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

migrating-openai-agents-sdk-to-pydantic-ai is a skill for Codex from pydantic/pydantic-ai. It costs 87 tokens per session (1,406 once invoked), scanned A, original, MIT.

A migration guide for moving Python applications from the OpenAI Agents SDK, a framework for agents and tool calls, to Pydantic AI. It traces a real run through tools, handoffs, guardrails, sessions, approvals, events, and the result returned to callers.

In plain words
What is it for?
Use it when an application uses OpenAI Agents SDK agents, runners, function tools, handoffs, guardrails, sessions, human approval, streaming, tracing, or sandbox agents.
Why use it?
It helps preserve application behavior instead of reproducing the original framework’s class structure. It also helps decide whether orchestration belongs in normal application code, an agent tool, or a separate agent workflow.

Skill for Codex

Written for Codex: agents/openai.yaml present. Also seen: mentions subagents; installed under .agents/ (shared by several agents).

Good fit Use it when an application uses OpenAI Agents SDK agents, runners, function tools, handoffs, guardrails, sessions, human approval, streaming, tracing, or sandbox agents.

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Install with agentmods
npx agentmods add skills/pydantic/pydantic-ai/migrating-openai-agents-sdk-to-pydantic-ai
About the project

Pydantic AI is a typed Python SDK for building AI agents that can use different language models and interfaces, including voice, image generation, and embeddings. Developers use it for applications ranging from structured data extraction to long-running multi-agent work. The catalogue entries provide workflows and configuration for its coding-agent and harness features.

pydantic/pydantic-ai · 20,645 stars · on GitHub · pydantic.dev

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add pydantic/pydantic-ai --skill migrating-openai-agents-sdk-to-pydantic-ai
Clone the repo
git clone --depth 1 https://github.com/pydantic/pydantic-ai

Made for: Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

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README.md
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Your own site
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Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

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Your own site · 80×15
<a href="https://agentmods.dev/skills/pydantic/pydantic-ai/migrating-openai-agents-sdk-to-pydantic-ai"><img src="https://agentmods.dev/badge/skills/pydantic/pydantic-ai/migrating-openai-agents-sdk-to-pydantic-ai.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 87 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,406 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00087 $0.01406
Opus 5.5 $0.00035 $0.00562
Sonnet 5.5 $0.00017 $0.00281
Haiku 4.5 $0.00009 $0.00141

Measured 1mo ago against content hash a4d08cccc6f6, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

migrating-openai-agents-sdk-to-pydantic-ai scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

Copies of this mod

1 near-identical copy found in the catalogue:

pydantic_ai_slim/pydantic_ai/.agents/skills/migrating-openai-agents-sdk-to-pydantic-ai/SKILL.md · 49 lines

How it starts

The opening of the file, as written. The whole thing — 49 lines — stays where its author put it; the contents beside it link to each section on GitHub.

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 with typed dependencies, tools, and outputs.
    • Manager with specialists: use explicit application orchestration, an agent tool, or 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 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.
    • Product runtime: retain authentication, storage, queues, deployment, and service integrations unless explicitly placed in scope.
  5. Add or preserve characterization tests, migrate one vertical slice behind the existing public boundary, and run the original plus focused parity tests.

Read the full file on GitHub · 49 lines

Files

What ships with it

3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 1mo ago First seen · 49 lines · 87 tokens per session scan A a4d08cccc6f6

Subscribe to this mod's changes

migrating-openai-agents-sdk-to-pydantic-ai is a skill published in the GitHub repository pydantic/pydantic-ai (20,645 stars, last pushed today), licensed MIT. It adds 87 tokens to every session and 1,406 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-16.