Anthropic 平台文档（英文全量）

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.

max_characters is only compatible with text_editor_20250728 and later versions of the text editor tool.

bash

curl https://api.anthropic.com/v1/messages \
  -H "content-type: application/json" \
  -H "x-api-key: $ANTHROPIC_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -d '{
    "model": "claude-opus-5",
    "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?"
      }
    ]
  }'

bash

ant messages create \
  --model claude-opus-5 \
  --max-tokens 1024 \
  --tool '{type: text_editor_20250728, name: str_replace_based_edit_tool, max_characters: 10000}' \
  --message '{role: user, content: There is a syntax error in my primes.py file. Can you help me fix it?}'

python

client = anthropic.Anthropic()

response = client.messages.create(
    model="claude-opus-5",
    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)

typescript

const anthropic = new Anthropic();

const response = await anthropic.messages.create({
  model: "claude-opus-5",
  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?"
    }
  ]
});

console.log(response);

csharp

var client = new AnthropicClient();

var response = await client.Messages.Create(
    new()
    {
        Model = Model.ClaudeOpus5,
        MaxTokens = 1024,
        Tools = [new ToolTextEditor20250728 { MaxCharacters = 10000 }],
        Messages =
        [
            new()
            {
                Role = Role.User,
                Content = "There's a syntax error in my primes.py file. Can you help me fix it?",
            },
        ],
    }
);

Console.WriteLine(response);

client := anthropic.NewClient()

response, err := client.Messages.New(context.TODO(), anthropic.MessageNewParams{
	Model:     anthropic.ModelClaudeOpus5,
	MaxTokens: 1024,
	Tools: []anthropic.ToolUnionParam{
		{OfTextEditor20250728: &anthropic.ToolTextEditor20250728Param{
			MaxCharacters: anthropic.Int(10000),
		}},
	},
	Messages: []anthropic.MessageParam{
		anthropic.NewUserMessage(anthropic.NewTextBlock("There's a syntax error in my primes.py file. Can you help me fix it?")),
	},
})
if err != nil {
	log.Fatal(err)
}
fmt.Println(response)

java

import com.anthropic.models.messages.ToolTextEditor20250728;
// ...
void main() {
  AnthropicClient client = AnthropicOkHttpClient.fromEnv();

  ToolTextEditor20250728 editorTool =
    ToolTextEditor20250728.builder()
      .maxCharacters(10000L)
      .build();

  MessageCreateParams params = MessageCreateParams.builder()
    .model(Model.CLAUDE_OPUS_5)
    .maxTokens(1024)
    .addTool(editorTool)
    .addUserMessage("There's a syntax error in my primes.py file. Can you help me fix it?")
    .build();

  Message message = client.messages().create(params);
  IO.println(message);
}

php

$client = new Client();

$response = $client->messages->create(
    model: 'claude-opus-5',
    maxTokens: 1024,
    tools: [ToolTextEditor20250728::with(maxCharacters: 10000)],
    messages: [
        [
            'role' => 'user',
            'content' => "There's a syntax error in my primes.py file. Can you help me fix it?",
        ],
    ],
);

echo $response;

ruby

client = Anthropic::Client.new

response = client.messages.create(
  model: "claude-opus-5",
  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?"
    }
  ]
)

puts response

Use the text editor tool in the following way:

* Include the text editor tool in your API request
* Provide a user prompt that may require examining or modifying files, such as "Can you fix the syntax error in my code?"

* Claude assesses what it needs to look at and uses the `view` command to examine file contents or list directory contents
* The API response will contain a `tool_use` content block with the `view` command

* Extract the file or directory path from Claude's tool use request
* Read the file's contents or list the directory contents
* If a `max_characters` parameter was specified in the tool configuration, truncate the file contents to that length
* Return the results to Claude by continuing the conversation with a new `user` message containing a `tool_result` content block

* After examining the file or directory, Claude may use a command such as `str_replace` to make changes or `insert` to add text at a specific line number.
* If Claude uses the `str_replace` command, Claude constructs a properly formatted tool use request with the old text and new text to replace it with

* Extract the file path, old text, and new text from Claude's tool use request
* Perform the text replacement in the file
* Return the results to Claude

* After examining and possibly editing the files, Claude provides a complete explanation of what it found and what changes it made

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.

Example for viewing a file:

json

{
  "type": "tool_use",
  "id": "toolu_01A09q90qw90lq917835lq9",
  "name": "str_replace_based_edit_tool",
  "input": {
    "command": "view",
    "path": "primes.py"
  }
}

Example for viewing a directory:

json

{
  "type": "tool_use",
  "id": "toolu_02B19r91rw91mr917835mr9",
  "name": "str_replace_based_edit_tool",
  "input": {
    "command": "view",
    "path": "src/"
  }
}

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

json

{
  "type": "tool_use",
  "id": "toolu_01A09q90qw90lq917835lq9",
  "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):"
  }
}

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

json

{
  "type": "tool_use",
  "id": "toolu_01A09q90qw90lq917835lq9",
  "name": "str_replace_based_edit_tool",
  "input": {
    "command": "create",
    "path": "test_primes.py",
    "file_text": "import unittest\nimport primes\n\nclass TestPrimes(unittest.TestCase):\n    def test_is_prime(self):\n        self.assertTrue(primes.is_prime(2))\n        self.assertTrue(primes.is_prime(3))\n        self.assertFalse(primes.is_prime(4))\n\nif __name__ == '__main__':\n    unittest.main()"
  }
}

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

json

{
  "type": "tool_use",
  "id": "toolu_01A09q90qw90lq917835lq9",
  "name": "str_replace_based_edit_tool",
  "input": {
    "command": "insert",
    "path": "primes.py",
    "insert_line": 0,
    "insert_text": "\"\"\"Module for working with prime numbers.\n\nThis module provides functions to check if a number is prime\nand to generate a list of prime numbers up to a given limit.\n\"\"\"\n"
  }
}

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:

bash

curl https://api.anthropic.com/v1/messages \
  -H "content-type: application/json" \
  -H "x-api-key: $ANTHROPIC_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -d '{
    "model": "claude-opus-5",
    "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?"
      }
    ]
  }'

bash

ant messages create \
  --model claude-opus-5 \
  --max-tokens 1024 \
  --tool '{type: text_editor_20250728, name: str_replace_based_edit_tool}' \
  --message '{role: user, content: There is a syntax error in my primes.py file. Can you help me fix it?}'

python

client = anthropic.Anthropic()

response = client.messages.create(
    model="claude-opus-5",
    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)

typescript

const anthropic = new Anthropic();

const response = await anthropic.messages.create({
  model: "claude-opus-5",
  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?"
    }
  ]
});

console.log(response);

csharp

var client = new AnthropicClient();

var response = await client.Messages.Create(
    new()
    {
        Model = Model.ClaudeOpus5,
        MaxTokens = 1024,
        Tools = [new ToolTextEditor20250728()],
        Messages =
        [
            new()
            {
                Role = Role.User,
                Content = "There's a syntax error in my primes.py file. Can you help me fix it?",
            },
        ],
    }
);

Console.WriteLine(response);

client := anthropic.NewClient()

response, err := client.Messages.New(context.TODO(), anthropic.MessageNewParams{
	Model:     anthropic.ModelClaudeOpus5,
	MaxTokens: 1024,
	Tools: []anthropic.ToolUnionParam{
		{OfTextEditor20250728: &anthropic.ToolTextEditor20250728Param{}},
	},
	Messages: []anthropic.MessageParam{
		anthropic.NewUserMessage(anthropic.NewTextBlock("There's a syntax error in my primes.py file. Can you help me fix it?")),
	},
})
if err != nil {
	log.Fatal(err)
}
fmt.Println(response)

java

import com.anthropic.models.messages.ToolTextEditor20250728;
// ...
void main() {
  AnthropicClient client = AnthropicOkHttpClient.fromEnv();

  ToolTextEditor20250728 editorTool =
    ToolTextEditor20250728.builder().build();

  MessageCreateParams params = MessageCreateParams.builder()
    .model(Model.CLAUDE_OPUS_5)
    .maxTokens(1024)
    .addTool(editorTool)
    .addUserMessage("There's a syntax error in my primes.py file. Can you help me fix it?")
    .build();

  Message message = client.messages().create(params);
  IO.println(message);
}

php

$client = new Client();

$response = $client->messages->create(
    model: 'claude-opus-5',
    maxTokens: 1024,
    tools: [new ToolTextEditor20250728()],
    messages: [
        [
            'role' => 'user',
            'content' => "There's a syntax error in my primes.py file. Can you help me fix it?",
        ],
    ],
);

echo $response;

ruby

client = Anthropic::Client.new

response = client.messages.create(
  model: "claude-opus-5",
  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?"
    }
  ]
)

puts response

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

json

{
  "id": "msg_01XAbCDeFgHiJkLmNoPQrStU",
  "model": "claude-opus-5",
  "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:

bash

curl https://api.anthropic.com/v1/messages \
  -H "content-type: application/json" \
  -H "x-api-key: $ANTHROPIC_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -d '{
    "model": "claude-opus-5",
    "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()"
          }
        ]
      }
    ]
  }'

bash

ant messages create <<'YAML'
model: claude-opus-5
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):
          2:     """Check if a number is prime."""
          3:     if n <= 1:
          4:         return False
          5:     if n <= 3:
          6:         return True
          7:     if n % 2 == 0 or n % 3 == 0:
          8:         return False
          9:     i = 5
          10:     while i * i <= n:
          11:         if n % i == 0 or n % (i + 2) == 0:
          12:             return False
          13:         i += 6
          14:     return True
          15:
          16: def get_primes(limit):
          17:     """Generate a list of prime numbers up to the given limit."""
          18:     primes = []
          19:     for num in range(2, limit + 1)
          20:         if is_prime(num):
          21:             primes.append(num)
          22:     return primes
          23:
          24: def main():
          25:     """Main function to demonstrate prime number generation."""
          26:     limit = 100
          27:     prime_list = get_primes(limit)
          28:     print(f"Prime numbers up to {limit}:")
          29:     print(prime_list)
          30:     print(f"Found {len(prime_list)} prime numbers.")
          31:
          32: if __name__ == "__main__":
          33:     main()
YAML

python

response = client.messages.create(
    model="claude-opus-5",
    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)

typescript

const anthropic = new Anthropic();

const response = await anthropic.messages.create({
  model: "claude-opus-5",
  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()'
        }
      ]
    }
  ]
});

console.log(response);

csharp

var client = new AnthropicClient();

var response = await client.Messages.Create(
    new()
    {
        Model = Model.ClaudeOpus5,
        MaxTokens = 1024,
        Tools = [new ToolTextEditor20250728()],
        Messages =
        [
            new()
            {
                Role = Role.User,
                Content = "There's a syntax error in my primes.py file. Can you help me fix it?",
            },
            new()
            {
                Role = Role.Assistant,
                Content = new MessageParamContent(new List<ContentBlockParam>
                {
                    new ContentBlockParam(new TextBlockParam()
                    {
                        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.",
                    }),
                    new ContentBlockParam(new ToolUseBlockParam()
                    {
                        ID = "toolu_01AbCdEfGhIjKlMnOpQrStU",
                        Name = "str_replace_based_edit_tool",
                        Input = new Dictionary<string, JsonElement>
                        {
                            ["command"] = JsonSerializer.SerializeToElement("view"),
                            ["path"] = JsonSerializer.SerializeToElement("primes.py"),
                        },
                    }),
                }),
            },
            new()
            {
                Role = Role.User,
                Content = new MessageParamContent(new List<ContentBlockParam>
                {
                    new ContentBlockParam(new ToolResultBlockParam()
                    {
                        ToolUseID = "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()",
                    }),
                }),
            },
        ],
    }
);

Console.WriteLine(response);

client := anthropic.NewClient()

response, err := client.Messages.New(context.TODO(), anthropic.MessageNewParams{
	Model:     anthropic.ModelClaudeOpus5,
	MaxTokens: 1024,
	Tools: []anthropic.ToolUnionParam{
		{OfTextEditor20250728: &anthropic.ToolTextEditor20250728Param{}},
	},
	Messages: []anthropic.MessageParam{
		anthropic.NewUserMessage(anthropic.NewTextBlock("There's a syntax error in my primes.py file. Can you help me fix it?")),
		anthropic.NewAssistantMessage(
			anthropic.NewTextBlock("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."),
			anthropic.NewToolUseBlock(
				"toolu_01AbCdEfGhIjKlMnOpQrStU",
				map[string]any{"command": "view", "path": "primes.py"},
				"str_replace_based_edit_tool",
			),
		),
		anthropic.NewUserMessage(
			anthropic.NewToolResultBlock(
				"toolu_01AbCdEfGhIjKlMnOpQrStU",
				"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()",
				false,
			),
		),
	},
})
if err != nil {
	log.Fatal(err)
}
fmt.Println(response)

java

AnthropicClient client = AnthropicOkHttpClient.fromEnv();

MessageCreateParams params = MessageCreateParams.builder()
  .model(Model.CLAUDE_OPUS_5)
  .maxTokens(1024)
  .addTool(ToolTextEditor20250728.builder().build())
  .addUserMessage("There's a syntax error in my primes.py file. Can you help me fix it?")
  .addAssistantMessageOfBlockParams(
    List.of(
      ContentBlockParam.ofText(
        TextBlockParam.builder()
          .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.")
          .build()
      ),
      ContentBlockParam.ofToolUse(
        ToolUseBlockParam.builder()
          .id("toolu_01AbCdEfGhIjKlMnOpQrStU")
          .name("str_replace_based_edit_tool")
          .input(
            ToolUseBlockParam.Input.builder()
              .putAdditionalProperty("command", JsonValue.from("view"))
              .putAdditionalProperty("path", JsonValue.from("primes.py"))
              .build()
          )
          .build()
      )
    )
  )
  .addUserMessageOfBlockParams(
    List.of(
      ContentBlockParam.ofToolResult(
        ToolResultBlockParam.builder()
          .toolUseId("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()")
          .build()
      )
    )
  )
  .build();

Message message = client.messages().create(params);
System.out.println(message);

php

$client = new Client();

$response = $client->messages->create(
    model: 'claude-opus-5',
    maxTokens: 1024,
    tools: [new ToolTextEditor20250728()],
    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()",
                ],
            ],
        ],
    ],
);

echo $response;

ruby

client = Anthropic::Client.new

response = client.messages.create(
  model: "claude-opus-5",
  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()"
        }
      ]
    }
  ]
)

puts response

Line numbers

In the preceding example, the view tool result includes file contents with line numbers prepended to each line (for example, "1: def is_prime(n)😊. Line numbers are not required, but they are essential for successfully using the view_range parameter to examine specific sections of files and the insert_line parameter to add content at precise locations.

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

json

{
  "id": "msg_01VwXyZAbCdEfGhIjKlMnO",
  "model": "claude-opus-5",
  "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:

bash

curl https://api.anthropic.com/v1/messages \
  -H "content-type: application/json" \
  -H "x-api-key: $ANTHROPIC_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -d '{
    "model": "claude-opus-5",
    "max_tokens": 1024,
    "tools": [
      {
        "type": "text_editor_20250728",
        "name": "str_replace_based_edit_tool"
      }
    ],
    "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."
          }
        ]
      }
    ]
  }'

bash

ant messages create <<'YAML'
model: claude-opus-5
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.
YAML

python

response = client.messages.create(
    model="claude-opus-5",
    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)

typescript

const response = await client.messages.create({
  model: "claude-opus-5",
  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."
        }
      ]
    }
  ]
});

console.log(response);

csharp

var client = new AnthropicClient();

var response = await client.Messages.Create(
    new()
    {
        Model = Model.ClaudeOpus5,
        MaxTokens = 1024,
        Tools = [new ToolTextEditor20250728()],
        Messages =
        [
            // Previous messages...
            new()
            {
                Role = Role.Assistant,
                Content = new MessageParamContent(new List<ContentBlockParam>
                {
                    new ContentBlockParam(new TextBlockParam()
                    {
                        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.",
                    }),
                    new ContentBlockParam(new ToolUseBlockParam()
                    {
                        ID = "toolu_01PqRsTuVwXyZAbCdEfGh",
                        Name = "str_replace_based_edit_tool",
                        Input = new Dictionary<string, JsonElement>
                        {
                            ["command"] = JsonSerializer.SerializeToElement("str_replace"),
                            ["path"] = JsonSerializer.SerializeToElement("primes.py"),
                            ["old_str"] = JsonSerializer.SerializeToElement("    for num in range(2, limit + 1)"),
                            ["new_str"] = JsonSerializer.SerializeToElement("    for num in range(2, limit + 1):"),
                        },
                    }),
                }),
            },
            new()
            {
                Role = Role.User,
                Content = new MessageParamContent(new List<ContentBlockParam>
                {
                    new ContentBlockParam(new ToolResultBlockParam()
                    {
                        ToolUseID = "toolu_01PqRsTuVwXyZAbCdEfGh",
                        Content = "Successfully replaced text at exactly one location.",
                    }),
                }),
            },
        ],
    }
);

Console.WriteLine(response);

client := anthropic.NewClient()

response, err := client.Messages.New(context.TODO(), anthropic.MessageNewParams{
	Model:     anthropic.ModelClaudeOpus5,
	MaxTokens: 1024,
	Tools: []anthropic.ToolUnionParam{
		{OfTextEditor20250728: &anthropic.ToolTextEditor20250728Param{}},
	},
	Messages: []anthropic.MessageParam{
		// Previous messages...
		anthropic.NewAssistantMessage(
			anthropic.NewTextBlock("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."),
			anthropic.NewToolUseBlock(
				"toolu_01PqRsTuVwXyZAbCdEfGh",
				map[string]any{
					"command": "str_replace",
					"path":    "primes.py",
					"old_str": "    for num in range(2, limit + 1)",
					"new_str": "    for num in range(2, limit + 1):",
				},
				"str_replace_based_edit_tool",
			),
		),
		anthropic.NewUserMessage(
			anthropic.NewToolResultBlock(
				"toolu_01PqRsTuVwXyZAbCdEfGh",
				"Successfully replaced text at exactly one location.",
				false,
			),
		),
	},
})
if err != nil {
	log.Fatal(err)
}
fmt.Println(response)

java

AnthropicClient client = AnthropicOkHttpClient.fromEnv();

MessageCreateParams params = MessageCreateParams.builder()
  .model(Model.CLAUDE_OPUS_5)
  .maxTokens(1024)
  .addTool(ToolTextEditor20250728.builder().build())
  // Previous messages would go here
  .addAssistantMessageOfBlockParams(
    List.of(
      ContentBlockParam.ofText(
        TextBlockParam.builder()
          .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."
          )
          .build()
      ),
      ContentBlockParam.ofToolUse(
        ToolUseBlockParam.builder()
          .id("toolu_01PqRsTuVwXyZAbCdEfGh")
          .name("str_replace_based_edit_tool")
          .input(
            ToolUseBlockParam.Input.builder()
              .putAdditionalProperty("command", JsonValue.from("str_replace"))
              .putAdditionalProperty("path", JsonValue.from("primes.py"))
              .putAdditionalProperty(
                "old_str",
                JsonValue.from("    for num in range(2, limit + 1)")
              )
              .putAdditionalProperty(
                "new_str",
                JsonValue.from("    for num in range(2, limit + 1):")
              )
              .build()
          )
          .build()
      )
    )
  )
  .addUserMessageOfBlockParams(
    List.of(
      ContentBlockParam.ofToolResult(
        ToolResultBlockParam.builder()
          .toolUseId("toolu_01PqRsTuVwXyZAbCdEfGh")
          .content("Successfully replaced text at exactly one location.")
          .build()
      )
    )
  )
  .build();

Message message = client.messages().create(params);
System.out.println(message);

php

$client = new Client();

$response = $client->messages->create(
    model: 'claude-opus-5',
    maxTokens: 1024,
    tools: [new ToolTextEditor20250728()],
    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.',
                ],
            ],
        ],
    ],
);

echo $response;

ruby

client = Anthropic::Client.new

response = client.messages.create(
  model: "claude-opus-5",
  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."
        }
      ]
    }
  ]
)

puts response

Finally, Claude provides a complete explanation of the fix:

json

{
  "id": "msg_01IjKlMnOpQrStUvWxYzAb",
  "model": "claude-opus-5",
  "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."
    }
  ]
}

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