Fix package root path calculation in rules service

[JeremyDev87]

Fix Package Root Path Calculation in Rules Service

Summary

This PR fixes a critical bug in the RulesService where the package root path calculation was incorrect for built environments. The service was using a hardcoded 2-step path resolution (../..) which worked for development but failed in production builds where the structure is dist/src/rules/ instead of dist/rules/.

Problem

Bug Description

The RulesService was incorrectly calculating the package root path in built environments:

Before:

• Always used ../.. (2 steps up) regardless of environment
• Assumed build structure: dist/rules/rules.service.js
• Actual build structure: dist/src/rules/rules.service.js

Impact:

• In production builds, the service couldn't locate .ai-rules directory
• MCP server failed to load rules when running from built code
• Only worked correctly in development environment

Root Cause

The code assumed the build output structure matched the source structure, but TypeScript compilation preserves the src/ directory structure in the dist/ output:

Source:  src/rules/rules.service.ts
Built:   dist/src/rules/rules.service.js  ← 3 steps up needed

Solution

Changes Made

1. Environment Detection

   • Added detection logic to distinguish between built and development environments
   • Checks if __dirname contains /dist/ or \dist\ (cross-platform)

2. Dynamic Path Resolution

   • Built environment: ../../.. (3 steps up from dist/src/rules/)
   • Development environment: ../.. (2 steps up from src/rules/)

3. Updated Comments

   • Corrected comments to reflect actual build structure
   • Added clear explanation of path resolution logic

Code Changes

File: mcp-server/src/rules/rules.service.ts

// Before
const packageRoot = path.resolve(__dirname, '../..');

// After
const isBuilt =
  __dirname.includes('/dist/') || __dirname.includes('\\dist\\');
const stepsUp = isBuilt ? '../../..' : '../..';
const packageRoot = path.resolve(__dirname, stepsUp);

Impact

Before Fix

• ❌ Production builds failed to locate .ai-rules directory
• ❌ MCP server couldn't load rules in built environment
• ❌ Only worked in development mode

After Fix

• ✅ Correctly resolves package root in both environments
• ✅ MCP server works in production builds
• ✅ Maintains backward compatibility with development environment
• ✅ Cross-platform path detection (Windows/Unix)

Testing

Test Scenarios

1. Development Environment

   • ✅ Service correctly resolves path from src/rules/
   • ✅ Finds .ai-rules directory at package root

2. Production Build

   • ✅ Service correctly resolves path from dist/src/rules/
   • ✅ Finds .ai-rules directory at package root

3. Cross-Platform

   • ✅ Works on Windows (\dist\ detection)
   • ✅ Works on Unix/Linux/macOS (/dist/ detection)

Verification Steps

1. Build the project: npm run build
2. Run MCP server from built code
3. Verify .ai-rules directory is found correctly
4. Confirm rules are loaded successfully

Related Issue

Closes #77

Files Changed

• mcp-server/src/rules/rules.service.ts - Fixed path calculation logic

Statistics

• 1 file changed
• 8 insertions, 4 deletions
• 1 bug fix (path resolution)

Technical Details

Path Resolution Logic

Development:
src/rules/rules.service.ts
  → ../.. (2 steps)
  → package root ✓

Production:
dist/src/rules/rules.service.js
  → ../../.. (3 steps)
  → package root ✓

Environment Detection

The fix uses a simple string check on __dirname:

• Checks for /dist/ (Unix-style paths)
• Checks for \dist\ (Windows-style paths)
• Works cross-platform without requiring path module operations

Notes

This is a critical fix for production deployments. Without this fix, the MCP server would fail to locate rules files when running from built code, making it unusable in production environments.

The fix maintains backward compatibility with development environments while correctly handling the production build structure.