mcpx

mcpx is a command line tool that turns remote MCP servers into an agent-friendly command surface.

It keeps MCP server registrations in a global user registry, discovers tool schemas, handles OAuth where possible, and exposes each MCP server as a root command:

mcpx posthog projects-get
mcpx sentry search-issues --input '{"query":"is:unresolved"}'

mcpx is designed for agents. The command surface is intentionally schema-first, stable, and explicit: tool calls pass input through --input, while mcpx's own control commands live under the @ namespace.

Requirements

• Bun
• macOS, Linux, or any environment that can run Bun executables

Install

Install the latest release:

curl -fsSL https://raw.githubusercontent.com/AIGC-Hackers/mcpx/main/install.sh | bash

By default, the installer downloads the executable JS bundle from GitHub Releases and installs it to ~/.local/bin/mcpx.

Set MCPX_INSTALL_DIR to choose another install directory.

Add MCP Servers

Register a remote MCP server globally:

mcpx @add --name posthog --url https://mcp.posthog.com/mcp
mcpx @add --name sentry --url https://mcp.sentry.dev/mcp
mcpx @add --name cf-docs --url https://docs.mcp.cloudflare.com/mcp
mcpx @add --name cf-bindings --url https://bindings.mcp.cloudflare.com/mcp
mcpx @add --name cf-observability --url https://observability.mcp.cloudflare.com/mcp

mcpx stores server configuration in:

~/.agents/mcpx/servers.json

OAuth tokens and client secrets are stored separately in the global token cache:

~/.agents/mcpx/tokens.json

Project directories do not need MCP config files. A project should decide which global servers are relevant by using schema selectors or a generated skill.

Call Tools

Call tools through the server command:

mcpx <server> <tool> --input '<json-or-json5>'

Examples:

mcpx posthog projects-get --input '{}'
mcpx sentry whoami --input '{}'

For complex payloads, use @- with a heredoc to keep the input readable:

mcpx cf-graphql graphql_query --input @- <<'JSON'
{
  "query": "query GetWorkerAnalytics($accountTag: String!, $scriptName: String!, $since: Time!, $until: Time!) { viewer { accounts(filter: {accountTag: $accountTag}) { workersInvocationsAdaptive(limit: 1000, filter: {scriptName: $scriptName, datetime_geq: $since, datetime_leq: $until}, orderBy: [datetimeHour_ASC]) { dimensions { datetimeHour scriptName status } sum { requests subrequests errors duration } quantiles { cpuTimeP50 cpuTimeP99 } } } } }",
  "operationName": "GetWorkerAnalytics",
  "variables": {
    "accountTag": "abc123def456",
    "scriptName": "my-worker",
    "since": "2026-04-20T00:00:00Z",
    "until": "2026-04-27T00:00:00Z"
  }
}
JSON

--input is the primary input path. It accepts inline JSON/JSON5, @file, and @- stdin inputs.

Discover Schemas

Print the command schema for agents:

mcpx --schema

Focus on one server:

mcpx --schema=.posthog

Focus on a set of servers:

mcpx --schema='.{posthog,sentry}'

Focus on an internal mcpx command:

mcpx --schema='.["@add"]'

Control Commands

mcpx control commands use the @ namespace so they do not collide with server names:

mcpx @add --name <server> --url <mcp-url>
mcpx @remove --name <server>
mcpx @skill

Server names cannot start with @.

Authentication

When @add detects OAuth, mcpx tries to complete authentication immediately. For OAuth servers that support dynamic client registration, mcpx registers a client automatically.

For OAuth servers that do not support dynamic client registration, such as Slack, mcpx prompts for a manual client_id and client_secret. These providers usually require a preconfigured redirect URL. mcpx uses:

http://127.0.0.1:65245/callback

Add and save that exact Redirect URL in the provider app settings before continuing the prompt.

When an OAuth token is close to expiry, mcpx refreshes it before calling the MCP tool and then continues the original command.

Output

mcpx optimizes output for humans and agents by default:

• text MCP content is printed directly
• JSON text content is rendered as TOON
• non-text content is saved to a temporary file and printed as file saved <path>

Use --raw to preserve raw server text output:

mcpx posthog projects-get --raw

Project Skills

Generate a project-local skill that tells agents which global MCP servers to use:

mcpx @skill --server posthog --server sentry

This writes:

.agents/skills/mcpx/SKILL.md

The generated skill instructs agents to discover tools with focused schema selectors and call MCP tools through mcpx.

License

MIT