OverpayingForAIPricing desk

Tool call · 7 checks · max 400 tokens · benched 2026-09-16

Qwen3.8 Max (0902) vs Qwen3.8 27B vs Qwen3.8 Flash vs Qwen3.7 Plus on emit a calendar tool call

Alibaba models side by side on "Emit a calendar tool call": Qwen3.8 Flash scores 10/10; Qwen3.8 Flash is the cheapest answer scoring 8+ at $0.09 per 1,000 runs. Outputs, checks, judge reasons, latency and cost.

The prompt every model received

System

You are a function-calling engine. Reply with JSON only, no prose, no code fences.

User

You have one tool:
{"name": "create_event", "parameters": {"title": "string", "start": "ISO 8601 date-time without timezone, e.g. 2026-01-31T09:00", "duration_minutes": "integer", "attendees": "array of email strings"}}

Produce the tool call for this user message as a JSON object of the shape {"name": string, "arguments": object}.

User: Book a 45-minute design review with [email protected] and [email protected] on 2 October 2026 at 3pm.

Rubric for the judge: Correct tool name, ISO start 2026-10-02T15:00, integer duration 45, both attendees in an array, a sensible title.

Side by side

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.

Qwen3.8 Max (0902)

qwen/qwen3.8-max-0902

10/10
Latency
1.5s
Cost
$0.00142
Per 1,000
$1.42

196 in · 171 out (107 reasoning) · 13 words · checks 7/7

  • json_valid
  • json_keys
  • regex
  • contains
  • regex
  • contains
  • contains
{"name": "create_event", "arguments": {"title": "Design Review", "start": "2026-10-02T15:00", "duration_minutes": 45, "attendees": ["[email protected]", "[email protected]"]}}

Judge: All rubric criteria met: correct tool name, proper ISO 8601 start datetime, integer duration of 45 minutes, both attendees in array format, and sensible title.

Qwen3.8 27B

qwen/qwen3.8-27b

10/10
Latency
796ms
Cost
$0.00041
Per 1,000
$0.41

196 in · 145 out (92 reasoning) · 2 words · checks 7/7

  • json_valid
  • json_keys
  • regex
  • contains
  • regex
  • contains
  • contains


{"name":"create_event","arguments":{"title":"Design Review","start":"2026-10-02T15:00","duration_minutes":45,"attendees":["[email protected]","[email protected]"]}}

Judge: All rubric requirements met: correct tool name, proper ISO 8601 start datetime, integer duration of 45 minutes, both attendees in array format, and sensible title.

Qwen3.8 Flash

qwen/qwen3.8-flash

10/10
top judge scorecheapest scoring 8+
Latency
2.9s
Cost
$9.1e-5
Per 1,000
$0.09

170 in · 140 out (66 reasoning) · 2 words · checks 7/7

  • json_valid
  • json_keys
  • regex
  • contains
  • regex
  • contains
  • contains


{"name":"create_event","arguments":{"title":"Design Review","start":"2026-10-02T15:00","duration_minutes":45,"attendees":["[email protected]","[email protected]"]}}

Judge: All rubric requirements met: correct tool name, proper ISO 8601 start datetime, integer duration of 45 minutes, both attendees in array format, and sensible title.

Qwen3.7 Plus

qwen/qwen3.7-plus

10/10
Latency
2.3s
Cost
$0.00101
Per 1,000
$1.01

170 in · 746 out (656 reasoning) · 19 words · checks 7/7

  • json_valid
  • json_keys
  • regex
  • contains
  • regex
  • contains
  • contains
{
  "name": "create_event",
  "arguments": {
    "title": "Design Review",
    "start": "2026-10-02T15:00",
    "duration_minutes": 45,
    "attendees": [
      "[email protected]",
      "[email protected]"
    ]
  }
}

Judge: All rubric requirements met: correct tool name, ISO start datetime 2026-10-02T15:00, integer duration 45, both attendees in array, and sensible title 'Design Review'.

Frequently asked

What does this prompt test?

Tool call: Correct tool name, ISO start 2026-10-02T15:00, integer duration 45, both attendees in an array, a sensible title. The deterministic checks are json_valid, json_keys, regex, contains, regex, contains, contains.

Which model should I pick for this task?

If the judge's bar of 8/10 is good enough for you, Qwen3.8 Flash at $0.09 per 1,000 runs. If you need the top score, Qwen3.8 Flash at $0.09 per 1,000 runs.

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