Practical overview
When it fits
Use Pydantic AI when you are building an AI-enabled Python application and want an agent loop that can be connected to different interfaces. Consider the separate Harness package when the workflow needs capabilities such as memory, planning, sub-agents or persistence.
Who it is for
- Python developers building applications that use AI models.
- Teams that need to present an agent through a web, terminal or voice interface.
- Developers assembling more complex agent workflows with memory, planning, guardrails or sub-agents.
Documented uses
- Build a typed agent that calls an AI model.
- Connect an agent to a web frontend, terminal or voice-call interface.
- Add image-generation or embedding capabilities to a Python application.
- Assemble a terminal coding agent with file access, shell tools and repository context.
Requirements & limits
The project repository is public and licensed under MIT.
- Pydantic AI is a developer framework, not a hosted end-user agent service.
- Harness, Graph and Evals are separate packages with distinct roles.
- The README demonstrates package installation with uv and model selection in agent configuration.
Check current requirements in the official documentation. Source-based guidance does not mean OpenViST has run or independently tested this project.
Build a typed sentiment agent with a validated result
Create a Python agent that returns sentiment labels and scores in a typed structure.
Before you start
- Python project with
pydantic-aiinstalled (uv add pydantic-aiis shown). - A model identifier and provider credentials when using a real model; the documented example uses
openai:gpt-6-sol. The README also identifiesAgent('test')as an offline option.
Steps
Define a Pydantic model for the result, such as a sentiment label and bounded score.
Create an
Agentwith that model as itsoutput_type.Optionally register a tool with
@agent.tool; the example uses aRunContextand returns review snippets.Call
agent.run_sync(...)and read the typed value fromresult.output.
Expected outcome
The example produces a validated `Sentiment` result, such as `label='positive'` and `score=0.9`.
Guide limitations
- The documented example uses a synchronous run; it does not describe deployment or a web interface.
- The real-model example requires a configured provider; the offline
testmodel does not call an LLM.
Generate an image file with the standalone image API
Generate an image from a prompt and write its returned bytes to a local file.
Before you start
- Python project with
pydantic-aiinstalled (uv add pydantic-aiis shown). - The example uses the
openai:gpt-image-2image model; provider setup details are not included in the documented example.
Steps
Import
PathandImageGeneratorfrompydantic_ai.Create an
ImageGeneratorforopenai:gpt-image-2.Call
generate_syncwith an image prompt.Write
result.image.datato a file, as shown withPath('logo.png').write_bytes(...).
Expected outcome
The example writes generated image data to `logo.png`.
Guide limitations
- This is a standalone image-generation API, not an agent run.
- The example does not document provider credential configuration or image-generation tests.
Compare options for AI coding assistance
These projects document a common task and share a project role. This is a source-based comparison, not an execution benchmark or a guarantee of interchangeability.
| Project | Documented purpose | Platform | Access and requirements |
|---|---|---|---|
| Pydantic AI | Build a typed agent that calls an AI model. | CLI, Cloud, Linux, macOS | The project repository is public and licensed under MIT. |
| Dexto | Define agents in YAML with a model, tools, storage and permissions. | CLI |
Sources & review
Source record details
- Source availability
- Active
- Sources checked
- 30 September 2026
- Original website title
- pydantic/pydantic-ai · Official homepage title · retained in its source language

