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evidai

πŸ‹ LemonCake β€” drop-in USDC billing for any API Β· monetize in 1 line Β· x402 + MCP

by evidai
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TypeScript
Remote

Server Configuration

Describes the environment variables required to run the server.

NameRequiredDescriptionDefault

No arguments

Capabilities

Features and capabilities supported by this server

CapabilityDetails
tools
{}
logging
{}
prompts
{}

Tools

Functions exposed to the LLM to take actions

NameDescription
setup

Show the LemonCake MCP first-run setup guide. No authentication required. Call this tool FIRST to learn what is missing and how to obtain a permit.

If LEMON_CAKE_PERMIT is not set, the server is in DEMO MODE: list_services returns 8 free demo services (search / echo / fx / translate / weather / geocode / time / dictionary) powered by real upstreams (Wikipedia, httpbin, Open-Meteo, Nominatim, etc.). call_service and check_balance respond with mock data so you can verify integration before signing.

Returns the current credential status (permit presence), demo-mode flag, and step-by-step instructions for getting a permit at /start/v2, including a sample MCP client config snippet ready to paste.

Returns: { version, apiUrl, mode, credentials, availableTools, setupSteps, permitUrl, docs } Errors: none β€” this tool always succeeds.

list_services

List approved API services available on the LemonCake marketplace. No authentication required.

Use this BEFORE call_service to discover serviceId values and per-call USDC pricing.

When LEMON_CAKE_PERMIT is missing, 8 demo services are prepended: demo_search β†’ Wikipedia opensearch demo_echo β†’ httpbin.org/anything demo_fx β†’ live FX rates (open.er-api) demo_translate β†’ 80+ languages (MyMemory) demo_weather β†’ current weather any lat/lon (Open-Meteo) demo_geocode β†’ place name β†’ lat/lon (OpenStreetMap Nominatim) demo_time β†’ IANA timezone time + DST (worldtimeapi) demo_dictionary β†’ English definitions / synonyms (dictionaryapi.dev) All real upstreams, no auth, free. Live users (permit set) see real marketplace entries; demo_* IDs remain callable directly.

Each item: { id, name, provider, type ('API' | 'MCP'), pricePerCall, [usage], [mode] }. Errors: HTTP-level errors are returned as Error: API <status>: <body>.

call_service

Invoke an upstream API service through LemonCake's pay-per-call proxy. Each successful call automatically debits USDC from your wallet via the permit you signed. LemonCake never holds your USDC β€” the transfer is direct wallet β†’ provider on Base.

PRECONDITIONS: β€’ LEMON_CAKE_PERMIT env var must be set for real services. Get one in ~30 seconds at https://lemoncake.xyz/start/v2 (sign in with Google, sign 1 EIP-712 permit, copy the blob). If missing, the tool returns a structured PERMIT_MISSING error with how-to-fix steps. β€’ DEMO MODE: any serviceId starting with demo_ works WITHOUT a permit and hits real free upstreams (Wikipedia / httpbin / Open-Meteo / Nominatim / MyMemory / dictionaryapi / worldtimeapi / open.er-api). 8 demos cover search / echo / fx / translate / weather / geocode / time / dictionary β€” useful for Glama Inspector or new-user trial. They are marked with mode: "demo" and incur no charge. β€’ serviceId must come from list_services.

BEHAVIOR: β€’ Returns the upstream response body verbatim (JSON or text), plus the X-Charge-Id and X-Amount-Usdc headers reported by the proxy. β€’ HTTP 402 Payment Required is returned as a normal result (NOT thrown) so the agent can autonomously stop spending when the daily $25 permit cap is exhausted. β€’ Pass the same idempotencyKey to retry safely without double-charging. β€’ This tool spends real money and contacts an external service β€” it is non-idempotent by default and has external side effects.

x402-COMPATIBLE INTERFACE: β€’ Successful calls include an x402Receipt field with { scheme, chain, asset, amount, recipient, paymentIntentId, settledAt }. Same shape as on-chain x402 receipts so the agent's payment-handling logic is portable. β€’ If upstream returns an x402 challenge (WWW-Authenticate: x402, X-402-* headers, or body.x402), it's parsed into x402Challenge for the agent to reason about. β€’ If upstream returns 202 + Retry-After + X-Payment-Status: pending, the result is { status: "PAYMENT_PENDING", paymentIntentId, retryAfterMs, retryContract }. Re-call with the same idempotencyKey to resume β€” no double-charge.

Returns: { status, chargeId, amountUsdc, response, x402Receipt?, x402Challenge?, hint? }

check_balance

Check the current on-chain USDC balance of the wallet that owns the configured permit.

PRECONDITIONS: β€’ DEMO MODE (no LEMON_CAKE_PERMIT): returns a canned $1.00 demo balance so trial users see something useful before signing. β€’ LIVE: queries Base USDC.balanceOf(owner) directly + reports remaining daily permit cap. LemonCake's backend doesn't store the balance β€” it's read from the chain.

Use BEFORE call_service to confirm sufficient funds and remaining daily cap.

Returns: { balanceUsdc, dailyCap, remainingToday, ownerAddress, [mode], [note] }

check_tax

Run a Japanese tax compliance check on a single transaction. No authentication required.

Performs three checks in one call:

  1. Validates the qualified-invoice registration number (T-number) against the NTA registry.

  2. Determines whether source-withholding (ζΊζ³‰εΎ΄εŽ) applies based on the service description.

  3. If withholding applies, computes the withholding amount and net payable.

Intended for Japanese corporations that pay AI / API services and need to file withholding correctly under the qualified-invoice (γ‚€γƒ³γƒœγ‚€γ‚ΉεˆΆεΊ¦) regime.

Returns: { invoice: { valid, name, ... }, withholding: { required, rate, amount, net } } Errors: invalid registrationNumber returns invoice.valid = false (not an exception).

get_service_stats

Return public usage statistics for every approved service on the marketplace. No authentication required.

Use this AFTER list_services and BEFORE call_service to pick a service based on real-world traction (call counts, USDC revenue, last-used timestamp).

Returns: an array of { serviceId, callCount, totalRevenueUsdc, lastCalledAt }.

Prompts

Interactive templates invoked by user choice

NameDescription
explore-demo[FREE Β· no auth needed] Walks Claude through all 8 demo services (search, fx, translate, weather, geocode, time, dictionary, echo). Best first step on Glama Inspector to confirm the server is alive and useful even without a permit.
japan-tax-check[FREE Β· no auth needed] Uses the check_tax tool to verify a ι©ζ Όθ«‹ζ±‚ζ›Έη™Ίθ‘ŒδΊ‹ζ₯­θ€…η•ͺ号 against the NTA registry. ChatGPT/Gemini cannot do this β€” they hallucinate registration numbers. Real second demo.
discover-marketplace[FREE Β· no auth needed] Lists every approved service with its category and price. Useful before deciding whether to sign a permit.
spend-with-budget[REQUIRES permit β€” sign one free at lemoncake.xyz/start/v2] Pattern: check_balance β†’ call_service β†’ check_balance again, demonstrating the on-chain daily cap enforced by the permit.
real-vs-demo[FREE for demo half Β· permit needed for real half] Hits the same logical query against demo_search (Wikipedia, free) and a real marketplace search service to see the difference. Gracefully skips the paid half if no permit is set.
japan-finance-bundle[REQUIRES permit for gBizINFO + e-Gov Β· check_tax part is free] Combines gBizINFO 法人情報 + ε›½η¨ŽεΊ invoice check + e-Gov 法什 in one workflow.

Resources

Contextual data attached and managed by the client

NameDescription

No resources

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