Trace Plugin can inspect and simulate supported schematic circuits using the same simulation engine as Trace desktop. The companion includes its own engine; you do not need to install Trace desktop or use the host's simulator.
Before running
- Connect a saved project using the KiCad or Altium setup guide.
- Select a schematic in the chat's document picker. Simulation is not a PCB-editor solver.
- Save intended host changes and keep a backup. Finish host dialogs before exporting.
- Know the actual supply voltages, stimulus, load, operating conditions and behavior you want to observe. A label is not a power source.
- Check exact device/package identity, model provenance and pin mapping. Unsupported devices are not silently interchangeable with generic models.
Hosted chat and model acquisition need compatible enabled services and your applicable Trace allowance. Local solver execution is a different workflow from Trace's advanced PCB placement/routing; it does not imply a separate credit balance.
Understand what each host exports
KiCad: saved schematic files
The companion uses KiCad's installed command-line tools to export the saved .kicad_sch hierarchy and pin/net information. It cannot read an unsaved live schematic through KiCad 10's API.
Both editor-style and disk-style simulation requests use saved files. An editor-style request refuses detected unsaved schematic changes; an explicit disk request still cannot see them. Save your intended schematic first and ensure the command-line tools were installed with KiCad.
Keep all required child sheets and model dependencies available. Annotation, duplicate identities, changing files and unsupported devices can refuse export or inspection. Simulation support for a saved hierarchy does not add live KiCad hierarchy-authoring support.
Altium: current documents and compiled connectivity
The companion reads Altium's current schematic documents through its connection and compiles the project to obtain pin/net membership. Its simulation export does not have a separate disk-only reader: a request described as disk still reads the documents Altium currently holds.
Save first for a reproducible handoff, and do not treat that source label as proof of saved-file equality. The exporter uses supported simulation parameters and model information, not every Altium simulator feature.
Repeated-sheet multi-channel designs are not supported by this exporter. Do not interpret a refusal as proof of a faulty circuit; use a separately reviewed single-channel project if you need to simulate one channel. Ordinary multi-unit parts are distinct from repeated channels.
Inspect one experiment before starting it
- Choose Ask and describe the experiment in ordinary language. For example: “Inspect this RC filter for an AC sweep using its saved values and a 1 V small-signal input. Do not edit CAD or save a reusable bench.”
- Have Trace identify the current nets and inspect the proposed analysis, sources, load and model coverage.
- Read readiness findings. Missing models or operating conditions mean not evaluated, not a failed measurement.
- When ready, explicitly request the inspected experiment to run once. Follow its simulation job card.
- Wait for a terminal result and read actual signals, measurements and assertions. A run identifier or queued state is only admission.
Ask can inspect, perform temporary experiments and read their results without changing CAD or saving a reusable bench. These experiments still create local run artifacts. Agent is required for persistent bench configuration or model installation, rebinding, replacement and repair.
Supported analyses include operating point, transient and AC. Digital models and Verilog-A depend on the engine's supported and qualified model types on this installation; a catalog entry or successful download is not universal compatibility.
For an existing circuit's missing model, ask for the exact part's available model and pin mapping. Review any proposed persistent installation separately. A provisional vendor model may provide observations but cannot be used for engineering pass/fail assertions until its compatibility is reviewed. User-supplied and AI-authored model provenance also needs explicit scrutiny.
Installing a simulation model or saving a bench is not just opening a viewer. It writes persistent simulation data; it is not automatic permission to modify the schematic or control hardware.
Use automatic review only when intended
Compatible builds expose AI Workflows → Automatic simulation review on the home screen, with project overrides under the chat's Workflows button.
Turning it on requests a behavioral review near schematic completion, including bounded model lookup when relevant. It is not a guarantee that every circuit can run or pass. Missing safe conditions or a suitable model remain named gaps. A direct simulation request can still work when the workflow is off.
The setting does not authorize physical measurements, programming, power control or silent CAD substitutions. Review any requested model/bench writes and their actual outcomes.
Open and inspect saved results
Use a simulation job card's Open, ask Trace to open that run, or choose Simulation runs from the companion menu while a project is connected. The menu can open the project's saved-run list without starting a solver.
The separate Simulation window offers:
- A run list and status/failure details.
- Transient traces, AC magnitude/phase and supported digital lanes.
- Operating-point numeric values, rather than a transient plot.
- Signal selection, fit/reset, zoom, pan and readout.
- Paged measurements, assertions and model information.
Opening, selecting or zooming a result does not run the circuit again, change CAD or alter saved samples. Stop requests cancellation of an active run. A model Install action offered for a catalog-related failure is a separate persistent download, not a read-only view action; review its license and resulting status.
Check source, currentness and numerical quality. A changed design makes old results historical. Missing or unverifiable provenance is unknown and non-certifying; it does not by itself prove that the circuit changed. In particular, an Altium current-document export must not be mistaken for a verified saved-disk snapshot.
Decide what the result actually proves
- Completed means execution ended, not that the design passed.
- With no evaluated assertions, report observations and not evaluated, not certification.
- Cancelled, timed-out, partial, worker-lost or unusable results cannot certify the experiment.
- A constants-only result is not usable circuit analysis.
- Read all relevant result pages; one page or a reduced plot is not the entire waveform.
- AC node voltage magnitude is not transfer gain unless a matching input from the same run is used.
- Simulation does not prove physical fit, manufacturing readiness or behavior of an assembled board.
Review actual run-bound stimulus and limits before relying on measurements. Do not change an acceptance limit or substitute a model merely to obtain a pass.
Recover without repeating uncertain writes
- Engine unavailable: check that your companion build includes simulation; opening a window or installing host ngspice does not repair an incomplete companion package.
- KiCad export unavailable: save the schematic, check its child files and installed command-line tools, then inspect again.
- Altium export refused: inspect host dialogs, annotations and repeated-channel limitations before retrying.
- Model binding changed: inspect the current pins and saved association. Rebind the cached model only when identity and mapping can be verified; do not download a different device to bypass the refusal.
- Model installation or save outcome unknown: retain the existing data and check the original outcome before another write.
- Design changed after inspection: inspect the same bench against the intended current source again before running.
- Resource limit: distinguish time, aggregate sample and output-byte limits. A budget refusal is not evidence of convergence failure.
Stop does not undo a model installation, bench save, CAD edit or completed run. Preserve the original artifacts and safe error message when contacting support.