Coding

CodingTools gives an agent four core file/shell tools to perform any coding task in a scoped directory.

CodingTools is a minimal toolkit for coding agents. Four core tools (read, edit, write, shell) let an agent run tests, use git, install packages, and edit code. Three exploration tools (grep, find, ls) are opt-in.

Example

1from kern.agent import Agent
2from kern.models.openai import OpenAIResponses
3from kern.tools.coding import CodingTools
4
5agent = Agent(
6    model=OpenAIResponses(id="gpt-5.4"),
7    tools=[CodingTools(base_dir=".")],
8    instructions="You are a coding assistant. Use the coding tools to help the user.",
9    markdown=True,
10)
11
12agent.print_response(
13    "List the files in the current directory and read the README.md file if it exists.",
14    stream=True,
15)

Warning

CodingTools can run arbitrary shell commands. By default restrict_to_base_dir=True scopes file and shell operations to base_dir and only allows commands in allowed_commands. Keep human supervision for untrusted prompts, and run inside a sandbox (container, VM, or Daytona) for untrusted code execution.

Toolkit Params

Parameter	Type	Default	Description
`base_dir`	`Optional[Path\|str]`	`cwd`	Root directory for file operations.
`restrict_to_base_dir`	`bool`	`True`	When True, file and shell operations cannot escape `base_dir`.
`max_lines`	`int`	`2000`	Maximum lines returned before truncating.
`max_bytes`	`int`	`50000`	Maximum bytes returned before truncating.
`shell_timeout`	`int`	`120`	Timeout in seconds for shell commands.
`enable_read_file`	`bool`	`True`	Enable the `read_file` tool.
`enable_edit_file`	`bool`	`True`	Enable the `edit_file` tool.
`enable_write_file`	`bool`	`True`	Enable the `write_file` tool.
`enable_run_shell`	`bool`	`True`	Enable the `run_shell` tool.
`enable_grep`	`bool`	`False`	Enable the `grep` tool.
`enable_find`	`bool`	`False`	Enable the `find` tool.
`enable_ls`	`bool`	`False`	Enable the `ls` tool.
`all`	`bool`	`False`	Enable all tools regardless of individual flags.
`allowed_commands`	`Optional[List[str]]`	sensible set	Allowed shell command names when `restrict_to_base_dir` is True.

Toolkit Functions

Function	Description
`read_file`	Read a file with line numbers and pagination (`offset`, `limit`).
`edit_file`	Exact text find-and-replace, returns a diff.
`write_file`	Create or overwrite a file.
`run_shell`	Execute a shell command with a timeout.
`grep`	Search file contents (opt-in).
`find`	Find files by glob pattern (opt-in).
`ls`	List directory contents (opt-in).

All functions have sync and async variants.

Developer Resources

Tools source
Basic usage
All tools
Workspace toolkit for a confirmation-gated alternative