Claude Code
storage
File Write Operations Failing with Permission Errors
Your application fails when trying to write files to disk, throwing EACCES, EPERM, or permission denied errors. File uploads, log writing, cache storage, or report generation all fail because the application process doesn't have write access to the target directories.
This commonly happens when Claude Code generates code that writes to absolute paths like /tmp, /var, or the project root directory, but the deployment environment (Docker container, cloud function, or restricted server) doesn't allow writes to those locations.
The code works perfectly in local development where you run as an admin user, but breaks immediately in production where the application runs as a restricted service account.
Error Messages You Might See
Error: EACCES: permission denied, open '/var/data/output.pdf'
EPERM: operation not permitted, mkdir '/app/uploads'
OSError: [Errno 13] Permission denied: '/opt/data/cache'
Read-only file system
Common Causes
- Hardcoded absolute paths — Code writes to /tmp or /var/data which may be read-only in containerized environments
- Read-only filesystem in serverless — Cloud functions and some container runtimes have read-only root filesystems
- Docker container running as non-root — The application user inside the container doesn't own the target directory
- Missing directory creation — Code tries to write a file before creating its parent directory
- SELinux or AppArmor restrictions — Security modules blocking file writes even when Unix permissions allow them
How to Fix It
- Use os.tmpdir() or platform-agnostic paths — Replace hardcoded paths with Node's os.tmpdir() or Python's tempfile.gettempdir()
- Create directories before writing — Always call fs.mkdirSync(dir, {recursive: true}) or os.makedirs(dir, exist_ok=True) before file operations
- Use /tmp in serverless — In AWS Lambda or similar, /tmp is the only writable directory. Configure your app to use it
- Set correct Docker permissions — Add RUN chown -R appuser:appuser /app/data in your Dockerfile for writable directories
- Use object storage for production — Replace local file writes with S3, GCS, or Supabase Storage for production deployments
Real developers can help you.
David Olverson
Solo dev shipping production apps with AI-assisted development. I specialize in rescuing broken Lovable/Bolt/Cursor builds and taking them to production. 10+ apps shipped including SaaS CRMs, gaming platforms, real estate tools, and Discord bots. Stack: Next.js 16, TypeScript, Tailwind CSS, FastAPI, PostgreSQL, Prisma. I use Claude Code with 50+ custom skills for rapid delivery. Average turnaround: 2-4 weeks from broken prototype to production.
Jared Hasson
Full time lead founding dev at a cyber security saas startup, with 10 yoe and a bachelor's in CS. Building & debugging software products is what I've spent my time on for forever
PawelPloszaj
I'm fronted developer with 10+ years of experience with big projects. I have small backend background too
Omar Faruk
As a Product Engineer at Klasio, I contributed to end-to-end product development, focusing on scalability, performance, and user experience.
My work spanned building and refining core features, developing dynamic website templates, integrating secure and reliable payment gateways, and optimizing the overall system architecture.
I played a key role in creating a scalable and maintainable platform to support educators and learners globally.
I'm enthusiastic about embracing new challenges and making meaningful contributions.
Krishna Sai Kuncha
Experienced Professional Full stack Developer with 8+ years of experience across react, python, js, ts, golang and react-native. Developed inhouse websearch tooling for AI before websearch was solved : )
Matthew Jordan
I've been working at a large software company named Kainos for 2 years, and mainly specialise in Platform Engineering. I regularly enjoy working on software products outside of work, and I'm a huge fan of game development using Unity. I personally enjoy Python & C# in my spare time, but I also specialise in multiple different platform-related technologies from my day job.
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ISHANTDEEP SINGH
Senior Software Engineer with 7+ years of experience in React, JavaScript, TypeScript, Next.js, and Node.js. I’ve also worked as a tech lead for startups, owning end-to-end technical execution including architecture, development, scaling, and delivery. I bring a strong mix of hands-on coding, product thinking, and technical leadership, and I’m comfortable building products from scratch as well as improving and scaling existing systems.
Yovel Cohen
I got a lot of experience in building Long-horizon AI Agents in production, Backend apps that scale to millions of users and frontend knowledge as well.
Vlad Temian
15+ years shipping production infrastructure for startups. Former CTO at qed.builders (acquired by The Sandbox).
Cursor ambassador and agentic tooling builder.
I've scaled systems, automated deployments, and built observability tools for AI coding workflows. I specialize in taking vibe-coded apps from broken prototype to production-ready: fixing Supabase auth/RLS, Stripe integrations, deployment pipelines, and cleaning up AI-generated spaghetti.
I build tools in this space (agentprobe, claudebin, micode) and understand both sides: how AI generates code and why it breaks.
https://blog.vtemian.com/
You don't need to be technical. Just describe what's wrong and a verified developer will handle the rest.
Get HelpFrequently Asked Questions
Why does file writing work locally but not in production?
Local development typically runs as your user with full permissions. Production environments (Docker, serverless, cloud VMs) run as restricted users with limited filesystem access. Always use platform-appropriate writable directories.
Where can I write files in AWS Lambda?
Only the /tmp directory is writable in Lambda, with a 512MB limit (configurable up to 10GB). For persistent storage, upload to S3 instead of writing locally.