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

No annotations, so the description carries the full burden. It usefully discloses the pricing model (5 free trial calls per signed wallet), which is real behavioral context, but it omits any error behavior, input size limits, or how the operation direction is selected.

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?

A single compact line, front-loaded with the tool name and core operation, with no filler. The trailing emoji and trial-call note are slightly promotional but still informative.

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 output schema, no annotations, and 5 completely undocumented parameters, the description should explain the return shape and how to trigger each direction. It leaves the agent guessing which of op/mode selects compress vs decompress.

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?

Schema coverage is 0% across 5 parameters (op, data, mode, text, input) and none are required. The description only implies that one field holds UTF-8 text and another holds base64 brotli, without mapping any of that to the actual parameter names or explaining op/mode.

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?

Names a specific verb+resource (Brotli compress/decompress) and the data formats involved (UTF-8 text <-> base64 brotli). It is clear what the tool does, though it does not distinguish itself from siblings like x402-gzip-compress/x402-deflate-compress beyond the algorithm name.

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 states both directions exist but never says when to choose this over base64, gzip-compress, or deflate-compress, nor which parameter selects compress vs decompress. No when/when-not guidance at all.

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