Agents And Tools Tool Use Text Editor Tool

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-sonnet-4-5",
    "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?"
      }
    ]
  }'

import Anthropic from '@anthropic-ai/sdk';

const anthropic = new Anthropic();

const response = await anthropic.messages.create({
  model: "claude-sonnet-4-5",
  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?"
    }
  ]
});

  public static void main(String[] args) {
      AnthropicClient client = AnthropicOkHttpClient.fromEnv();

      ToolStrReplaceBasedEditTool20250728 editorTool = ToolStrReplaceBasedEditTool20250728.builder()
              .build();

      MessageCreateParams params = MessageCreateParams.builder()
              .model(Model.CLAUDE_SONNET_4_0)
              .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);
  }

</CodeGroup>

Claude will use the text editor tool first to view the file:

```json
{
"id": "msg_01XAbCDeFgHiJkLmNoPQrStU",
"model": "claude-sonnet-4-5",
"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"
    }
  }
]
}

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-sonnet-4-5",
    "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()"
                }
            ]
        }
    ]
  }'

import Anthropic from '@anthropic-ai/sdk';

const anthropic = new Anthropic();

const response = await anthropic.messages.create({
  model: "claude-sonnet-4-5",
  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()"
          }
      ]
    }
  ]
});

  public static void main(String[] args) {
      AnthropicClient client = AnthropicOkHttpClient.fromEnv();

      ToolStrReplaceBasedEditTool20250728 editorTool = ToolStrReplaceBasedEditTool20250728.builder()
          .build();

      MessageCreateParams params = MessageCreateParams.builder()
          .model(Model.CLAUDE_SONNET_4_0)
          .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);
      System.out.println(message);
  }

</CodeGroup>


Tip: Line numbers
In the example above, the view tool result includes file contents with line numbers prepended to each line (e.g., "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 will identify the syntax error and use the `str_replace` command to fix it:

```json
{
"id": "msg_01VwXyZAbCdEfGhIjKlMnO",
"model": "claude-sonnet-4-5",
"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):"
    }
  }
]
}

{
  "id": "msg_01IjKlMnOpQrStUvWxYzAb",
  "model": "claude-sonnet-4-5",
  "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."
    }
  ]
}