MultiModel Dev OS v4.2.0

What This Release Delivers

multimodel-dev-os@4.2.0 ships the Localhost Gateway Foundation alongside the established workspace governance and Skill OS standard. It adds a local mock gateway runtime, deterministic provider/model metadata loading, dry-run route planning, resilience simulation, preview-only client configuration, and local in-memory observability while preserving a strict zero-runtime-dependency posture.

Installation & Upgrade

Install or upgrade to v4.2.0 via npm:

npm install -g multimodel-dev-os@4.2.0
multimodel-dev-os status
multimodel-dev-os verify

Or run via npx:

npx multimodel-dev-os@latest init
npx multimodel-dev-os@latest verify

Gateway Foundation

• Localhost Mock Gateway Runtime: Runs on 127.0.0.1 with GET /health, GET /v1/models, and POST /v1/chat/completions.
• Deterministic Responses: Mock non-streaming JSON and SSE streaming chunk responses.
• Provider & Model Registries: Runtime-readable snapshots for providers, models, local-models, and routing presets.
• Dry-Run Route Planning: Scoring and route explanations without sending traffic to external services.
• Resilience Simulation: Dry-run simulation for fallbacks, retries, timeouts, circuit breakers, quotas, and rate limits.
• Client Configuration Previews: Dry-run configuration generator for AI coding clients and IDE extensions.
• Local In-Memory Observability: Bounded request events, traces, metrics, usage accounting, cost estimation, and redacted audit logs.

The mock provider is the only executable provider in v4.2.0. External providers remain metadata-only.

Skill OS & Workspace Governance

• Workspace Instructions: Centralized instructions in AGENTS.md with synced adapters for Antigravity, Claude Code, Cursor, Codex, Gemini, and VS Code.
• Declarative Skill OS: Skill, prompt, workflow, permission, and guardrail registries with Ed25519 signatures and automated policy checks.
• RACE+ Framework: Structured prompt templates and public operator templates.

Security & Privacy Model

• Zero Runtime Dependencies: Published package relies strictly on Node.js 20+ standard library modules.
• Approval-Gated Writes: File updates and adapter synchronization require explicit approval.
• Loopback Defaults: Gateway server binds to 127.0.0.1 loopback by default.
• Redacted Local Observability: No prompt or completion payload is logged; zero external telemetry.

Compatibility Boundaries

• Mock-Only Execution: The gateway executes only bundled mock models.
• Metadata-Only Providers: External API credentials are not loaded and no external HTTP calls are made.
• Disabled Live Retries: Fallback execution and retry probing are disabled.
• Preview-Only Configs: Client configuration plans are preview-only.

See v4.2 Known Limitations.

Verification Pipeline

The v4.2.0 release is validated by strict cross-platform checks:

npm run build           # Compiles src/ to bin/multimodel-dev-os.js
npm run check:build     # Verifies CLI binary freshness
npm test                # Executes Vitest test suite
npm run verify          # Runs strict audit & docs checks
npm run docs:build      # Compiles VitePress documentation portal
npm pack --dry-run      # Validates package tarball structure

Release & Publication Matrix

• npm Release: multimodel-dev-os@4.2.0 (Public / Latest)
• GitHub Release: v4.2.0 (Public / Latest)
• License: MIT
• Node.js Requirement: >= 20.0.0