Which x402 facilitators actually settle payments, measured by probing each with a real signed EIP-3009 payload. Tells you which are keyless, which need API keys, which are testnet-only and which are unreachable. Free. Use before choosing a facilitator.
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the responsibility for behavioral transparency. It discloses the probing method with real signed EIP-3009 payloads, states that the tool is free, and describes the classification outcomes. It does not mention potential side effects or failure modes, but is honest about its active probing nature.
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 two punchy sentences that front-load the core purpose and method, then add actionable context about cost and use timing. Every clause earns its place, with no redundancy or filler.
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 no-parameter, no-output-schema tool, this description is surprisingly complete: it states what it does, how it does it, what result categories to expect, and when to use it. Nothing essential is missing for an agent to decide whether to call it.
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?
The tool has zero parameters and the schema is empty, so the baseline of 4 applies. The description does not need to explain parameters, and it compensates by describing what the tool measures and returns.
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 the tool's purpose: determining which x402 facilitators actually settle payments. It specifies the method (probing with a real signed EIP-3009 payload) and the distinct output categories (keyless, API-key, testnet-only, unreachable), making it easy to distinguish from sibling merchant- and gas-focused tools.
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 explicitly says 'Use before choosing a facilitator,' giving a clear when-to-use directive. It does not explicitly name when not to use it or mention specific alternatives, but the facilitator-focused scope is enough to guide an agent.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.
Each tool targets a distinct aspect of the x402 ecosystem: endpoint liveness, deep merchant audit, facilitator comparison, gas pricing, market analytics, and verified merchant listings. There is no real overlap between tools.
All tools share the x402_ prefix and snake_case, but only audit_merchant and check_endpoint follow a verb_noun pattern. The remaining tools are noun phrases like gas_price, market_stats, and verified_merchants, making the naming conventions mixed yet still readable.
Six tools is well-scoped for an ecosystem intelligence server. Each tool fills a distinct niche and none feel redundant or superfluous.
The tool set covers the entire discovery and research workflow for the x402 economy: checking endpoints, finding verified merchants, auditing merchant trustworthiness, choosing facilitators, estimating gas costs, and assessing market viability. No obvious dead ends or critical gaps.