Project configuration

rosette.toml is the project configuration file for Rosette. It records project metadata, names GDS layers, and configures verification and snapshot behavior. This page is the canonical reference for its supported sections and keys.

Config discovery

An explicit config_path passed to a Python loader or CLI command always wins. Otherwise:

• Commands operating on a design search from the design file's directory toward the filesystem root and use the nearest rosette.toml.
• Direct calls to load_layer_map, load_drc_rules, load_dfm_config, and load_checks_config search from the current directory upward.
• rosette update must run from the project directory containing rosette.toml.

Rosette recognizes six top-level sections:

Unknown keys produce warnings rather than errors. Valid settings in the same section still load, so warnings can catch typos without breaking existing projects.

Project

rosette init writes project metadata used by rosette update:

[project]
name = "my-chip"
template = "generic"

Layers

Each child table under [layers] assigns a semantic name to one GDS layer/datatype pair:

[layers.silicon]
number = 1
datatype = 0
color = "#ff69b4"
fill = "solid"
opacity = 0.7
description = "Silicon waveguides"

Layer names must map to unique (number, datatype) pairs. If [layers] is absent or empty, Rosette provides silicon as 1/0 and text as 10/0.

Layer references

DRC and DFM settings accept any of these forms:

Design rule checking

DRC supports global settings, per-layer rules, and typed inter-layer rules. See Design rule checking for workflows and result handling.

Global DRC settings

[drc]
warning_margin = 0.01

An absent [drc] section loads an empty rule set.

Per-layer rules

[drc.layers.silicon]
min_width = 0.12
min_spacing = 0.13
acute_angle = 60
no_overlap = true

Dimensions use design units, normally micrometers. Angles use degrees.

Density is a nested table:

[drc.layers.silicon.density]
min = 0.20
max = 0.80
window = 100.0
step = 50.0
region_layer = "chip_boundary"

Inter-layer rules

Every [[drc.rules]] entry requires type, accepts an optional name, and supports only the fields associated with that type.

[[drc.rules]]
type = "spacing"
layer1 = "p_doping"
layer2 = "n_doping"
min_spacing = 0.5
name = "PN_SPC"

Design for manufacturability

DFM prediction is disabled when [dfm] is absent or empty. Once the section contains settings, layers is required and must contain at least one explicit layer reference.

[dfm]
resolution = 0.01
padding = 1.0
model = "gaussian"
sigma = 0.08
threshold = 0.5
keep_raster = false
layers = ["silicon"]
max_area_deviation = 0.10
severity = "warning"

Per-layer tables override model or tolerance settings for one layer:

[dfm.layer.silicon]
sigma = 0.05
max_area_deviation = 0.05
severity = "warning"

Design checks

[checks] configures connectivity and route bend-radius checks. If the section or file is absent, the defaults below apply.

[checks]
position_tolerance = 0.001
angle_tolerance = 0.1
width_tolerance = 0.000001
check_widths = true
min_bend_radius = 5.0
severity = "error"

Numeric tolerances must be finite and nonnegative; angle_tolerance cannot exceed 180 degrees, and min_bend_radius must be positive. Warning-only runs pass while retaining their diagnostics.

Snapshots

[snapshots] controls pruning for snapshots written to the default .rosette/snapshots/ directory:

[snapshots]
retain = 50

An invalid non-integer value falls back to 20. The rosette shot --retain option overrides the config for one invocation. See Snapshots for output and pruning details.

Unsupported historical settings

[build] and [project].version are not part of the schema. Build output is controlled by command options such as rosette build --output; package version information belongs to the installed Rosette package rather than a project file.