ruby-dev — Google Antigravity CLI (agy) Harness Port

This directory contains a complete, self-contained port of ruby-dev-plugin for the Google Antigravity CLI (agy).

Upstream repository files outside harness/antigravity/ and other harness ports (such as harness/mistral-vibe/) remain completely untouched. This directory holds all harness-specific adapters, subagents, role skills, references, workflow tasks, workspace rules, and validation tooling.

Directory Layout

harness/antigravity/
├── plugin.json               # Antigravity plugin manifest (validated via `agy plugin validate`)
├── README.md                 # This documentation
├── rules/
│   └── AGENTS.md             # Antigravity workspace rules (coding standards, invariants, gates)
├── agents/                   # 6 Antigravity agent definitions:
│   ├── rubyist.md            # Main-thread orchestrator agent (with inlined workflow logic)
│   ├── specifier.md          # Phase 1: Requirements to Gherkin scenarios + QA procedure
│   ├── implementer.md        # Phase 2: Unit tests + code implementation
│   ├── cleaner.md            # Phase 3: Complexity reduction to CRAP threshold
│   ├── hardener.md           # Phase 4: Mutation testing + security scans
│   └── verifier.md           # Phase 5: Dependency checks, Zeitwerk checks, SIFT audit
├── skills/                   # 13 domain skills + 5 role skills (paths rebound to relative):
│   ├── role-specifier/
│   ├── role-implementer/
│   ├── role-cleaner/
│   ├── role-hardener/
│   ├── role-verifier/
│   └── <domain-skills>/      # analyse, data-engineer, genai, gui, multi-db, perf,
│                             # refactor, ruby-nlp, scaffold, sift, tui, yardoc, evals
├── references/               # Shared conventions (dry-rb, quality gates, subagent mandates)
├── tasks/                    # Deterministic workflow tasks (analysis gems, survey, dispatch, gate, synthesize)
└── scripts/
    ├── install.sh            # Global and project-local installer script
    ├── rubydex-mcp.sh        # Starts the rubydex MCP server for the current project
    └── validate.sh           # Automated verification test script

Installation

The installer scripts/install.sh configures the plugin for Antigravity:

1. User-Global Installation (Recommended)

Installs the plugin into ~/.gemini/config/plugins/ruby-dev and copies the rubyist orchestrator agent to ~/.gemini/agents/rubyist.md, making it available across all projects:

bash harness/antigravity/scripts/install.sh --global

To symlink rather than copy (useful during active development):

bash harness/antigravity/scripts/install.sh --global --symlink

2. Project-Local Installation

Installs the plugin into .agents/plugins/ruby-dev inside the target project workspace:

bash harness/antigravity/scripts/install.sh --local

Verifying Installation

Verify the plugin is discovered by Antigravity:

agy plugin list

Start the interactive orchestrator:

agy --agent rubyist

rubydex MCP Server

The subagents query Ruby code structure through the rubydex MCP server (rdx mcp). Antigravity reads MCP servers from the user-level ~/.gemini/config/mcp_config.json, so register it there. Replace <repo> with the path of this checkout:

{
  "mcpServers": {
    "rubydex": {
      "command": "<repo>/harness/antigravity/scripts/rubydex-mcp.sh",
      "args": []
    }
  }
}

scripts/rubydex-mcp.sh starts bundle exec rdx mcp when the project's Gemfile.lock resolves rubydex, falls back to a global rdx, and exits with a message on stderr when the working directory has no Gemfile (rubydex 0.4.2 indexing raises Bundler::GemfileNotFound there). The script indexes its working directory, so the server must start in the project root. Whether agy starts MCP servers in the workspace directory has not been verified for this port.

The orchestrator's tasks/analysis-gems.md step adds rubydex, decode, and bake to the project Gemfile, so after the first route the project bundle provides rdx.

Harness Translation Mapping Table

Dispatch Workflow & Invariants Preserved

1. Orchestrator Invariant: rubyist NEVER writes or edits .rb files directly. All code edits are delegated to phase subagents via invoke_subagent.
2. Fixed Phase Sequence: Subagents run strictly in sequence: specifier → implementer → cleaner → hardener → verifier (Non-applicable phases are skipped with an explicit rationale in the dispatch plan).
3. Plan Before Spawning: The orchestrator outputs a structured dispatch plan before issuing any subagent dispatch.
4. Pinned Parallel Contracts: Parallel stages must share a pinned type contract written field-by-field in CONTRACTS before dispatch, and results are reconciled before compacting.
5. Verify, Don't Relay: Before accepting a subagent's claim (e.g. "all tests pass"), the orchestrator runs the verification check (bundle exec rspec, ruby -c, etc.) in its own context.
6. Capped Rollbacks: A blocking quality gate failure triggers rollback to the target phase, with a hard cap of 2 rollbacks per gate.
7. Report Compaction: Every subagent returns a compact CHANGED / FINDINGS / UNRESOLVED / NEXT report, keeping orchestrator context lean.

Automated Validation

To run the automated suite verifying plugin validity, link resolution, and zero Claude tokens:

bash harness/antigravity/scripts/validate.sh