Mr Boxington

• Mr Boxington

  • Repository: jdx/mr-boxington (Person/Jeff Dickey/GitHub/mr-boxington). GitHub/Star: 652 (checked 2026-11-01 Sun).
  • A shared cache for cargo builds, run as the mbx command. Cargo still resolves dependencies, plans builds, and runs tools; mbx restores matching compiler outputs from one shared store and compiles the rest. No daemon or cache server is needed for local use. [1]
  • Equivalent compilations share cache keys when checkout paths differ, so building one git worktree warms the next.
  • The store has a disk budget. Managed target/ directories are collected when their checkout disappears, goes unused, or exceeds its budget. mbx gc --dry-run previews a collection.
  • Independent Cargo commands share CPU and memory permits and deduplicate identical compilations in flight.
  • CI can reuse the cache through the GitHub/Action cache, a compatible cache server, or an S3-compatible bucket. jdx/mr-boxington-action sets it up. Pull request builds only read from a cache server or bucket; writes come from pushes to protected branches.
  • Install with mise (mise use --global --tool-option mr_boxington=true rust mr-boxington), or with cargo install mbx --locked followed by mbx setup.
  • Builds on ideas from sccache and kache; kache directly inspired its design.
  • Licensed under MIT.
  • Written in Rust.

• Setup with mise

  • Set the mr_boxington option on the rust tool and add mr-boxington as its own tool. Cargo then runs through mbx under mise exec, mise tasks, activated shells and mise's shims, with no mbx setup step. [2]
    • toml

      [tools]
      rust = { version = "latest", mr_boxington = true }
      mr-boxington = "latest"

  • Calling a toolchain's cargo directly, such as ~/.cargo/bin/cargo, skips mbx. Check with command -v cargo. [2]
  • My global mise config turns it on: dotfiles#181.

• Typical commands

  • mbx doctor — check the setup
  • mbx cache stats — cache size and hits
  • mbx gc --dry-run — preview what garbage collection would remove
  • mbx explain --last — why the last build hit or missed

• Footnotes

  • [1] https://mr-boxington.jdx.dev/

  • [2] https://github.com/jdx/mise/blob/main/docs/lang/rust.md#share-cargo-builds-with-mr-boxington