What It Checks

• Platform detection for Windows, macOS, Linux, and WSL where reasonably detectable.
• Core tool availability and versions for opam, ocaml, dune, OCaml LSP (ocaml-lsp-server or ocamllsp), and ocamlformat.
• Whether opam appears initialized.
• Active and available opam switches.
• Heuristic shell environment sync by comparing the resolved ocaml command with the active opam switch bin directory where possible.
• Installed opam packages for dune, ocaml-lsp-server, ocamlformat, and optional utop.
• VS Code OCaml Platform extension detection when the code command is available.

What It Does Not Do

• It does not replace opam, dune, ocaml-lsp, or editor setup docs.
• It does not run opam init, opam switch create, or opam install for you.
• It does not edit shell startup files or modify user shell configuration.
• It does not implement destructive auto-fixes.
• It does not claim to diagnose every possible OCaml setup issue.

Installation From Source

git clone https://github.com/funwithcthulhu/doctor
cd doctor
opam install . --deps-only --with-test
dune build
dune runtest

If your shell has not been synced with the active opam switch, use opam exec -- dune build and opam exec -- dune runtest.

Local Install

opam pin add doctor . -y

When testing uncommitted local changes, prefer a path pin so opam reads the working tree instead of git+file://...#main:

opam pin add doctor . -y --kind=path

After publication to opam-repository, the expected user flow is:

opam update
opam install doctor
doctor check

Usage

doctor check
doctor version
doctor --help

doctor version prints:

doctor 0.1.0

Example Output

$ doctor check
OCaml Doctor

[OK] platform detected: macOS
[OK] opam found: 2.2.1
[OK] OCaml found: 5.2.0
[OK] dune found: 3.17.0
[OK] OCaml LSP found: 1.19.0 (ocamllsp)
[WARN] ocamlformat not installed
       Suggested fix: opam install ocamlformat
[OK] active switch: 5.2.0
[WARN] VS Code OCaml Platform extension not detected
       Suggested fix: Install extension ocamllabs.ocaml-platform in VS Code.

Summary: 6 OK, 2 WARN, 0 ERROR

Exit Codes

• 0: no warnings or errors
• 1: one or more warnings, no errors
• 2: one or more errors
• 3: unexpected internal failure

Development

Build:

dune build

Run tests:

dune runtest

Run locally without installing:

dune exec doctor -- check

If dune is not available on PATH, prefix these commands with opam exec --.

Tests use injectable process runners and deterministic fixtures. They should not require the local machine to have opam configured, VS Code installed, or a specific shell setup.

Contribution Ideas

• Improve shell detection for PowerShell, cmd.exe, MSYS2, and Cygwin.
• Add JSON output for editor integrations and issue templates.
• Add more editor checks without making VS Code mandatory.
• Improve opam switch environment explanations on Windows.
• Add targeted diagnostics for common dune and LSP project-layout problems.

Release Process

Maintainer release steps are documented in RELEASE.md.