UCP Playgroundo4-mini (Reasoning)/Models/o4-mini (Reasoning)
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OpenAIOpenAI

o4-mini (Reasoning)

OpenAI's compact reasoning model. Currently non-functional for shopping — 92.9% tool error rate with almost every tool call failing. Appears to struggle with MCP tool schemas entirely. Not recommended until OpenAI addresses the tool-use reliability issues.

Avg Tokens69,805Avg Duration39.3sTurns to Checkout11.5
CheckoutCartSearchTurnsTokens9.128.978.5617
Shopping Score21/100
Weak

Scores computed from real agent sessions against live UCP-enabled stores. Not estimated — every data point is from an actual tool call, checkout attempt, and store response.

Shopping Score Breakdown

Checkout Rate40%9.1%
Cart Rate20%28.9%
Search Rate10%78.5%
Turn Efficiency15%6%
Token Efficiency15%17%
21.5% of sessions failed with errors.

Top Stores

StoreCheckout %Cart %
••••••••••••••••66.7%66.7%
everlane.com60%60%
••••••••••••••••33.3%33.3%
saltwarp.shop0%0%
••••••••••••••••0%0%
••••••••••••••••0%0%
craze.wtf0%0%
goswingofficial.com0%50%
••••••••••••••••0%0%
teveo.com0%50%

Known Issues

Non-Functionalhigh

92.9% tool error rate — almost every tool call fails.

Schema Incompatibilityhigh

Cannot correctly format MCP tool arguments. Not usable for shopping agent tasks.

Token Usage

Avg per Session69,805
Fleet Average74,927
vs Fleet−7%
Median (p50)29,827
p90151,792
Prompt / Completion split
Prompt 67,106 (96%) Completion 2,699 (4%)
Daily Average Tokens (last 30 days)
Distribution range
Min0p2515,542p5029,827p7577,138p90151,792Max721,744

Test o4-mini (Reasoning) on Your Store

Run a live agent session to see how o4-mini (Reasoning) handles your store's checkout flow end-to-end.

Run Agent Session

Compare With Other Models

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