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.

Last updated Methodology by Dileep Chagam

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Success rate by suite

Higher is better
Appointments59 scenariosMedicare23 scenarios
  • Gemini 3.1 Flash LiveGoogle
    93%
    32%
  • Cascade, GPT-4.1Not ranked
    97%
    83%
Each model's share of calls that passed every check, on each suite.
Verdict

Which to pick

Pick Gemini 3.1 Flash Live Preview for handling interruptions (0.02 higher). Pick Flux → GPT-4.1 → ElevenLabs Flash for reliability across repeated calls (20.7 points higher), calls that pass every check (17.1 points higher), getting the agent's replies right (3.3 points higher), saving the caller's data correctly (14.9 points higher), fewer stalled calls (2.5 points lower) and fast replies (0.71s sooner).

Every metric, side by side

Reliability

Scenarios that passed on all three runs.

Gemini 3.1 Flash Live
62.2%6th
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%5th
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%6th
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%5th
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%6th
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
4.985th
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
2.88s11th
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

Lower is betterMedianTo p90
Medianp90
  • 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

  • Reliable on bookings.
All 3 notes on Gemini 3.1 Flash Live
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, and none fails every run.
All 4 notes on Cascade, GPT-4.1
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?

Flux → GPT-4.1 → ElevenLabs Flash is more reliable, by 20.7 points. Gemini 3.1 Flash Live Preview passed 51 of 82 scenarios on all three runs, and Flux → GPT-4.1 → ElevenLabs Flash passed 68. A scenario only counts when every run of it passed.

Is Gemini 3.1 Flash Live Preview better than a cascaded STT, LLM and TTS pipeline?

On reliability, no: the Flux → GPT-4.1 → ElevenLabs Flash cascade passes more scenarios on every run. 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. Both ran as the same agent, with the same prompt and tools.

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

Flux → GPT-4.1 → ElevenLabs Flash, by 14.9 points. 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.

Is Gemini 3.1 Flash Live Preview faster than Flux → GPT-4.1 → ElevenLabs Flash?

No. 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 handles interruptions better, Gemini 3.1 Flash Live Preview or Flux → GPT-4.1 → ElevenLabs Flash?

Gemini 3.1 Flash Live Preview, by 0.02 on a 0 to 5 scale. Gemini 3.1 Flash Live Preview scores 4.98 and Flux → GPT-4.1 → ElevenLabs Flash 4.96 for how well the agent handled being talked over.

Which goes silent on callers less often, Gemini 3.1 Flash Live Preview or Flux → GPT-4.1 → ElevenLabs Flash?

Flux → GPT-4.1 → ElevenLabs Flash, by 2.5 points. The agent went silent for 10 seconds or more on 3.3% of Gemini 3.1 Flash Live Preview calls and 0.8% of Flux → GPT-4.1 → ElevenLabs Flash calls.

Which is cheaper, 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.

Where does the Gemini 3.1 Flash Live Preview vs Flux → GPT-4.1 → ElevenLabs Flash data come from?

Cekura ran both as the whole agent in the same open-source Pipecat pipeline, with the same prompt, tools and connection. A simulated caller worked through all 82 scenarios on live calls, three times each, 2,952 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.