ocaml-opam-tinyflags-add-flag - SKILL.md Agent Skill

name: ocaml-opam-tinyflags-add-flag description: Add a TinyFlags flag to an OCaml project with implementation, tests, and rollout notes.

Add TinyFlags Flag

Use this skill when adding a feature flag to an OCaml project that depends on agentxm-example-tinyflags.

Workflow

Find the OCaml module that constructs the Tinyflags.t flag set from a (name, flag) list (typically lib/<pkg>/flags.ml or similar).
Add the flag as either a Boolean (Tinyflags.Bool.make_exn ...) or a VariantFlag (Tinyflags.Variant.make_exn ...) entry.
Prefer kebab-case flag names that mirror the call-site behavior.
Add or update alcotest coverage in test/ for default behavior and rollout behavior. Run via dune runtest or dune exec ./test/<name>.exe.
Update the package's README or .opam description when the flag is user-facing.

Boolean Flags

Use Tinyflags.Bool.make_exn ~default:false () for a disabled-by-default feature.

Use Tinyflags.Bool.make_exn ~default:false ~rollout:10 () for a percentage rollout. Rollout bucketing is deterministic on the Tinyflags.Context.t [id] field — thread a stable identifier (user, session, account) through the request boundary.

Variant Flags

Use Tinyflags.Variant.make_exn ~default:"classic" ["classic"; "semantic"] when the call site needs a named treatment instead of true / false.

Use ~rollout to allocate traffic:

Tinyflags.Variant.make_exn
  ~default:"classic"
  ~rollout:[ ("semantic", 10) ]
  [ "classic"; "semantic" ]

Done Criteria

New flag has an explicit ~default argument (boolean) or ~default argument (variant) tied to a member of the variant list.
Rollout percentage is an int in 0..100.
Variant rollout pairs reference only declared variants.
alcotest cases cover default behavior and at least one rollout boundary.
Dead match branches are not introduced.