nushell-mcp

nushell-mcp is a Rust stdio MCP server that exposes trusted local Nushell execution through structured MCP tools.

Tools

Core Nushell tools:

• nu_version: runs nu --version.
• nu_eval: runs inline code with nu --no-config-file --commands <command>.
• nu_script: runs a .nu script file with optional positional arguments.

Nushell convenience tools inspired by git-bash-opencode-plugin:

• nu_grep: search file contents with pattern/path/recursive/ignore-case options.
• nu_find: find files or directories with name, extension, type, and recursion filters.
• nu_read: read file head, tail, or first lines with optional line numbers.
• nu_ls: list directory contents.

Git workflow tools inspired by git-opencode-plugin:

• git_status: working tree status, optionally porcelain.
• git_diff: unstaged, staged, or ref diff.
• git_log: recent commit history.
• git_tree: commit graph with branch topology.
• git_branch: list, create, or switch branches.
• git_commit: stage files and commit through a temporary message file.
• git_stash: push, pop, list, or drop stashes.
• git_precommit_review: summarize staged changes before committing.

Every tool returns JSON text with:

• ok
• exit_code
• signal
• timed_out
• duration_ms
• stdout
• stderr
• stdout_truncated
• stderr_truncated
• command
• error

Build

& "$env:USERPROFILE\.cargo\bin\cargo.exe" build --release

The release binary is written to:

D:\nushell-mcp\target\release\nushell-mcp.exe

Nushell must be on PATH as nu, or configured with:

$env:NUSHELL_MCP_NU_PATH = "C:\Path\To\nu.exe"

Quick checks:

.\target\release\nushell-mcp.exe --version
.\target\release\nushell-mcp.exe health --json
powershell -ExecutionPolicy Bypass -File .\scripts\mcp_smoke.ps1

OpenCode

Add this server to opencode.json or opencode.jsonc:

{
  "mcp": {
    "nushell": {
      "type": "local",
      "command": ["D:\\nushell-mcp\\target\\release\\nushell-mcp.exe"],
      "enabled": true,
      "timeout": 120000,
      "environment": {
        "NUSHELL_MCP_NU_PATH": "C:\\Path\\To\\nu.exe"
      }
    }
  }
}

If nu is already on PATH, omit environment.

Codex

Add this to config.toml:

[mcp_servers.nushell]
command = "D:/nushell-mcp/target/release/nushell-mcp.exe"
args = []

[mcp_servers.nushell.env]
NUSHELL_MCP_NU_PATH = "C:/Path/To/nu.exe"

If nu is already on PATH, omit the env block.

Security

This server intentionally executes arbitrary Nushell and Git commands with the permissions of the MCP host process. Enable it only for trusted local clients and trusted workspaces.

The implementation invokes nu directly with argument vectors, not through another shell. It also enforces bounded timeouts and per-stream output capture limits, but it is not a sandbox.

Reference Plugins

The expanded tool set borrows workflow ideas from:

• https://github.com/stevenke1981/git-opencode-plugin.git
• https://github.com/stevenke1981/git-bash-opencode-plugin.git

This project remains an MCP server. It does not copy OpenCode plugin hooks such as message transforms, compaction guidance, or shell.env.