Tools & Approval Modes

Copilot Shell executes file operations, shell commands, search, and other tasks through built-in tools. This document covers the tool system and approval modes.

Built-in Tools

Copilot Shell provides the following core tools:

Tool	Function
File Read/Write	Read, create, and edit files
Shell Execution	Run shell commands
Code Search	Full-text search powered by ripgrep
File Search	Find files by name pattern
Directory Listing	List directory contents
Web Search	Search the internet for information
MCP Tools	Call external tools via MCP protocol

Use the /tools command to see all available tools in the current session.

Approval Modes

Approval modes determine whether Copilot Shell requires user confirmation before executing tools. Set via the /approval-mode command or the tools.approvalMode configuration key.

plan

Only generates an action plan without executing any tool calls. Useful for reviewing AI decision-making.

default (Default)

Requests confirmation before each tool call. The user can:

• Press y or Enter to confirm
• Press n to reject
• Press a to accept all for the current session

auto-edit

Auto-approves file edit operations; other operations (such as shell commands) still require confirmation. Suitable when you trust the AI's code modifications but want to control external command execution.

yolo

Auto-approves all tool calls without any confirmation.

[!WARNING]

yolo mode skips all safety confirmations. Recommended only in controlled environments or when combined with sandbox hooks. Can also be specified at launch with cosh --yolo or cosh -y.

Tool Filtering

Allowlist

Set specific tools for auto-execution without confirmation:

{
  "tools": {
    "allowed": ["ReadFile", "ListDir", "GrepSearch"]
  }
}

Tools on the allowlist execute automatically even in default mode.

Excluding Tools

Prevent specific tools from being called:

{
  "tools": {
    "exclude": ["WebSearch"]
  }
}

Excluded tools are invisible to the AI and will not appear in the tool list.

Shell Tool Configuration

Interactive Shell (PTY)

When enabled, shell commands execute through a pseudo-terminal, supporting sudo, interactive programs, etc.:

{
  "tools": {
    "shell": {
      "enableInteractiveShell": true
    }
  }
}

Output Display

{
  "tools": {
    "shell": {
      "showColor": true,
      "pager": "cat"
    }
  }
}

Tool Output Truncation

When tool output is too large, Copilot Shell automatically truncates it to save tokens:

{
  "tools": {
    "enableToolOutputTruncation": true,
    "truncateToolOutputThreshold": 50000,
    "truncateToolOutputLines": 200
  }
}

• truncateToolOutputThreshold: Trigger truncation above this character count (-1 to disable)
• truncateToolOutputLines: Number of lines to keep after truncation

Search Tool

Copilot Shell uses the built-in ripgrep for code search by default:

{
  "tools": {
    "useRipgrep": true,
    "useBuiltinRipgrep": true
  }
}

• useRipgrep: Enable ripgrep (faster than the default implementation)
• useBuiltinRipgrep: Use the bundled rg binary. Set to false to use the system rg