A deterministic C runtime providing transport-level routing for ACP/MCP-style agent protocols.

Website • Docker Hub • MCP Agentic • MCP Agentic Skills

stdio Bus kernel acts as a process supervisor and message router between external clients (IDEs, CLIs, services) and worker processes. It handles NDJSON-framed JSON-RPC messages with session-based routing, while remaining completely agnostic to protocol semantics.

• Zero AI logic: All routing is deterministic based on session identifiers
• Single-threaded: One event loop using epoll (Linux) or kqueue (macOS)
• No external dependencies: Only libc and POSIX APIs
• Protocol agnostic: Forwards messages unchanged, parsing only routing fields
• Session affinity: Messages with the same sessionId route to the same worker
• Backpressure management: Configurable limits prevent memory exhaustion

• C11-compliant compiler (GCC 4.9+ or Clang 3.4+)
• Make or CMake 3.10+
• Node.js 18+ (for running example workers)

Pre-compiled binaries for multiple platforms are available in the /releases directory. Each version contains ready-to-use stdio_bus binaries for different architectures:

Available platforms:

• macOS: darwin-amd64 | darwin-arm64
• Linux: linux-amd64 | linux-arm64 | linux-armv7
• Linux (musl): linux-musl-amd64 | linux-musl-arm64

Verification: SHA256 checksums available at checksums.sha256

Download the appropriate binary for your platform and make it executable:

# Example for Linux AMD64
curl -L -o stdio_bus https://github.com/stdiobus/stdiobus/releases/v2.0.3/linux-amd64/stdio_bus
chmod +x stdio_bus

Pre-built multi-architecture images available on Docker Hub:

docker pull stdiobus/stdiobus:latest

Supported platforms: linux/amd64, linux/arm64, linux/arm/v7

Available tags: latest, v2.0.3, main, develop

See Docker Hub for complete usage examples and configuration.

Embedded stdio_bus runtime for your application process — no external daemon, no Docker, no TCP hop.

MCP server that connects IDE clients to ACP-compatible agents through stdio Bus: @stdiobus/mcp-agentic

Exposes 8 MCP tools covering agent discovery, session lifecycle, one-shot delegation, and health checks. Supports in-process agents and external worker processes. Includes a Provider Factory API for OpenAI, Anthropic, and Google Gemini with a unified interface, runtime parameter control per session and per prompt, and a defineProvider() contract for custom or private LLM integrations.

See mcp-agentic for provider setup, tool reference, and IDE integration.

Manifest-driven CLI launcher for MCP server modules in the stdio Bus ecosystem: @stdiobus/mcpx

Replaces hardcoded shell commands in mcp.json with a single portable entrypoint — mcpx run <module>. Each module is described by a module.json manifest that defines runtime, entry point, environment defaults, and arguments. Supports Node.js, Python, Go, Rust, Shell, and Docker runtimes. Works with any MCP client: Kiro, Cursor, Claude Desktop, Windsurf.

See mcpx for manifest reference and environment management.

Structured, validated, machine-readable skills for AI agents delivered over MCP via stdio Bus: @stdiobus/skills

An MCP server that exposes agent skills as a machine-parseable knowledge base — not documentation for humans. Skills are organized in a 5-layer hierarchy (Concepts → API → Patterns → Guardrails → Diagnostics), CI-validated against real framework types, and served through five MCP tools: list_skills, read_skill, list_references, read_reference, search_skills. Ships with two skill collections: Runtime Web (12 skills for @worktif/runtime) and stdio Bus SDKs (C++, Node.js, Rust).

See skills for the skill catalog and agent consumption protocol.

Protocol workers for stdio Bus kernel: @stdiobus/workers-registry

Includes ACP Registry launcher for routing to any registered agent (Claude, Goose, Cline, GitHub Copilot and others), OpenAI-compatible endpoint bridge, MCP-to-ACP proxy for IDE integration, standalone ACP agent for protocol testing, and echo workers for protocol validation. Workers run as child processes of the kernel, communicating via NDJSON over stdin/stdout. Authentication supports API keys and OAuth 2.1 with PKCE (GitHub, Google, Azure AD, AWS Cognito, OIDC).

See workers-registry for the full worker catalog, configuration, and authentication setup.

Apache License, Version 2.0