---
title: SDK Agents
description: Provider-backed AI SDK agent wrappers for Anthropic and OpenAI that work like first-class Smithers agents.
---

`AnthropicAgent` and `OpenAIAgent` are thin wrappers around the [AI SDK](https://ai-sdk.dev) `ToolLoopAgent` with class-style ergonomics matching the [CLI agents](/integrations/cli-agents).

## Import

```ts
import {
  AnthropicAgent,
  OpenAIAgent,
  tools,
} from "smithers-orchestrator";
import { stepCountIs } from "ai";
```

## Quick Start

```ts
const claude = new AnthropicAgent({
  model: "claude-opus-4-6",
  tools,
  instructions: "You are a careful planner.",
  stopWhen: stepCountIs(40),
});

const codex = new OpenAIAgent({
  model: "gpt-5.3-codex",
  tools,
  instructions: "You are a precise implementation agent.",
  stopWhen: stepCountIs(40),
});
```

```tsx
{/* outputs comes from createSmithers() */}
<Task id="plan" output={outputs.plan} agent={claude}>
  Analyze the repository and propose a migration plan.
</Task>
```

## Model Input

Both classes accept a model ID string (`"claude-opus-4-6"`, `"gpt-5.3-codex"`) or a prebuilt AI SDK language model instance.

## Options

Constructors forward standard AI SDK `ToolLoopAgent` settings:

- `instructions`
- `tools`
- `stopWhen`
- `maxOutputTokens`
- `temperature`
- `providerOptions`
- `prepareCall`

The only addition is `model`: the wrapper resolves model-ID strings automatically.

## Hijack Support

SDK agents do not reopen a provider-native CLI. Smithers persists the agent conversation and reopens it through a Smithers-managed REPL via `smithers hijack <runId>`.

Live-run behavior:

- Smithers captures response history after each step via `onStepFinish`.
- `smithers hijack` waits until history is durable, cancels the live run, and opens the REPL.
- On clean REPL exit, Smithers writes updated message history back and resumes the workflow automatically.

Limits:

- Conversation hijack stays on the same agent implementation. Cross-engine hijack is not supported.
- Smithers reconstructs the original task agent from the workflow source.

## CLI vs SDK

| | CLI Agents | SDK Agents |
|---|---|---|
| Billing | Provider subscription / local CLI | API billing |
| Tools | Provider CLI tool ecosystem | Smithers [tools](/integrations/tools) [sandbox](/components/sandbox) |
| Flexibility | Native CLI flags | AI SDK `providerOptions` |

Pass a raw `ToolLoopAgent` directly if you prefer. The wrappers are convenience, not a separate runtime.

## Example: Dual Setup

```ts
const useCli = process.env.USE_CLI_AGENTS === "1";

export const claude = useCli
  ? new ClaudeCodeAgent({
      model: "claude-opus-4-6",
      dangerouslySkipPermissions: true,
    })
  : new AnthropicAgent({
      model: "claude-opus-4-6",
      tools,
      instructions: "You are a careful planner.",
      stopWhen: stepCountIs(40),
    });
```

## Next Steps

- [CLI Agents](/integrations/cli-agents)
- [Built-in Tools](/integrations/tools)
- [Agents and Tools](/concepts/agents-and-tools)