Virtual Filesystem
Give agents a PostgreSQL-backed virtual filesystem with per-session isolation so file work stays in the database instead of your laptop disk.
Overview
Virtual Filesystem is an MCP server for the Build phase that exposes a PostgreSQL-backed POSIX-style file layer with session isolation for agents.
What is this MCP server?
- PostgreSQL-backed virtual FS with optional auto-init (VFS_AUTO_INIT)
- Session isolation via VFS_SESSION_ID and optional RLS (VFS_ENABLE_RLS)
- Shared stores plus POSIX-oriented operations for agent file workflows
- npm package mcp-virtual-fs v0.2.2 with stdio transport
- DATABASE_URL required secret for production-grade persistence
- Server version 0.2.2 published as npm package mcp-virtual-fs
- 4 documented environment variables: DATABASE_URL, VFS_AUTO_INIT, VFS_SESSION_ID, VFS_ENABLE_RLS
Community signal: 2 GitHub stars.
What problem does it solve?
Agents that read and write local files create messy, non-resumable state and no clean way to isolate parallel sessions.
Who is it for?
Builders running multi-step agent pipelines who already use PostgreSQL and want durable, isolatable agent workspaces via MCP.
Skip if: Anyone who only needs ephemeral one-off scripts with no persistence requirement or no Postgres available.
What do I get? / Deliverables
After setup, agents manipulate files in a database-backed VFS with session boundaries and optional RLS instead of your repo filesystem.
- MCP tools for agent file CRUD against a Postgres-backed VFS
- Configurable session isolation and optional database-enforced RLS
- Resumable agent workspaces via deterministic VFS_SESSION_ID
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Journey fit
Persistent agent workspaces belong in Build when you integrate storage and session state into the product or dev workflow. integrations captures wiring an external datastore (PostgreSQL) and MCP tools for POSIX-style file operations agents expect.
How it compares
Database-backed virtual FS MCP integration, not a local filesystem skill or S3 browser tool.
Common Questions / FAQ
Who is Virtual Filesystem for?
Indie developers and small teams building agent features who need shared, persistent file semantics backed by PostgreSQL rather than ad hoc temp directories.
When should I use Virtual Filesystem?
Use it during Build integrations when agents must create, update, or share files across sessions, restarts, or multiple concurrent tasks.
How do I add Virtual Filesystem to my agent?
Provision PostgreSQL, set DATABASE_URL (and optional VFS_AUTO_INIT, VFS_SESSION_ID, VFS_ENABLE_RLS), install mcp-virtual-fs from npm, and register the stdio MCP server in your client.