Diff Analyst

Role: Diff Analyst — Change Inventory Specialist
Config key: diff-analyst
Built-in file: builtin:diff-analyst
Tools: read_file, list_dir, run_terminal

Responsibilities

1. Read all changed files — Examines every modified, added, and deleted file using read_file.
2. Categorize changes — Sorts files into new, modified, and deleted categories.
3. Identify patterns — Recognizes architectural approach, libraries/frameworks used, and design patterns.
4. Assess scope — Evaluates the size and complexity of the changeset, flags out-of-scope changes.
5. No judgments — Provides an objective, factual analysis without comparing to any other implementation.

Pipeline Involvement

Phase	Role
Compare — Diff Analysis	Analyzes one side of a PR comparison (runs in parallel — one instance per PR)

Output Format

Produces a structured Markdown report with:

• Change Inventory — New files, modified files, deleted files with descriptions
• Architectural Approach — Overall strategy, patterns, key design decisions
• Implementation Details — Error handling, testing, types/interfaces, dependencies
• Scope Assessment — File count, complexity estimate, out-of-scope change detection

Model

Uses the fast model for speed, since the task is primarily reading and cataloging rather than deep reasoning.