mancube/mergestro-gate repository overview

⁠Mergestro Gate (mancube/mergestro-gate)

A behavioral merge gate for AI-generated code — it mutation-tests your diff and blocks merges whose new code isn't actually covered by tests.

LLM-written code compiles, looks plausible, and ships with tests that assert nothing. Mergestro Gate runs differential mutation testing on the changed lines: it mutates your diff, reruns the suite, and any mutant that survives is a line your tests don't really check. It also runs static slop, security, and convention lanes over the same diff. One verdict, gate-able in CI.

• Image: mancube/mergestro-gate — slop-gate CLI on Alpine (rust:1-alpine), with the Rust toolchain + cargo-mutants baked in, so the mutation gate runs fully in-container (no toolchain to wire up).
• Arch: linux/amd64 (arm64 buildable on demand — see Multi-arch below) · Runs as: nonroot (uid 65532)
• Binary inside: /usr/local/bin/slop-gate (entrypoint) · Workdir / mount point: /work
• Source / full docs: github.com/lucheeseng827/mergestro-gate · Apache-2.0

⁠Tags

Pin a version in CI: mancube/mergestro-gate:0.5.0.

⁠What's inside

• slop-gate — the gate CLI (entrypoint).
• cargo + rustc + cargo-mutants — the Rust mutation engine compiles and tests each mutant, so it needs a toolchain at run time. Baked in.
• git — merge-base / diff against the base ref.

The non-Rust engines (Python / JS / Go / JVM) are advisory PoCs and are not bundled — add their toolchains yourself if you need them.

⁠Quick start

The container's workdir is /work — mount your repo there. It must be a git checkout with the base ref fetched (e.g. git fetch origin main).

# Behavioral gate over the working tree's diff vs origin/main:
docker run --rm -v "$PWD:/work" mancube/mergestro-gate:0.5.0 \
  --repo /work --base origin/main

# Predict the mutant workload first, without building/testing (fast):
docker run --rm -v "$PWD:/work" mancube/mergestro-gate:0.5.0 \
  estimate --repo /work --base origin/main

# Summarise telemetry from prior runs (--metrics-file output):
docker run --rm -v "$PWD:/work" mancube/mergestro-gate:0.5.0 \
  analyze --metrics-file /work/slop-gate-metrics.jsonl

# Help / version:
docker run --rm mancube/mergestro-gate:0.5.0 --help

⁠As a CLI base layer

Prefer your own toolchained image? Copy the binary in and bring your own cargo-mutants:

FROM rust:1-bookworm
COPY --from=mancube/mergestro-gate:0.5.0 /usr/local/bin/slop-gate /usr/local/bin/slop-gate
RUN cargo install cargo-mutants
ENTRYPOINT ["slop-gate"]

⁠Multi-arch

Published images are linux/amd64. An arm64 build exists but is opt-in — the arm64 leg compiles cargo-mutants under QEMU emulation (slow), so it's run on demand via the repo's Publish Docker image workflow rather than every release.

⁠In CI

For GitHub Actions, the Mergestro Gate Action⁠ is simpler than wiring this image into a job (it runs on a toolchained runner). Use this image for local runs, non-GitHub CI, and as a self-contained gate environment.

⁠Links

• Source & docs: https://github.com/lucheeseng827/mergestro-gate⁠
• License: Apache-2.0