Summary

Workspace merge only detects textual git conflicts (merge markers). Semantic conflicts (broken imports, type mismatches, logic errors from independently correct changes) are not detected.

Finding (from codebase audit)

• src/synthorg/engine/workspace/git_worktree.py:549-550:

  # Git diff --diff-filter=U only detects textual conflicts;
  # semantic conflict detection is not yet implemented

• Only ConflictType.TEXTUAL conflicts are created
• The design spec (engine.md, section 9.3) requires: "Semantic conflicts: review agent evaluates merged result"

Impact

When two agents work on parallel workspace branches and their changes are merged:

• Textual conflicts (merge markers) are caught correctly
• But merged code can have correct syntax yet broken semantics (e.g., Agent A renames a function, Agent B adds a call to the old name - merge succeeds but code is broken)

Approach Options

1. LLM-based review: After merge, pass the diff to an LLM agent asking "does this merged result have semantic conflicts?"
2. AST-based analysis: Parse merged code, check for undefined references, type mismatches
3. Test-based validation: Run the test suite on the merged result to detect regressions
4. Hybrid: Quick AST check + targeted LLM review for suspicious patterns

Design Spec Reference

• Engine design page, section 9.3 (Workspace Isolation, Strategy 1)

Files to Modify

• src/synthorg/engine/workspace/git_worktree.py (add semantic analysis after merge)
• Possibly new module src/synthorg/engine/workspace/semantic_analyzer.py