Tool call · 5 checks · max 400 tokens · benched 2026-09-16
OpenAI models side by side on "Emit a weather tool call": GPT-5.4 Nano scores 10/10; GPT-5.4 Nano is the cheapest answer scoring 8+ at $0.05 per 1,000 runs. Outputs, checks, judge reasons, latency and cost.
System
You are a function-calling engine. Reply with JSON only, no prose, no code fences.
User
You have one tool:
{"name": "get_weather", "parameters": {"city": "string", "unit": "one of 'c' or 'f'"}}
Produce the tool call for this user message as a JSON object of the shape {"name": string, "arguments": object}.
User: What's it like in Lisbon right now? Fahrenheit please.Rubric for the judge: Exactly {"name":"get_weather","arguments":{"city":"Lisbon","unit":"f"}} with no extra keys or text.
Every cell is one OpenRouter call at temperature 0 with the prompt's token cap and reasoning effort "low" where the model supports it. Cost is usage × the catalogue rate in models.json. Quality is one judge call to anthropic/claude-haiku-4.5 against the prompt's rubric, cached per prompt version.
openai/gpt-5.5
105 in · 21 out · 1 words · checks 5/5
{"name":"get_weather","arguments":{"city":"Lisbon","unit":"f"}}Judge: Output exactly matches the required format with correct tool name, city, and unit parameters, and no extra keys or text.
openai/gpt-5.4
105 in · 35 out (12 reasoning) · 1 words · checks 5/5
{"name":"get_weather","arguments":{"city":"Lisbon","unit":"f"}}Judge: Output exactly matches the required format with correct tool name, city, and unit parameters, and no extra keys or text.
openai/gpt-5.4-mini
105 in · 34 out (11 reasoning) · 1 words · checks 5/5
{"name":"get_weather","arguments":{"city":"Lisbon","unit":"f"}}Judge: Output exactly matches the required format with correct tool name, city, and unit parameters, and no extra keys or text.
openai/gpt-5.4-nano
105 in · 21 out · 1 words · checks 5/5
{"name":"get_weather","arguments":{"city":"Lisbon","unit":"f"}}Judge: Output exactly matches the required format with correct tool name, city, and unit parameters, and no extra keys or text.
openai/gpt-5.3-codex
105 in · 40 out (17 reasoning) · 1 words · checks 5/5
{"name":"get_weather","arguments":{"city":"Lisbon","unit":"f"}}Judge: Output exactly matches the required format with correct tool name, city, and unit parameters, and no extra keys or text.
Tool call: Exactly {"name":"get_weather","arguments":{"city":"Lisbon","unit":"f"}} with no extra keys or text. The deterministic checks are json_valid, json_keys, regex, regex, regex.
If the judge's bar of 8/10 is good enough for you, GPT-5.4 Nano at $0.05 per 1,000 runs. If you need the top score, GPT-5.4 Nano at $0.05 per 1,000 runs.
Run it yourself
Re-run this prompt on OpenAI with your own OpenRouter key, or tweak the wording and see what changes.
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