Lesson 2: Multi-Provider

Run the same task with Claude, Codex, and Gemini — the client code stays the same

What You’ll Learn

How to run the exact same goal with three different providers. The model construction changes, but AgentClient usage is identical.

The Pattern

Provider-specific code is isolated to model construction. Everything after AgentClient.create(model) is portable:

// Provider-specific: build the model
AgentModel model = buildModel(provider);

// Portable: same code regardless of provider
AgentClient client = AgentClient.create(model);
AgentClientResponse response = client.run("Create hello.txt with 'Hello!'");

Step 1: Run with Claude

ClaudeAgentModel model = ClaudeAgentModel.builder()
    .defaultOptions(ClaudeAgentOptions.builder()
        .model("claude-sonnet-4-5")
        .yolo(true)
        .build())
    .build();

AgentClient client = AgentClient.create(model);
AgentClientResponse response = client.run(
    "Create a file named hello.txt with 'Hello from Claude!'"
);

Step 2: Run with Codex

Swap the model — the client code is identical:

CodexAgentModel model = new CodexAgentModel(
    CodexClient.create(),
    CodexAgentOptions.builder()
        .model("gpt-5-codex")
        .skipGitCheck(true)
        .build(),
    null
);

AgentClient client = AgentClient.create(model);
AgentClientResponse response = client.run(
    "Create a file named hello.txt with 'Hello from Codex!'"
);

skipGitCheck(true) lets Codex work in any directory. Without it, Codex requires a git repository. See Codex Reference for details.

Step 3: Run with Gemini

GeminiAgentModel model = new GeminiAgentModel(
    GeminiClient.create(),
    GeminiAgentOptions.builder()
        .model("gemini-2.5-flash")
        .yolo(true)
        .build(),
    null
);

AgentClient client = AgentClient.create(model);
AgentClientResponse response = client.run(
    "Create a file named hello.txt with 'Hello from Gemini!'"
);

What Stayed the Same

Across all three providers, these two lines are identical:

AgentClient client = AgentClient.create(model);
AgentClientResponse response = client.run(goal);

The only difference is which model you construct. That’s the portable API — AgentClient doesn’t know or care which provider is behind it.

Provider Differences

While the client API is portable, providers have different capabilities:

Capability	Claude	Codex	Gemini
Non-git directory	Works	Works (skipGitCheck=true)	Works
Structured output	JSON Schema	Not supported	Not supported
Session resume	Supported	Not supported	Not supported
Permission modes	Multiple	full-auto only	yolo only

With Spring Boot

In Spring Boot applications, you don’t construct models manually. Use starter dependencies and Maven profiles to switch providers without changing code at all — see the Switching Providers how-to guide.

Next Steps

• Switching Providers — The Spring Boot profile pattern for zero-code provider switching
• Configuration Reference — All configuration options across providers
• Defaults Philosophy — Why LOOSE mode exists and how it affects each provider