X402 Discovery MCP vs Rhumb
A side-by-side look at the X402 Discovery MCP and Rhumb MCP servers: transport, auth, tools, quality signals, and the config to install either one in Claude, Cursor, Windsurf or VS Code.
Verdict: choose X402 Discovery MCP for aggregators work as a local process; choose Rhumb for aggregators as a local process. You can also run both side by side in one mcpServers block.
Which MCP server should you choose?
Choose X402 Discovery MCP when
- You need dedicated capabilities in the Aggregators domain.
- You prefer a local stdio subprocess transport.
- Its auth model fits you: API key required.
- You want tools like
x402_discover, x402_health, x402_register.
Choose Rhumb when
- You need dedicated capabilities in the Aggregators domain.
- You prefer a local stdio subprocess transport.
- You have the keys it needs:
RHUMB_API_KEY. - You want tools like
find_services, get_score, get_alternatives.
Feature & specification comparison
Rows where the two servers differ are marked.
| Spec | ||
|---|---|---|
| Category | Aggregators | Aggregators |
| Quality signal | 53/100 · Good | 64/100 · Good |
| Install command | Confirmed | Confirmed |
| Transport | Local subprocess (stdio) | Local subprocess (stdio) |
| Auth | API key required | Not declared |
| Pricing | Freemium | Not declared |
| Required env vars | None listed | RHUMB_API_KEY |
| Verified owner | Community listing | Community listing |
| GitHub stars | 4 | 4 |
| Directory activity | 2 views 0 installs 0 upvotes | 2 views 0 installs 0 upvotes |
| Tools | 9 | 21 |
| Full listing | View X402 Discovery MCP | View Rhumb |
Tools & capabilities
X402 Discovery MCP tools 9
x402_discoverSemantic search across the live catalog by keyword, category, max pricex402_healthReal-time uptime + latency check for any registered servicex402_registerRegister a new x402 service (HTTPS-only, rate-limited)x402_attestERC-8004 trust score and reputation signals for a servicex402_scanFull x402 compliance scan: live config, trust score, mismatch detectionscout_routeDiscover best service for an intent + execute x402 paymentscout_discoverQuery discovery catalog without executingscout_executeExecute x402 payment to a known service URLscout_auditView agent spend log and budget status
Rhumb tools 21
find_servicesSearch indexed Services by what you need them to do. Returns ranked Services with AN Scores. Use this when you know the problem but not which Service to call. For Capability-level search (e.g. 'email.send'), use discover_capabilities instead.get_scoreGet the full AN Score breakdown for a Service: execution quality, access readiness, autonomy level, tier label, and freshness. Use after find_services to evaluate a specific Service.get_alternativesFind alternative Services, ranked by AN Score. Use when a Service doesn't meet your needs or you want to compare options in the same category.get_failure_modesGet known failure patterns, impact severity, and workarounds for a service. Use BEFORE integrating to write defensive code, or AFTER hitting an error to diagnose it.discover_capabilitiesBrowse Capabilities by domain or search text. A Capability is an action (e.g. 'email.send', 'payment.charge') that multiple providers can fulfill. Use this when you know WHAT you need to do but not which Service does it. Returns Capability IDs for resolve_capability. Different from find_services: find_services searches Services, this searches Capabilities.resolve_capabilityGiven a Capability ID, and optionally a credential mode, returns ranked providers with health status, cost per call, auth methods, endpoint patterns, execute guidance, and machine-readable recovery fields like recovery_hint.resolve_url, recovery_hint.credential_modes_url, and, when applicable, recovery_hint.alternate_execute_hint or recovery_hint.setup_handoff, plus typo recovery when the capability ID is wrong. If the capability ID is wrong, returns a capability search URL plus suggested capabilities instead of a blank dead end. This is the core routing decision: 'I need email.send, and maybe a specific credential mode, which provider or recovery handoff should I use?' Call this before execute_capability to understand your options.execute_capabilityCall a Capability through Rhumb Resolve. Typical workflow: discover_capabilities → resolve_capability → estimate_capability → execute_capability. Default credential mode is auto: Rhumb uses Rhumb Resolve when an active managed config exists, otherwise falls back to byok. Legacy 'byo' is still accepted as an input alias. Other explicit modes: rhumb_managed — zero-config through Rhumb Resolve when available; byok — BYOK via agent_token + method + path; agent_vault — use a key from credential_ceremony via agent_token + method + path. Alternative: pass x_payment for a per-call USDC payment with no account needed. Use check_credentials to inspect live readiness globally or for a specific Capability before choosing a rail.estimate_capabilityEstimate the active execution rail, cost, and health before a Capability call; anonymous direct system-of-record paths also preserve machine-readable execute_readiness handoffs. Returns cost in USD, circuit health, and endpoint pattern. Default credential mode is auto: Rhumb uses Rhumb Resolve when an active managed config exists, otherwise falls back to byok. Legacy 'byo' is still accepted as an input alias. Always call this before execute_capability for cost-sensitive workflows — no charge for estimates.credential_ceremonyGet step-by-step instructions to obtain API credentials for a Service. Returns signup steps, expected token format (prefix, pattern), verification endpoint, estimated time, and whether human intervention is needed. Use before calling in agent_vault mode. Call without params to list all Services with available ceremonies.check_credentialsInspect live credential-mode readiness, globally or for a specific Capability. Call without params to see which BYOK bridges or direct bundles are already configured and which Capabilities are ready now through Rhumb-managed rails. Pass a Capability to inspect provider-level mode status, configured readiness, and ceremony availability for that specific path.budgetCheck or set your call spending limit. Budgets are enforced BEFORE a call — you get HTTP 402 (not a surprise bill) when you'd exceed your limit. Call with no params to check current budget and remaining balance.spendGet your spending breakdown for a billing period: total USD spent, call count, average cost per call, broken down by Capability and by provider. Use to audit costs or optimize routing.- +9 more on the listing page
Ready-to-paste client configs
Paste either block (or both) into your client config, e.g. claude_desktop_config.json or ~/.cursor/mcp.json. We only show a config when the install command is confirmed.
X402 Discovery MCP
{
"mcpServers": {
"rplryan-x402-discovery-mcp": {
"command": "uvx",
"args": [
"x402-payment-harness"
]
}
}
}
Rhumb
{
"mcpServers": {
"supertrained-rhumb": {
"command": "npx",
"args": [
"-y",
"--package",
"rhumb-mcp@latest",
"rhumb-mcp"
],
"env": {
"RHUMB_API_KEY": "YOUR_RHUMB_API_KEY_HERE"
}
}
}
}
Frequently asked questions
X402 Discovery MCP is categorized under Aggregators and uses a local stdio subprocess. Rhumb belongs to Aggregators and uses a local stdio subprocess. Pick X402 Discovery MCP for aggregators work and Rhumb for aggregators.
Copy the mcpServers block from the config section on this page into your client's config (for example claude_desktop_config.json or ~/.cursor/mcp.json), then fully restart the client.
X402 Discovery MCP is listed as freemium — a free tier with paid plans. Auth: api key required. Rhumb has no declared pricing — check the project's own site. If a server needs environment variables such as API keys, define them under the env key in your client's MCP config.
Yes. MCP clients support multiple servers: add rplryan-x402-discovery-mcp and supertrained-rhumb as separate keys in the same mcpServers object, and your assistant will call tools from either one.
On AllMCPs, X402 Discovery MCP has a quality signal of 53/100 (Good) with 2 views, 0 installs and 4 GitHub stars. Rhumb has 64/100 (Good) with 2 views, 0 installs and 4 GitHub stars.