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🔍 Read the full analysis: DeepSeek V4.1 Flash 1017: A Cost-Conscious Option For AI Agents on ThorstenMeyerAI.com

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TL;DR

DeepSeek released V4.1 Flash 1017 on October 17, replacing the September model on its website, app and API without changing the listed token prices. Its own tests show gains across 11 benchmarks, with larger improvements on some agent tasks; independent verification is limited, and the company’s comparisons use selected rivals that are not the latest generation.

DeepSeek released DeepSeek-V4.1-Flash-1017 on October 17, replacing the September version across its website, app and API. The company says the update improves scores on all 11 benchmarks it published and can reduce agent-task costs through shorter outputs; the listed token prices are unchanged. The results are DeepSeek’s own, and independent testing remains limited.

The new model is served as deepseek-flash, and DeepSeek says the older names deepseek-v4-flash and deepseek-v4-flash-vision-exp also route to version 1017. Its weights are available under the MIT license, according to the source material. DeepSeek describes the update as minor, but its model card reports higher scores than the September release in each of the 11 listed benchmark rows.

The largest listed changes include Terminal-Bench 4.0, which rose from 31.2 to 42.3, and ProgramBench, which rose from 20.3 to 29.1. DeepSWE v1.1 increased more modestly, from 74.2 to 77.0. These figures are benchmark scores, not independently verified measures of real-world performance. DeepSeek’s table also shows 1017 leading four of the 11 rows; Claude Opus 5 leads six and GPT-5.6 Sol leads one.

DeepSeek lists prices of $0.15 per million input tokens for cache misses and $0.003 for cache hits during off-peak periods; output costs $0.60 per million tokens off-peak. Peak-hour rates are higher, and the company’s price schedule defines peak periods as specified weekday hours in UTC. DeepSeek says shorter outputs can lower total task costs, but actual bills depend on token use, caching and scheduling.

The model is described as a sparse Mixture of Experts with image input and a one-million-token context window. The source material reports differing parameter counts depending on how they are counted: a 552-billion-parameter backbone with fewer active parameters during use, while Hugging Face lists 763 billion. DeepSeek has not specified what changed in training. A separate account cited in the source attributes the improvement to post-training reinforcement learning with self-feedback; that explanation is not confirmed by DeepSeek in the supplied material.

At a glance
updateWhen: Released October 17, 2026; current API…
The developmentDeepSeek replaced its V4.1 Flash model with version 1017, reporting improved benchmark scores and lower costs for some agent tasks.
Thorsten Meyer AI
Open weights · MIT

Infographic · DeepSeek V4.1 Flash 1017

Better on every benchmark, a fraction of the cost per task, and still behind the frontier.

DeepSeek’s October update improves all eleven scores it published over the September version. Against the four rivals DeepSeek picked, it leads four benchmarks and trails seven. Its real advantage is the price of a finished task.

~$0.20Per DeepSWE task at 77.0% solved. The September version needed about $0.50 for 74.2%.
+11.1Points on Terminal-Bench 4.0 (31.2 → 42.3), the biggest gain over September.
4 of 11Benchmarks where 1017 beats every rival in DeepSeek’s own table. Claude Opus 5 leads six.

1017 vs the September version

Score per benchmark (0–100), sorted by gain. Hover a row for the exact values.

V4.1 Flash (September)V4.1 Flash 1017
  1. Terminal-Bench 4.042.331.2+11.1
  2. ProgramBench29.120.3+8.8
  3. Apex Bench v1.172.164.6+7.5
  4. HLE (no tools)42.636.8+5.8
  5. Automation-Bench60.554.8+5.7
  6. Chartography83.078.9+4.1
  7. Agents' Last Exam35.431.8+3.6
  8. BabyVision92.589.6+2.9
  9. DeepSWE v1.177.074.2+2.8
  10. NL2Repo-Bench68.265.4+2.8
  11. ZeroBench-main51.049.0+2.0

Against the best rival per benchmark

Points ahead of or behind the strongest of Kimi K3, GLM-5.3, GPT-5.6 Sol and Claude Opus 5 on each row.

1017 leads1017 trails
  1. Automation-Benchbest rival: Claude Opus 5 50.3+10.2
  2. Agents' Last Exambest rival: Claude Opus 5 28.6+6.8
  3. Apex Bench v1.1best rival: Claude Opus 5 65.8+6.3
  4. DeepSWE v1.1best rival: Claude Opus 5 74.0+3.0
  5. Chartographybest rival: Claude Opus 5 84.0-1.0
  6. BabyVisionbest rival: Claude Opus 5 94.1-1.6
  7. ZeroBench-mainbest rival: GPT-5.6 Sol 53.0-2.0
  8. NL2Repo-Benchbest rival: Claude Opus 5 75.3-7.1
  9. ProgramBenchbest rival: Claude Opus 5 37.0-7.9
  10. Terminal-Bench 4.0best rival: Claude Opus 5 51.8-9.5
  11. HLE (no tools)best rival: Claude Opus 5 56.3-13.7

Cost per DeepSWE task

USD per task, linear scale to $10, as read from DeepSeek’s chart.

  1. 1017, low effortabove 72% of DeepSWE solvedabout $0.10
  2. 1017, default77.0% of DeepSWE solvedjust under $0.20
  3. V4.1 Flash (September)74.2% of DeepSWE solvedabout $0.50
  4. Frontier models on the chartGPT-6 Astra, Gemini 3.8 Flash, Claude Opus 5$2 to $10+

None of the frontier models on DeepSeek’s chart reached 77%.

API price per 1M tokens

Token typeOff-peakPeak
Input, cache miss$0.15$0.30
Input, cache hit$0.003$0.006
Output$0.60$1.20

Peak: weekdays 01:00–04:00 and 06:00–10:00 UTC, excluding Chinese public holidays.

All scores are DeepSeek’s own and not independently reproduced; rivals are the ones DeepSeek chose (GPT-5.6 Sol and Claude Opus 5, not the current GPT-6 and Opus 5.5 models). Sources: DeepSeek model card, DeepSeek API pricing, cost per task via The Decoder (17–18 Oct 2026).
Powered by Thorsten Meyer AI

Lower Costs for Agent Work

The update’s commercial case is less about leading every benchmark and more about the cost of completing repeated tasks. AI agents that run code, search files or perform multi-step workflows can make many model calls. A lower token price and shorter output may make those workflows less expensive, particularly for developers running them at scale.

DeepSeek’s reported DeepSWE figures, as described by The Decoder, put version 1017 at 77% for just under $0.20 per task; a lower-effort setting reportedly exceeded 72% at about $0.10. The September model was listed at about $0.50 per task for a 74.2% score. Those are source-reported benchmark costs, not a universal price for an agent job. Task design, tools, retries and model settings can change the total.

Kingy AI’s early pilot provides a small, independent check on performance and cost. It reports that 1017, GPT-6.1 Sol and Claude Sonnet 5.5 each passed 14 of 14 runs across seven small tasks, with 1017 costing roughly a quarter as much. The sample is too small to establish broad reliability or rank the models, and one task took 1017 about 27 seconds compared with roughly three seconds for Sonnet. For teams weighing deployment, the results point to a possible price advantage while leaving speed and performance on larger workloads open.

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How the October Update Fits

DeepSeek released the previous V4.1 Flash version on September 10, 2026. The October 17 release replaces it for users calling the default flash model, so API customers may receive the new version without changing the model name. The source says the update is also tuned for DeepSeek Harness version 0.2.1-rc.1 or later, as well as Tencent’s CodeBuddy and WorkBuddy.

The model card’s comparisons are useful for tracking changes against September, but they do not establish how 1017 compares with every current system. DeepSeek selected the rivals in its table, including GPT-5.6 Sol and Claude Opus 5. The source notes that newer model versions were not included. It also cites higher Terminal-Bench results for current frontier systems from a separate report, while cautioning that different evaluations are not directly comparable.

The source material also describes a second DeepSeek announcement: developer access to the company’s search engine through agent tools called Search and Fetch. Further details are not provided in the material, so the scope, availability and pricing of those tools cannot be established here.

“The case for 1017 isn’t leaderboard rank. It’s economics.”

— Thorsten Meyer, ThorstenMeyerAI.com

Independent Checks Remain Limited

No independent reproduction of DeepSeek’s 11 benchmark results is included in the supplied material. Benchmark scores can vary with harnesses, prompts, tool access and evaluation procedures. DeepSeek’s table specifies some of those conditions—for example, Terminal-Bench ran in the Claude Code harness—but the results still come from the company’s own model card.

The rival comparisons also have limits: the table uses selected models, and the supplied account says several newer systems were not included. Separate results for newer models use different evaluations, so they cannot be treated as direct head-to-head scores. The small Kingy AI pilot offers an initial outside data point, but its task set is too limited to settle questions about performance across longer or more varied work.

Other details remain unresolved. DeepSeek has not explained what changed in training, and the source’s account of self-feedback reinforcement learning is attributed to The Decoder rather than confirmed in the company’s stated update. The source material gives only a brief description of the Search and Fetch tools, leaving their rollout and commercial terms unclear.

API Use and Broader Testing

Developers using DeepSeek’s default deepseek-flash route are already directed to version 1017, according to the release details. The next practical test will be whether teams see similar cost and quality results on their own agent workloads, where prompt length, caching, tool calls and failed attempts affect total spend.

Further independent evaluations could clarify how the model performs across larger samples and against current competitors under matched conditions. Developers will also need fuller details on DeepSeek’s Search and Fetch tools to judge how they fit into agent systems. The supplied material does not give a date for additional results or a schedule for those tools, so both remain developing.

Key Questions

When did DeepSeek release V4.1 Flash 1017?

DeepSeek released V4.1 Flash 1017 on October 17, 2026. It replaced the September version on the company’s website, app and API, according to the source material.

Did DeepSeek raise its API prices for the update?

No price increase is reported. The source says the update’s listed token prices are unchanged, though peak and off-peak rates differ and total cost depends on usage and caching.

Does 1017 lead DeepSeek’s benchmark table?

It leads four of the 11 rows in the table provided by DeepSeek. Claude Opus 5 leads six, and GPT-5.6 Sol leads one. The table compares selected models and is not an independent evaluation.

Have independent testers confirmed DeepSeek’s benchmark gains?

The supplied material says DeepSeek’s benchmark results have not been independently reproduced. Kingy AI reports a small pilot across seven tasks, but that test does not establish broad performance across agent workloads.

What is not yet known about the update?

DeepSeek has not publicly specified what changed in training, according to the source. The extent of performance on larger real-world workloads and details about the announced Search and Fetch tools also remain unclear.

Source: ThorstenMeyerAI.com

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