A/B Testing & Multivariate

With Edgit’s independent versioning, you can run:

2 agent versions × 3 prompt versions × 2 configs = 12 variants
All running in production at the same time
Each user gets a consistent experience
Data-driven decisions on what actually works

A/B Testing Basics

Simple A/B Test

Test two prompt versions:

# Create two versions
edgit tag create analysis-prompt v1.0.0  # Control
edgit tag create analysis-prompt v2.0.0  # Treatment

# Tag for deployment (underlying: components/prompts/analysis-prompt/prod-control)
edgit tag set analysis-prompt prod-control v1.0.0
edgit push --tags --force

edgit tag set analysis-prompt prod-treatment v2.0.0
edgit push --tags --force

Ensemble configuration:

ensemble: ab-test-simple

agents:
  # Control group (50% of users)
  - name: analyzer-control
    operation: think
    component: analysis-prompt@v1.0.0
    config:
      model: claude-3-5-sonnet-20241022
    condition: ${input.user_id % 2 === 0}

  # Treatment group (50% of users)
  - name: analyzer-treatment
    operation: think
    component: analysis-prompt@v2.0.0
    config:
      model: claude-3-5-sonnet-20241022
    condition: ${input.user_id % 2 === 1}

output:
  result: ${analyzer-control.output || analyzer-treatment.output}
  variant: ${analyzer-control.executed ? 'control' : 'treatment'}
  quality_score: ${analyzer-control.score || analyzer-treatment.score}

Test Results

# After collecting data
curl https://metrics.example.com/ab-test/analysis-prompt

# Results:
# Control (v1.0.0):   Success rate: 92%, Avg quality: 0.85
# Treatment (v2.0.0): Success rate: 95%, Avg quality: 0.91

# Treatment wins! Deploy to everyone
edgit tag set analysis-prompt prod v2.0.0
edgit push --tags --force

Multivariate Testing

Test multiple variables simultaneously.

2×2 Test: Prompt × Model

ensemble: multivariate-prompt-model

agents:
  # Variant 1: Old prompt + GPT-4
  - name: variant-1
    operation: think
    component: analysis-prompt@v1.0.0
    config:
      model: gpt-4
    condition: ${(input.user_id % 4) === 0}

  # Variant 2: Old prompt + Claude
  - name: variant-2
    operation: think
    component: analysis-prompt@v1.0.0
    config:
      model: claude-3-5-sonnet-20241022
    condition: ${(input.user_id % 4) === 1}

  # Variant 3: New prompt + GPT-4
  - name: variant-3
    operation: think
    component: analysis-prompt@v2.0.0
    config:
      model: gpt-4
    condition: ${(input.user_id % 4) === 2}

  # Variant 4: New prompt + Claude
  - name: variant-4
    operation: think
    component: analysis-prompt@v2.0.0
    config:
      model: claude-3-5-sonnet-20241022
    condition: ${(input.user_id % 4) === 3}

output:
  result: ${variant-1.output || variant-2.output || variant-3.output || variant-4.output}
  variant:
    prompt_version: ${variant-1.executed || variant-2.executed ? 'v1.0.0' : 'v2.0.0'}
    model: ${variant-1.executed || variant-3.executed ? 'gpt-4' : 'claude'}

3×3 Test: Agent × Prompt × Config

ensemble: multivariate-3x3

agents:
  # 9 combinations total
  - name: analyzer-v1-prompt-v1-config-v1
    agent: analyzer@v1.0.0
    component: prompt@v1.0.0
    config: config@v1.0.0
    condition: ${(input.user_id % 9) === 0}

  - name: analyzer-v1-prompt-v1-config-v2
    agent: analyzer@v1.0.0
    component: prompt@v1.0.0
    config: config@v2.0.0
    condition: ${(input.user_id % 9) === 1}

  - name: analyzer-v1-prompt-v2-config-v1
    agent: analyzer@v1.0.0
    component: prompt@v2.0.0
    config: config@v1.0.0
    condition: ${(input.user_id % 9) === 2}

  # ... 6 more combinations

Results: Discover that analyzer v2.0.0 + prompt v1.0.0 + config v2.0.0 is the optimal combination.

Sticky Sessions

Critical: Users must get the same variant every time.

Bad (Random)

# ❌ Don't do this - user gets different variant each request
condition: ${Math.random() < 0.5}

Problem: Inconsistent experience. User sees different results each time they refresh.

Good (Sticky)

# ✓ Do this - user always gets same variant
condition: ${hash(input.user_id) % 2 === 0}

Benefit: Consistent experience. Same user always gets same variant.

Implementation

ensemble: sticky-ab-test

agents:
  - name: analyzer-control
    operation: think
    component: prompt@v1.0.0
    condition: |
      ${(() => {
        const hash = input.user_id.split('').reduce((acc, char) => {
          return ((acc << 5) - acc) + char.charCodeAt(0);
        }, 0);
        return Math.abs(hash) % 2 === 0;
      })()}

  - name: analyzer-treatment
    operation: think
    component: prompt@v2.0.0
    condition: |
      ${(() => {
        const hash = input.user_id.split('').reduce((acc, char) => {
          return ((acc << 5) - acc) + char.charCodeAt(0);
        }, 0);
        return Math.abs(hash) % 2 === 1;
      })()}

Or simpler with modulo:

condition: ${parseInt(input.user_id, 36) % 2 === 0}

Traffic Splitting

50/50 Split

agents:
  - name: control
    condition: ${input.user_id % 2 === 0}  # 50%
  - name: treatment
    condition: ${input.user_id % 2 === 1}  # 50%

90/10 Split

agents:
  - name: control
    condition: ${input.user_id % 10 !== 0}  # 90%
  - name: treatment
    condition: ${input.user_id % 10 === 0}  # 10%

33/33/33 Split (3 variants)

agents:
  - name: variant-a
    condition: ${input.user_id % 3 === 0}  # 33%
  - name: variant-b
    condition: ${input.user_id % 3 === 1}  # 33%
  - name: variant-c
    condition: ${input.user_id % 3 === 2}  # 33%

Dynamic Split (via KV)

state:
  schema:
    traffic_split: object

agents:
  - name: get-split-config
    operation: storage
    config:
      type: kv
      key: ab-test-traffic-split
    state:
      set: [traffic_split]

  - name: control
    operation: think
    component: prompt@v1.0.0
    condition: ${Math.random() * 100 < state.traffic_split.control_percentage}

  - name: treatment
    operation: think
    component: prompt@v2.0.0
    condition: ${Math.random() * 100 < state.traffic_split.treatment_percentage}

Update split via KV:

# Start with 10% treatment
wrangler kv:key put --namespace-id=$KV_ID "ab-test-traffic-split" \
  '{"control_percentage": 90, "treatment_percentage": 10}'

# Increase to 50%
wrangler kv:key put --namespace-id=$KV_ID "ab-test-traffic-split" \
  '{"control_percentage": 50, "treatment_percentage": 50}'

Metrics Collection

Track variant performance:

ensemble: ab-test-with-metrics

agents:
  - name: analyzer-control
    operation: think
    component: prompt@v1.0.0
    condition: ${input.user_id % 2 === 0}

  - name: analyzer-treatment
    operation: think
    component: prompt@v2.0.0
    condition: ${input.user_id % 2 === 1}

  # Store metrics
  - name: record-metrics
    operation: storage
    config:
      type: d1
      query: |
        INSERT INTO ab_test_metrics
        (user_id, variant, success, quality_score, latency_ms, timestamp)
        VALUES (?, ?, ?, ?, ?, ?)
      params:
        - ${input.user_id}
        - ${analyzer-control.executed ? 'control' : 'treatment'}
        - ${analyzer-control.success || analyzer-treatment.success}
        - ${analyzer-control.score || analyzer-treatment.score}
        - ${analyzer-control.latency_ms || analyzer-treatment.latency_ms}
        - ${Date.now()}

output:
  result: ${analyzer-control.output || analyzer-treatment.output}
  variant: ${analyzer-control.executed ? 'control' : 'treatment'}

Query results:

-- Overall success rate by variant
SELECT
  variant,
  COUNT(*) as requests,
  AVG(CASE WHEN success THEN 1.0 ELSE 0.0 END) as success_rate,
  AVG(quality_score) as avg_quality,
  AVG(latency_ms) as avg_latency
FROM ab_test_metrics
WHERE timestamp > datetime('now', '-7 days')
GROUP BY variant;

-- Results:
-- control:   10000 requests, 92% success, 0.85 quality, 250ms latency
-- treatment:  1000 requests, 95% success, 0.91 quality, 280ms latency

Advanced: Sequential Testing

Don’t run forever. Stop when you have statistical significance.

Bayesian A/B Test

# scripts/analyze-ab-test.py
import scipy.stats as stats

# Get data
control_successes = 920
control_total = 1000

treatment_successes = 950
treatment_total = 1000

# Bayesian analysis
control_posterior = stats.beta(control_successes + 1, control_total - control_successes + 1)
treatment_posterior = stats.beta(treatment_successes + 1, treatment_total - treatment_successes + 1)

# Probability treatment is better
samples = 10000
control_samples = control_posterior.rvs(samples)
treatment_samples = treatment_posterior.rvs(samples)
prob_treatment_better = (treatment_samples > control_samples).mean()

print(f"Probability treatment is better: {prob_treatment_better:.2%}")

if prob_treatment_better > 0.95:
    print("✓ Treatment wins! Deploy to all users.")
elif prob_treatment_better < 0.05:
    print("❌ Control wins! Keep current version.")
else:
    print("⚠ Inconclusive. Collect more data.")

Auto-Promote Winner

# .github/workflows/ab-test-auto-promote.yml
name: AB Test Auto-Promote

on:
  schedule:
    - cron: '0 */6 * * *'  # Every 6 hours

jobs:
  analyze:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - name: Analyze AB Test
        run: |
          python scripts/analyze-ab-test.py > results.txt

      - name: Auto-Promote if Winner
        run: |
          if grep -q "✓ Treatment wins" results.txt; then
            edgit tag set analysis-prompt prod v2.0.0
            edgit push --tags --force
            echo "✅ Auto-promoted treatment to production"
          fi

Real-World Examples

Example 1: Prompt Iteration

ensemble: prompt-iteration

agents:
  # Current production (baseline)
  - name: baseline
    operation: think
    component: extraction-prompt@v1.0.0
    condition: ${input.user_id % 5 === 0}  # 20%

  # Variant 1: More detailed instructions
  - name: detailed
    operation: think
    component: extraction-prompt@v1.1.0
    condition: ${input.user_id % 5 === 1}  # 20%

  # Variant 2: Fewer instructions (simpler)
  - name: simple
    operation: think
    component: extraction-prompt@v1.2.0
    condition: ${input.user_id % 5 === 2}  # 20%

  # Variant 3: Different tone
  - name: formal
    operation: think
    component: extraction-prompt@v1.3.0
    condition: ${input.user_id % 5 === 3}  # 20%

  # Variant 4: With examples
  - name: with-examples
    operation: think
    component: extraction-prompt@v1.4.0
    condition: ${input.user_id % 5 === 4}  # 20%

Result: “with-examples” variant wins with 97% success rate. Deploy to all.

Example 2: Model Selection

ensemble: model-selection

agents:
  # GPT-4 (expensive, accurate)
  - name: gpt4
    operation: think
    component: prompt@v1.0.0
    config:
      model: gpt-4
    condition: ${input.user_id % 3 === 0}

  # Claude (fast, good quality)
  - name: claude
    operation: think
    component: prompt@v1.0.0
    config:
      model: claude-3-5-sonnet-20241022
    condition: ${input.user_id % 3 === 1}

  # GPT-3.5 (cheap, fast)
  - name: gpt35
    operation: think
    component: prompt@v1.0.0
    config:
      model: gpt-3.5-turbo
    condition: ${input.user_id % 3 === 2}

Result: Claude has 94% success rate at 40% the cost of GPT-4. Winner!

Example 3: Agent Implementation

ensemble: agent-implementation

agents:
  # Old scraper implementation
  - name: scraper-v1
    agent: scraper@v1.0.0
    config:
      url: ${input.url}
    condition: ${input.user_id % 2 === 0}

  # New scraper with better fallback
  - name: scraper-v2
    agent: scraper@v2.0.0
    config:
      url: ${input.url}
    condition: ${input.user_id % 2 === 1}

Result: v2.0.0 has 99% success rate vs 92% for v1.0.0. Deploy new version.

Best Practices

1. Start with Small Traffic

# ❌ Don't
# 50/50 split immediately

# ✓ Do
# 90/10 split first (10% to treatment)

2. Use Statistical Significance

# ❌ Don't
# if treatment_success > control_success: deploy_treatment()

# ✓ Do
# if prob_treatment_better > 0.95: deploy_treatment()

3. Test One Thing at a Time

# ❌ Don't test everything at once
# Changed: prompt, model, config, agent implementation

# ✓ Do test incrementally
# First test: new prompt (keep model/config/agent same)
# Second test: new model (keep prompt/config/agent same)

4. Monitor for Weeks, Not Hours

# ❌ Don't
# Run test for 1 hour, declare winner

# ✓ Do
# Run test for at least 7 days to capture weekly patterns

5. Consider Sample Size

# Need enough data for statistical significance
min_sample_size = 1000  # per variant

if control_total < min_sample_size or treatment_total < min_sample_size:
    print("⚠ Not enough data yet. Keep collecting.")

Next Steps

Deployment Strategies

Canaries, progressive rollouts

Versioning Guide

Master independent versioning

Rollback & Time Travel

Emergency rollbacks

CLI Reference

Complete command documentation

Edgit

Getting Started

Guides

Reference

A/B Testing & Multivariate

A/B Testing Basics

Simple A/B Test

Test Results

Multivariate Testing

2×2 Test: Prompt × Model

3×3 Test: Agent × Prompt × Config

Sticky Sessions

Bad (Random)

Good (Sticky)

Implementation

Traffic Splitting

50/50 Split

90/10 Split

33/33/33 Split (3 variants)

Dynamic Split (via KV)

Metrics Collection

Advanced: Sequential Testing

Bayesian A/B Test

Auto-Promote Winner

Real-World Examples

Example 1: Prompt Iteration

Example 2: Model Selection

Example 3: Agent Implementation

Best Practices

1. Start with Small Traffic

2. Use Statistical Significance

3. Test One Thing at a Time

4. Monitor for Weeks, Not Hours

5. Consider Sample Size

Next Steps

Deployment Strategies

Versioning Guide

Rollback & Time Travel

CLI Reference

Edgit

Getting Started

Guides

Reference

​A/B Testing Basics

​Simple A/B Test

​Test Results

​Multivariate Testing

​2×2 Test: Prompt × Model

​3×3 Test: Agent × Prompt × Config

​Sticky Sessions

​Bad (Random)

​Good (Sticky)

​Implementation

​Traffic Splitting

​50/50 Split

​90/10 Split

​33/33/33 Split (3 variants)

​Dynamic Split (via KV)

​Metrics Collection

​Advanced: Sequential Testing

​Bayesian A/B Test

​Auto-Promote Winner

​Real-World Examples

​Example 1: Prompt Iteration

​Example 2: Model Selection

​Example 3: Agent Implementation

​Best Practices

​1. Start with Small Traffic

​2. Use Statistical Significance

​3. Test One Thing at a Time

​4. Monitor for Weeks, Not Hours

​5. Consider Sample Size

​Next Steps

Deployment Strategies

Versioning Guide

Rollback & Time Travel

CLI Reference

A/B Testing Basics

Simple A/B Test

Test Results

Multivariate Testing

2×2 Test: Prompt × Model

3×3 Test: Agent × Prompt × Config

Sticky Sessions

Bad (Random)

Good (Sticky)

Implementation

Traffic Splitting

50/50 Split

90/10 Split

33/33/33 Split (3 variants)

Dynamic Split (via KV)

Metrics Collection

Advanced: Sequential Testing

Bayesian A/B Test

Auto-Promote Winner

Real-World Examples

Example 1: Prompt Iteration

Example 2: Model Selection

Example 3: Agent Implementation

Best Practices

1. Start with Small Traffic

2. Use Statistical Significance

3. Test One Thing at a Time

4. Monitor for Weeks, Not Hours

5. Consider Sample Size

Next Steps