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?

It is short, but brevity here is under-specification rather than economy: the first clause is a redundant restatement and the second is malformed, so no sentence earns its place apart from the billing note.

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 two-parameter computation tool with no annotations, no output schema, and no parameter descriptions, the definition supplies essentially nothing an agent needs to invoke it 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?

Both parameters ('values' and 'window') are undocumented in the schema at 0% description coverage, and the description adds no meaning at all — not the expected format of 'values' (CSV? JSON array?) nor how 'window' is interpreted. With 0% coverage the description was required to compensate and does not.

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?

"Median Filter: Median of filter" is a tautology that restates the tool name, and the second clause is not even grammatical. Nothing states what the tool actually does to the values, and in a catalog of hundreds of sibling numeric/statistical tools (x402-median, x402-weighted-median, x402-moving-average) an agent gets no basis for distinguishing it.

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 when-to-use guidance, no mention of the alternatives it competes with, and no prerequisites. The only contextual sentence concerns billing, not usage.

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