Use for dspy.Refine, dspy.BestOfN, output constraints, validation, reward functions, and iterative output refinement.
npx skills add https://github.com/OmidZamani/dspy-skills --skill dspy-output-refinement-constraints
Improve output quality using iterative refinement (dspy.Refine) and best-of-N selection (dspy.BestOfN) with custom constraint validation.
| Input | Type | Description |
|-------|------|-------------|
| module | dspy.Module | Module to refine |
| reward_fn | callable | Constraint validation function |
| N | int | Number of attempts |
| threshold | float | Minimum reward to accept |
| Output | Type | Description |
|--------|------|-------------|
| refined_output | dspy.Prediction | Validated, refined result |
Refine iteratively improves outputs across multiple attempts:
import dspy
dspy.configure(lm=dspy.LM("openai/gpt-4o-mini"))
# Base module
summarizer = dspy.ChainOfThought("document -> summary: str")
# Reward function: checks constraints
def summary_reward(args, pred):
summary = pred.summary
word_count = len(summary.split())
if word_count > 100 or len(summary) < 50:
return 0.0
if "important" not in summary.lower():
return 0.5
return 1.0
# Refine module
refined_summarizer = dspy.Refine(
module=summarizer,
reward_fn=summary_reward,
N=3,
threshold=1.0
)
# Use it
result = refined_summarizer(document="Long document text here...")
print(result.summary)
Generate N outputs and pick the best:
import dspy
def json_reward(args, pred):
"""Validate JSON format and fields."""
import json
try:
data = json.loads(pred.output)
if not {'name', 'age', 'email'}.issubset(data.keys()):
return 0.3
if '@' not in data.get('email', ''):
return 0.5
return 1.0
except json.JSONDecodeError:
return 0.0
# BestOfN: try 5 times, pick best
extractor = dspy.Predict("text -> output: str")
best_extractor = dspy.BestOfN(module=extractor, reward_fn=json_reward, N=5, threshold=1.0)
result = best_extractor(text="John Doe, 30 years old, [email protected]")
print(result.output) # Best valid JSON
Complex validation with scoring:
import dspy
import re
def comprehensive_reward(args, pred):
"""Validate format, length, and content."""
text = pred.answer
score = 0.0
# Length: 50-150 words (33%)
word_count = len(text.split())
if 50 <= word_count <= 150:
score += 0.33
# Format: capitalized, ends with period (33%)
if re.match(r'^[A-Z]', text) and text.endswith('.'):
score += 0.33
# Content: required terms present (34%)
if all(term in text.lower() for term in ['data', 'analysis']):
score += 0.34
return score
# Use with Refine
qa = dspy.ChainOfThought("question -> answer: str")
refined_qa = dspy.Refine(module=qa, reward_fn=comprehensive_reward, N=4, threshold=0.9)
result = refined_qa(question="What is data science?")
import dspy
import json
import logging
logger = logging.getLogger(__name__)
class StructuredExtractor(dspy.Module):
"""Extract structured data with validation."""
def __init__(self):
self.extractor = dspy.Predict(
"text -> json_output: str"
)
self.refined = dspy.Refine(
module=self.extractor,
reward_fn=self.validation_reward,
N=3,
threshold=0.9
)
def validation_reward(self, args, pred):
"""Validate JSON structure and business logic."""
try:
data = json.loads(pred.json_output)
score = 0.0
# Required fields
if {'product', 'price', 'quantity'}.issubset(data.keys()):
score += 0.4
# Type validation
if isinstance(data.get('price'), (int, float)) and data['price'] > 0:
score += 0.3
if isinstance(data.get('quantity'), int) and data['quantity'] > 0:
score += 0.3
return score
except (json.JSONDecodeError, TypeError) as e:
logger.warning(f"Validation failed: {e}")
return 0.0
def forward(self, text: str):
try:
return self.refined(text=text)
except Exception as e:
logger.error(f"Extraction failed: {e}")
return dspy.Prediction(json_output='{}')
# Usage
extractor = StructuredExtractor()
result = extractor(text="iPhone 15, $999, quantity: 50")
print(result.json_output)
DSPy 2.6+ deprecates dspy.Assert/dspy.Suggest. Use Refine with reward functions:
# Old: dspy.Assert(len(output) < 100, "Too long")
# New:
def reward(args, pred):
return 1.0 if len(pred.output) < 100 else 0.0
refined = dspy.Refine(module=module, reward_fn=reward, N=3, threshold=1.0)
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Take omidzamani/dspy-output-refinement-constraints from the repository into ~/.claude/skills for personal
use, or into .claude/skills inside a project.
The agent identifies a skill by the name field in its header. Two skills with the
same name cannot sit side by side — one of them will be ignored.