Tool call · 7 checks · max 400 tokens · benched 2026-11-05
Meta models side by side on "Emit a calendar tool call": Llama 4 Scout scores 10/10; Llama 4 Scout is the cheapest answer scoring 8+ at $0.03 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": "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.
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.
meta/muse-spark-1.3
166 in · 422 out (377 reasoning) · 5 words · checks 1/7
{"name": "create_event", "arguments": {"title": "Judge: Output is incomplete and malformed - the JSON is cut off mid-string with no closing quotes, braces, or attendees array.
meta/muse-glimmer-30b
168 in · 165 out (91 reasoning) · 13 words · checks 7/7
{"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.
meta-llama/llama-4-maverick
156 in · 55 out · 13 words · checks 7/7
{"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.
meta-llama/llama-4-scout
156 in · 55 out · 13 words · checks 7/7
{"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.
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.
If the judge's bar of 8/10 is good enough for you, Llama 4 Scout at $0.03 per 1,000 runs. If you need the top score, Llama 4 Scout at $0.03 per 1,000 runs.
Run it yourself
Re-run this prompt on Meta with your own OpenRouter key, or tweak the wording and see what changes.
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