MCPHub

Additional documentation:

• English Handbook
• 中文手册

MCPHub is a generic Rust-based hub for managing upstream MCP servers.

The core idea is simple:

• register upstream MCP endpoints under stable ids
• discover their tools through the MCP protocol
• cache those tool descriptors locally
• call upstream tools by endpoint_id + tool_name
• expose hub-native MCP tools through a stdio facade
• grow toward a CLI-style facade over schema-driven invocation

Implemented In This First Rust Slice

• standalone Cargo project
• persistent endpoint registry
• HTTP endpoint registration
• stdio endpoint registration
• MCP tool discovery through rmcp
• direct upstream tool invocation
• CLI for register/list/discover/call
• stdio MCP facade server (serve-stdio)
• structured tool catalog output with list-tools --json
• schema inspection with tool-info, including tool-info --all --json <endpoint_id>
• qualified-name invocation such as context7/resolve-library-id
• nested CLI argument assignment via dotted --set
• schema-driven local invoke flow with positional KEY=VALUE
• runtime health checks with observable connection reuse
• local daemon mode for cross-command runtime reuse
• richer schema handling for defaults, enums, and simple composed schemas

Planned Next

• namespaced / qualified-name invocation options
• richer output formatting for content types
• health monitoring and refresh policies
• better CLI argument coercion from cached JSON schema

Quick Start

cd MCPHub
cargo run -- register-http docs-main http://127.0.0.1:19840/mcp
cargo run -- discover docs-main
cargo run -- list-tools docs-main
cargo run -- tool-info docs-main/search
cargo run -- tool-info --all --json docs-main
cargo run -- call docs-main/search --arguments-json "{\"query\":\"rust\",\"domain\":\"docs\"}"
cargo run -- invoke docs-main/search query=rust domain=docs
cargo run -- daemon start
cargo run -- invoke docs-main/search query=rust domain=docs --daemon

To inspect cached schemas as JSON:

cargo run -- list-tools docs-main --json

To register a stdio server:

cargo run -- register-stdio my-server python --arg -m --arg my_mcp_server

To serve MCPHub itself as a stdio MCP facade:

cargo run -- serve-stdio

To inspect every cached tool for one endpoint, including starter input templates:

cargo run -- tool-info --all --json context7

You can also inspect one cached tool directly by qualified name:

cargo run -- tool-info context7/resolve-library-id --json

To use the schema-driven local facade form:

cargo run -- invoke context7/resolve-library-id libraryName=react query=react

To observe connection reuse inside a single long-lived runtime:

cargo run -- health context7 --repeat 2 --json

To reuse one runtime across separate shell invocations, start the local daemon:

cargo run -- daemon start
cargo run -- daemon status
cargo run -- health context7 --daemon --json
cargo run -- invoke context7/resolve-library-id libraryName=react query=react --daemon
cargo run -- daemon stop