Importing Build Files

must can import existing build files and produce a starter Mustfile.toml. Supports Makefiles, Justfiles, and Taskfiles.

Supported formats

Format	File	--format flag	Auto-detected by filename
Make	Makefile	make (default)	Any file not matching below
Just	justfile, Justfile	just	justfile or justfile.*
Taskfile	Taskfile.yml, Taskfile.yaml	taskfile	Taskfile*.yml / Taskfile*.yaml

Basic usage

# Auto-detect format from filename
must import --makefile Makefile
must import --makefile justfile
must import --makefile Taskfile.yml

# Explicit format
must import --makefile build.tasks --format just

This generates:

1. Mustfile.toml — converted recipes
2. MUSTFILE_IMPORT_REPORT.md — detailed report

What gets imported

From Makefile

Makefile construct	Mustfile equivalent
target: deps	[recipe.target] with deps
$(VAR)	${VAR}
Recipe body	script = "..." with type = "shell"
.PHONY	phony = true
Pattern rules	Skipped (needs manual conversion)
Shell functions	Preserved as-is in script
Automatic variables ($@, $<, $^)	Expanded inline

From Justfile

Justfile construct	Mustfile equivalent
recipe_name:	[recipe.recipe_name]
recipe_name: dep1 dep2	deps = ["dep1", "dep2"]
Recipe body	script = "..." with type = "shell"
export VAR = "value"	[env] VAR = "value"
set shell := [...]	Skipped (noted in report)
[linux] / [windows] attributes	Skipped (noted in report)

From Taskfile

Taskfile construct	Mustfile equivalent
tasks: name: cmds:	[recipe.name] with script
deps: [build]	deps = ["build"]
desc: "description"	Noted in report
cmds: list	Joined into single script

Import report

The generated MUSTFILE_IMPORT_REPORT.md contains:

• Successfully converted recipes
• Skipped rules (pattern rules, attributes, etc.)
• Variables that need manual review
• Suggestions for converting to first-class recipe types

Example:

# Import Report

## Converted (12 recipes)
- build → shell
- test → shell
- clean → shell (phony)
- lint → shell (phony)

## Needs review (3 items)
- `release` uses pattern rule — convert manually
- `deploy` calls SSH — may need secrets handling
- `CFLAGS` has complex expansion — verify

## Suggestions
- `build` compiles C code → consider `c-bin` type
- `test` runs pytest → consider `py-test` type

Converting to first-class types

After import, consider upgrading shell recipes to first-class types:

# Before (imported)
[recipe.build]
type   = "shell"
script = "cargo build --release -p my-app"

# After (first-class)
[recipe.build]
type    = "rust-bin"
package = "my-app"

Benefits: automatic caching, cross-compilation support, toolchain version tracking.

Or: use bridge mode instead

If you'd rather not convert, just use must directly against your existing build files — no import needed:

cd my-makefile-project
must build    # auto-detects Makefile, runs: make

See Bridge Recipes for details.