Agent replaceability

Summary

Demonstrates how SDD standards (MCP, AGENTS.md, Agent Skills, ACP) enable switching between different coding agents and IDEs without changing your workflow. Shows using Codex with migrated skills and ACP Registry for agent installation.

Key Takeaways

• SDD is agent-agnostic: specs operate at a higher level, not tied to any specific agent or IDE
• ACP enables plug-and-play: the Agent Client Protocol makes connecting agents to editors seamless via the ACP Registry
• Standards future-proof your workflow: as new agents and models emerge, your specs and skills remain portable

视频信息：Agent replaceability

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English Script

Spec-Driven Development moves the work from the how to the what and why. Since agents and models progress so fast, you don’t want your workflow tied to just one choice. In this lesson, we see how standards let us switch agents while keeping our workflow and even our tools. These agent standards help for this goal. MCP for external tools, AGENTS.md for rules, Agent Skills for capturing repeatable workflows with extra context, and ACP for connecting agents to clients. For example, Codex is a leading AI agent from OpenAI. It runs in a desktop app and in editors as well as in a terminal. Let’s see it in action. Here is our feature spec skill from lesson 12 copied into Codex, which stores them in a different path. It runs just fine once migrated. This lets you switch back and forth between agents in the same project, keeping your SDD workflow.

We can also use different editors with different agents using the Agent Client Protocol standard. ACP makes it easy to connect agents and editors. If your agent and client support ACP, you have a perfect match. To make this plug and play even easier, the ACP registry automates finding, installing, and connecting agents with their clients. The ACP Registry covers the whole life cycle, making it easier to mix and match. For example, in JetBrains IDEs, the AI Chat window leads to installation from the ACP Registry. The IDE can then show a listing of compatible agents. OpenCode is a popular open source agent. The ACP registry makes it easy to add to our IDE. Clicking install automates both the installation of OpenCode itself if needed, which is nice, and integration into the IDE. Once finished, your IDE now has native integration with a new agent. You can use this new agent alongside the other agents. in your same editor as part of SDD.

These new agent standards are bringing new possibilities, but how do they actually work? The ACP architecture was designed to ease plugging together agents and clients. In fact, the protocol matches what’s used in LSP. ACP is more than you think. For example, it covers Next Edit Suggestion in the editor and plan mode. To go one step further with ACP, you can write your own custom agent, install it locally in your tool. Which agent to choose? The industry changes fast and benchmark sites have sprung up with leaderboards providing different evaluations. Of course, these leaderboards change fast. So make sure to keep up to date and base your decision on the criteria that matter to you. Our specs work at a higher level, not tied to any one agent or IDE. In this lesson, we prove that. We built our workflow and tools to be independent of the agent. As more standards emerge, this flexibility should grow.