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

Annotations already declare readOnlyHint=false, idempotentHint=true, openWorldHint=true, and destructiveHint=false. The description adds valuable context: the tool is free, and with tx_hash it verifies canonical USDC, recipient, exact amount, success, time window, 10 confirmations, and that the hash was never used before. It does not detail failure modes or authentication requirements, but this is a strong addition beyond the annotations.

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 description is a single, tightly structured sentence: it front-loads 'Free.' and then cleanly separates the two usage modes with 'With only order:' and 'With tx_hash:'. Every clause earns its place with no redundancy.

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?

Given the tool's two-mode complexity, no output schema, and full schema coverage, the description is largely complete. It explains the return of a download link and the extensive verification steps, but omits what happens on verification failure and does not guide tool selection relative to siblings.

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 100%, so the schema already documents both parameters. The description significantly enriches semantics: `order` alone yields status and a fresh download link once paid; `tx_hash` triggers a detailed set of verification checks. This adds meaning far beyond the schema's minimal descriptions.

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 clearly states what the tool does in two modes: with only `order` it returns status and download link; with `tx_hash` it verifies a Base transaction. It uses specific verbs and resources, but does not explicitly distinguish itself from siblings like `create_transfer_order` or `buy_file_x402`.

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 explains how to use the tool's two parameter combinations (order only vs. order + tx_hash), which implies usage. However, it never states when to choose this tool over alternatives such as `create_transfer_order` or `buy_file_x402`, nor does it provide exclusions or prerequisites beyond the free note.

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