OpenAI function calling：モデル用のread_urlツール

{
  "type": "function",
  "function": {
    "name": "read_url",
    "description": "Read a public web page and return its main content as Markdown, with its title and source URL. Use it when the user gives a link or when a page must be read to answer.",
    "parameters": {
      "type": "object",
      "properties": {
        "url": { "type": "string", "description": "The http or https address of the page." },
        "max_chars": { "type": "integer", "description": "Most characters to return, 1000 to 500000. Default 20000." }
      },
      "required": ["url"],
      "additionalProperties": false
    }
  }
}

import json
import os

import requests
from openai import OpenAI

READ_URL = {
    "type": "function",
    "function": {
        "name": "read_url",
        "description": "Read a public web page and return its main content as Markdown, with its title and source URL.",
        "parameters": {
            "type": "object",
            "properties": {
                "url": {"type": "string", "description": "The http or https address of the page."},
                "max_chars": {"type": "integer", "description": "Most characters to return. Default 20000."},
            },
            "required": ["url"],
            "additionalProperties": False,
        },
    },
}


def read_url(url, max_chars=20000):
    resp = requests.get(
        "https://webreaderapi.com/api/v1/read",
        headers={"Authorization": "Bearer " + os.environ["WEBREADER_API_KEY"]},
        params={"url": url, "max_chars": max_chars},
        timeout=75,
    )
    body = resp.json()
    if resp.status_code != 200:
        return "Could not read the page: " + body["error"]["code"]
    return "# " + (body.get("title") or url) + "\nSource: " + body["final_url"] + "\n\n" + body["markdown"]


client = OpenAI()
model = os.environ.get("OPENAI_MODEL", "gpt-4.1-mini")
messages = [{"role": "user", "content": "What does https://example.com/blog/first-post announce? Answer in two sentences."}]

for _ in range(4):
    reply = client.chat.completions.create(model=model, messages=messages, tools=[READ_URL])
    msg = reply.choices[0].message
    if not msg.tool_calls:
        print(msg.content)
        break
    messages.append(msg)
    for call in msg.tool_calls:
        args = json.loads(call.function.arguments)
        messages.append({"role": "tool", "tool_call_id": call.id, "content": read_url(**args)})