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OpenROAD and the Era of Agents

Andrew B. Kahng��University of California, San Diego

abk@ucsd.edu

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Outline

  • The agentic era in EDA

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  • Case studies in OpenROAD

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  • Emerging challenges for agentic open-source EDA

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The agentic lever (LLMs 🡪 Agents 🡪 R&D Acceleration )

  • Scaling is design-based
  • Tools are bespoke
  • Ecosystem is consolidated
  • Optimization imperative = do better and faster, with less

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From “EDA tools” to “EDA R&D collaborators”

IC design �optimization �(PPA, schedule, cost)

LLMs + tool use

EDA = tools �(synthesis, P&R, STA, etc.)

(Human +) Agentic R&D loop�(read logs, tweak params, edit code, check/eval + iterate)

Multi-hours/multi-days reasoning

Comprehend large codebases

Invoke tool commands

Self iteration with feedback

LLMs in EDA (2026 ++)

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From assistance to autonomy: two levels

  • Fact: Agents (in EDA) will operate across differing levels of abstraction
    • Abstraction determines search space, feedback signal, and risk
    • Open-source EDA is the perfect (and our only) testbed !!!
  • Two levels (~patterns)
    • Code-level agents modify algorithmic structure (source code) �🡨 “Improve the global swap operator in the dpl module of OpenROAD”
    • Flow-level agents modify control variables (tool flow, parameters, objectives) �🡨 “Minimize ECP with < 2% area/power/PDP degradation by tuning ORFS configs”
  • Is the agent reasoning about heuristics (code and operators) or about � policies (parameters and sequencing)? (Inevitably, agents will reason about both!)

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OpenROAD as a foundation for agentic EDA research

Code-level��GR-evolve 🡪 grt��HELIX 🡪 dpl, gpl��AuDoPEDA 🡪 dpl, gpl, rsz

Flow-level��ORFS-Agent �🡪 flow knobs

Assistants ��OR-Assistant, OpenROAD-Agent 🡪 scripts + user queries�

Open code

Open APIs

Open benchmarks

“~13% WL/ECP gains, 40% fewer iterations”

94% pass-rate vs. 0% for foundational models”

Up to 9% HPWL, 23% RWL reduction across 2 PDKs

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Three frontiers of recent progress in OpenROAD

“~40% fewer iterations than autotuners”

“~19% power gains”

“~9% HPWL gains”

  • Treat EDA tools as black-boxes; tune parameters and orchestrate flows
  • ORFS-Agent (UCSD) OpenROAD-Agent (ASU) ORAssistant (PII)
  • Algorithms unchanged; agents learn the policy
  • Agents can read, edit, compile and benchmark across multi-language codebases
  • AuDoPEDA (UCSD)
  • Algorithms change; formal verification; closed-loop guardrails
  • Per-design code evolution; tool specializes to the workload
  • HELIX (UCSD)�GR-Evolve (ASU)
  • Algorithms change; one tool per design vs. one tool for all designs

Flow tuners

Repo-scale coding

Bespoke, design-adaptive tools

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Outline

  • The agentic era in EDA

​

  • Case studies in OpenROAD

​

  • Emerging challenges for agentic open-source EDA

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Evolving placement and routing in OpenROAD

Synthesis

Floorplan

GPL

DPL

CTS

GRT

DRT

Coding evolution targets

HELIX

GR-Evolve

Attributes

HELIX (placement) – UCSD

GR-Evolve (routing) – ASU

Target

Global + detailed placement (gpl, dpl)

Global routing (grt)

Method

(μ+λ) evolutionary search with literature-guided operators

Stateless agentic loop with persistent QoR history

Knowledge base

97 papers + documentation + pseudocode + parameter list

Distilled router summaries + source

Key results

9% HPWL and 23% RWL (max) �4.5% / 5.6% geomean

8.7% post-DR WL (max)

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Repository-grounded coding agents for OpenROAD

Repo graph + documentation

Literature-grounded planning

Plan localization �(map plan to edit surfaces)

Autonomous execution loop �(apply diffs, build, run flow, measure QoR)

Formal diff checking �(Lean; Aristotle; AXLE)

Target

Module(s)

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Diff scope

Routed wirelength

dpl

-5.4%

11 files, ~1k LoC

Effective clock period

gpl, rsz

-10.0%

11 files, ~330 LoC

Total power

rsz

-19.4%

9 files, ~1k Loc

Removing any single stage dramatically reduces valid diff-rate!

No execution loop

Full system

No documentation

No formal gate

No localization

No planning

92/100

54/100

44/100

41/100

37/100

26/100

Valid diffs out of 100 trials

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ORFS-agent – LLM-driven flow autotuning

  • Design flow tuning is high-dimensional
    • 1000s (actually 10000s) of knobs in RTL-to-GDS
  • Plain Bayesian Optimization struggles – weak domain priors; poor high-D scaling
  • Key idea: LLM-driven flow autotuner 🡪 ORFS-agent
    • Read logs; reason in context; interpret bottlenecks; propose structured parameter updates; iterate with tool feedback

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Comparison of ORFS-agent and OR-AutoTuner w.r.t. wirelength and ECP

Normalization: Results with OR-AT4 params and 375 iterations set as 1.0

Baseline: OR-AT �(4 vars, 375 iters) ≡ 1.0

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ORFS-agent uses ~40% fewer iterations, iso-QOR

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Also: ≈ 13% gains in WL or ECP (single-objective) �(details: MLCAD25 paper)

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Improving a SOTA Hypergraph Partitioner (OpenROAD/par)

  • TritonPart = SOTA hypergraph partitioner (> hMETIS, KaHyPar)
  • Has ILP “boundary optimization” step (with CPLEX or OR-Tools)
  • Autonomous AI diff “lowers the variance” of solver step
  • Substantial wins over TritonPart
  • Even with the weaker OR-Tools solver, finds world’s best-ever solutions!

Kahng talk 20251020

Titan23 suite, LLM-evolved diff

Cut reduction (%) vs. TritonPart

K = 2

K = 3

K = 4

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Outline

  • The agentic era in EDA

​

  • Case studies in OpenROAD

​

  • Emerging challenges for agentic open-source EDA

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Challenge 1: validation & evaluation

  • Agents are non-deterministic; flows are slow and expensive
    • Reproducibility & traceability – same prompt, different code
    • Cost: minutes to hours per RTL-to-GDS candidate
    • Improvements at GR / placement may only show after detailed routing
  • What “correct” means is no longer obvious
    • DRC-clean is necessary; not sufficient
    • Multi-objective: WL, timing, power, area, runtime
    • Generalization across designs and PDKs
  • What we need
    • Standardized testbeds: ORFS, MacroPlacement, etc.
    • Hard gates: DRC, build, regression tests – reject before scoring
    • Formal contracts where possible: Lean / SMT / static analysis
    • Statistical rigor: seed sweeps, confidence intervals, ablations

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Challenge 2: humans + agents; IP & creators’ rights

  • Where does the human belong in the loop?
    • Objective definition, trade-offs, safety -- not API debugging
    • Agents explore; humans judge and are accountable
    • Risk: deskilling if agents become opaque oracle “experts”

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  • IP and creators’ rights are murky (in the ‘agentic future’ …)
    • Who owns an LLM-evolved diff? Model? Prompter? Repo? (If it reads on a patent claim?)
    • Permissively-licensed code bases might accept agent diffs (is usability clouded?)
    • Training with public “scraped” corpora (creator rights, opt-ins, … ?)
    • Attribution and credit when an agent rediscovers known techniques

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  • What does “authorship” mean for agent-generated EDA code?

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Challenge 3: project & ecosystem governance

  • Agents change the contribution model
    • PRs at machine speed: how does review scale?
    • Bot accounts, auto-generated commits 🡪 what counts as a maintainer signal?
    • Risks: hallucinated, or subtly-wrong code overwhelming reviewers
  • Ecosystem-level questions
    • Reproducibility: pin commits, PDKs, agents, prompts
    • Saturated benchmarks: need open, evolving evaluation suites
    • Compute access: who can run repo-scale evolution? 🡨 equity in research
    • Co-evolution: agent capabilities and tool APIs both moving targets
  • In an ideal (OpenROAD) future …
    • CI-enforced QoR gates: non-regressing diffs, machine-checkable invariants
    • Provenance metadata: model, prompt, evaluation context per diff
    • Versioned manifests: OpenROAD commit + ORFS + PDK + agent 🡪 replay any result

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Toward an open vertical environment for EDA agents

Environment scaffolding�(The substrate agents act inside)

Agent capabilities�(What we want agents to do)

Ecosystem and governance

(What OpenROAD can achieve)

Episode schema for EDA

(workspace, actions, constraints, QoR)

Lexicographic, constraint-aware rewards

(hard gates 🡪 QoR frontier 🡪 cost)�

Open evolving agent benchmark suite

Cross-stage state & observability

(RTL ↔ verif ↔ synth ↔ PD ↔ signoff causality)

Cross-tier orchestration

(flow-level + code-level in one loop)

Reproducibility manifests�(pinned commits, PDKs, agent versions, prompts)

Multi-fidelity ladder

(lint 🡪 sim 🡪 synth 🡪 PD 🡪 signoff audit)

Trajectory-grounded training + research-grade memory

CI-enforced QoR gates + machine-checkable invariants

Fast learned surrogates as first-class env citizens

Code-level R&D

Industrial calibration loop + compute equity

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Thank You!

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Flow-level agents – architecture

High-level objective�“Minimize ECP with < 2% PDP degradation”

LLM planner

  • Parse documents
  • Parse codebase / scripts
  • Parse misc. corpus
  • Decompose objective
  • Generate flow script
  • Propose parameters

Execution layer

  • Invoke tools
  • Monitor logs
  • Capture metrics

EDA tools

LLM

Feedback

Knowledge�corpus

  • ChipNeMo (NVIDIA) (2023)
    • Pretraining on expert-engineer scripts
    • Combines ICL with document retrieval
    • Generates high-quality Tcl scripts for timing analysis, etc.
  • ChatEDA (CUHK) (2024)
    • Translates flow automation to an agentic task
    • Rich training corpora, CoT prompting, usage of multi-agents
  • ORAssistant (Precision Innovation) (2024)
    • Automated script generation and chatbot for OpenROAD ecosystem
  • ORFS-agent (UCSD) (2025)
    • LLM-driven iterative optimization agent for parameter tuning in the OpenROAD-flow-scripts repo.

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Treat EDA tools as black-boxes; LLM decomposes objective into subtasks; each subtask is translated to scripts

Response

Query

Query

Response

Invoke

PPA

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Code-level agents – architecture

High-level objective�“Reduce HPWL by improving global swap operator in OpenROAD’s dpl”

  • Parse source code
  • Parse relevant modules
  • Parse misc. corpus
  • Understand dependencies

Code parser

  • Propose code edits
  • Introduce new cost terms
  • Tune hyperparameters
  • Refactor control logic

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LLM reasoner

  • Build tool
  • Run benchmark suite
  • Sanity checks
  • Linters

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Compiler + regression tests

EDA tools

QoR metrics

Feedback

Feedback

Modify internal heuristics and algorithms; LLM reads, proposes and edits code diffs

  • EvoPlace (CUHK) (2025)
    • Python code edits inside DREAMPlace framework
  • SATLUTION (NVIDIA) (2025)
    • C++ code diffs targeting Boolean Satisfiability problems
    • Directly evolves solver repositories
  • -EVO (UCSD) (2025)
    • C++ code diffs targeting placement algorithms in OpenROAD
    • Directly evolves placement repositories
  • AuDoPEDA (UCSD) (2026)
    • Proposes research directions + expands them into executable code diffs
  • VLM-MPL (UCSD) (2026)
    • Vision language models-based macro placer

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LLM

Query

Response

Response

Query

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AuDoPEDA: Documentation 🡪 Planning 🡪 Diff 🡪 QoR Loop

  • Parse OpenROAD via tree-sitter
  • Build cross-language property graph
  • Generate hierarchical doc cards
  • Create machine-readable API/invariant summaries

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  • Retrieve from repo docs, EDA literature corpus
  • DSPy-compiled planning program
  • Outputs: research hypothesis, proposed interventions, QoR targets

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  • Map plan 🡪 specific files/functions
  • Generate granular diff plan: pre-checks, run config, QoR probes, rollback conditions

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  • Codex-class agent
  • Apply diffs
  • Build
  • Run flow
  • Extract QoR
  • Hill climb under safety gates

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Convert codebase to structured knowledge

Planning is typed and validated

Converts research intent into executable diffs

Accept only if QoR improves

QoR

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A merge-ready OpenROAD PR (agent-driven)

What “merge-ready” requires

  • Passed regression/PPA �guardrails
  • Iterated on review feedback + �merge conflicts
  • Auto-generated docs + configs + �PR descriptions
  • Only manual step: human-expert �sign-off
  • End-to-end LLM cost: ~$30
  • Human-edits: 0 (except sign-off)

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Links

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Hypergraph partitioning – beyond quality: speed

Same cutsize with significantly faster runtime!

Better cutsize than TritonPart

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