Tool & function calling

Define tools as JSON schemas; the model decides when to call them and returns structured arguments you execute. All 154 tool-capable models on MeshTok follow the OpenAI tools API. Top picks for agentic work: DeepSeek V4 Pro, GLM 5.2, Claude Sonnet 5.

Define a tool

tools = [{
  "type": "function",
  "function": {
    "name": "get_weather",
    "description": "Get the current weather in a city.",
    "parameters": {
      "type": "object",
      "properties": {
        "city": { "type": "string", "description": "City name" },
        "unit": { "type": "string", "enum": ["c", "f"] }
      },
      "required": ["city"]
    }
  }
}]

Python: full agentic loop

from openai import OpenAI
client = OpenAI(base_url="https://meshtok.com/v1", api_key="sk-...")

messages = [{"role": "user", "content": "What's the weather in Tokyo?"}]

# 1. Let the model decide which tool to call
resp = client.chat.completions.create(
    model="deepseek/deepseek-v4-pro",
    messages=messages,
    tools=tools,
)
tool_call = resp.choices[0].message.tool_calls[0]
print(tool_call.function.name, tool_call.function.arguments)
# get_weather {"city":"Tokyo","unit":"c"}

# 2. Execute the tool yourself, then feed the result back
import json
result = get_weather(**json.loads(tool_call.function.arguments))
messages.append(resp.choices[0].message)
messages.append({
    "role": "tool", "tool_call_id": tool_call.id,
    "content": json.dumps(result),
})

# 3. Model produces the final natural-language answer
final = client.chat.completions.create(model="deepseek/deepseek-v4-pro", messages=messages)
print(final.choices[0].message.content)

Parallel tool calls

Frontier models (GPT-5.x, Claude 5, GLM 5.2) can request multiple tool calls in a single response. Iterate message.tool_calls, dispatch them concurrently, then append all results before the next turn.

Forcing tool use

Pass tool_choice: {"type":"function","function":{"name":"get_weather"}} to force a specific tool, or "required" to force any tool. Use "auto" (default) to let the model decide.