Context

Implement the first set of built-in tools for file system operations. These are the most fundamental tools that agents need for code generation, file management, and workspace interaction.

Acceptance Criteria

• read_file tool: read file contents with optional line range
• write_file tool: create or overwrite files
• edit_file tool: modify specific sections of existing files
• list_directory tool: list files and directories with optional filtering
• delete_file tool: remove files (elevated access only)
• All tools implement the tool interface from Implement hierarchical delegation (task flows down, results flow up) #12
• Path validation: prevent workspace escape (no ../ traversal attacks)
• Workspace boundary enforcement per agent access level
• Comprehensive error handling (file not found, permission denied, disk full, etc.)
• Unit tests with temporary directories for all operations
• Edge case tests: empty files, large files, binary files, symlinks

Dependencies

• Depends on Implement hierarchical delegation (task flows down, results flow up) #12 (basic tool system — tool interface and registry)

Design Spec Reference

Section 11.1 — Built-in Tools