Autonomous agents require robust execution harnesses that can route between multiple model providers (Anthropic Claude, OpenAI, Google Gemini, local Ollama/vLLM), handle real-time streaming deltas, and dynamically interact with Model Context Protocol (MCP) tool servers.

OmniChat Harness (GitHub: ziuus/omnichat-harness) is a TypeScript/Bun-powered orchestration framework and development environment built specifically for multi-provider agent development, streaming evaluation, and MCP server interop.

Key Architectural Capabilities

  • Unified Multi-Provider Gateway: Transparent abstraction over Claude 3.5 Sonnet, GPT-4o, Gemini 2.0 Flash, and local models.
  • Native Model Context Protocol (MCP): Full support for client connections to filesystem, database, browser, and custom MCP tools.
  • Real-Time Streaming Engine: Zero-lag Server-Sent Events (SSE) and WebSocket conduits for token streaming and structured tool call dispatch.
  • Agent Memory & Session Journaling: Append-only execution transcripts, prompt cache optimization, and replayable execution trees.

Quick Start with Bun 

git clone https://github.com/ziuus/omnichat-harness.git cd omnichat-harness bun install bun run dev

Explore the repository, star the project, and inspect our MCP integrations:
https://github.com/ziuus/omnichat-harness