check_sellerBefore paying an x402 seller on Robinhood Chain, check its address against Fivebar's wash screen: whether it's among the sellers whose payments passed in the last 24 hours, its buyers and volume, and its agent record if it's a registered agent.
| Name | Required | Description | Default |
|---|---|---|---|
| address | Yes |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds real value beyond that by naming the data source (Fivebar's wash screen) and the specific signals returned – 24h payment pass status, buyers, volume, and conditional agent record – which tells the agent this is a reputational screen, not a balance lookup. Return shape and latency are not described.
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?
One sentence, zero filler, with the use-case trigger placed first and the returned signals following. Every clause carries information the agent needs.
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?
No output schema exists, so the description must convey what comes back – and it does, listing the pass status, buyer/volume metrics, and agent record. What's missing is how to interpret an absent/failed screen result and the address format expected, which matters for a one-parameter decision tool.
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 description coverage is 0% for the single required 'address' parameter. The description partially compensates by framing it as the seller's address to be screened, but it never states expected format (hex address vs ENS-style name), which chain, or whether it must be a seller that has already transacted.
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 (check) and resource (an x402 seller's address on Robinhood Chain) and enumerates what is inspected: 24h payment pass status, buyers, volume, agent record. That scoping separates it from generic siblings like token_risk or wallet_holdings, though it does not explicitly say how it differs from agent_lookup despite overlapping on 'agent record'.
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 trigger is explicit and front-loaded: 'Before paying an x402 seller on Robinhood Chain.' That tells the agent exactly when to reach for it. It stops short of naming alternatives or stating when-not-to-use (e.g., for non-x402 addresses or plain token risk).
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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