Text editor tool

Claude can use an Anthropic-schema text editor tool to view and modify text files, helping you debug, fix, and improve your code or other text documents. This allows Claude to directly interact with your files, providing hands-on assistance rather than just suggesting changes.

For model support, see the Tool reference.

When to use the text editor tool

Some examples of when to use the text editor tool are:

• Code debugging: Have Claude identify and fix bugs in your code, from syntax errors to logic issues.
• Code refactoring: Let Claude improve your code structure, readability, and performance through targeted edits.
• Documentation generation: Ask Claude to add docstrings, comments, or README files to your codebase.
• Test creation: Have Claude create unit tests for your code based on its understanding of the implementation.

Use the text editor tool

Provide the text editor tool (named str_replace_based_edit_tool) to Claude using the Messages API.

You can optionally specify a max_characters parameter to control truncation when viewing large files.

client = anthropic.Anthropic()

response = client.messages.create(
    model="claude-opus-4-7",
    max_tokens=1024,
    tools=[
        {
            "type": "text_editor_20250728",
            "name": "str_replace_based_edit_tool",
            "max_characters": 10000,
        }
    ],
    messages=[
        {
            "role": "user",
            "content": "There's a syntax error in my primes.py file. Can you help me fix it?",
        }
    ],
)

print(response)

The text editor tool can be used in the following way:

Text editor tool commands

The text editor tool supports several commands for viewing and modifying files:

view

The view command allows Claude to examine the contents of a file or list the contents of a directory. It can read the entire file or a specific range of lines.

Parameters:

• command: Must be "view"
• path: The path to the file or directory to view
• view_range (optional): An array of two integers specifying the start and end line numbers to view. Line numbers are 1-indexed, and -1 for the end line means read to the end of the file. This parameter only applies when viewing files, not directories.

str_replace

The str_replace command allows Claude to replace a specific string in a file with a new string. This is used for making precise edits.

Parameters:

• command: Must be "str_replace"
• path: The path to the file to modify
• old_str: The text to replace (must match exactly, including whitespace and indentation)
• new_str: The new text to insert in place of the old text

create

The create command allows Claude to create a new file with specified content.

Parameters:

• command: Must be "create"
• path: The path where the new file should be created
• file_text: The content to write to the new file

insert

The insert command allows Claude to insert text at a specific location in a file.

Parameters:

• command: Must be "insert"
• path: The path to the file to modify
• insert_line: The line number after which to insert the text (0 for beginning of file)
• insert_text: The text to insert

Example: Fixing a syntax error with the text editor tool

This example demonstrates how Claude uses the text editor tool to fix a syntax error in a Python file.

First, your application provides Claude with the text editor tool and a prompt to fix a syntax error:

client = anthropic.Anthropic()

response = client.messages.create(
    model="claude-opus-4-7",
    max_tokens=1024,
    tools=[{"type": "text_editor_20250728", "name": "str_replace_based_edit_tool"}],
    messages=[
        {
            "role": "user",
            "content": "There's a syntax error in my primes.py file. Can you help me fix it?",
        }
    ],
)

print(response)

Claude uses the text editor tool first to view the file:

{
  "id": "msg_01XAbCDeFgHiJkLmNoPQrStU",
  "model": "claude-opus-4-7",
  "stop_reason": "tool_use",
  "role": "assistant",
  "content": [
    {
      "type": "text",
      "text": "I'll help you fix the syntax error in your primes.py file. First, let me take a look at the file to identify the issue."
    },
    {
      "type": "tool_use",
      "id": "toolu_01AbCdEfGhIjKlMnOpQrStU",
      "name": "str_replace_based_edit_tool",
      "input": {
        "command": "view",
        "path": "primes.py"
      }
    }
  ]
}

Your application should then read the file and return its contents to Claude:

response = client.messages.create(
    model="claude-opus-4-7",
    max_tokens=1024,
    tools=[{"type": "text_editor_20250728", "name": "str_replace_based_edit_tool"}],
    messages=[
        {
            "role": "user",
            "content": "There's a syntax error in my primes.py file. Can you help me fix it?",
        },
        {
            "role": "assistant",
            "content": [
                {
                    "type": "text",
                    "text": "I'll help you fix the syntax error in your primes.py file. First, let me take a look at the file to identify the issue.",
                },
                {
                    "type": "tool_use",
                    "id": "toolu_01AbCdEfGhIjKlMnOpQrStU",
                    "name": "str_replace_based_edit_tool",
                    "input": {"command": "view", "path": "primes.py"},
                },
            ],
        },
        {
            "role": "user",
            "content": [
                {
                    "type": "tool_result",
                    "tool_use_id": "toolu_01AbCdEfGhIjKlMnOpQrStU",
                    "content": '1: def is_prime(n):\n2:     """Check if a number is prime."""\n3:     if n <= 1:\n4:         return False\n5:     if n <= 3:\n6:         return True\n7:     if n % 2 == 0 or n % 3 == 0:\n8:         return False\n9:     i = 5\n10:     while i * i <= n:\n11:         if n % i == 0 or n % (i + 2) == 0:\n12:             return False\n13:         i += 6\n14:     return True\n15: \n16: def get_primes(limit):\n17:     """Generate a list of prime numbers up to the given limit."""\n18:     primes = []\n19:     for num in range(2, limit + 1)\n20:         if is_prime(num):\n21:             primes.append(num)\n22:     return primes\n23: \n24: def main():\n25:     """Main function to demonstrate prime number generation."""\n26:     limit = 100\n27:     prime_list = get_primes(limit)\n28:     print(f"Prime numbers up to {limit}:")\n29:     print(prime_list)\n30:     print(f"Found {len(prime_list)} prime numbers.")\n31: \n32: if __name__ == "__main__":\n33:     main()',
                }
            ],
        },
    ],
)

print(response)

Claude identifies the syntax error and uses the str_replace command to fix it:

{
  "id": "msg_01VwXyZAbCdEfGhIjKlMnO",
  "model": "claude-opus-4-7",
  "stop_reason": "tool_use",
  "role": "assistant",
  "content": [
    {
      "type": "text",
      "text": "I found the syntax error in your primes.py file. In the `get_primes` function, there is a missing colon (:) at the end of the for loop line. Let me fix that for you."
    },
    {
      "type": "tool_use",
      "id": "toolu_01PqRsTuVwXyZAbCdEfGh",
      "name": "str_replace_based_edit_tool",
      "input": {
        "command": "str_replace",
        "path": "primes.py",
        "old_str": "    for num in range(2, limit + 1)",
        "new_str": "    for num in range(2, limit + 1):"
      }
    }
  ]
}

Your application should then make the edit and return the result:

response = client.messages.create(
    model="claude-opus-4-7",
    max_tokens=1024,
    tools=[{"type": "text_editor_20250728", "name": "str_replace_based_edit_tool"}],
    messages=[
        # Previous messages...
        {
            "role": "assistant",
            "content": [
                {
                    "type": "text",
                    "text": "I found the syntax error in your primes.py file. In the `get_primes` function, there is a missing colon (:) at the end of the for loop line. Let me fix that for you.",
                },
                {
                    "type": "tool_use",
                    "id": "toolu_01PqRsTuVwXyZAbCdEfGh",
                    "name": "str_replace_based_edit_tool",
                    "input": {
                        "command": "str_replace",
                        "path": "primes.py",
                        "old_str": "    for num in range(2, limit + 1)",
                        "new_str": "    for num in range(2, limit + 1):",
                    },
                },
            ],
        },
        {
            "role": "user",
            "content": [
                {
                    "type": "tool_result",
                    "tool_use_id": "toolu_01PqRsTuVwXyZAbCdEfGh",
                    "content": "Successfully replaced text at exactly one location.",
                }
            ],
        },
    ],
)

print(response)

Finally, Claude provides a complete explanation of the fix:

{
  "id": "msg_01IjKlMnOpQrStUvWxYzAb",
  "model": "claude-opus-4-7",
  "stop_reason": "end_turn",
  "role": "assistant",
  "content": [
    {
      "type": "text",
      "text": "I've fixed the syntax error in your primes.py file. The issue was in the `get_primes` function at line 19. There was a missing colon (:) at the end of the for loop line.\n\nHere's what I changed:\n\nFrom:\n```python\nfor num in range(2, limit + 1)\n```\n\nTo:\n```python\nfor num in range(2, limit + 1):\n```\n\nIn Python, a colon is required at the end of statements that start a new code block, such as for loops, if statements, function definitions, etc. Without the colon, Python raises a syntax error because it doesn't know where the code block begins.\n\nYour code should now run correctly. The function will properly generate a list of prime numbers up to the specified limit."
    }
  ]
}

Implement the text editor tool

The text editor tool is implemented as a schema-less tool. When using this tool, you don't need to provide an input schema as with other tools; the schema is built into Claude's model and can't be modified.

The tool type is type: "text_editor_20250728" for Claude 4 models.

Handle errors

When using the text editor tool, various errors may occur. Here is guidance on how to handle them:

Follow implementation best practices

Pricing and token usage

The text editor tool uses the same pricing structure as other tools used with Claude. It follows the standard input and output token pricing based on the Claude model you're using.

In addition to the base tokens, the following additional input tokens are needed for the text editor tool:

For more detailed information about tool pricing, see Tool use pricing.

Integrate the text editor tool with other tools

The text editor tool can be used alongside other Claude tools. When combining tools, ensure you:

• Match the tool version with the model you're using
• Account for the additional token usage for all tools included in your request

Change log

Next steps

Here are some ideas for how to use the text editor tool in more convenient and powerful ways:

• Integrate with your development workflow: Build the text editor tool into your development tools or IDE
• Create a code review system: Have Claude review your code and make improvements
• Build a debugging assistant: Create a system where Claude can help you diagnose and fix issues in your code
• Implement file format conversion: Let Claude help you convert files from one format to another
• Automate documentation: Set up workflows for Claude to automatically document your code

The text editor tool enables Claude to work directly with your codebase, supporting workflows from debugging to automated documentation.