CekuraBench
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GoogleCascade baseline

Gemini 3.1 Flash Live Preview vs Flux → GPT-4.1 → ElevenLabs Flash

Flux → GPT-4.1 → ElevenLabs Flash is ahead on reliability, success rate, agent responses, data accuracy, stalled calls and response time, and Gemini 3.1 Flash Live Preview on interruption.

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Success rate by suite

Appointments59 scenariosMedicare23 scenarios
  • GPT Realtime 2.1OpenAI
    92%
    81%
  • GPT-Live 1 + Sol lowOpenAI
    97%
    49%
  • Gemini 3.8 Live ThinkingGoogle
    82%
    61%
  • Grok Think Fast 2.0xAI
    96%
    25%
  • Gemini 3.1 Flash LiveGoogle
    93%
    32%
  • Phonic v1Phonic
    97%
    14%
  • Realtime 2.1 MiniOpenAI
    84%
    4%
  • Nova 2 SonicAmazon
    80%
    6%
  • Cascade, GPT-4.1Not ranked
    97%
    83%
Each model's share of calls that passed every check, on each suite.

Every metric, side by side

Reliability

Scenarios that passed on all three runs.

Gemini 3.1 Flash Live
62.2%5th
Cascade, GPT-4.1
82.9%

Cascade, GPT-4.1, 20.7 points higher

Success rate

Calls that passed every check.

Gemini 3.1 Flash Live
76.0%4th
Cascade, GPT-4.1
93.1%

Cascade, GPT-4.1, 17.1 points higher

Agent responses

Calls where the agent's replies reached the expected outcome.

Gemini 3.1 Flash Live
95.9%5th
Cascade, GPT-4.1
99.2%

Cascade, GPT-4.1, 3.3 points higher

Data accuracy

Calls where everything the agent saved matched exactly.

Gemini 3.1 Flash Live
79.2%4th
Cascade, GPT-4.1
94.1%

Cascade, GPT-4.1, 14.9 points higher

Stalled calls

Calls where the agent went silent for 10 seconds or more.

Gemini 3.1 Flash Live
3.3%5th
Cascade, GPT-4.1
0.8%

Cascade, GPT-4.1, 2.5 points lower

Interruption

How well it handled being talked over, 0 to 5.

Gemini 3.1 Flash Live
4.984th
Cascade, GPT-4.1
4.96

Gemini 3.1 Flash Live, 0.02 higher

Response time

Median time to start replying after the caller finishes.

Gemini 3.1 Flash Live
2.88s8th
Cascade, GPT-4.1
2.17s

Cascade, GPT-4.1, 0.71s sooner

Cost / min

One minute of call at the vendor's published rates.

Gemini 3.1 Flash Live
$0.0703rd
Cascade, GPT-4.1
No verified rate

Not comparable

The small figure is the place among ranked models. The cascade is not ranked.

Cascade, GPT-4.1 answers first

Cascade, GPT-4.1 2.17s, Gemini 3.1 Flash Live 2.88s at the median.

Response time, median to p90

MedianTo p90
Medianp90
  • Phonic v1Phonic
    Phonic v1: median 1.59s, p90 1.86s
    1.59s1.86s
  • Grok Think Fast 2.0xAI
    Grok Think Fast 2.0: median 1.62s, p90 1.94s
    1.62s1.94s
  • GPT Realtime 2.1OpenAI
    GPT Realtime 2.1: median 1.94s, p90 2.46s
    1.94s2.46s
  • GPT-Live 1 + Sol lowOpenAI
    GPT-Live 1 + Sol low: median 2.02s, p90 2.42s
    2.02s2.42s
  • Realtime 2.1 MiniOpenAI
    Realtime 2.1 Mini: median 2.08s, p90 2.75s
    2.08s2.75s
  • Nova 2 SonicAmazon
    Nova 2 Sonic: median 2.18s, p90 2.76s
    2.18s2.76s
  • Gemini 3.8 Live ThinkingGoogle
    Gemini 3.8 Live Thinking: median 2.32s, p90 3.06s
    2.32s3.06s
  • Gemini 3.1 Flash LiveGoogle
    Gemini 3.1 Flash Live: median 2.88s, p90 4.00s
    2.88s4.00s
  • Cascade, GPT-4.1Not ranked
    Cascade, GPT-4.1: median 2.17s, p90 2.51s
    2.17s2.51s
2.0s3.0s4.0s
Seconds from the caller finishing to the agent starting to reply, per model.

What we saw on the calls

Gemini 3.1 Flash Live Preview

  • Steady on the short form, though it repeats lookups it already made.
  • On the long form it hands the caller over with the wrong details.
  • Slowest to reply; after several tool calls its replies fall behind or go missing.
  • Sometimes says goodbye without hanging up.
Model
models/gemini-3.1-flash-live-preview
Setting
Thinking level high
Voice
Charon
Turn taking
Shared local turn detection
Audio
16 kHz
Cost
Averaged over the calls with a usage record.

Flux → GPT-4.1 → ElevenLabs Flash

  • Most scenarios pass every run; none fails every run.
  • Rare long-form slips: a reference from an earlier step left out.
  • Not the quickest to reply, but almost never leaves the caller waiting.
Model
flux-general-en → gpt-4.1 → eleven_flash_v2_5
Setting
No reasoning setting
Voice
ElevenLabs 21m00Tcm4TlvDq8ikWAM
Turn taking
Speech-to-text turn detection
Audio
16 kHz
Cost
Not published: no verified combined rate for the three services.
See the full leaderboardReference agent

Related comparisons

Frequently asked questions

Is Gemini 3.1 Flash Live Preview or Flux → GPT-4.1 → ElevenLabs Flash more reliable?

Gemini 3.1 Flash Live Preview passed 51 of 82 scenarios on all three runs, and Flux → GPT-4.1 → ElevenLabs Flash passed 68. Flux → GPT-4.1 → ElevenLabs Flash is ahead, by 20.7 points.

Which saves caller data more accurately, Gemini 3.1 Flash Live Preview or Flux → GPT-4.1 → ElevenLabs Flash?

Gemini 3.1 Flash Live Preview saved everything exactly right on 79.2% of the calls that save data, and Flux → GPT-4.1 → ElevenLabs Flash on 94.1%. On Appointments, 96.5% against 98.8%. On Medicare, 34.8% against 81.8%. A call counts only when nothing is missing, wrong, extra or saved twice.

Which responds faster, Gemini 3.1 Flash Live Preview or Flux → GPT-4.1 → ElevenLabs Flash?

Flux → GPT-4.1 → ElevenLabs Flash starts replying 0.71s sooner at the median. Gemini 3.1 Flash Live Preview takes 2.88s at the median and 4.00s at p90; Flux → GPT-4.1 → ElevenLabs Flash takes 2.17s and 2.51s. Both are measured on the call audio, from the caller finishing to the agent starting to reply.

Which costs less, Gemini 3.1 Flash Live Preview or Flux → GPT-4.1 → ElevenLabs Flash?

There is no verified per-minute rate for Flux → GPT-4.1 → ElevenLabs Flash, so cost cannot be compared yet.

How were Gemini 3.1 Flash Live Preview and Flux → GPT-4.1 → ElevenLabs Flash compared?

Both ran as the whole agent in the same open-source Pipecat pipeline, with the same prompt, tools and phone line. A simulated caller worked through all 82 scenarios on live calls, three times each, 2,214 calls across the benchmark. A call passes only when the agent said the right things and saved the right data. The cascade runs the same agent for reference and is never ranked.