openscad-bosl2

name	openscad-bosl2
description	Write or edit OpenSCAD (.scad) files using the BOSL2 library. Use whenever the user is designing a 3D-printable part — jigs, holders, brackets, enclosures, fixtures, household items — and the file is OpenSCAD. Covers the user's house style (BOSL2 idioms, anchors, epsilon/layer_height baselines, Customizer parameters) and links to detailed BOSL2 reference sub-docs.

OpenSCAD with BOSL2

This skill guides Claude in writing OpenSCAD code that matches the user's house style: BOSL2-first, anchor-driven, parametric, Customizer-friendly, and tuned for FDM 3D printing.

The user's specific printer model is named in the project / parent CLAUDE.md. The CLAUDE.md typically only names the model — look up its specs (build volume, max nozzle/bed temps, enclosure, multi-material, hardened nozzle) in references/printers.md. If the CLAUDE.md doesn't name a printer, or names one that isn't in the table, ask before designing around capacity or material assumptions.

When to use

Whenever you are creating or editing a .scad file. Most of the user's parts are utility prints — workshop jigs, tool holders, brackets, household fixtures — though some are display / cosmetic models.

Required preamble

Every .scad file should start like this:

include <BOSL2/std.scad>
// include <BOSL2/rounding.scad>     // add when using offset_sweep, os_circle, etc.

/* [Geometry] */
// ... user-facing customizer parameters ...

/* [Hidden] */
$fn = 256;              // 100 for drafts, 256 for finished parts
epsilon = 0.01;         // offset cutters in difference() to avoid z-fighting
layer_height = 0.2;     // pick from context; do NOT expose to the Customizer

The three baselines are non-negotiable:

Variable	Purpose
epsilon	Extend cutters in difference() so coplanar faces don't z-fight. Typical: 0.01 (or 0.001 for tight tolerances).
layer_height	Snap z-axis features (floor thickness, label depths, embossed text) to integer multiples for clean prints. Common emboss depth: 2 * layer_height to 4 * layer_height.
$fn	Polygon resolution — set globally, override per-call only when needed.

Picking a layer_height value

layer_height is a constant in [Hidden], not a Customizer parameter. Infer a value from the user's request:

• Fine detail / cosmetic part (visible features, embossed text, organic curves): 0.12 or 0.16.
• Default / general utility part (most jigs, holders, brackets): 0.2.
• Fast / structural part (large, low-detail, strength matters more than finish): 0.28 or 0.32.

If the user's intent is unclear — e.g. they could plausibly want either a fast draft or a polished finish — ask before guessing. A one-line question is cheaper than printing the wrong thing.

House style

Prefer BOSL2 primitives over OpenSCAD built-ins

Use this	Not this	Why
cuboid([x,y,z])	cube([x,y,z])	Accepts chamfer=, rounding=, edges=, anchor=
cyl(d=, h=)	cylinder(d=, h=)	Accepts chamfer1=, chamfer2=, rounding1/2=, anchor=
right(5), up(10)	translate([5,0,0])	One-line clarity for single-axis moves
rot(from=v1, to=v2)	manual Euler angles	Aligns one direction with another without trig

Use raw cube/cylinder only when you genuinely need them.

There's no need to scan existing projects to determine style, use the guides in this skill.

Anchor everything explicitly

Pick a deliberate reference point on every primitive — anchor=BOTTOM+LEFT+FRONT, anchor=TOP, etc. Don't rely on default centering. This makes positioning robust to dimension changes.

cuboid([60, 40, 10], anchor=BOTTOM+LEFT+FRONT);     // corner at origin
cyl(d=20, h=30, anchor=BOTTOM);                      // sits on the build plate

Chamfer or round every exposed vertex

As a default, every external vertex (edges and corners on the printed surface) should have a small chamfer or roundover, typically 0.5–1.0 mm. Sharp printed corners chip easily; a tiny break makes the part dramatically more robust and pleasant to handle. Use the built-in chamfer= / rounding= on cuboid() / cyl() rather than adding it after the fact.

cuboid([60, 40, 10], anchor=BOTTOM, chamfer=0.5);          // simple break
cyl(d=20, h=30, anchor=BOTTOM, chamfer1=1, chamfer2=0.5);  // bigger at the base

Skip this only when there's a reason — a mating face that needs to stay flat, an edge that disappears against another part, or a cosmetic line that should remain crisp.

Bounding-box vectors

Name dimensions as [x, y, z] lists and access via .x/.y/.z:

BASE = [60, 40, 10];
cuboid(BASE, anchor=BOTTOM);
right(BASE.x/2) up(BASE.z) cyl(d=8, h=20);

This avoids passing three loose numbers around and makes the code resilient to resizes.

Customizer parameters

Top of file. Use OpenSCAD Customizer annotations:

// Wall thickness in mm
wall = 4;             // [3:0.5:8]
// Number of legs
n_legs = 4;           // [3, 4, 5, 6]
// Print left-handed
left_handed = false;

Group related params with tab markers (/* [Geometry] */, /* [Print] */, /* [Hidden] */). Variables before the first { and outside [Hidden] show up in the Customizer.

See references/customizer.md for the full annotation grammar.

Difference() with epsilon

When subtracting, extend the cutter past the surface by epsilon so the faces don't coincide:

difference() {
    cuboid(BASE, anchor=BOTTOM);
    down(epsilon)                                    // extend below the floor
        cyl(d=8, h=BASE.z + 2*epsilon, anchor=BOTTOM);
}

Wrap multi-part output in union() or module()

A comment helps the slicer (and the next reader) understand intent:

// One object for the slicer
union() {
    base();
    handle();
}

If there are multiple discrete objects in one file, each should be in their own module() or union() at the top level.

Echo derived dimensions

When a value is computed from inputs, echo it so the user can sanity-check:

slot_w = (assembly_w - 7 * gap) / 6;
echo(str("Slot width: ", slot_w, "mm"));

Print orientation

Model the part in its final / functional orientation, then add a single top-level rotate() to flip it for printing. Leave a comment so the orientation can be toggled:

// Orient for printing — comment out for editing
rotate([90, 0, 0]) down(BASE.z) right(BASE.x/2)
    part();

Pick the print orientation from the part's mechanical job, not just what lays flat. FDM prints are anisotropic: layer-adhesion bonds are weaker than the filament itself, so prints are weak in tension along the build (Z) axis and prone to splitting between layers under load. When choosing an orientation:

• Identify the load paths. Where will tension, bending, or impact actually hit the part? A hook, hinge, bracket arm, lever, or screw boss has a clear "this must not snap" axis.
• Align primary tensile loads with the build plate (X/Y), not Z. A hook that pulls upward in use should be printed lying on its side, so the pull direction runs along the layers, not across them.
• For multi-axis strength, consider printing diagonally — rotated ~30–45° around X or Y so no single load axis is purely Z. This trades a small support penalty for much better all-direction toughness, and is often worth it for jigs and fixtures that get knocked around.
• Overhangs and bridging also matter, but mechanical strength usually wins when the two conflict — supports are fixable, a snapped part isn't.

If the load path isn't obvious from the brief — e.g. a holder that might or might not get yanked on — ask before committing to an orientation.

Filament choice

Suggest a filament once you understand what the part is for. Strongly prefer "easy" filaments — they print reliably on most consumer FDM printers without an enclosure, filament dryer, or hardened nozzle. Only reach for harder materials when there's a specific technical reason, and check the project / parent CLAUDE.md to confirm the printer can handle them (max nozzle/bed temp, enclosure, hardened nozzle).

Filament	Strength / toughness	Heat resistance	UV / outdoor	Ease	Best for
PLA	Stiff but brittle, low impact	~60 °C (sags in a hot car)	Poor	Easiest	Indoor / display / models, low-load jigs, prototypes, cosmetic parts
PETG	Tough, decent impact, slight flex	~75 °C	OK	Easy	Default for utility parts — workshop jigs, holders, brackets, fixtures, anything mildly mechanical or outdoor-adjacent
PETG-CF	Stiffer than PETG, dimensionally stable, more brittle	~75 °C	OK	Easy	Tight-tolerance jigs, parts where deflection matters more than impact, structural inserts

Mention harder filaments only when justified:

• ABS / ASA — needs an enclosure; better heat resistance (~95 °C) and UV (ASA) than PETG. Suggest only for hot-environment or sun-exposed outdoor parts.
• Nylon (PA / PA-CF) — abrasion-resistant and tough; needs drying. Suggest for living hinges, gears, snap-fits seeing real cycles.
• Polycarbonate (PC) — extreme strength and heat; hard to print. Suggest only for high-load structural parts.
• TPU — flexible. Suggest only when the part must compress, bend, or grip.

When suggesting, name one primary recommendation and one fallback, and give the reason in one sentence:

"PETG is the default here — it'll handle being knocked around in the workshop and resists the occasional drop better than PLA. PLA would also work if it'll only see indoor light duty."

If the use case is genuinely ambiguous (display or working tool? indoor or outdoor?), ask before recommending.

Export format

When telling the user how to take a .scad file into the slicer, recommend 3MF over STL wherever the slicer supports it (Bambu Studio, OrcaSlicer, PrusaSlicer, recent Cura, SuperSlicer — i.e. essentially every modern slicer). 3MF preserves precision, includes units, supports multi-material/colour, and produces smaller files than ASCII STL.

OpenSCAD exports 3MF directly:

openscad -o part.3mf part.scad

Suggest STL only when the target tool genuinely doesn't accept 3MF.

Pre-configured 3MF projects. If the user has set up a slicer template (see openscad-pack-3mf under Tools), prefer it — it produces a .3mf that opens in Bambu Studio / OrcaSlicer with their printer, filament, and process already set up, plus the template's baked default settings. For any setting where your part-specific recommendation diverges from those defaults, pass --set KEY=VALUE so the override travels with the file. Don't fall back to plain openscad -o part.3mf just because you'd change one or two settings — list the divergences as --set flags and the user gets a one-click slice.

Slicer parameters

After delivering the .scad file, recommend slicer settings unless the user has already specified them. Always include layer height; include the others when they're relevant to the part. Keep the recommendation to a few lines — not a full slicer profile.

Always recommend:

• Layer height — match the value in the .scad file (so embossed text, label depths, and floor thicknesses snap cleanly). Mention it explicitly so the user knows to set the slicer accordingly.
• Supports — say whether they're likely needed in the recommended print orientation. Most parts can be oriented to avoid them; flag any overhangs >45° from vertical or unbridgeable spans (>~10 mm). If supports are needed, suggest tree supports painted onto the offending faces (most modern slicers — Bambu Studio, OrcaSlicer, PrusaSlicer — support this).

Recommend when relevant:

• Infill type:
  • Grid — default. Fast crosshatch-style pattern with decent strength in XY; weak in Z but that's true of all infills. (Bambu Studio also has a similar "Cross Hatch" pattern.)
  • Cubic / Adaptive Cubic — slightly tougher than Grid with similar speed; Adaptive Cubic concentrates infill near walls for less material at the same effective strength. Good upgrade when the part takes real load.
  • Gyroid — near-isotropic strength, but slow. Reserve for parts that genuinely need omnidirectional toughness (hooks, pulled-on brackets) — not as a blanket default.
  • Lightning — fastest, but only supports the top layers; only use for cosmetic / hollow parts.
  • Concentric — for flexible (TPU) parts that need to compress evenly.
• Infill density:
  • 10–15 % — cosmetic / display / hollow models.
  • 15–25 % — light utility (most jigs, holders).
  • 30–50 % — load-bearing, mechanical, brackets that get yanked on.
  • 60 %+ — high-stress structural parts. Consider thicker walls instead — wall count usually contributes more to strength than infill density past ~40 %.
• Wall (perimeter) count:
  • 2 — cosmetic / non-structural.
  • 3 — default.
  • 4–5 — strength-critical parts (hooks, brackets, anything that bears tension or impact). Often a better strength investment than raising infill.
• Top / bottom layer count:
  • 4 — default.
  • 5–6 — pressure-tight, watertight, or cosmetic flat tops where pillowing would show.
• Brim — recommend for small-footprint parts, tall thin parts, or anything with marginal bed contact.
• Ironing — recommend for visible flat top surfaces where appearance matters (badges, labelled tops, display pieces).

Skip parameters that don't apply (e.g. don't recommend ironing on a part with no flat top). A typical recommendation might read:

"Suggested slicer settings: 0.2 mm layer height, PETG, 4 walls, 25 % cubic infill, 6 top / 5 bottom layers, no supports needed in this orientation, auto brim 7 mm."

These match the defaults baked into the canonical openscad-pack-3mf template — biased a notch toward strength and cosmetic flat-top quality vs. Bambu's stock 0.2 mm preset. Change them in the recommendation when the part calls for it (e.g. raise infill density for a load-bearing bracket, change pattern to gyroid for genuinely omnidirectional load, drop walls/shells back to 3/4 for fast cosmetic prints).

Tools

This skill ships helper scripts and binaries. Always invoke them by their full path inside the skill — the working directory is rarely the skill repo, so tools/openscad-check will fail in most projects. Use:

~/.claude/skills/openscad-bosl2/tools/openscad-check FILE.scad
~/.claude/skills/openscad-bosl2/tools/openscad-render FILE.scad

(That path works because the skill is installed user-level via symlink. If a particular project installs the skill at <project>/.claude/skills/openscad-bosl2/ instead, adjust accordingly.)

openscad-check and openscad-render are bash scripts. openscad-pack-3mf and openscad-build-template are Go binaries built from cmd/ — run make in the skill's clone after git pull if anything under cmd/ or internal/ changed.

openscad-check

Syntax / semantic check without doing any geometry work. Run this after every meaningful edit to a .scad file — it catches parse errors, unknown modules, undefined variables, and (by default) treats warnings as failures.

~/.claude/skills/openscad-bosl2/tools/openscad-check path/to/part.scad
~/.claude/skills/openscad-bosl2/tools/openscad-check --lenient path/to/part.scad   # don't fail on warnings
~/.claude/skills/openscad-bosl2/tools/openscad-check a.scad b.scad c.scad          # batch

Exit codes: 0 clean, 1 one or more files failed, 2 usage / OpenSCAD missing.

Don't claim a file "compiles" or "is correct" without running this.

openscad-render

Render a .scad file to a PNG for visual review. Default is a full CGAL render with the camera framed to fit (--viewall --autocenter).

~/.claude/skills/openscad-bosl2/tools/openscad-render part.scad                       # -> part.png
~/.claude/skills/openscad-bosl2/tools/openscad-render --preview part.scad             # fast ThrownTogether
~/.claude/skills/openscad-bosl2/tools/openscad-render --size 1600x1200 part.scad      # custom resolution
~/.claude/skills/openscad-bosl2/tools/openscad-render -o /tmp/p.png part.scad         # explicit output path
~/.claude/skills/openscad-bosl2/tools/openscad-render --camera 0,0,0,55,0,25,200 part.scad  # specific view
~/.claude/skills/openscad-bosl2/tools/openscad-render --view axes,edges part.scad     # show axes + edges

Use --preview for quick visual sanity-checks on large/heavy files; the default render is slower but matches what slicers will see.

Where the PNG goes. Without -o, the tool writes part.png next to the source .scad — leave it there. Don't pass -o /tmp/... unless the user asks. Renders living next to the source make them easy to find later, easy to diff against future renders, and easy to surface back to the user via openscad-show.

openscad-show

Open one or more rendered PNGs in the platform's default image viewer (open on macOS, xdg-open on Linux, start on Windows). Use this whenever the user asks to see / look at / show me a render.

~/.claude/skills/openscad-bosl2/tools/openscad-show part.png
~/.claude/skills/openscad-bosl2/tools/openscad-show a.png b.png c.png    # multiple
~/.claude/skills/openscad-bosl2/tools/openscad-show /path/to/dir          # most recent .png in that dir
~/.claude/skills/openscad-bosl2/tools/openscad-show -n 3 /path/to/dir     # top 3 most recent

For a directory argument, the tool picks the most recently modified .png — useful when the user says "show me the latest render of the bracket" and Claude knows the project dir but not the exact filename. The tool prints each path it opens to stdout, so Claude can see what was actually launched.

Default flow when the user asks to see a render:

1. If a render hasn't happened yet for the current part, run openscad-render first (writes the PNG next to the .scad).
2. Pass that PNG (or the project directory) to openscad-show.

Both scripts honour $OPENSCAD to override the binary path; otherwise they search PATH and standard install locations including /Applications/OpenSCAD.app/Contents/MacOS/OpenSCAD.

openscad-pack-3mf

Splice OpenSCAD geometry into a slicer template project 3MF — the output opens in Bambu Studio / OrcaSlicer with the user's printer, filament, and process settings already applied (Bambu's project format is the only way slicer settings travel with a 3MF; this tool reuses a pre-saved project as a template).

When to use it: by default, every time. The template carries one fixed set of slicer defaults (baked in by openscad-build-template); for any setting where your part-specific recommendation diverges, pass --set KEY=VALUE to override on top of the template. The override is written into the project's settings and added to the slicer's "differs from preset" list, so it survives a project open instead of silently re-syncing.

For filament selection, use --filament-type / --ams-slot / --filament instead of --set (filament is a multi-key concern — temps, flow ratios, fan speeds — that only stays consistent when set together from a real Bambu profile).

# Recommendation aligns with template defaults — splice and go:
~/.claude/skills/openscad-bosl2/tools/openscad-pack-3mf part.scad

# Recommendation diverges (load-bearing bracket: more infill, omnidirectional pattern, supports on):
~/.claude/skills/openscad-bosl2/tools/openscad-pack-3mf \
    --set sparse_infill_density=50% \
    --set sparse_infill_pattern=gyroid \
    --set enable_support=1 \
    part.scad

# Use whatever PETG is currently in the AMS (preferred — survives spool changes):
~/.claude/skills/openscad-bosl2/tools/openscad-pack-3mf --filament-type PETG part.scad

# Pick a specific AMS slot:
~/.claude/skills/openscad-bosl2/tools/openscad-pack-3mf --ams-slot 2 part.scad

# Force a specific Bambu profile regardless of AMS state:
~/.claude/skills/openscad-bosl2/tools/openscad-pack-3mf \
    --filament "Bambu PETG HF @BBL X1C" part.scad

Filament selection rules:

• Prefer --filament-type TYPE (e.g. PLA, PETG, PETG-CF, ABS) — the tool reads Bambu Studio's cached AMS state and picks the first slot loaded with that type. The user doesn't have to re-edit the recommendation when they change spools.
• Use --ams-slot N (0-indexed) when you specifically need slot N's filament.
• Use --filament NAME only when AMS isn't loaded with the right type or you need a specific profile (e.g. Bambu PLA Matte @BBL X1C over a Generic PLA).
• At most one of these flags per call. Apply before --set, so --set nozzle_temperature=260 cleanly fine-tunes the filament's value.
• Caveat: AMS state is updated via MQTT when Bambu Studio is connected to the printer. If spools are swapped while Bambu Studio is closed, the cache goes stale.

Common Bambu Studio override keys (use the slicer-native names verbatim):

Key	Example values
layer_height	0.12, 0.16, 0.2, 0.28
wall_loops	2, 3, 4, 5
top_shell_layers	4, 5, 6
bottom_shell_layers	4, 5
sparse_infill_density	15%, 25%, 40%, 60%
sparse_infill_pattern	crosshatch, cubic, gyroid, grid, lightning, concentric
enable_support	0 (off), 1 (on)
support_type	tree(auto), tree(organic), normal(auto)
brim_type	auto_brim, outer_only, no_brim
brim_width	5, 8
ironing_type	topmost, top, no ironing

For filament-side keys (temperatures, flow ratios, fan speeds, etc.) prefer --filament* over piecewise --set. Use --set nozzle_temperature=260 only as a fine-tune on top of a filament selection. Values are written as strings — Bambu's project_settings.config is all-strings. --set / --filament etc. only work with --slicer bambu-studio for now.

Fall back to plain openscad -o part.3mf part.scad only if the user explicitly doesn't want a configured project, or if they don't have a template set up yet.

~/.claude/skills/openscad-bosl2/tools/openscad-pack-3mf part.scad         # -> part-packed.3mf
~/.claude/skills/openscad-bosl2/tools/openscad-pack-3mf -o /tmp/p.3mf part.scad
~/.claude/skills/openscad-bosl2/tools/openscad-pack-3mf part.3mf          # accepts pre-rendered 3MF too
~/.claude/skills/openscad-bosl2/tools/openscad-pack-3mf --slicer prusa-slicer part.scad   # different slicer template
~/.claude/skills/openscad-bosl2/tools/openscad-pack-3mf -t /path/to/custom.3mf part.scad

By default it looks up ~/.config/openscad-bosl2/templates/<slicer>.3mf (default <slicer> = bambu-studio). The template stores the settings; the tool replaces the geometry and centres the new part on the build plate.

To set up a template the first time:

1. Render the seed: openscad -o /tmp/seed.3mf ~/.claude/skills/openscad-bosl2/tools/template-seed.scad
2. Open /tmp/seed.3mf in your slicer; set printer / filament / process / supports / etc. as you'd like them.
3. File → Save Project As… to anywhere, e.g. /tmp/my-template.3mf.
4. Run openscad-build-template on the saved project. It applies the skill's default overrides (and strips placement transforms / thumbnails) and writes the canonical template to ~/.config/openscad-bosl2/templates/bambu-studio.3mf.

After that, every openscad-pack-3mf run produces a 3MF ready to slice with those settings.

AMS state — cache by default, live MQTT opt-in: the tool always syncs the printer's current AMS slot contents (from BambuStudio.conf's cache, or live MQTT if creds are set) into every slot of the output project, so the user's saved template doesn't show stale filaments. The cache stays current as long as Bambu Studio has recently been open with the printer online. Don't push the user toward live MQTT unless they ask for it; the cache is the right answer for almost everyone.

--ams-slot N and --filament-type T both build on top of the default sync — they additionally set the active object's filament (slot 0) to a specific AMS slot's profile. --filament NAME skips the sync entirely on the assumption that the user wants a specific profile not necessarily in the AMS.

Live MQTT reads are useful only in a narrow case: the user swaps AMS spools while Bambu Studio is closed, and they're willing to enable LAN-only mode (Bambu firmware after ~May 2024 only allows local MQTT in LAN-only mode, which disables Bambu Cloud / Handy / MakerWorld direct-print).

If credentials are configured (env vars and/or a CLAUDE.md block), the tool tries MQTT first and falls back to the cache transparently when it can't connect — no error, just a one-line stderr note. Recognised env vars (env overrides CLAUDE.md):

export BAMBU_ACCESS_CODE=12345678          # ALWAYS recommend env, never CLAUDE.md
export BAMBU_SERIAL=00M09C460402058        # optional; may also be in CLAUDE.md
export BAMBU_HOST=192.168.1.42             # optional; may also be in CLAUDE.md

## Bambu printer (MQTT)

- Serial: 00M09C460402058
- Host: 192.168.1.42

The access code is a secret — never tell the user to put it in CLAUDE.md (CLAUDE.md is loaded into prompt context). Always recommend BAMBU_ACCESS_CODE. Serial and host are fine in CLAUDE.md if the user wants Claude to know which printer is in use.

The success summary reports AMS state: live (MQTT, <host>) when MQTT succeeds, otherwise cached (BambuStudio.conf).

Limitations (v1): single object only; single plate; the canonical template's transform is overwritten on every splice (parts always land centred on plate, on z=0); MQTT requires Host (auto-discovery via mDNS may come later).

openscad-build-template

Convert a slicer-saved project .3mf into a canonical openscad-pack-3mf template — applies the skill's default overrides for layer height / wall count / shell layers / infill / brim, ensures Bambu Studio honours them on open (by adding the keys to different_settings_to_system), strips placement transforms, and drops stale thumbnails.

~/.claude/skills/openscad-bosl2/tools/openscad-build-template /tmp/my-template.3mf
~/.claude/skills/openscad-bosl2/tools/openscad-build-template --slicer bambu-studio /tmp/my.3mf
~/.claude/skills/openscad-bosl2/tools/openscad-build-template -o ~/foo.3mf /tmp/my.3mf

Run this any time the SKILL.md slicer-parameter defaults change, or whenever you save a fresh slicer project you want to use as the basis. Currently only bambu-studio is implemented; PrusaSlicer / OrcaSlicer / Cura would each need their own override-key set added to the tool.

Reference sub-docs

Read the relevant sub-doc before reaching for a primitive you don't know:

• references/bosl2-shapes.md — 2D and 3D primitives (square, rect, circle, ellipse, polygons, stars, teardrop2d, cuboid, cyl, sphere, spheroid), the anchor/spin/orient system, basic attachment.
• references/bosl2-transforms.md — movement helpers, rotation (rot/xrot/from=,to=), distributors (xcopies, grid_copies, arc_copies, mirror_copy), mutators (top_half, chain_hull, round2d, shell2d, minkowski_difference).
• references/bosl2-rounding.md — built-in rounding/chamfer, rounded_prism(), edge_profile() + mask2d_*, 3D edge/corner masks. Three-tier model: pick the simplest tool that does the job.
• references/customizer.md — full Customizer annotation reference: dropdowns, sliders, spinboxes, text, vectors, tabs, presets, -p / -P CLI.
• references/printers.md — common FDM printer specs (Bambu A1/P1S/X1C/X1E/H2D, Prusa MK4S/Core One/XL, Creality K1/K1 Max/K2 Plus): build volume, max temps, enclosure, multi-material support. Use when the user mentions a printer or the project's CLAUDE.md doesn't capture limits.
• references/bosl2-tutorials.md — index of all BOSL2 tutorials (most linked, not preloaded — fetch on demand). Also points at the BOSL2 cheatsheet for full API lookup.

Common gotchas

• cube() defaults to center=false, cuboid() defaults to centred. Pick one style per file.
• Forgetting epsilon in difference() causes z-fighting in the preview and (sometimes) holes in the render.
• Variables after the first { are invisible to the Customizer. Keep all customizable params at the top.
• edge_profile() and mask2d_* need diff() wrapping the parent to actually subtract.
• Quadrant order for per-corner rounding is counter-clockwise from back-right (I, II, III, IV). Test with distinct values if unsure.
• Mixing rounding= and chamfer= on the same edge is not allowed. Pick one per edge.

Skeleton

include <BOSL2/std.scad>

/* [Geometry] */
// Outer width
width = 60;             // [20:5:200]
// Outer depth
depth = 40;             // [20:5:200]
// Wall thickness
wall = 3;               // [1:0.5:6]

/* [Hidden] */
$fn = 256;
epsilon = 0.01;
layer_height = 0.2;     // chosen for general utility part; not a Customizer param

BASE = [width, depth, 4 * layer_height];

echo(str("Base: ", BASE.x, " × ", BASE.y, " × ", BASE.z, " mm"));

// One object for the slicer
union() {
    difference() {
        cuboid(BASE, anchor=BOTTOM, rounding=2, edges="Z");
        // ... cutouts, with epsilon offsets ...
    }
    // ... additive features ...
}