DSPy -- Programmatic Prompt Optimization

# script_id: day_017_dspy/inline_signature
import dspy

# Simple inline signature: "input_field -> output_field"
# This tells DSPy: take a question, produce an answer
classify = dspy.Predict("sentence -> sentiment")

result = classify(sentence="DSPy makes prompt engineering obsolete!")
print(result.sentiment)  # "positive"

# script_id: day_017_dspy/class_based_signature
import dspy

class FactCheck(dspy.Signature):
    """Verify whether a claim is supported by the provided context."""

    context: str = dspy.InputField(desc="Reference text with known facts")
    claim: str = dspy.InputField(desc="The claim to verify")
    verdict: str = dspy.OutputField(desc="'supported', 'refuted', or 'not enough info'")
    evidence: str = dspy.OutputField(desc="Quote from context supporting the verdict")

# DSPy uses the docstring, field names, and descriptions
# to automatically construct the optimal prompt

# script_id: day_017_dspy/modules_predict_cot
import dspy

# Configure the language model
lm = dspy.LM("openai/gpt-4o-mini")
dspy.configure(lm=lm)

# Predict: basic prompt, no reasoning
basic_qa = dspy.Predict("question -> answer")

# ChainOfThought: adds step-by-step reasoning automatically
cot_qa = dspy.ChainOfThought("question -> answer")

# Both have the same signature, but ChainOfThought
# adds a "reasoning" field internally before producing the answer
result = cot_qa(question="What is 15% of 240?")
print(result.reasoning)  # "15% means 15/100. 15/100 * 240 = 36"
print(result.answer)     # "36"

# script_id: day_017_dspy/multi_hop_qa
import dspy

class MultiHopQA(dspy.Module):
    """Answer questions that require multiple reasoning steps."""

    def __init__(self):
        # Each sub-module handles one step
        self.generate_query = dspy.ChainOfThought(
            "question -> search_query"
        )
        self.generate_answer = dspy.ChainOfThought(
            "context, question -> answer"
        )

    def forward(self, question: str) -> dspy.Prediction:
        # Step 1: Generate a search query from the question
        query_result = self.generate_query(question=question)

        # Step 2: Retrieve context (using a DSPy retriever or custom function)
        context = self.retrieve(query_result.search_query)

        # Step 3: Generate answer from retrieved context
        answer_result = self.generate_answer(
            context=context,
            question=question
        )
        return answer_result

    def retrieve(self, query: str) -> str:
        # Placeholder -- plug in your vector DB here
        return f"Retrieved context for: {query}"

# Usage
program = MultiHopQA()
result = program(question="Who founded the company that created GPT-4?")
print(result.answer)

# script_id: day_017_dspy/optimizer_and_evaluator
import dspy
from dspy.evaluate import Evaluate

# 1. Define your program
qa = dspy.ChainOfThought("question -> answer")

# 2. Prepare training examples
trainset = [
    dspy.Example(
        question="What is the capital of France?",
        answer="Paris"
    ).with_inputs("question"),
    dspy.Example(
        question="Who wrote Romeo and Juliet?",
        answer="William Shakespeare"
    ).with_inputs("question"),
    # ... more examples (10-200 is typical)
]

# 3. Define a metric: how to score predictions
def exact_match(example, prediction, trace=None):
    return example.answer.lower() == prediction.answer.lower()

# 4. Compile with BootstrapFewShot
optimizer = dspy.BootstrapFewShot(
    metric=exact_match,
    max_bootstrapped_demos=4,  # Max few-shot examples to include
    max_labeled_demos=4
)

# This runs your program on training data, finds the best
# few-shot examples, and bakes them into the prompt
compiled_qa = optimizer.compile(qa, trainset=trainset)

# 5. Use the compiled (optimized) program
result = compiled_qa(question="What is the capital of Japan?")
print(result.answer)  # "Tokyo"

# script_id: day_017_dspy/optimizer_and_evaluator
import dspy
from dspy.evaluate import Evaluate

# Your compiled program
compiled_qa = ...  # from optimizer step above

# Held-out test set (never seen during compilation)
testset = [
    dspy.Example(
        question="What is the largest planet?",
        answer="Jupiter"
    ).with_inputs("question"),
    dspy.Example(
        question="Who painted the Mona Lisa?",
        answer="Leonardo da Vinci"
    ).with_inputs("question"),
]

# Define evaluation metric
def fuzzy_match(example, prediction, trace=None):
    """Check if the expected answer appears in the prediction."""
    return example.answer.lower() in prediction.answer.lower()

# Run evaluation
evaluator = Evaluate(
    devset=testset,
    metric=fuzzy_match,
    num_threads=4,
    display_progress=True
)

score = evaluator(compiled_qa)
print(f"Accuracy: {score}%")

# script_id: day_017_dspy/manual_vs_dspy_comparison
# ---- MANUAL APPROACH ----
# Fragile, model-specific, hard to maintain

def classify_manual(text: str) -> str:
    response = client.chat.completions.create(
        model="gpt-4o-mini",
        messages=[
            {"role": "system", "content": """You are a sentiment classifier.
Classify the sentiment as positive, negative, or neutral.
Here are some examples:
- "I love this!" -> positive
- "This is terrible" -> negative
- "It's okay I guess" -> neutral
Return ONLY the sentiment label."""},
            {"role": "user", "content": text}
        ]
    )
    return response.choices[0].message.content.strip()


# ---- DSPy APPROACH ----
# Declarative, portable, auto-optimized

class SentimentClassifier(dspy.Module):
    def __init__(self):
        self.classify = dspy.Predict(
            "text -> sentiment: str"  # That's it. No prompt needed.
        )

    def forward(self, text: str):
        return self.classify(text=text)

# Compile with examples -- DSPy finds optimal few-shot demos
optimizer = dspy.BootstrapFewShot(metric=exact_match)
classifier = optimizer.compile(SentimentClassifier(), trainset=train_data)

# Switch models? Just recompile.
dspy.configure(lm=dspy.LM("anthropic/claude-sonnet-4-20250514"))
classifier_claude = optimizer.compile(SentimentClassifier(), trainset=train_data)

# script_id: day_017_dspy/quick_reference
import dspy

# Configure LM
dspy.configure(lm=dspy.LM("openai/gpt-4o-mini"))

# Inline signature
predict = dspy.Predict("question -> answer")

# Chain of thought
cot = dspy.ChainOfThought("question -> answer")

# Compile with optimizer
optimizer = dspy.BootstrapFewShot(metric=my_metric)
compiled = optimizer.compile(my_module, trainset=examples)

# Evaluate
from dspy.evaluate import Evaluate
score = Evaluate(devset=testset, metric=my_metric)(compiled)