Settings

Settings come from four layers; later ones win:

1. built-in defaults;
2. your user config, ~/.config/b123d-print/config.toml (or $XDG_CONFIG_HOME/b123d-print/config.toml);
3. the workspace config, the nearest b123d-print.toml at or above the part script (or the current folder);
4. environment variables.

b123d-print config shows the settings in effect and which files were found; over MCP, list_parts does. Printer-specific values (hole_comp, printer, material) belong in the user config; the workspace config is for values that belong to the project.

# ~/.config/b123d-print/config.toml
[print]
hole_comp = 0.4      # mm added to hole diameters when cutting
hole_comp_h = 0.5    # the same for horizontal holes (default: hole_comp)
clearance = 0.2      # per side, sliding fit (the default)
press_fit = 0.05     # per side, pressed together
free_fit = 0.3       # per side, turns or moves freely
pip_clearance = 0.3  # between parts printed in place
min_wall = 0.8       # Wall checks fail below this unless they set their own limit
max_overhang = 45    # degrees from vertical
max_bridge = 10      # mm; longer bridges warn
max_triangles = 50000  # import_model refuses bigger meshes
formats = ["step", "stl", "3mf", "png"]
style = "functional"   # design review style for parts without STYLE
filament_price = 25    # per kg: design_metrics shows a cost
print_flow = 10        # mm^3/s for the rough print-time estimate

Keys

Keys go under [print] or [workspace] (the template puts parts_dir under [workspace]). An unknown key is an error, so typos don't pass silently.

Key	Default	What it does
hole_comp	0.0	mm added to hole diameters when cutting; see Hole compensation
hole_comp_h	same as hole_comp	the same for horizontal holes (axis in XY): hole_comp(__file__, horizontal=True)
clearance	0.2	mm per side between mating parts that slide, the default fit; part scripts read it with clearance(__file__)
press_fit	0.05	mm per side for parts pressed together
free_fit	0.3	mm per side for parts that turn or move freely
pip_clearance	0.3	mm between parts printed in place; the gap check fails below it
min_wall	0.8	Wall checks fail below this (mm) unless a check sets its own min; the thin check warns below it
max_overhang	45	degrees from vertical; steeper downward faces are reported
max_bridge	10	mm; longer bridges warn
max_triangles	50000	import_model refuses meshes with more triangles (simplify them first); measured: a 56k-triangle original takes about a minute to check
printer	"" (generic)	optional printer profile
material	""	optional material profile: pla, petg, asa, abs, tpu or your own
formats	all four	what export writes: step, stl, 3mf, png (formats)
style	"" (functional)	the design review style for parts whose script sets no STYLE: functional, modern, least_cost, rugged, soft or your own
filament_price	none	price per kg of filament; design_metrics then shows a cost next to the filament estimate
print_flow	10	mm³/s the printer sustains, for design_metrics' rough print-time estimate (standard hotend 8-12, high-flow 20 and more)
parts_dir	"parts"	folder in the workspace that holds <name>/<name>.py

All clearances are per side. Part scripts read any of them with load_settings(__file__), e.g. FREE_FIT: float = load_settings(__file__).free_fit. The fit coupon measures the fits and the overhang/bridge coupon the limits.

With a printer set, min_wall, max_overhang and max_bridge come from the printer, then the values you measured for that printer + material (hole_comp, hole_comp_h, the fits, max_overhang, max_bridge; stored with b123d-print printer calibrate) replace the user config's, unless the workspace config or the environment sets them; a material's clearance replaces the default the same way.

Environment variables

Variable	Does
B123D_PRINT_HOLE_COMP	overrides hole_comp
B123D_PRINT_HOLE_COMP_H	overrides hole_comp_h
B123D_PRINT_CLEARANCE	overrides clearance
B123D_PRINT_PRESS_FIT	overrides press_fit
B123D_PRINT_FREE_FIT	overrides free_fit
B123D_PRINT_PIP_CLEARANCE	overrides pip_clearance
B123D_PRINT_MIN_WALL	overrides min_wall
B123D_PRINT_MAX_OVERHANG	overrides max_overhang
B123D_PRINT_MAX_BRIDGE	overrides max_bridge
B123D_PRINT_MAX_TRIANGLES	overrides max_triangles
B123D_PRINT_FORMATS	overrides formats, e.g. step,3mf
B123D_PRINT_PRINTER	overrides printer
B123D_PRINT_WORKSPACE	the MCP server's workspace when --workspace is not given
B123D_PRINT_TIMEOUT	the MCP server's per-build time limit in seconds when --timeout is not given
B123D_PRINT_CHECK_TIMEOUT	the MCP server's time limit for a check call in seconds when --check-timeout is not given (default 300, or the build limit if that is longer)
B123D_PRINT_MAX_BUILDS	the MCP server's --max-builds; also holds across all server processes of the user (one per SSH connection)
B123D_PRINT_TRANSPORT	the MCP server's --transport (stdio or http)
B123D_PRINT_HOST	the MCP server's --host (HTTP; the Docker image sets 0.0.0.0)
B123D_PRINT_PORT	the MCP server's --port (HTTP)
B123D_PRINT_ALLOWED_HOSTS	the MCP server's --allowed-hosts (HTTP)
B123D_PRINT_SHUTDOWN_GRACE	the MCP server's --shutdown-grace (HTTP)
B123D_PRINT_PUBLIC_URL	the MCP server's --public-url (HTTP download links)
B123D_PRINT_LINK_TTL	the MCP server's --link-ttl (HTTP download links)
B123D_PRINT_RETENTION_DAYS	the MCP server's --retention-days: a named HTTP workspace nobody used for this many days is removed (default 30; 0 = never)
B123D_PRINT_LINK_SECRET	key that signs download links; default: derived from B123D_PRINT_TOKEN, so changing the token also invalidates old links
B123D_PRINT_TOKENS_FILE	the MCP server's --tokens-file: named tokens (HTTP)
B123D_PRINT_JOB_QUEUE	the MCP server's --job-queue: builds go to a separate worker (HTTP)
B123D_PRINT_TOKEN	the bearer token HTTP clients must send (Over the network)
B123D_PRINT_TOKEN_FILE	path of a file holding that token, instead of B123D_PRINT_TOKEN
B123D_PRINT_SANDBOX	none turns the OS sandbox off (the Docker image does; the container is the sandbox)
B123D_PRINT_CONFIG_IN_WORKSPACE	1 keeps the user config in <workspace>/.config/ (set in the Docker image, whose home folder does not last)

A generated table of the keys with the comments from the code is in the Reference.