clab

AI-powered GitLab MR code review as a Claude Code skill.
Fetches the diff, runs lint rules, and posts inline comments — no external services, no Node.js.
Can also analyze past MRs to generate project-specific review rules automatically.

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How it works

/clab-review <MR_URL>

Claude Code invokes Go binaries in sequence:

Binary	What it does
clab-fetch-diff	Fetches MR metadata + full paginated diff → /tmp/gl_mr_data.json
clab-lint-rules	Runs regex-based lint rules → /tmp/gl_mr_auto_findings.json
clab-post-comments	Posts findings as inline GitLab discussions
clab-list-mrs	Lists MR IIDs by count, specific IDs, or date range (used by prepare-rules)

Claude performs a semantic review on top of the lint output, then calls clab-post-comments with the combined findings.

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Demo

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Installation

curl -fsSL https://raw.githubusercontent.com/mberneti/clab/main/install.sh | bash

Installs clab-fetch-diff, clab-lint-rules, clab-post-comments, and clab-list-mrs to /usr/local/bin.

Custom install directory:

CLAB_INSTALL_DIR=~/.local/bin curl -fsSL https://raw.githubusercontent.com/mberneti/clab/main/install.sh | bash

Specific version:

CLAB_VERSION=v1.0.0 curl -fsSL https://raw.githubusercontent.com/mberneti/clab/main/install.sh | bash

Supports Linux and macOS on amd64 and arm64. Pre-built archives are on the Releases page.

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Setup

1. Create a GitLab personal access token

Go to GitLab → User Settings → Access Tokens and create a token with the api scope.

2. Add the skills to your Claude Code or Cursor project

mkdir -p .claude/commands
curl -fsSL https://raw.githubusercontent.com/mberneti/clab/main/commands/clab-review.md \
  -o .claude/commands/clab-review.md
curl -fsSL https://raw.githubusercontent.com/mberneti/clab/main/commands/clab-prepare-rules.md \
  -o .claude/commands/clab-prepare-rules.md

Cursor users: same steps, Cursor reads .claude/commands/ and exposes them as / slash commands in the chat panel.

3. Create the config file

cat > .claude/gitlab-mr-review.env << 'EOF'
GITLAB_TOKEN=glpat-xxxxxxxxxxxxxxxxxxxx
GITLAB_HOST=gitlab.com
GITLAB_PROJECT=your-group%2Fyour-repo
EOF

Never commit this file. Add .claude/gitlab-mr-review.env to .gitignore.

4. (Optional) Project-specific rules

curl -fsSL https://raw.githubusercontent.com/mberneti/clab/main/gitlab-mr-review-rules.md \
  -o .claude/gitlab-mr-review-rules.md

Rules format:

RULE[critical] no-eval     — never use eval() in client code
RULE[major]    no-any      — no TypeScript `any` casts
RULE[minor]    rtl-missing — user-facing text must have dir="rtl"

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Usage

Works in Claude Code and Cursor — both read .claude/commands/ and invoke the same / slash commands.

Review a single MR

/clab-review <MR_URL>
/clab-review <MR_IID>                    # uses GITLAB_PROJECT from config
/clab-review <MR_URL> --dry-run          # print findings, don't post
/clab-review <MR_URL> --rules-only       # print active rules and exit
/clab-review <MR_URL> --severity major+  # only major and critical

Generate rules from past MRs

/clab-prepare-rules --last 20
/clab-prepare-rules --mr-ids 123,456,789
/clab-prepare-rules --since 2026-01-01
/clab-prepare-rules --since 2026-01-01 --until 2026-03-31
/clab-prepare-rules --last 10 --dry-run   # print suggestions, don't write file
/clab-prepare-rules --last 10 --append    # append to existing rules file

Analyzes findings across multiple MRs, identifies recurring patterns, and writes them as named rules to .claude/gitlab-mr-review-rules.md.

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Built-in rules

Severity	Rule ID	What it catches
critical	no-secrets	Hardcoded tokens, passwords, API keys
major	dead-code	Commented-out code blocks (>3 consecutive lines)
minor	todo-comment	TODO/FIXME without a ticket reference
minor	large-file	File diff > 400 lines — suggests splitting

Project-specific rules from .claude/gitlab-mr-review-rules.md are applied on top.

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Binary CLI reference

All binaries read config from environment variables. The skill sets them from .claude/gitlab-mr-review.env.

clab-fetch-diff [output.json]

Env:  GITLAB_TOKEN  GITLAB_HOST  GITLAB_PROJECT_ID  GITLAB_MR_IID
Out:  /tmp/gl_mr_data.json  (default)

clab-lint-rules [input.json] [output.json]

In:   /tmp/gl_mr_data.json          (default)
Out:  /tmp/gl_mr_auto_findings.json (default)

clab-post-comments [findings.json]

Env:  GITLAB_TOKEN  GITLAB_HOST  GITLAB_PROJECT_ID  GITLAB_MR_IID
In:   /tmp/gl_mr_findings.json  (default)

clab-list-mrs [flags] [output.json]

Env:    GITLAB_TOKEN  GITLAB_HOST  GITLAB_PROJECT_ID
Out:    /tmp/gl_mr_list.json  (default)
Flags:
  --last N                 last N MRs (any state), newest first
  --mr-ids IID,IID,...     specific MR IIDs
  --since YYYY-MM-DD       MRs created on or after date
  --until YYYY-MM-DD       MRs created on or before date (combine with --since)

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Building from source

git clone https://github.com/mberneti/clab.git
cd clab
make build    # ./bin/
make release  # cross-compile all platforms → ./dist/

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License

MIT