Retry Logic with Tenacity¶

Tenacity is a Python library for adding retry logic to your applications. Combined with Instructor, it helps handle API failures, rate limits, and validation errors.

Basic Retry with Exponential Backoff¶

The most common pattern uses exponential backoff to delay retries:

import instructor
from pydantic import BaseModel
from tenacity import retry, stop_after_attempt, wait_exponential

client = instructor.from_provider("openai/gpt-4.1-mini")


class UserInfo(BaseModel):
    name: str
    age: int
    email: str


@retry(stop=stop_after_attempt(3), wait=wait_exponential(multiplier=1, min=4, max=10))
def extract_user_info(text: str) -> UserInfo:
    """Extract user information with retry logic."""
    return client.create(
        response_model=UserInfo,
        messages=[{"role": "user", "content": f"Extract user info: {text}"}],
    )


try:
    user = extract_user_info("John is 30 years old with email john@example.com")
    print(f"Success: {user.name}, {user.age}, {user.email}")
    #> Success: John, 30, john@example.com
except Exception as e:
    print(f"Failed after retries: {e}")

Error-Specific Retries¶

Retry only on specific error types for better control:

import instructor
from openai import APIError, RateLimitError
from pydantic import BaseModel, ValidationError
from tenacity import (
    retry,
    retry_if_exception_type,
    stop_after_attempt,
    wait_exponential,
)

client = instructor.from_provider("openai/gpt-4.1-mini")


class UserInfo(BaseModel):
    name: str
    age: int
    email: str


# Retry on API errors with longer delays
@retry(
    retry=retry_if_exception_type((RateLimitError, APIError)),
    stop=stop_after_attempt(5),
    wait=wait_exponential(multiplier=2, min=1, max=60),
)
def handle_api_errors(text: str) -> UserInfo:
    return client.create(
        response_model=UserInfo,
        messages=[{"role": "user", "content": text}],
    )


# Retry on validation errors with shorter delays
@retry(
    retry=retry_if_exception_type(ValidationError),
    stop=stop_after_attempt(3),
    wait=wait_exponential(multiplier=1, min=1, max=10),
)
def handle_validation_errors(text: str) -> UserInfo:
    return client.create(
        response_model=UserInfo,
        messages=[{"role": "user", "content": text}],
    )

Custom Retry Conditions¶

Retry based on the result content rather than exceptions:

import instructor
from pydantic import BaseModel
from tenacity import retry, retry_if_result, stop_after_attempt

client = instructor.from_provider("openai/gpt-4.1-mini")


class UserInfo(BaseModel):
    name: str
    age: int
    email: str


def should_retry(result: UserInfo) -> bool:
    """Retry if the result doesn't meet quality criteria."""
    return result.age < 0 or result.age > 150 or not result.email


@retry(retry=retry_if_result(should_retry), stop=stop_after_attempt(3))
def extract_valid_user(text: str) -> UserInfo:
    return client.create(
        response_model=UserInfo,
        messages=[{"role": "user", "content": text}],
    )

Context-Based Validation with Retries¶

Use the context parameter to pass runtime data to validators:

import instructor
from pydantic import BaseModel, ValidationInfo, field_validator, ValidationError
from tenacity import retry, retry_if_exception_type, stop_after_attempt, wait_exponential

client = instructor.from_provider("openai/gpt-4.1-mini")


class Citation(BaseModel):
    """A claim with a supporting quote from source text."""

    claim: str
    quote: str

    @field_validator('quote')
    @classmethod
    def verify_quote_exists(cls, v: str, info: ValidationInfo):
        context = info.context
        if context:
            source_text = context.get('source_text', '')
            if v not in source_text:
                raise ValueError(f"Quote '{v}' not found in source text.")
        return v


@retry(
    retry=retry_if_exception_type(ValidationError),
    stop=stop_after_attempt(3),
    wait=wait_exponential(multiplier=1, min=2, max=10),
)
def extract_citation(claim: str, source_text: str) -> Citation:
    return client.create(
        response_model=Citation,
        messages=[
            {
                "role": "system",
                "content": "Extract the claim and find an exact quote from the source.",
            },
            {
                "role": "user",
                "content": "Source: {{ source_text }}\n\nClaim: {{ claim }}",
            },
        ],
        context={"source_text": source_text, "claim": claim},
    )


source = "The Eiffel Tower was completed in 1889 and stands 330 meters tall."
citation = extract_citation("The tower is over 300 meters", source)
print(f"Quote: {citation.quote}")

Logging and Monitoring¶

Add logging to track retry attempts:

import logging
import instructor
from pydantic import BaseModel
from tenacity import after_log, before_log, retry, stop_after_attempt, wait_exponential

client = instructor.from_provider("openai/gpt-4.1-mini")


class UserInfo(BaseModel):
    name: str
    age: int
    email: str


logger = logging.getLogger(__name__)
logging.basicConfig(level=logging.INFO)


@retry(
    stop=stop_after_attempt(3),
    wait=wait_exponential(multiplier=1, min=4, max=10),
    before=before_log(logger, logging.INFO),
    after=after_log(logger, logging.ERROR),
)
def logged_extraction(text: str) -> UserInfo:
    return client.create(
        response_model=UserInfo,
        messages=[{"role": "user", "content": text}],
    )

Instructor's Built-in Retries¶

Instructor has built-in retry support that works alongside Tenacity:

import instructor
from instructor import Mode
from pydantic import BaseModel
from tenacity import retry, stop_after_attempt

client = instructor.from_provider(
    "openai/gpt-4.1-mini",
    mode=Mode.JSON,
    max_retries=3,
    retry_delay=1,
)


class UserInfo(BaseModel):
    name: str
    age: int
    email: str


# Combine Instructor and Tenacity retries for additional resilience
@retry(stop=stop_after_attempt(2))
def double_retry_extraction(text: str) -> UserInfo:
    return client.create(
        response_model=UserInfo,
        messages=[{"role": "user", "content": text}],
    )

Failed Attempts Tracking¶

When retries fail, Instructor provides detailed failure history:

import instructor
from instructor.core.exceptions import InstructorRetryException
from pydantic import BaseModel, field_validator

client = instructor.from_provider("openai/gpt-4.1-mini")


class UserInfo(BaseModel):
    name: str
    age: int

    @field_validator('age')
    @classmethod
    def validate_age(cls, v):
        if v < 0 or v > 150:
            raise ValueError(f"Age {v} is invalid")
        return v


try:
    result = client.create(
        response_model=UserInfo,
        messages=[{"role": "user", "content": "Extract: John is -5 years old"}],
        max_retries=3,
    )
except InstructorRetryException as e:
    print(f"Failed after {e.n_attempts} attempts")
    for attempt in e.failed_attempts:
        print(f"Attempt {attempt.attempt_number}: {attempt.exception}")

Failed attempts are automatically propagated to reask handlers, enabling contextual error messages and progressive corrections.

Best Practices¶

Choose Appropriate Strategies¶

Error Type	Attempts	Min Delay	Max Delay
Rate limits	5	1s	60-120s
Validation errors	2-3	1s	10s
Network errors	4	2s	30s

Always Set Stop Conditions¶

from tenacity import retry, stop_after_attempt

# Good: bounded retries
@retry(stop=stop_after_attempt(3))
def bounded_retry():
    pass

# Bad: could retry forever
@retry()  # Don't do this!
def unbounded_retry():
    pass

Troubleshooting¶

Infinite retries: Always set stop_after_attempt() or stop_after_delay().

Too many retries: Use retry_if_exception_type() to retry only on specific errors.

Still hitting rate limits: Increase max delay and use wait_exponential() with higher multipliers.