GitHub - Ajith-82/virtuoso-bridge-lite: Bridge between LLM-Agent and Cadence Virtuoso. A new infrastructure for Agentic Analog and Mixed-Signal Design.

A new infrastructure for Agentic Analog and Mixed-Signal Design. LLM Agents drive Cadence Virtuoso instances — locally or remotely — turning tedious handcrafting into automated design flows.

Why is this a "New Infrastructure"?

1. Deep Virtuoso Integration — Control across Schematic, Layout, Maestro, and Spectre.

Flexible programming: execute inline SKILL, load .il files, or use Python APIs
Four design domains: schematic editing, layout generation, simulation setup (Maestro), and standalone Spectre with PSF parsing

2. Scalable Architecture — Multi-server, multi-session, built for distributed design clusters.

Multi-profile SSH: connect to N design servers, each with independent tunnel
Run parallel simulations across servers and accounts
Verified across macOS, Windows, and Linux

3. AI-Native Design — Built for coding agents (Claude Code, Cursor, etc.) to drive Virtuoso.

CLI-first: virtuoso-bridge start/status/restart, no GUI needed
Ships with pre-defined agent skill files (skills/) — the agent knows how to use the bridge immediately
Optimized for high-frequency agent interactions with persistent SSH tunnels

If you are an AI agent, read AGENTS.md first and follow its setup checklist.

Choose your setup

You want to...	Use this path	Needs
Drive Virtuoso on a remote EDA server	Remote mode	SSH access, running Virtuoso, `load(...)` in CIW
Drive Virtuoso on the same machine	Local mode	Running Virtuoso, `VB_REMOTE_HOST=localhost`
Run Spectre from netlists	Spectre simulator	`spectre` on PATH, or `VB_CADENCE_CSHRC`
Run reproducible IC optimization workflows	Optimizer skill + optional external workflow CLI	Spectre/OCEAN setup, requirement files
Let a coding agent operate Cadence	Agent skills	Link `skills/` into your agent's skill directory

Virtuoso SKILL execution and Spectre simulation are independent. You can run Spectre without the SKILL bridge, and you can use the SKILL bridge without Spectre.

Quick Start

# 0. Get the source
git clone https://github.com/Arcadia-1/virtuoso-bridge-lite.git
cd virtuoso-bridge-lite

# 1. Install in a virtual environment
uv venv .venv
source .venv/bin/activate
uv pip install -e .

# 2. Create ~/.virtuoso-bridge/.env
virtuoso-bridge init user@host [-J user@jump-host]
# Or: virtuoso-bridge init      # empty template; edit VB_REMOTE_HOST yourself

# 3. Start and verify
virtuoso-bridge start          # starts tunnel and prints the CIW load(...) line
virtuoso-bridge status         # tunnel + Virtuoso daemon + Spectre availability

On Windows PowerShell, replace the activation line with .\.venv\Scripts\Activate.ps1.

from virtuoso_bridge import VirtuosoClient
client = VirtuosoClient.from_env()
client.execute_skill("1+2")  # VirtuosoResult(status=SUCCESS, output='3')

Useful first commands after the bridge is up:

virtuoso-bridge windows       # list all open Virtuoso windows
virtuoso-bridge screenshot    # screenshot CIW to the user artifact directory
virtuoso-bridge export-visio MyLib MyCell -o MyCell.vsdx  # Windows + Visio

…or skip Python entirely — run SKILL straight from the shell:

# One-liner — full VirtuosoResult JSON on stdout
virtuoso-bridge eval 'getCurrentTime()'

# Multi-line SKILL via heredoc (auto-wrapped in progn; returns the last form)
virtuoso-bridge eval --stdin <<'EOF'
let((libs)
  libs = mapcar(lambda((l) l~>name) ddGetLibList())
  printf("found %d libraries\n" length(libs))
  libs)
EOF

# Whole .il file — uploaded automatically in SSH mode
virtuoso-bridge load my_script.il

For detailed setup (jump hosts, multi-profile, local mode), see AGENTS.md.

CLI reference

All commands take -p PROFILE / --env PATH to pick a non-default config; run virtuoso-bridge <cmd> --help for full flags.

Command	What it does
Tunnel / lifecycle
`init [user@host] [-J jump]`	Write a starter `.env` (no args = empty template)
`start [--bind-venv]`	Start SSH tunnel + deploy daemon; `--bind-venv` (with `-p X`) also binds the active virtualenv to profile `X`
`stop`	Stop the SSH tunnel
`restart`	Restart tunnel + daemon
`status`	Tunnel + daemon health + Spectre availability
`license`	Check Spectre license availability
Profile binding
`profile show`	Print the resolved profile, its source, and the active venv binding path
`profile bind PROFILE --venv`	Pin the active virtualenv to `PROFILE` (naked `from_env()` calls in that venv resolve to it)
`profile clear --venv`	Remove the venv binding
SKILL execution
`load FILE.il`	Run a `.il` file in Virtuoso (uploads it in SSH mode). VS Code task–friendly; outputs `VirtuosoResult` JSON
`eval 'EXPR'` / `eval --stdin`	Run an inline SKILL expression; supports multi-statement via auto-wrapped `progn(...)`
Interaction / diagnostics
`windows`	List all open Virtuoso windows (number + name)
`screenshot [ciw\|current\|N] [-o DIR\|FILE]`	Capture a window; defaults to the user artifact screenshots directory
`dismiss-dialog`	X11 path: find and dismiss blocking GUI dialogs (saves you when SKILL channel deadlocks on a modal)
`list-windows [--json]`	X11 path: enumerate Virtuoso-related windows, including frame/child IDs and suggested modal actions
`dismiss-window WINDOW_ID [--action enter\|escape\|alt-y\|alt-n]`	X11 path: send an explicit action to one window ID returned by `list-windows`
`snapshot [-o DIR] [--history H]`	Dump the focused Virtuoso window (maestro/schematic/...) — brief by default, full disk dump with `-o`
Export
`export-visio LIB CELL -o OUT.vsdx`	Render a Virtuoso schematic to Microsoft Visio (Windows + pywin32)
SKILL Finder
`skill-find <query>`	Search SKILL functions by name (fuzzy/prefix/suffix/exact/regex)
`skill-info <fn>`	Get detailed More Info docs for a SKILL function

Snapshot a maestro run

Pull the currently-focused maestro session's setup + latest-run artifacts to a local folder:

virtuoso-bridge snapshot -o output                       # auto-picks newest history
virtuoso-bridge snapshot -o output --history Interactive.160   # pin a specific history

Output tree (one example):

output/20260422_142137__MyLib__myTB/
├── maestro.sdb, active.state                    # raw Cadence files
├── state_from_sdb.xml, state_from_active_state.xml  # filtered, high-signal
├── state_from_skill.txt                         # SKILL-probe setup summary
└── Interactive.N/
    ├── Interactive.N.{log,rdb,msg.db}           # run-level (rdb = SQLite)
    └── <pt>/<tb>/
        ├── netlist/   → netlist, input.scs, qpInformation.ils, paramInfo.ils
        └── psf/       → spectre.out, logFile, dcOp.dc, *.ac, *.tran, ...

Per-point netlist/ keeps only the 4 files that actually describe the design (main SPICE netlist, testbench top level, FOM definitions, corner label). Psf keeps stdout + logs + non-binary analysis results. The full rule set — including what's commented out and why — lives in src/virtuoso_bridge/virtuoso/maestro/snapshot_filter.yaml; edit the YAML (uncomment / comment lines) to add or drop files, no code change needed. Binary waveforms (*.raw, wavedb/) are never pulled — read them through reader.runs.read_results instead.

Exposing skills to your coding agent

The skills/ directory ships Claude Code skills (virtuoso, spectre, optimizer). They are not symlinked into the repo's .claude/skills/ on purpose — repo-tracked symlinks break on Windows and hardcode one user's absolute paths. Instead, each user links them into their own ~/.claude/skills/ once after cloning:

# macOS / Linux
mkdir -p ~/.claude/skills
ln -s "$(pwd)/skills/virtuoso"  ~/.claude/skills/virtuoso
ln -s "$(pwd)/skills/spectre"   ~/.claude/skills/spectre
ln -s "$(pwd)/skills/optimizer" ~/.claude/skills/optimizer

# Windows (PowerShell, Developer Mode or elevated shell)
New-Item -ItemType Directory -Force "$env:USERPROFILE\.claude\skills" | Out-Null
New-Item -ItemType SymbolicLink -Path "$env:USERPROFILE\.claude\skills\virtuoso"  -Target "$PWD\skills\virtuoso"
New-Item -ItemType SymbolicLink -Path "$env:USERPROFILE\.claude\skills\spectre"   -Target "$PWD\skills\spectre"
New-Item -ItemType SymbolicLink -Path "$env:USERPROFILE\.claude\skills\optimizer" -Target "$PWD\skills\optimizer"

Cursor and other agents that load skills from a user-level directory follow the same pattern — point their skills path at skills/ in this repo.

Architecture

VirtuosoClient — pure TCP SKILL client. Sends SKILL as JSON, gets results. No SSH awareness.
SpectreSimulator — runs Spectre simulations remotely via SSH shell commands, transfers netlists and results via rsync.
SSHClient — maintains a persistent ControlMaster connection that multiplexes three channels: TCP port-forwarding (SKILL execution via the daemon), SSH shell commands (Spectre invocation), and rsync file transfer. Optional — bypassed in local mode.

Fully decoupled: VirtuosoClient works with any TCP endpoint — SSH tunnel, VPN, direct LAN, or local. Multiple connection profiles are supported, each managing an independent tunnel to a separate design server.

Want to understand the raw mechanism? Start with src/virtuoso_bridge/virtuoso/basic/resources/ramic_bridge.il and src/virtuoso_bridge/virtuoso/basic/bridge.py.

Want to use Virtuoso locally without SSH? See Local mode in AGENTS.md.

Comparison with skillbridge

Feature	virtuoso-bridge-lite	skillbridge
Core mechanism	`ipcBeginProcess` + `evalstring`	`ipcBeginProcess` + `evalstring`
Local mode	Yes	Yes
Remote execution	SSH tunnel, jump host, auto-reconnect	Not supported
Calling style	String-based: `execute_skill("dbOpenCellViewByType(...)")`	Pythonic mapping: `ws.db.open_cell_view_by_type(...)`
Load .il files	`client.load_il()`	Not supported
Layout / schematic API	`client.layout.edit()` context manager	Raw SKILL only
Spectre simulation	Built-in runner + PSF parser	Not supported
AI agent support	Skill files, CLI-first, command logging	Not designed for agents
Python ↔ SKILL types	String-based	Auto bidirectional mapping
IDE tab completion	No (not needed by agents)	Yes (Jupyter, PyCharm stubs)

In short: Both projects are built on the same Cadence SKILL IPC facility, using the same core mechanism: ipcBeginProcess + evalstring + ipcWriteProcess. Here are the core lines from each:

virtuoso-bridge-lite — src/virtuoso_bridge/virtuoso/basic/resources/ramic_bridge.il

RBIpc = ipcBeginProcess(
  sprintf(nil "%s %L %L %L" RBPython RBDPath host RBPort)
  "" 'RBIpcDataHandler 'RBIpcErrHandler 'RBIpcFinishHandler "")

procedure(RBIpcDataHandler(ipcId data)
  if(errset(result = evalstring(data)) then
    ipcWriteProcess(ipcId sprintf(nil "%c%L%c" 2 result 30))
  else
    ipcWriteProcess(ipcId sprintf(nil "%c%L%c" 21 errset.errset 30))
  )
)

skillbridge — skillbridge/server/python_server.il

pyStartServer.ipc = ipcBeginProcess(
  executableWithArgs "" '__pyOnData '__pyOnError '__pyOnFinish pyStartServer.logName)

defun(__pyOnData (id data)
  foreach(line parseString(data "\n")
    capturedWarning = __pyCaptureWarnings(errset(result=evalstring(line)))
    ipcWriteProcess(id lsprintf("success %L\n" result))
  )
)

The divergence is in what's built on top: skillbridge stays thin — a Pythonic RPC client for interactive local use. virtuoso-bridge-lite adds SSH remote access, high-level layout/schematic APIs, Spectre simulation, and an AI-agent-ready harness.

Citation

If you use virtuoso-bridge in academic work, please cite:

@article{zhang2025virtuosobridge,
  title   = {Virtuoso-Bridge: An Agent-Native Bridge for Remote Analog and Mixed-Signal Design Automation},
  author  = {Zhang, Zhishuai and Li, Xintian and Sun, Nan and Jie, Lu},
  year    = {2025}
}

Authors

Zhishuai Zhang — Tsinghua University
Xintian Li — Tsinghua University
Nan Sun — Tsinghua University
Lu Jie — Tsinghua University

Name		Name	Last commit message	Last commit date
assets		assets
docs		docs
examples		examples
scripts		scripts
skills		skills
src/virtuoso_bridge		src/virtuoso_bridge
stats		stats
tests		tests
tools		tools
.gitattributes		.gitattributes
.gitignore		.gitignore
AGENTS.md		AGENTS.md
LICENSE		LICENSE
README.md		README.md
pyproject.toml		pyproject.toml

Navigation Menu

Repository files navigation

Why is this a "New Infrastructure"?

Choose your setup

Quick Start

CLI reference

Snapshot a maestro run

Exposing skills to your coding agent

Architecture

Comparison with skillbridge

Citation

Authors

Star History

About

Releases

Packages

Contributors

Languages

Latest commit

History

Folders and files

Repository files navigation

Why is this a "New Infrastructure"?

Choose your setup

Quick Start

CLI reference

Snapshot a maestro run

Exposing skills to your coding agent

Architecture

Comparison with skillbridge

Citation

Authors

Star History

About

Resources

Stars

Watchers

Forks

Releases

Packages

Contributors

Languages