Tutorials, comparisons and design patterns for building autonomous agents that self-fund, call 345+ models and orchestrate MCP Tools.
The default agent wallet is an EOA, and an EOA key has one spending limit: everything. This is a deep dive into the on-chain layer that fixes it — ERC-4337 smart accounts, session keys, the ERC-7715/7710 permission standards, Coinbase Spend Permissions, paymasters that pay gas in USDC, and the asset-enforced spend mandate on the horizon.
A2A carries the message, AP2 shapes it, x402 settles it. The A2A x402 extension wires the three together with a five-state payment machine over the A2A Task lifecycle. We read the v0.1 spec: identifiers, data structures, metadata keys, and the security rules that keep private keys away from the model.
MCP's authorization specification makes remote servers OAuth 2.1 resource servers and clients OAuth 2.1 clients. We walk the 401 discovery flow, RFC 9728 Protected Resource Metadata, RFC 8707 resource indicators, the confused-deputy prohibition, and what it all means for agents that pay per call.
x402 gets the headlines, but the real work happens one layer down. EIP-3009's transferWithAuthorization is the signed authorization that moves stablecoins gaslessly. We read the spec, the typehashes, the front-running trap, and where the model runs out of room.
Enterprise AI agents fail not because they cannot talk, but because they remember the wrong thing, forget the important thing, or retain what they should delete. Oracle Agent Memory 26.6, released July 10, 2026, introduces full CRUD capabilities for threads, messages, memories, and profiles—built on an in-database architecture that eliminates vector database round-trips.
Darktrace reports 92% of security professionals are concerned about AI agent impact. Gravitee finds 48% of production agents run unsecured. Mastercard launches Agent Pay for Machines with 40+ partners including Aave, Coinbase, Polygon, and Solana. Open USD (OUSD) launches June 30 with 140+ partners, challenging Circle and Tether. MiCA enforcement begins July 1 across Europe. The infrastructure for autonomous agent payments is being built in real time.
MCP 2026-07-28 is the protocol's biggest architectural change since launch. Going stateless removes the initialize handshake, enables horizontal scaling, and introduces Multi Round-Trip Requests. This post explains the changes and what they mean for LLM4Agents and autonomous agent infrastructure.
A plain-prompt eval stops measuring your agent at the exact moment the agent starts doing its job: the first tool call. This tutorial wraps the LLM4Agents conversation loop in a Promptfoo custom provider — about forty lines of TypeScript — so the eval exercises the real thing: system prompt, MCP allowlist, tool rounds, and settled cost. It covers the three asserts that catch real agent regressions (did it use the tool, did it stay within its round budget, did it repeat itself), wires the suite into GitHub Actions so a prompt edit that breaks retrieval fails the PR, and addresses the elephant in the runner: Promptfoo is now owned by OpenAI, and why that is acceptable for this stack.