filesystem-agents

Create a ToolLoopAgent with a model, instructions, and a bash tool built via a factory function that takes a Vercel Sandbox. The tool uses a Zod schema with .describe() on every field and executes commands through sandbox.runCommand, returning stdout, stderr, and exitCode.

It reads your project files and checks specific markers: whether lib/agent.ts exists, whether it imports ToolLoopAgent, whether lib/tools.ts contains createBashTool, whether Sandbox.create() is called, and whether loadSandboxFiles is present. Each marker maps to a specific lesson.

The most common causes are instructions that never mention the tool by name, a vague tool description, missing .describe() calls on Zod schema fields, or an empty tools object in the ToolLoopAgent config. Check each of these in order.

The loadSandboxFiles function must be awaited before the agent export, since the sandbox starts empty. Also verify that writeFiles paths are relative to the sandbox root, not your local project root.

Yes. The domain mapping reference covers decision criteria, directory structure designs (flat, by date, by category, hierarchical), and transformation patterns for converting API responses, CSVs, or database rows into markdown files the agent can navigate.

The sandbox provides a minimal Linux environment with standard coreutils such as ls, cat, grep, find, awk, sed, and sort. Specialized tools like jq or python are not installed by default but can be added via apt-get or replaced with TypeScript tools.