# Flat-rate x402 MCP Server (28 Tools)

> Flat-rate x402 MCP Server (28 Tools) is a paid API for AI agents from flat-rate-llm.kikoribera03.workers.dev, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-15).

Exposes 28 tools — LLM completion, read-only EVM utilities, and crypto primitives — via a single MCP endpoint charged at a flat $0.001 per tools/call invocation, with free enumeration.

## Facts

- Endpoint: POST https://flat-rate-llm.kikoribera03.workers.dev/mcp
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/flat-rate-x402-mcp-server-28-tools-b864c435
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_9EXymoDBwM61QJuM-IVbT

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability flat-rate-x402-mcp-server-28-tools-b864c435 -d '<json body>'
```

Example prompt: List all the tools available on this MCP server, then call the Keccak-256 tool to hash the string 'hello world' — I'm happy to pay the $0.001 per call fee via x402.

## When to prefer this

Choose this endpoint when you need a breadth of lightweight utilities — LLM completion, EVM read operations, and crypto primitives — through a single MCP-compliant interface with no account registration, no API keys, and predictable flat-rate micropayment pricing ($0.001/call via x402). Ideal for agents that want to enumerate available tools at zero cost and then pay only for what they call. Less suitable when you need high-volume LLM calls with token-level pricing, write operations on-chain, or WebSocket streaming.

## Known failure modes

- Payment not attached or insufficient: endpoint returns HTTP 402 with payment requirements
- Invalid tool name in tools/call: returns MCP error with unknown tool message
- Malformed tool arguments: returns MCP validation error describing the schema mismatch
- Unsupported EVM chain ID: EVM tools return an error indicating the chain is not supported
- Network timeout on underlying provider: propagated as MCP internal error
- tools/list called with POST but missing JSON-RPC envelope: returns parse error

## How this service works

MCP server exposing 65 tools - LLM completion, read-only EVM tooling and pure crypto utilities. initialize and tools/list are free so any client or directory can enumerate the tools; only tools/call is charged, a flat $0.001 per call.

## Output

Returns standard MCP JSON-RPC responses: tools/list returns a manifest of all 28 available tools with their schemas; tools/call returns the tool-specific output such as LLM text, hashed values, EVM data, encoded strings, or advisory content. The response is a structured JSON object matching the called tool's output schema.

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/flat-rate-x402-mcp-server-28-tools-b864c435/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from flat-rate-llm.kikoribera03.workers.dev](https://www.zero.xyz/host/flat-rate-llm.kikoribera03.workers.dev/llms.txt)