memory-mcp — persistent memory for AI agents, paid per call via x402

Persistent, semantically-searchable memory for AI agents, exposed over the Model Context Protocol (MCP) and plain HTTP, paid per call via x402 in USDC on Base mainnet. There are no accounts and no API keys — your wallet address is your namespace, so any agent that can sign an x402 payment can write and recall memory across sessions, hosts, and frameworks. A free trial tier and owner-signed EIP-712 grants for sharing a namespace across agents are described below.

mem.borisinc.com/mcp (streamable HTTP MCP) · Base mainnet USDC · facilitator: xpay

Your wallet is your memory: every paid call is namespaced to the paying wallet. No accounts, no API keys — pay $0.001 and your agent has permanent, semantically searchable memory across sessions, hosts, and frameworks.

Quickstart

Full walkthrough, including a free no-wallet trial (5 records, 24h, IP-scoped, not private) you can hit before bringing a wallet: https://mem.borisinc.com/quickstart

MCP endpoint (streamable HTTP): https://mem.borisinc.com/mcp

Related MCP server: tartarus-mcp

Shared namespaces (EIP-712 grants)

A namespace owner can delegate read/write/rw access to another agent by signing an EIP-712 Grant (namespace, grantee, mode, expires) — build the payload with GET /grant/payload?namespace=&grantee=&mode=read|write|rw&days=30, then have the grantee attach on_behalf=<owner>&grant=<base64 blob> to its own paid calls. Grants are capped at 90 days and use EOA signatures in v1 — this lets, for example, a research agent write into a shared namespace that an execution agent reads from, without ever handing over the owner's key.

Namespaces also support ERC-8004 agent-keyed addressing (agent:8453:<id>), so memory can survive wallet rotation for a registered on-chain agent.

Free wallet-keyed tier (zero payment, real memory)

An agent gets real, private, persistent memory with zero payment by proving wallet ownership instead of paying: GET /free/memory/write and GET /free/memory/search take header X-Wallet-Auth: <base64 JSON {address,ts,signature}> where signature is an EIP-191 personal_sign of borismem-free:<address>:<ts> (ts within 600s). MCP tools memory_write_free / memory_search_free take the same base64 blob as a wallet_auth arg. This writes into the same namespace your paid calls use — the free tier fills the real memory, not a side namespace. Capped at 1000 writes + 500 searches per wallet per rolling 30 days (counted from memory-calls.db); over cap returns 402 with a pointer to the paid tier or /subscribe. The IP-keyed /trial/* tier (5 records, 24h, not private) is unchanged and still exists for agents that haven't got a wallet yet.

MCP registry

Registered on the MCP registry as com.borisinc/memory (https://mem.borisinc.com/mcp, streamable-http).

Ops: memory-mcp.service :8407, ledger memory-calls.db, store memories.db, embeddings via donk GPU (1024-dim). Test client: mcp_buyer.py.