simt-dev

Shared agent rules, skills and git hooks for a repository.

One command adopts a repository: it reads what the repo actually runs, projects the matching rules into the files your agent already reads, and installs a pre-commit hook that refuses a commit which breaks a gate that repo can genuinely run.

• Nothing is declared that cannot run. Every gate is probed against the working tree before it is written. A gate whose tool is absent is dropped, with a remedy naming the package to install — never silently present, never silently absent.
• Nothing an agent reads is written twice. Each rule goes to exactly one place, chosen by what the harness actually reads.
• The rules are a projection, not a copy. They carry markers, so check can tell drift from a deliberate edit, and sync can regenerate.
• The tool explains itself. rules why answers "why did I get told this?" from a numbered record of the decisions behind the rules, with the rejected alternatives attached.

Install

Requires Node >= 22.20.0 (the PyPI install can supply it, see below).

# pinned, per repository - what CI and a teammate both get
npm i -D simt-dev@0.2.0

# or globally, if you would rather not add a dependency
npm i -g simt-dev@0.2.0

# or with no install at all, for a one-off
npx -y simt-dev@0.2.0 check

From PyPI

The same tool, from the same bytes. The wheel carries the exact contents the npm tarball carries — the wheel is not a wrapper around npm install, so nothing is fetched when you install it.

pip install simt-dev

# and if this machine has no node at all
pip install "simt-dev[node]"

simt is the command on both channels. Where node comes from is resolved in this order, and the first one that answers wins: SIMT_DEV_NODE, the bundled node from the node extra, then node on your PATH. If none of them resolve, you get a message naming the remedy rather than a placeholder node path.

From Homebrew

brew install QuazarMedia/homebrew-tap/simt-dev

The formula declares its own node dependency, so brew install gives you a working command on a machine that has never had Node.

Pin the version. The tool writes a content digest into the files it generates, and an unpinned upgrade changes them under you.

Use

simt init            # adopt or scaffold this repository (dry-run; --yes to write)
simt doctor          # what this repo is, and whether its config is healthy
simt check           # the gate: projection drift, manifest validity, policy
simt sync --yes      # regenerate the projection
simt upgrade --yes   # move every consumer of this tool to this version
simt rules why ADR-042   # why a rule says what it says, and what was rejected
simt compare         # what changed across every repository that adopted it

init and sync print a plan and write nothing without --yes. Neither commits or pushes.

What it writes

Anything outside the markers is yours. simt-dev never edits it and never reverts it.

Platform

macOS and Linux. The hooks are POSIX sh; there is no Windows build and no plan for one. npm i on Windows fails with npm's EBADPLATFORM, which npm will not let a package explain — so the answer is here: use WSL2, and the gate works normally inside it.

A Windows checkout without WSL2 can still read every rule this tool generates, because the projection is plain text in AGENTS.md and the per-harness rule files. Only the hooks and the CI gate need the POSIX host.

How the rules are chosen

Detection reads what the repository runs — its dependency manifests, its build files, its CI workflows — and resolves that against a registry of capabilities. Resolution is a scored ranking over path, keyword, name, capability and stack: no model, no network, no guessing, so a pull request can meaningfully diff the answer.

Not every ecosystem has a profile yet. A Go, Rust, .NET, Ruby, Swift, Dart or Elixir repository is detected and gets facts, but it is adopted with the core rules and no gates until its gate templates are written. A repository with no gates is a repository with an agent and no pre-commit hook — better than one with a hook that runs nothing, but not full support, and this README will not pretend otherwise.

Every behaviour that is a choice rather than a detail has a numbered record, and the records are readable with simt rules why <id>. If the tool ever does something you did not expect, that command is the shortest path from the symptom to the reason.

Licence

Apache-2.0. See LICENSE.