# Experiment: Impact of Context on Diff Summary Quality

## Overview

Research conducted during Sprint 3 to evaluate the impact of context on diff summary quality.

## Findings

Despite the summary quality being similar with or without context and currently not very good without preprocessing, the customer appreciated the findings as valuable for future work.

## Experimental Data

Two experiments were conducted to evaluate the impact of context on diff summary quality.

### Experiment 1: Without Repository URL

See [experiment-context-impact-1.md](./experiment-context-impact-1.md) for full details.

### Experiment 2: With Repository URL

See [experiment-context-impact-2.md](./experiment-context-impact-2.md) for full details.

### Methodology

The experiment was designed to evaluate whether providing repository context (specifically the repository URL) improves the quality of diff summaries generated by an AI assistant.

**Repository Used**: The Opal repository (https://github.com/permitio/opal) was selected as the test case. This is a Python-based project that provides authorization and policy management capabilities.

**Test Diff**: Both experiments used the same git diff output containing changes to:
- `.github/workflows/on_release.yml` - Added version bumping mechanism
- `.github/workflows/pre-commit.yml` - Updated Python version
- `packages/opal-common/opal_common/monitoring/apm.py` - Refactored Datadog APM trace filtering
- `scripts/start.sh` - Fixed Datadog APM enablement logic and changed file permissions

**Prompt Variations**:
1. **Experiment 1 (Without Context)**: The prompt did not include the repository URL. The assistant was instructed to summarize changes based solely on the diff output.
2. **Experiment 2 (With Context)**: The prompt explicitly included the repository URL (`https://github.com/permitio/opal`) and instructed the assistant to use both the diff and repository URL for context.

**Evaluation Method**: Both summaries were generated using the same AI model and compared for:
- Accuracy of technical details
- Completeness of coverage
- Clarity and organization
- Use of repository-specific context

### Results Summary

**Summary Comparison**:

Both summaries correctly identified the main changes across all four modified files. However, notable differences emerged:

1. **Repository Context Usage**:
   - **Experiment 2 (With URL)**: Explicitly mentions the repository name (`permitio/opal`) in the opening statement, demonstrating awareness of the repository context.
   - **Experiment 1 (Without URL)**: No repository-specific context is mentioned.

2. **Detail Level**:
   - **Experiment 2**: Provides slightly more detailed explanations, particularly for the PyPI version bumping mechanism, noting that the `semver2pypi.py` script is "inferred from `run` command" rather than present in the diff.
   - **Experiment 1**: Also comprehensive but uses slightly different phrasing, describing the script as "not provided in this diff."

3. **Technical Accuracy**:
   - Both summaries accurately describe:
     - The version bumping workflow changes
     - Python version updates
     - Datadog APM trace filtering improvements
     - The corrected shell script logic for APM enablement
   - Both correctly identify the logical flaw in the original `start.sh` condition.

4. **Structure and Organization**:
   - Both summaries use similar hierarchical organization with clear section headers.
   - Experiment 2's summary is slightly more verbose (247 lines vs 246 lines in the raw output).

5. **Impact Assessment**:
   - Both summaries explain the purpose and impact of changes effectively.
   - Experiment 2 provides slightly more context about why certain changes were made (e.g., "likely due to newer dependencies" for Python version update).

**Key Finding**: The inclusion of the repository URL resulted in minimal qualitative improvement. The summaries are substantially similar in accuracy, completeness, and clarity. The main difference is the explicit mention of the repository name in Experiment 2, but this does not significantly enhance the technical understanding of the changes.

## Conclusions

The experiment demonstrates that **providing repository URL context has minimal impact on diff summary quality** when the diff itself contains sufficient information. Both summaries achieved similar levels of:

- **Technical Accuracy**: Both correctly identified and explained all changes
- **Completeness**: Both covered all four modified files comprehensively
- **Clarity**: Both were well-organized and easy to understand

**Implications**:

1. **For Current Implementation**: The repository URL may not be necessary for generating high-quality summaries when diffs are self-contained and well-structured. This suggests that preprocessing or diff enhancement might be more valuable than repository context.

2. **For Future Work**: 
   Further experiments could evaluate:
     - Providing additional repository metadata (description, README, project structure)
     - Including related file contents referenced in the diff
     - Adding commit message context
     - Combining multiple context sources

3. **Resource Efficiency**: Since repository URL context provides minimal benefit, focusing computational resources on diff preprocessing and enhancement may yield better results.

**Recommendation**: Prioritize diff preprocessing and enhancement techniques over repository URL context for improving summary quality. The repository URL can be included for completeness but should not be considered a primary quality improvement mechanism.

