everything
Official MCP test server that exercises every protocol feature. Built for developers testing MCP clients, not for everyday use.
Score
85/100
91,237 stars
10,424 forks
A low score is not a verdict on quality. Young and niche tools start low by design. How we calculate scores
The Open Source Drop Lens
By Erik Loyd, SaaS CEO and former COO/CFO of an AWS Premier Partner.
Updated Sep 2026
The Everything server is a test rig, not a tool. It exercises the MCP features a client has to handle: tools, prompts, resources, sampling, elicitation, logging, progress notifications and argument completions, so client builders can check their work against something known.
One npx command runs it over stdio, SSE or streamable HTTP. There is no service behind it and nothing to pay for.
The MCP steering group maintains it as a reference implementation. Building or debugging an MCP client? Install it. Everyone else can skip it, and nobody should run it where the environment holds secrets: its get-env tool returns every environment variable to the model.
Cost Breakdown
fully freeFree tier: Free and open source (the project is moving from MIT to Apache 2.0). No underlying service.
Self-hosted: Runs locally through npx or as an installed npm package, over stdio, SSE or streamable HTTP.
Paid: None.
Nothing to pay for. Its get-env tool hands every environment variable to the model, so keep secrets out of its environment.
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