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

With no annotations the description carries the burden, and it discloses the paid-call pricing model ($0.002 USDC/call, x402, eip155:8453), the billing edge case (unknown tx = not charged), and the return shape ('verdict + decoded transfers'). It stops short of saying whether a failed verification returns a false verdict or an error, which is the one behavioral detail an agent still needs.

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 dense sentence plus a bracketed pricing banner; every clause earns its place and the check list is front-loaded. The price tag preceding the purpose is slightly awkward ordering but costs almost nothing.

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 6-parameter tool with no annotations and no output schema, the description covers purpose, checks, cost, billing edge case, and return contents. It lacks only detail on the verdict's shape and failure-mode behavior, which matters because there is no output schema to fall back on.

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 baseline is 3, but the description adds real semantics by mapping params to checks — 'at least min_amount', 'enough confirmations', and the parenthetical that 'from' is optional while 'to' is expected. That clarifies the optionality contract beyond the schema's per-field text.

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?

States a specific verb and resource ('Verify a USDC payment on Base') and enumerates exactly what is checked: tx success, recipient/sender match, min_amount, confirmations. This clearly separates it from siblings like usdc_balance (balance read) or x402_probe (endpoint probing).

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 implied (verify a payment before trusting it) and the billing rule 'Unknown tx = not charged' tells the agent it is safe to call speculatively, but there is no explicit when-to-use or when-not-to-use versus usdc_balance / x402_probe / sanctions_crypto_address.

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