OCaml opam¶

ID: opam
Links: Home page · Documentation · Repository
Upstream stars: ⭐ 1,382
Last commit: 2026-09-22
Version requirement: >= 2
Platforms: 🅱️ BSD · 🐧 Linux · 🍎 macOS
Operations: installed · search · install · upgrade · upgrade_all · remove · sync
purl types: pkg:opam/
CLI name: opam
Every call: opam --color=never --yes <command>
Issues and PRs: 📦 manager: opam
Source: opam.toml

opam is the OCaml package manager (https://opam.ocaml.org).

Every listing goes through --short --columns=name,version, which opam documents as dropping the header and joining columns with a space, giving one name version pair per line with no alignment to strip.

No outdated: opam list --upgradable reports what would move, but naming both the installed and the candidate version in one listing needs a column set this definition cannot verify against an upstream sample, so the operation is left undeclared and upgrade --all still works.

Every operation targets opam’s currently active switch, which is whatever OPAMSWITCH or the current directory resolves to, exactly as a bare opam call in the same shell would. Per-switch targeting is not supported yet.

What `mpm` adds to `opam`¶

Through mpm, opam gains --exact and --extended search, to narrow to exact names or match descriptions.

Bigger still, mpm reaches across every manager at once: mpm installed and mpm outdated cover opam alongside every other manager you run in one table, mpm upgrade --all updates them together, and mpm sbom exports the whole machine as one bill of materials.

Every mpm command also gains --dry-run and --plan previews, cross-scheme version comparison and purl identifiers. See manager augmentations for how each one is built.

Your `opam` commands, in `mpm`¶

You already know opam: each operation maps one-to-one onto mpm, in an interface shared by every manager.

To…	With `opam`	With `mpm`
List what’s installed	`opam list --installed --short --columns=name,version`	`mpm --opam installed`
Search for a package	`opam list --search <query> --short --columns=name,version`	`mpm --opam search <query>`
Install a package	`opam install <package_id>`	`mpm install pkg:opam/<package_id>`
Upgrade one package	`opam upgrade <package_id>`	`mpm --opam upgrade <package_id>`
Upgrade everything	`opam upgrade`	`mpm --opam upgrade --all`
Remove a package	`opam remove <package_id>`	`mpm remove pkg:opam/<package_id>`

Prefix any command above with --dry-run to simulate the underlying manager calls without touching the system: the safe way to watch what mpm would do before trusting it.

Operations¶

Operation	Supported	Notes
`installed`	✅
`outdated`
`orphans`
`search`	✅	Exact and extended search backfilled by `mpm`.
`install`	✅
`upgrade`	✅
`upgrade_all`	✅
`remove`	✅
`sync`	✅
`cleanup`
`doctor`

Configuration¶

Ignore opam on the mpm CLI by passing the --no-opam option.
Ignore it for every run in your configuration:
```
[mpm]
opam = false
```
Raise the timeout of all opam calls:
```
[mpm.overrides.opam]
timeout = 900
```

Run mpm config-template opam to print all overridable settings for your configuration file:

[mpm.overrides.opam]
cli_names = [
    "opam",
]
cli_search_path = []
dry_run = false
ignore_auto_updates = true
plan = false
post_args = []
pre_args = [
    "--color=never",
    "--yes",
]
pre_cmds = []
requirement = ">=2.0.0"
stop_on_error = false
unmaintained = false
version_cli_options = [
    "--version",
]
version_regexes = [
    "(?P<version>\\d+(?:\\.\\d+)+\\S*)",
]

The arguments and environment variables listed in the box atop this page are forced on every opam call, so runs stay quiet, non-interactive and reproducible: the defaults you would set in CI anyway.

Recipes¶

A few jobs you would otherwise script around opam, one mpm command each:

Snapshot and clone a machine: mpm --opam dump opam.toml, then mpm restore opam.toml on the next one.
Export a compliance SBOM: mpm --opam sbom (CycloneDX by default, --spdx for SPDX).

Privilege escalation¶

mpm runs this manager as the current user and never prepends sudo by default. Flip the policy for its privileged operations with --sudo or the per-manager sudo override.

None of its operations is privileged.

See privilege escalation for the full policy.

Cooldown¶

State of OCaml opam’s release-age gating, from the cooldown support table:

Status: ❌ None

A cooldown only pays off where a compromised release can be withdrawn while the clock runs, and can only be emulated where the registry dates its releases. From the retraction table:

Registry: Git-manifest indexes
Retraction: Index revert: reverting the manifest, Portfile or derivation commit withdraws the version
Publish date: ❌ only the commit date, which is client-set and trivially backdated. A date declared in the manifest, like winget’s optional ReleaseDate, is author-supplied too and no sounder

With --cooldown set, mpm skips this manager’s install and upgrade operations rather than run them unguarded (fail-closed); --cooldown best-effort opts back in.

Reference traces¶

A collection of raw native outputs captured from the manager’s own CLI and recorded in the bundled definition. If you know OCaml opam well and a transcript below looks wrong, or a newer release changed its output format, report it.

$ opam list --installed --short --columns=name,version
base-bigarray base
base-threads base
dune 3.11.1
ocaml 4.14.1
ocamlfind 1.9.6

$ opam list --search {query} --short --columns=name,version
lwt 5.7.0
lwt_ppx 2.1.0
lwt_ssl 1.2.0

Version check¶

The version is probed by running:

$ opam --version
2.1.5

and extracted with:

r"(?P<version>\d+(?:\.\d+)+\S*)"

Upstream project¶

Metrics	`ocaml/opam`
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Changelog¶

8.0.0 (2026-09-20)
- Add the OCaml opam package manager with installed, search, install, upgrade, remove and sync support.