Feature request: Workflow for adding features to existing large codebases (50K+ LOC)

[developerisnow]

Context

After digging into the codebase, I found that CodeMachine already has some building blocks for this use case. This issue is now more of a discussion/clarification request than a pure feature request.

Use Case

Adding medium-sized features (3-10K LOC) to existing large codebases (50K+ LOC)

This is different from:

• Generating new projects from scratch (what codemachine-one optimizes for)
• Small bug fixes
• Complete rewrites/refactoring

What I Found in the Codebase

✅ Already Exists:

1. Context Manager Agent (05-context-manager-agent.md) already does:

   • Phase 0: Project Reconnaissance (ls -R based ground-truth mapping)
   • Phase 1: Reads 2-4 most critical existing source files
   • Phase 2: Generates .codemachine/prompts/context.md with file summaries, recommendations, tips

2. Controller workflows support track-based selection - could theoretically do:

export default {
  controller: true,
  tracks: {
    question: 'New project or add feature?',
    options: {
      new: { label: 'Full Generation' },
      feature: { label: 'Add to Existing' },
    },
  },
  steps: [
    // Skip heavy planning for feature addition
    resolveStep('principal-analyst', { tracks: ['new'] }),
    resolveStep('blueprint-orchestrator', { tracks: ['new'] }),
    resolveStep('context-manager'), // Both tracks
    resolveStep('code-generation'),
    resolveStep('git-commit'),
  ],
}

3. Issue How to tweak workflow and resume codemachine ? #42 workaround: Manually add tasks to .codemachine/tasks/ and delete memory/behavior.json

❓ Questions Remaining:

1. Is creating a custom feature-addition.workflow.js the recommended approach?
2. Would you consider adding an official "lightweight" workflow template for this use case?
3. Any tips for optimizing Context Manager for large (50K+ LOC) codebases - does it handle them well?

Related Issues

• 2000 lines of code in 5 hours with more than 2M tokens ~160 USD on Claude Code #50 (default workflow overkill for small projects)
• How to tweak workflow and resume codemachine ? #42 (workflow customization, resume, adding features after completion)
• Does CodeMachine provide a non-interactive way to script agent runs? #51 (non-interactive mode)

Thanks for the great tool! Just trying to understand the best path forward for this use case.