Rhumb MCP Server
Agent-native tool intelligence for the Model Context Protocol.
Three execution layers: raw provider access (Layer 1), intelligent routing (Layer 2), and deterministic composed recipes (Layer 3, beta with a truthful public catalog). Every provider rated with the AN Score. Every execution produces a chain-hashed receipt.
Zero-config quickstart
No governed API key needed for discovery. Install and start immediately:
npx -y --package rhumb-mcp@latest rhumb-mcp
Or add to Claude Desktop / Cursor / any MCP client:
{
"mcpServers": {
"rhumb": {
"command": "npx",
"args": ["-y", "--package", "rhumb-mcp@latest", "rhumb-mcp"]
}
}
}
Ask your agent:
- "Find me the best email API for agents"
- "What's the AN Score for Stripe?"
- "Check whether any Rhumb recipes are published yet"
Current callable scope
Rhumb is strongest today for research, extraction, generation, and narrow enrichment.
Treat it as capability infrastructure first, not as a general business-agent automation layer yet. Layer 2 is the real production surface today; Layer 3 is still beta with an intentionally sparse public catalog.
Discovery breadth is wider than current execution breadth: Rhumb scores 999 services and exposes 435 capability definitions, but current governed execution is concentrated in 28 callable providers.
Resolve mental model
- Service = vendor Rhumb evaluates and compares
- Capability = executable action your MCP client can route and execute
- Recipe = deterministic multi-step workflow on top of capabilities (beta, sparse public catalog)
- Layer 2 is the default path — discover → resolve → estimate → execute
- Default auth for repeat traffic = governed API key or wallet-prefund on
X-Rhumb-Key
- Bring BYOK or Agent Vault only when provider control is the point
- Use x402 only when zero-signup per-call payment is the point
Canonical onboarding map: https://rhumb.dev/docs#resolve-mental-model
What's new in v2.0.0
Rhumb Resolve — three execution layers:
| Layer | What | How |
|---|
| Layer 1 | Raw provider access | You pick the provider. Escape hatch + trust anchor. |
| Layer 2 | Capability routing | Rhumb routes to the best-fit supported provider for the call, using AN Score, availability / circuit state, estimated cost, latency proxy, credential mode, and explicit policy constraints. |
| Layer 3 | Deterministic recipes (beta) | Compiled DAG workflows. Multi-step, budget-enforced, content-firewalled. No published recipes yet. |
New infrastructure:
- Execution receipts (chain-hashed, HMAC-signed)
- Route explanations (why this provider was chosen)
- AN Score structural separation (read-only cache, auditable)
- Billing event stream (chain-hashed, 15+ event types)
- Trust dashboard inputs for observed availability, costs, and reliability
- Recipe safety controls (content firewall, idempotency, nesting depth, fan-out rate limiting)
- Kill switches (per-agent, per-provider, per-recipe, global with authenticated two-person auth)
- Audit trail (append-only, chain-hash verification, export API)
Migration from 0.x
- All v1 endpoints remain fully backward compatible — no breaking changes
- New v2 endpoints available alongside v1
execute_capability now returns _rhumb_v2 metadata with attribution and receipts- New tools for recipe-catalog inspection, receipts, and telemetry
- Update:
npx -y --package rhumb-mcp@latest rhumb-mcp
| Tool | What it does |
|---|
find_services | Search indexed Services by what you need them to do |
get_score | Get the full AN Score breakdown for a Service: execution quality, access readiness, autonomy level, tier label, and freshness |
get_alternatives | Find alternative Services, ranked by AN Score |
get_failure_modes | Get known failure patterns, impact severity, and workarounds for a service |
discover_capabilities | Browse Capabilities by domain or search text |
resolve_capability | Given 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 |
{
"mcpServers": {
"rhumb": {
"command": "npx",
"args": ["-y", "rhumb-mcp@latest"],
"env": {
"RHUMB_API_KEY": "rk_your_key_here"
}
}
}
}
Get a governed API key at https://rhumb.dev/auth/login (GitHub, Google, or email — 30 seconds).
| Tool | What it does |
|---|
execute_capability | Call a Capability through Rhumb Resolve |
estimate_capability | Estimate the active execution rail, cost, and health before a Capability call; anonymous direct system-of-record paths also preserve machine-readable execute_readiness handoffs |
credential_ceremony | Get step-by-step instructions to obtain API credentials for a Service |
check_credentials | Inspect live credential-mode readiness, globally or for a specific Capability |
rhumb_list_recipes | List the current published Rhumb Layer 3 recipe catalog |
rhumb_get_recipe | Get the full published definition for a Rhumb recipe, including input/output schemas and step topology |
rhumb_recipe_execute | Execute a published Rhumb Layer 3 recipe once one is live in the public catalog |
get_receipt | Retrieve an execution receipt by ID |
| Tool | What it does |
|---|
budget | Check or set your call spending limit |
spend | Get your spending breakdown for a billing period: total USD spent, call count, average cost per call, broken down by Capability and by provider |
check_balance | Check your current Rhumb credit balance in USD |
get_payment_url | Get a checkout URL to add credits to your Rhumb balance |
get_ledger | Get your billing history: charges (debits), top-ups (credits), and auto-reload events |
| Tool | What it does |
|---|
routing | Get or set how Rhumb auto-selects providers when you don't specify one in execute_capability |
usage_telemetry | Get your execution analytics — calls, latency, errors, costs, and provider health for your Rhumb usage |
Discovery (free): find_services, get_score, get_alternatives, get_failure_modes, discover_capabilities, resolve_capability
Execution (auth): execute_capability, estimate_capability, credential_ceremony, check_credentials, rhumb_list_recipes, rhumb_get_recipe, rhumb_recipe_execute, get_receipt
Financial (auth): budget, spend, check_balance, get_payment_url, get_ledger
Operations (auth): routing, usage_telemetry
Discovery spans 999 scored services, but current governed execution spans 28 callable providers.
Best current fit: research, extraction, generation, and narrow enrichment. Treat general business-agent automation as future scope, not the current callable promise.
Common workflows
"I need an email provider for agents."
find_services → search the landscapeget_score → inspect a specific providerget_failure_modes → see where it breaks in practice
2) Route a capability (no auth)
"I need email.send. What should I use?"
discover_capabilities → find the capability IDresolve_capability → get ranked providers, optional credential-mode filtering, 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, or search suggestions when the capability ID is wrong
3) Check readiness (auth required)
"Can I call deployment.list right now, and on which rail?"
check_credentials → call without params for account-wide configured BYOK/direct-bundle readiness, or pass a capability to inspect provider-level mode status and ceremony availability
4) Execute (auth required)
"Send the email with the cheapest provider above my quality floor."
estimate_capability → check the active execution rail, health, and cost before executionexecute_capability → perform the actionget_receipt → verify the HMAC-signed execution record
5) Check recipe availability / run a recipe (auth required)
"Is there already a published Rhumb workflow for this?"
rhumb_list_recipes → check what is actually live in the public catalogrhumb_get_recipe → inspect a recipe only after it appears thererhumb_recipe_execute → run the compiled recipe once it is published- Public note: the Layer 3 catalog is currently sparse/empty, so most real work should use Layer 2 capabilities today
x402 micropayments
No account needed — pay per call with USDC on Base:
{
"env": {
"RHUMB_X402_WALLET_ADDRESS": "0x...",
"RHUMB_X402_PRIVATE_KEY": "0x..."
}
}
Local development
cd packages/mcp
npm ci
npm run dev
Test and build
npm test
npm run type-check
npm run build
License
MIT