iCoder-27B

Recursive AI-Led Development of a Frontier Industrial Coding Model

How little human involvement is sufficient for an agent to develop a frontier model? We concentrate expert knowledge into high-density, low-frequency Research Skills, then let an agent evolve data, coordinate SFT, OPSD, and RLVR, and revise the training strategy through executable evidence.

Frontier performance, compact scale.

iCoder-27B leads RTLLM, shares the best TritonBench-G result, and ranks second on KernelBench L2 Fast and CVDP.

Industrial coding performance reported in the paper. Higher is better within every benchmark.

Human insight sets the direction. The agent compounds it.

Experts provide executable Research Skills once; the agent owns concrete experiments, diagnoses failures, and revises the recipe.

Human-guided self-evolving training framework from Research Skills through Data, SFT, OPSD, and RLVR to iCoder-27B

Executable Research Skills

Objectives, stage scaffolds, permission boundaries, launch procedures, and trusted verifiers become a reusable process prior—not a fixed experiment script.

OPSD as the bridge

The model learns from failures it can repair with task-specific guidance while the deployed policy remains conditioned on the original task.

RLVR that fails closed

Compilation and execution ground the reward. Unjudgeable trajectories are masked; exploit behavior is ineligible before any scalar reward is assigned.

What the agent discovered.

The final recipe was not written in advance. It emerged from failures, controlled ablations, and verifier-grounded evidence.

  1. 01

    Train near the moving capability boundary: tasks that are impossible teach little, and mastered tasks stop producing useful variation.

  2. 02

    Privileged context should route credit, not become a deployment dependency. Useful feedback changes what is learned while the policy still sees the bare task.

  3. 03

    Reward validity comes before reward scale. Kernel exploits and false RTL verdicts forced eligibility gates and fail-closed supervision.

  4. 04

    Trajectory budget is part of the learning rule. Length filtering silently removed valuable responses until prompt and response budgets were coupled.

  5. 05

    We open-source the agent-developed training trajectory: iCoder-27B-SFTiCoder-27B-OPSDiCoder-27B.

Industrial coding benchmark.

Every value below is reproduced from the paper’s main result table, with repeated benchmark labels grouped for faster comparison.

Benchmark Metric iCoder
27B
Qwen3.6
27B
InCoder
32B
InCoder-32B
Thinking
DeepSeek
V4-Pro
GLM
5.2
Kimi
K2.6
GPT
5.5
Claude
Opus-4.8
Hy3 Gemini
3.5-Flash
VerilogEvalSpec-to-RTL avg@486.370.162.565.969.966.072.490.182.783.889.1
Code-complete avg@486.070.858.254.279.874.878.591.481.981.683.8
RTLLMFunctional avg@468.049.648.044.267.564.059.066.064.753.563.5
CVDPFunctional avg@5 (%)44.133.936.930.338.539.542.139.547.739.729.7
RealBenchSyntax pass@5 (%)61.738.360.055.036.743.358.380.083.341.768.3
Functional pass@5 (%)26.716.746.736.716.725.025.028.336.716.726.7
ArchXBenchFunctional pass@1 (%)49.335.236.629.650.750.742.356.354.947.950.7
KernelBench L1Compiled (%)9587888593969398959494
Correct (%)6132514732503243554245
Fast (%)251218181326522302123
KernelBench L2Compiled (%)97899093919884100979899
Correct (%)7428656340401741705678
Fast (%)401714152530724372947
KernelBench L3Compiled (%)908660608690821008498100
Correct (%)341230204301838401858
Fast (%)104141220068214
TritonBench-GCorrectness pass@1 (%)20.111.417.918.519.019.019.019.520.119.514.9

Bold is best; underline is second-best. KernelBench L1/L2 contain 100 tasks and L3 contains 50; L3 counts are reported as percentages.

Beyond one-shot generation.

In evaluation-driven loops, iCoder repeatedly proposes, executes, measures, and refines complete RTL designs and GPU kernels.

Evaluation-driven RTL optimization trajectories across eight designs
Long-horizon RTL optimization. iCoder reaches one win, five ties, and two losses against HY3, while approaching its mean cell-count reduction with 51% as many reported output tokens.
Evaluation-driven GPU kernel optimization trajectories across eight operators
GPU-kernel optimization. iCoder obtains the strongest archived endpoint on Vector Sum and Cumulative Sum and remains close to the fastest result on several additional operators.