Changelog

All notable changes are documented here. Kessetsu follows Semantic Versioning for product releases and versions its machine contracts independently.

[Unreleased]

[1.3.0] — 2026-09-26

Kessetsu 1.3.0 expands the verified circuit workflow beyond single-run design: repeatable multi-condition studies, local research-data comparison and fitting, supported SPICE import, physical-part handoff, larger-schematic navigation, installed agent discovery and provider-neutral proposal review. These workflows remain model- and scope-bounded; they do not claim hardware or manufacturing validation.

Provider-neutral agent proposal review

• Analyze → Review agent proposal… creates a versioned, source-hash-bound task envelope for any external agent; Kessetsu does not upload source or require a provider account.
• Returned kessetsu.agent-proposal.v1 JSON remains separate from the document while the user reviews its summary and line diff. Unknown schemas, stale base revisions, oversized payloads and invalid source fail without changing the open circuit.
• A proposal must compile with verified schematic connectivity and complete a real local browser simulation before it can be accepted. Acceptance is explicit, marks the source unsaved and offers one-step Undo accepted proposal; closing or cancelling leaves the document untouched.
• This handoff is a provider-independent review boundary, not a hosted model, autonomous design guarantee or claim that an agent's explanation is verified. Core simulation/assertion results remain separate from proposal text.

Agent capability discovery

• kess capabilities --format json returns the deterministic kessetsu.capabilities.v1 installed-build manifest inside the normal CLI envelope, including command I/O behavior, live contract versions, calculator/language entry points, engineering metrics, export capabilities, workload limits, documentation links and a safe agent workflow.
• Discovery is side-effect free and does not require a circuit or Ngspice. Export and measurement entries use their Core-owned catalogs rather than a separate frontend list.
• Unsupported-metric diagnostics now use the same complete catalog and include the dynamic rise_time, fall_time, settling_time, overshoot and energy metrics.

Schematic navigation and quality

• The Web schematic inspector can find and center components or named nets, follow logical pins, highlight a complete net, show model provenance and navigate structured reusable-block groups.
• Multiway aligned nets move an obstructed branch hub to a clear pin escape, avoiding duplicate wire segments and stacked junction dots without changing canonical connectivity.
• KiCad handoff schematics use roomier native spacing, hide retained pin metadata by default and place named-net labels on short outward stubs so editable exports open without text collisions.
• The visual and real KiCad/LTspice corpus now includes loaded filters, transistor drivers and independently parameterized reusable filter/amplifier instances.

Physical part identity

• part statements attach optional manufacturer, MPN, footprint, complete logical-pin mapping and user notes plus condition-qualified provided voltage/current/dissipation limits to an electrical component without changing its value, model or connectivity.
• Core validates assignments against catalog pins, preserves module-instance identity and exposes kessetsu.physical-parts.v2 separately in Circuit IR. Unknown/incomplete mappings and malformed or condition-free limits fail closed.
• Physical metadata and reusable-block navigation advance compile reports to kessetsu.compile.v9; simulation netlists remain byte-identical when only metadata changes.
• Native and Web simulation expose kessetsu.part-stress.v1: model stress versus user-provided limits, including conditions/citation and explicit unavailable states. This advisory comparison is separate from requirements, exit status, datasheet compliance and safe-operating-area claims.
• Deterministic BOM CSV groups matching selections and keeps unresolved/incomplete rows visible; kessetsu.handoff.v2 also records provided ratings while retaining IR identity, footprint readiness and exact model dependencies.
• KiCad uses the declared footprint and physical pad numbers only with a complete pin map. A bare footprint remains visible in BOM/handoff evidence but is not silently attached to the schematic.
• The shared export contract advances to kessetsu.export.v3; CLI and Web expose BOM CSV and handoff JSON through the existing Export flow.
• Physical components retain structured reusable-block ancestry independently of their canonical flattened electrical identifiers. Existing source-only share links from compatible Core revisions are recompiled rather than rejected.

Supported SPICE netlist import

• kess import converts a declared Ngspice-compatible subset into ordinary editable .kess and recompiles it through the canonical Core before writing output.
• Initial coverage includes literal R/C/L, independent DC/AC/SINE/PULSE/PWL voltage/current sources, selected built-in diode/BJT/MOSFET models and OP/TRAN/AC/DC analyses.
• Original component/net names receive deterministic reversible mappings. SPICE numeric suffixes, including its case-insensitive milli M, are normalized without changing electrical values.
• Literal .param NAME=value relationships remain typed editable parameters; Kessetsu infers the unit from supported uses and rejects unused or dimensionally conflicting parameters.
• Source-embedded .SUBCKT topologies become editable module definitions and root X cards become use instances. Explicit ports, local connectivity, literal typed defaults and named overrides are retained; unsupported nesting or implicit globals fail instead of being flattened.
• Unsupported directives, control blocks, include paths, models, expressions and device families fail with source-line diagnostics instead of producing a partial circuit.

Portable research packages

• kess study package writes a new atomic research folder with the exact specification and source, complete result JSON, summary/full-data CSV, labeled SVG, printable HTML and rerun guide.
• kessetsu.research-package.v1 records every payload hash, plotted analysis/signal/case, model citation/license/hash, original simulator and solver identity, and interpretation limits.
• Redistributable external models retain their exact relative paths; prohibited model bodies are never copied and remain precise user-supplied dependency requirements.

Reproducible memristor protocol

• A 24-case signed pulse study characterizes amplitude, duration, starting state, modeled resistance change, current and energy for the exact bundled threshold-model dependency.
• A separate 16-case timestep-refinement study exposes bounded numerical sensitivity, while a held-out stimulus remains separate from the displayed sweep rather than influencing it.
• An executable regression, headless notebook and public guide retain explicit units, model identity, solver evidence and the distinction between synthetic simulation and physical validation.

Finite calibration and validation

• Core-owned kessetsu.fit.v1 evaluation selects only among completed finite study candidates using declared calibration observations; holdout validation never influences selection.
• Dimensionless weighted RMS scoring uses explicit per-signal uncertainty and weight while preserving complete residual comparisons, score masks, failures, case/data/model/solver identities, boundary hits and near-equivalent candidates in kessetsu.fit-result.v1.
• kess fit evaluate, typed Python tables and a headlessly executable synthetic notebook share the same contract. The workflow makes no continuous/global optimum, physical-mechanism, identifiability or extrapolation claim.
• Typed external subcircuit parameters can be swept as ordinary root study axes, allowing exact hash-bound local models to participate without editing their model text.

Typed external model parameters

• External subcircuits may expose a bounded, unit-typed allowlist of existing .SUBCKT parameters; instances can bind literals or root parameter expressions without editing model text.
• Resolved per-instance values and provenance remain in Circuit IR and survive canonical SPICE, LTspice, KiCad and Schematic JSON export. Unknown names, unit mismatches, duplicates and parameters absent from the exact hash-bound library fail closed.
• Compile reports advance to kessetsu.compile.v6, canonical schematics to kessetsu.schematic.v3, and model manifests/locks to v3; v4/v5 source shares remain explicitly supported.

Research-data foundation

• Local kess data preview/import/compare and shared Core/WASM contracts for explicitly mapped CSV, engineering units, calibration, raw-source identity and missing-row accounting.
• Scalar reference comparison with explicit windows/shifts, interpolation and coverage; full residuals and sample-weighted bias, MAE, RMSE and maximum error.
• Local Web research-data workspace for CSV preview, explicit mapping, two-dataset overlay, residual metrics and evidence download without changing the open circuit or uploading data.
• Typed projection of the current successful transient, AC-magnitude or DC simulation into the same research-data comparison flow, retaining solver/result/vector provenance.
• Native --include simulation evidence and kess data from-simulation close Web/CLI projection parity without moving interpolation or residual semantics into adapters.
• Optional local Python package for safe CLI invocation, exact contract validation, typed simulation/study/research tables and pandas conversion; includes a headlessly verified Jupyter workflow from circuit simulation through residual evidence and plots.
• Synthetic tutorial files and detailed research-data guide. Arbitrary direct study-result comparison remains outside this data-command surface.

Local parameter studies

• Shared versioned study specifications and deterministic list/linear/log grids, revisions, temperatures, nominal/corner and seeded uniform/Gaussian tolerance studies.
• Native kess study create/plan/run/export, durable per-case checkpoints and cancellation/resume guarded by source, requirements, models and solver/Core build identity.
• Web Analyze → Parameter study: configure, run, stop/resume, inspect failures, compare reports, apply parameters and download full JSON/numeric CSV, summary CSV, SVG or HTML reports.
• Finite-grid objectives retain all outcomes and choose only feasible evaluated candidates; no global-optimum, hardware-validity or production-yield claims.
• Explicit-window rise/fall/settling time, directional overshoot and signed integrated energy; measurement contract advances to kessetsu.measurement.v3. Legacy metrics retain semantics.
• Explicit budgets and detailed study guide.

Compatibility and upgrade

• Existing literal circuits remain valid. Kessetsu 1.3.0 advances compile reports to kessetsu.compile.v9, canonical schematics to kessetsu.schematic.v3, model manifests/locks to v3, engineering measurements to v3 and exports to kessetsu.export.v3; the stable kessetsu.cli.v1, simulation and assertion envelopes are unchanged.
• Compatible v4/v5 source-share links are recompiled through the current Core. Unknown future schemas still fail closed. Local external-model bodies and provider credentials are never embedded in share links or agent-task envelopes.
• Install with the normal guided command to upgrade. Release archives retain complete source, documentation, examples, Python adapter, notices, exact version metadata and per-artifact hashes.

[1.2.0] — 2026-09-18

Website and documentation

• Simplified landing copy and route-specific loading messages.
• Refreshed landing schematic from the shared Core instead of a hand-drawn mockup.
• On-site changelog, documentation navigation and section index, plus a complete Web editor guide.
• Removed internal roadmap, historical evaluation reports and operational notes from current public source and new release packages; technical test specifications remain test inputs.
• Clear Windows installation/session guidance with a directly usable launcher path.

Compatibility

Existing literal circuits continue to work. Upgrade CLI and Web usage to 1.2.0 for parameters, new AC metrics and browser local models. Compile reports now use kessetsu.compile.v5 and measurements kessetsu.measurement.v2; CLI, assertions and requirements envelopes are unchanged. Existing v4 source-share links are recompiled; unknown future schemas are rejected. Independent .kessreq limits remain literal. Local model files must be supplied separately; the official PSpice OPA197 model remains native-only. Model identity is not hardware validation.

Local external devices and model files

• Catalog-backed comparator and two-terminal external subcircuits, instantiated with device; shared typed pins, ERC, schematic and all seven export formats.
• Explicit local model selection in Web Circuit details. Exact file/hash/entry validation, portable Ngspice library checks and native-only compatibility diagnostics before execution. Files stay in memory, never in drafts, share URLs, manifests or ordinary model-body exports.
• Generic comparator and published threshold-memristor examples, with exact files/defaults, attribution/license and electrical comparison coverage. Existing official OPA197 stays user-acquired/native-only, not redistributed or substituted.
• Optional transient uic for model initial conditions; ordinary analyses retain their previous serialization and behavior. External header defaults/continuations are supported.
• Fix repeated primitive assertion limits producing duplicate Ngspice measurement records; each assertion retains its own limit and evaluation.

Reusable circuit examples

• Add complete RC filter and non-inverting amplifier examples with independently configured instances, fixed simulation assertions and access through File → Examples in Web.
• Preserve structured module-instance paths on virtual IR interfaces, including literal blocks without parameter provenance; electrical IDs and flattened backend topology remain unchanged.
• Document ports versus parameters, defaults, loading, model assumptions and portable source-embedded block identity in the cookbook. No registry or external block imports.

Parameter diagnostics and compilation limits

• Preserve actual declaration/module-input positions through nested elaboration without changing default provenance or guessing parameter locations from similarly named comments.
• Bound source size, parsed/expanded statements and expression work; share node accounting across numeric roles and reject unsupported nested waveform calls without parser recursion.
• Preserve supported literal/quoted waveforms, existing source examples and backend semantics.

Reproducible parameter inputs

• Add shared versioned root numeric inputs and repeatable CLI --param NAME=VALUE for circuit checking, compilation, simulation, tests and exports, without editing source files.
• Recalculate dependent defaults, reject unknown/duplicate/invalid inputs before writes or simulation and retain original defaults/effective override provenance in typed IR.
• Return portable effective .kess through --include effective-source; expose the same pure input contract in WASM without adding persistent editor override state.
• Preserve line endings/comments during materialization and allow trailing // comments without consuming a statement's required line ending.

Parameterized inline measurements

• Accept {expression} in design-owned assertion thresholds and supported numeric metric arguments: time windows, target/reference frequency, THD fundamental and clipping rails.
• Resolve typed IR quantities before simulation; preserve literal signal/device/policy names, existing measurement semantics and sorted assertion-field provenance.
• Keep independent .kessreq numeric fields literal-only, with explicit expression rejection.

Parameterized excitation and analyses

• Accept {expression} in all numeric slots of unquoted ac, sine, sine_ac, pulse and pwl voltage/current sources, with lexical module parameter binding.
• Accept expressions for transient step/stop, AC points/start/stop and DC start/stop/step. Keep scale keywords/source names literal and require positive integral AC point counts.
• Resolve typed values directly into IR; retain waveform-field and optional sorted analysis-field provenance without changing literal backend output.

CLI output protection

• Check netlist and model-lock destinations before either write. Reuse byte-identical locks without rewriting; require --force for different existing lock contents.
• Reject source/lock and netlist/lock destination aliases even with --force.

Explicit AC measurements

• Added gain_at(out,in,frequency), lower_cutoff(out,in[,reference_frequency]) and upper_cutoff(out,in[,reference_frequency]) to the shared CLI/Web evaluator.
• Interpolate magnitude along log frequency without extrapolation; require explicit references for ambiguous disjoint bands and report missing edges as errors.
• Measurement contract v2 adds these metrics without changing legacy metrics or the CLI/assertion/requirements envelopes. Editor completion and hover describe the new calls.

Schematic geometry and editable exports

• Verify actual conductive paths, pin contacts, isolated crossings and matching semantic labels, rather than trusting wire net tags. Invalid drawing geometry blocks export.
• Preserve pin escape space, separate crowded components and keep reference/value blocks close to their symbols. Negative supply markers and their captions point outward.
• Map LTspice symbols to native rotations/mirrors and reroute from their actual pins; preserve orthogonal paths and validate the resulting geometry before export.
• Place KiCad reference/value properties from the shared schematic annotations and draw conductive joins explicitly. Added an original dense-bias regression circuit.

Builtin diode portability

• Corrected 1N4148, 1N4007 and the default diode path to use portable Ngspice diode directives without descriptive or non-enforced rating fields. Electrical coefficients are unchanged; repaired builtin models have provenance version 1.0.1 and new content hashes, retaining their legacy/unverified attribution. Exact model packages are unchanged.
• Added real native/browser OP regression coverage for both named models and the default.

Parameterized circuit foundation

• Independent module parameter scopes and named use overrides, with recalculated defaults, typed caller binding and structured instance-path/override provenance.

• Declared module ports in IR/ERC, scoped local nets and flattened-path collision errors. Virtual module ports are excluded from physical schematic-pin expectations, without weakening physical connection checks.

• Top-level typed param declarations and bounded, unit-checked arithmetic in passive and DC-source values.

• Parameter/dependency and resolved-field provenance in kessetsu.parameters.v1; all electrical and drawing backends still consume resolved Circuit IR.

• Source completion/highlighting without new editor panels; compile contract v5 with explicit v4 source-share compatibility and unchanged exact-package checks.

• Prefix/exponent overflow/underflow validation and bounded module recursion/expansion diagnostics.

Parameterized module analyses/assertions must be placed at the circuit root until their context/target handling is implemented.

[1.1.0] — 2026-09-16

Circuit tools

• Shared nominal divider/RC calculations with typed SI inputs, exact/E12/E24 values, achieved results and editable circuit templates.
• kess tool divider and kess tool rc-lowpass with the existing JSON envelope and explicit .kess output.
• Local browser tools at /tools/, with generated-circuit download, editor continuation and recovery of the previous browser circuit.
• Discoverable toolkit links on desktop/mobile landing pages; simulation without assertions shows completion instead of a misleading 0/0 requirements summary.

Web and discovery

• Build-time HTML for the existing landing and installation pages, with distinct route titles and descriptions.
• Public guides and references at /docs/, generated from the reviewed Markdown sources without a JavaScript requirement; sitemap covers all public content pages.
• GitHub project description, topics and canonical product homepage updated. No analytics or circuit uploads added.

[1.0.1] — 2026-09-16

Distribution

• Guided CLI installation page with OS selection, copyable commands, first-circuit download, simulator prerequisites, updates, and manual fallback.
• Per-user Windows and POSIX bootstrappers that select official stable releases, verify archive/executable integrity and version, configure PATH, preserve previous bundles, and refuse unmanaged paths. The CLI binary remains the independently released stable version.

Fixed

• LTspice export emits dotted analysis directives and correct DC-source references. The first analysis is active; additional analyses remain selectable comments with an explicit warning. Target-application smoke compares pin connectivity and component data rather than reference presence alone.
• Windows ZIP packaging uses portable slash-separated entries on both Windows PowerShell 5 and PowerShell 7, preserving strict installer path validation.

Documentation

• Concise public roadmap and documentation index, with account-specific execution prose removed from published reports while preserving evaluation outcomes and limitations.
• Reviewed public-document manifest and focused publication checks for future release packaging.

[1.0.0] — 2026-09-16

First public release.

Product

• One Rust Core shared by native CLI and WebAssembly.
• Zero-account Web Hub with live compile/ERC, canonical schematic, real browser Ngspice simulation, plots, assertions, seven export formats and versioned share URLs.
• Local Web document workflow with .kess open, native in-place Save and Save As on Chromium, browser-local Save plus explicit .kess download on Firefox and other fallback browsers, explicit naming, deterministic export filenames and versioned draft recovery.
• Project-level actions stay in the global toolbar, while the Simulation panel owns Run/Cancel, execution state, plots and requirement results.
• Selected lowercase Kessetsu wordmark, signal-line identity and matching favicon with a self-hosted, license-bundled Inter glyph subset.
• Agent-oriented CLI with stdin, kessetsu.cli.v1 JSON, stable diagnostics/exit codes and safe artifact writes.
• Evaluator-owned kessetsu.requirements.v1 files with exact-byte SHA-256 provenance and optional pinning for supervised agent/CI loops.
• Fail-closed test semantics: zero assertions cannot pass, unknown metrics fail before simulation, and ambiguous repeated analyses are rejected without breaking distinct DC-source sweeps.
• Complete typed PWL source parsing with dimensional values and non-negative, strictly increasing time points.
• OP, transient, AC and DC sweep datasets; engineering metrics for gain, cutoff/bandwidth, phase/frequency, output power, efficiency, THD, clipping and dissipation.
• Typed builtin/user/package models with exact versions, hashes, licenses and lockfile provenance.
• Typed, hash-bound external op-amp subcircuit references for native CLI simulation, including safe source-relative resource binding, PSpice compatibility, deterministic lock/provenance metadata, and explicit no-embedding export behavior.
• Deterministic Schematic IR with connectivity and visual-quality gates.
• SVG, PNG, PDF, Schematic JSON, SPICE, KiCad and LTspice export.
• RC, gain-stage and four-stage 8 Ω / approximately 2 W power-amplifier benchmark parity across CLI and Web.

Distribution

• Windows x86-64 bundle with Ngspice 46 sidecar.
• Linux x86-64, macOS x86-64 and macOS arm64 CLI bundles with verified system-Ngspice discovery.
• Absolute bundled/explicit/PATH simulator provenance and a portable Ngspice MOS1 KESSETSU_PMOS_V1@1.0.1 directive verified across supported runners.
• Per-artifact SHA-256, release manifest and clean-machine simulation smoke workflow.
• AGPL-3.0-only public license with a separately negotiated commercial-license path; license/source notices are bundled in CLI and Web distributions.

Migration

This is the first versioned release, so there is no earlier public schema to migrate. Prototype users should note that render is now functional, editable export uses kess export --target ..., compile reports are kessetsu.compile.v4, and browser share links require kessetsu.share.v1; unknown older payloads fail closed.