thinking.md•4.86 kB
# Thinking
Thinking (or reasoning) is the process by which a model works through a problem step-by-step before
providing its final answer.
This capability is typically disabled by default and depends on the specific model being used.
See the sections below for how to enable thinking for each provider.
## OpenAI
When using the [`OpenAIChatModel`][pydantic_ai.models.openai.OpenAIChatModel], text output inside `<think>` tags are converted to [`ThinkingPart`][pydantic_ai.messages.ThinkingPart] objects.
You can customize the tags using the [`thinking_tags`][pydantic_ai.profiles.ModelProfile.thinking_tags] field on the [model profile](models/openai.md#model-profile).
### OpenAI Responses
The [`OpenAIResponsesModel`][pydantic_ai.models.openai.OpenAIResponsesModel] can generate native thinking parts.
To enable this functionality, you need to set the
[`OpenAIResponsesModelSettings.openai_reasoning_effort`][pydantic_ai.models.openai.OpenAIResponsesModelSettings.openai_reasoning_effort] and [`OpenAIResponsesModelSettings.openai_reasoning_summary`][pydantic_ai.models.openai.OpenAIResponsesModelSettings.openai_reasoning_summary] [model settings](agents.md#model-run-settings).
By default, the unique IDs of reasoning, text, and function call parts from the message history are sent to the model, which can result in errors like `"Item 'rs_123' of type 'reasoning' was provided without its required following item."`
if the message history you're sending does not match exactly what was received from the Responses API in a previous response, for example if you're using a [history processor](message-history.md#processing-message-history).
To disable this, you can disable the [`OpenAIResponsesModelSettings.openai_send_reasoning_ids`][pydantic_ai.models.openai.OpenAIResponsesModelSettings.openai_send_reasoning_ids] [model setting](agents.md#model-run-settings).
```python {title="openai_thinking_part.py"}
from pydantic_ai import Agent
from pydantic_ai.models.openai import OpenAIResponsesModel, OpenAIResponsesModelSettings
model = OpenAIResponsesModel('gpt-5')
settings = OpenAIResponsesModelSettings(
openai_reasoning_effort='low',
openai_reasoning_summary='detailed',
)
agent = Agent(model, model_settings=settings)
...
```
## Anthropic
To enable thinking, use the [`AnthropicModelSettings.anthropic_thinking`][pydantic_ai.models.anthropic.AnthropicModelSettings.anthropic_thinking] [model setting](agents.md#model-run-settings).
```python {title="anthropic_thinking_part.py"}
from pydantic_ai import Agent
from pydantic_ai.models.anthropic import AnthropicModel, AnthropicModelSettings
model = AnthropicModel('claude-sonnet-4-0')
settings = AnthropicModelSettings(
anthropic_thinking={'type': 'enabled', 'budget_tokens': 1024},
)
agent = Agent(model, model_settings=settings)
...
```
## Google
To enable thinking, use the [`GoogleModelSettings.google_thinking_config`][pydantic_ai.models.google.GoogleModelSettings.google_thinking_config] [model setting](agents.md#model-run-settings).
```python {title="google_thinking_part.py"}
from pydantic_ai import Agent
from pydantic_ai.models.google import GoogleModel, GoogleModelSettings
model = GoogleModel('gemini-2.5-pro')
settings = GoogleModelSettings(google_thinking_config={'include_thoughts': True})
agent = Agent(model, model_settings=settings)
...
```
## Bedrock
## Groq
Groq supports different formats to receive thinking parts:
- `"raw"`: The thinking part is included in the text content inside `<think>` tags, which are automatically converted to [`ThinkingPart`][pydantic_ai.messages.ThinkingPart] objects.
- `"hidden"`: The thinking part is not included in the text content.
- `"parsed"`: The thinking part has its own structured part in the response which is converted into a [`ThinkingPart`][pydantic_ai.messages.ThinkingPart] object.
To enable thinking, use the [`GroqModelSettings.groq_reasoning_format`][pydantic_ai.models.groq.GroqModelSettings.groq_reasoning_format] [model setting](agents.md#model-run-settings):
```python {title="groq_thinking_part.py"}
from pydantic_ai import Agent
from pydantic_ai.models.groq import GroqModel, GroqModelSettings
model = GroqModel('qwen-qwq-32b')
settings = GroqModelSettings(groq_reasoning_format='parsed')
agent = Agent(model, model_settings=settings)
...
```
## Mistral
Thinking is supported by the `magistral` family of models. It does not need to be specifically enabled.
## Cohere
Thinking is supported by the `command-a-reasoning-08-2025` model. It does not need to be specifically enabled.
## Hugging Face
Text output inside `<think>` tags is automatically converted to [`ThinkingPart`][pydantic_ai.messages.ThinkingPart] objects.
You can customize the tags using the [`thinking_tags`][pydantic_ai.profiles.ModelProfile.thinking_tags] field on the [model profile](models/openai.md#model-profile).