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Email verification tool with the Anthropic API

Pass a tool definition to the Messages API, run verify_email when the model returns a tool_use block, and send the result back as a tool_result. SDK signatures change, so confirm them in Anthropic’s current documentation.

Tool definition

tools = [{
    'name': 'verify_email',
    'description': 'Check whether one email address can receive mail. status unknown means no conclusion, not invalid.',
    'input_schema': {
        'type': 'object',
        'properties': {'email': {'type': 'string'}},
        'required': ['email'],
    },
}]

Run the tool

# `message` is the assistant reply from client.messages.create(..., tools=tools)
results = []
for block in message.content:
    if block.type == 'tool_use' and block.name == 'verify_email':
        out = verify_email(block.input['email'])  # see the AI tool pattern page
        results.append({
            'type': 'tool_result',
            'tool_use_id': block.id,
            'content': str(out),
        })
# send results as the next user message, then call the API again

Notes

Use a model name from Anthropic’s current list in your own configuration. Keep VALIDREACH_API_KEY on the server and cap tool calls per run.