# migrating-openai-agents-sdk-to-pydantic-ai

Guides the step-by-step migration of Python apps from OpenAI Agents SDK to Pydantic AI and Harness. Preserves public contracts, handoffs, and streaming.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 308 installs · ★ 145
- Author: pydantic
- License: MIT · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/pydantic/skills/tree/HEAD/skills/migrating-openai-agents-sdk-to-pydantic-ai/SKILL.md
- Updated: 2026-10-16
- HTML: https://affpapa.org/en/nevibecode/skills/migrating-openai-agents-sdk-to-pydantic-ai

## What it does

The skill starts by inspecting application entrypoints and dependency files. It traces calls to `Runner.run`, `run_sync`, or `run_streamed`, captures baseline behavior with characterization tests, and plans a slice-by-slice refactor. The existing service infrastructure, storage, and external boundaries remain untouched during migration.

It maps source concepts to Pydantic AI primitives. Application state from `RunContextWrapper.context` turns into typed `deps`, while OpenAI handoffs become explicit routing or tool calls. Ordinary agents move to the core `Agent` class, reserving Pydantic AI Harness for specific requirements like subagents, persistence, or sandbox execution with `Coder`.

Projects built directly on the OpenAI Responses API without the Agents SDK runtime cannot use this workflow.

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add pydantic/skills --skill migrating-openai-agents-sdk-to-pydantic-ai -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/migrating-openai-agents-sdk-to-pydantic-ai/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/migrating-openai-agents-sdk-to-pydantic-ai/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add pydantic/skills --skill migrating-openai-agents-sdk-to-pydantic-ai -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/migrating-openai-agents-sdk-to-pydantic-ai/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add pydantic/skills --skill migrating-openai-agents-sdk-to-pydantic-ai -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/migrating-openai-agents-sdk-to-pydantic-ai/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install pydantic/skills migrating-openai-agents-sdk-to-pydantic-ai
```

2. **Manually: put the files in place**
- File: `.github/skills/migrating-openai-agents-sdk-to-pydantic-ai/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add pydantic/skills --skill migrating-openai-agents-sdk-to-pydantic-ai -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/pydantic/skills --path skills/migrating-openai-agents-sdk-to-pydantic-ai
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/migrating-openai-agents-sdk-to-pydantic-ai/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add pydantic/skills --skill migrating-openai-agents-sdk-to-pydantic-ai -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/pydantic/skills/tree/HEAD/skills/migrating-openai-agents-sdk-to-pydantic-ai/SKILL.md

## When to use it
- migrate `agents.Agent` and `Runner` pipelines to Pydantic AI
- convert `RunContextWrapper.context` into typed runtime dependencies
- replace OpenAI handoff semantics with explicit application routing
- adapt human-in-the-loop approvals using `HandleDeferredToolCalls`

## Example prompts
- Migrate our `Runner.run_streamed` implementation in `src/agent.py` to Pydantic AI.
- Refactor agent handoffs to explicit routing without changing caller-visible output.
- Set up `HandleDeferredToolCalls` to replace OpenAI human approval checkpoints.

## Source text · SKILL.md · MIT

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: f73de7bd9bc77fc7.

BEGIN THIRD-PARTY FILE f73de7bd9bc77fc7
```text
---
name: migrating-openai-agents-sdk-to-pydantic-ai
description: Migrate Python OpenAI Agents SDK applications to Pydantic AI and, when warranted, Pydantic AI Harness. Use for `agents.Agent`, `Runner`, function tools, handoffs, guardrails, sessions, human approval, streaming, or `SandboxAgent`. Do not use for applications built directly on the OpenAI Responses API without the Agents SDK runtime.
---

# Migrate OpenAI Agents SDK to Pydantic AI

Preserve caller-visible behavior, not OpenAI Agents SDK object shapes. Migrate the smallest complete runtime slice and leave application infrastructure in place.

## Work from the running application

1. Read repository instructions, dependency files, tests, and runtime entrypoints. Record the installed `openai-agents`, Pydantic AI, and Harness versions.
2. Trace one representative `Runner.run`, `run_sync`, or `run_streamed` call through instructions, context, model settings, tools, handoffs, guardrails, session state, approvals, events, tracing, and the public result. Inspect the callers that consume `final_output`, `last_agent`, `new_items`, `to_input_list()`, interruptions, or streamed events.
3. Establish a deterministic baseline at the existing application boundary. Record only behavior the active path uses.
4. Classify the slice before designing it:
   - **Ordinary agent:** use one reusable Pydantic AI [`Agent`](https://pydantic.dev/docs/ai/core-concepts/agent/) with typed dependencies, tools, and outputs.
   - **Manager with specialists:** use explicit application orchestration, an agent tool, or Harness [`SubAgents`](https://pydantic.dev/docs/ai/harness/subagents/) according to who must own the final response.
   - **Handoff workflow:** first decide whether changing the active agent, its instructions, and the next-turn owner is observable. A nested agent tool is not a handoff.
   - **Sandbox or coding agent:** evaluate Harness [`Coder`](https://pydantic.dev/docs/ai/harness/coder/) and its component capabilities. Choose an execution environment separately; a shell allowlist is not isolation.
   - **Realtime or voice path:** treat transport, interruption, audio, and live-session behavior as a separate migration slice using Pydantic AI [realtime agents](https://pydantic.dev/docs/ai/realtime/overview/).
   - **Product runtime:** retain authentication, storage, queues, deployment, and service integrations unless explicitly placed in scope.
```
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