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Overview

One of Forge’s most powerful features: compare results from multiple AI agents side-by-side. See which approach works best, cherry-pick the best parts, or combine solutions.

Why Compare?

Different AI agents have different strengths: Solution: Try multiple, compare results, choose the best!

Quick Comparison

Via CLI

Via Web UI

1

Open Task

Click on task card in Kanban board
2

View Attempts Tab

Click Attempts tab to see all attempts
3

Select Attempts to Compare

Check boxes next to 2+ attempts
4

Click 'Compare'

Opens split-view comparison interface

Comparison Views

File-by-File Diff

Output:

Side-by-Side Code Comparison

Output:

Statistics Comparison

Output:

Detailed Comparison

Test Results

Output:

Code Quality Metrics

Output:

Performance Analysis

Output:

Visual Comparison (Web UI)

The Forge UI provides rich visual comparisons:

Split-Screen Editor

  • Left pane: Attempt 1 code
  • Right pane: Attempt 2 code
  • Synchronized scrolling
  • Inline diff highlighting

Architecture Diagram

Auto-generated comparison:

Decision Matrix

Build a decision matrix to choose systematically:
Output:

Cherry-Picking Best Parts

Sometimes you want to combine approaches:

Manual Cherry-Pick

Via Web UI

  1. Open comparison view
  2. Select blocks of code from different attempts
  3. Click “Create Combined Attempt”
  4. Forge creates new attempt merging selected parts

Common Comparison Scenarios

Feature Implementation

Question: Which agent implemented the feature most completely?

Bug Fix

Question: Which fix actually solves the bug without breaking anything?

Refactoring

Question: Which refactor improves code without changing behavior?

Export Comparison Reports

Generate Report

Share with Team


Best Practices

Test All Attempts

Don’t just read code - run tests:
Code that looks good but fails tests is useless

Check Edge Cases

Specifically test edge cases:
Simple cases are easy; edges matter

Consider Maintainability

Today: All work Six months from now: Which will you understand?Prefer clear code over clever code

Document Your Choice

Future you will thank you

Advanced: A/B Testing in Production

For critical features, deploy multiple attempts for A/B testing:
Monitor metrics:
  • Response times
  • Error rates
  • User feedback
Choose winner based on real-world data!

Troubleshooting

Issue: Comparing large attempts is slowSolutions:
  • Use --files-only to skip detailed diffs
  • Compare specific files: --file src/auth/login.ts
  • Increase timeout: --timeout 300
Issue: Attempts look identicalSolutions:
  • Check if comparing same attempt twice
  • Use --ignore-whitespace to see real changes
  • Try --context 10 for more surrounding lines
Issue: Can’t run tests in worktreesSolutions:
  • Ensure dependencies installed in each worktree
  • Check test paths are correct
  • Use --setup-cmd "npm install" first

Next Steps

Merging & Cleanup

Merge your chosen attempt to main

Managing Attempts

Learn more about working with attempts

Specialized Agents

Create agents optimized for different tasks

Parallel Execution

Run multiple attempts simultaneously