agent-utils-mcp is a "Swiss Army knife"-style utility server for AI agents, exposing 18 tools via both MCP (Streamable HTTP) and REST API. The project was developed by aparajithn, with the code hosted on GitHub, and the online service address is https://agent-utils-mcp.onrender.com。
Purpose The project aims to provide AI agents with a set of commonly used foundational tool capabilities, including JSON validation, base64 encoding/decoding, hash computation, UUID generation, regular expression testing, Markdown conversion, date-time conversion, cron expression parsing, and JWT decoding. These tools are exposed as an MCP server and REST API, making it easy for agents to call them directly during task execution.
Main capabilities
- Provides 18 tools, covering common development and operations scenarios such as data validation, encoding conversion, hashing, identifier generation, regex testing, text and time format conversion, cron parsing, and JWT decoding.
- Supports both MCP (Streamable HTTP) and REST API access methods. All tools can also be accessed via REST endpoints, with the path format /api/v1/{tool_name}.
- Provides OpenAPI documentation (https://agent-utils-mcp.onrender.com/docs）、Google A2A agent card (/.well-known/agent-card.json), Smithery server card (/.well-known/mcp/server-card.json), and OpenAPI specification (/openapi.json).
Usage
- Add this server to the MCP configuration of an MCP client (such as Claude Desktop, Cursor, Windsurf) to use it.
- You can also call the REST endpoint /api/v1/{tool_name} directly.
- Free quota: each IP can make 100 free requests every 24 hours.
- Payment method: after exceeding the free quota, the server returns HTTP 402 and a machine-readable payment requirement (x402 v1). Any client that supports x402 can automatically pay and retry. The price is approximately 0.001 USDC per request (Base network).
- Manual payment: a base64-encoded JSON envelope must be included in the X-Payment request header, containing an EIP-3009 TransferWithAuthorization signed with the payer's EIP-712 key (USDC on Base), with the amount required to match exactly, the recipient being the server wallet, and the nonce unused. The server performs cryptographic verification before processing the request (signature recovery as well as amount, recipient, deadline, and replay checks).
- Payment settlement: after setting X402_SETTLER_PRIVATE_KEY, each verified payment is executed on-chain within seconds, submitting the EIP-3009 transferWithAuthorization to the USDC contract on Base, with USDC transferred from the payer to X402_WALLET_ADDRESS. The settlement key does not need to be the key of the receiving wallet, because an EIP-3009 authorization can be executed by any address, so a dedicated gas-only ephemeral key can be used to submit it, while the funds still go to the main wallet; that key only needs to hold a small amount of ETH on Base for gas. Failed settlements are retried with exponential backoff; if all retries fail, the full payment authorization is written to the log (CRITICAL) so it can be manually redeemed, and payments are not silently lost.
Tech stack and deployment
- Python 3.11 + FastAPI + MCP SDK (Streamable HTTP).
- Deployed on Render (automatic scaling).
Use cases Suitable for developers who need to quickly integrate common tool capabilities for AI agents, especially when building agent applications in the MCP ecosystem, where multiple practical tools can be called through a unified interface and billed by usage via x402 micropayments.
Limitations
- The free quota is 100 requests per IP every 24 hours; payment is required after exceeding it.
- Paid usage uses USDC (Base network), requiring an x402-supporting client or manually constructing the payment header.
- The specific input/output formats, parameter details, and error codes for each tool are not yet provided in the materials.
