ES5 shim for ES6 (ECMAScript 6) Reflect and Proxy objects
ES5 shim for ES6 (ECMAScript 6) Reflect and Proxy objects. That is what the harmony mcp server brings to an AI assistant: the same capability, reachable through the Model Context Protocol rather than a separate app or dashboard.
Read Why should I use this library?
Because this one is hosted, setup is mostly authentication — you point your client at the endpoint and approve access. Nothing runs on your machine, so there is no runtime to keep patched.
The server publishes 5 tools. What each one is for:
iojs — -harmony_proxies (>= 2.3.0)membranes — wrappers that transitively isolate two object-graphsobserver — a self-hosted implementation of the ES7 Object.observe notification mechanismprofiler — a simple profiler to collect usage statistics of an objectProxies-for — arrays are serialized as JSON objects rather than as JSON arrays. That is, JSON.stringify(new Proxy([], {})) returns "{}" rather than "[]". [ReadThis sits in the developer tooling group, where several servers overlap in what they claim to do but differ sharply once you actually set them up. Harmony's toolset — iojs, membranes, observer and 2 more — is a fair guide to whether it matches your workflow. It is maintained by tvcutsem; worth a glance at recent repository activity before you build anything load-bearing on it.
We check each listing at SyncDev against the project's documentation before it goes live — if something here drifts out of date, it is a bug worth reporting.
| Tool | What it does |
|---|---|
| iojs | -harmony_proxies (>= 2.3.0) |
| membranes | wrappers that transitively isolate two object-graphs. |
| observer | a self-hosted implementation of the ES7 Object.observe notification mechanism. |
| profiler | a simple profiler to collect usage statistics of an object. |
| Proxies-for | arrays are serialized as JSON objects rather than as JSON arrays. That is, JSON.stringify(new Proxy([], {})) returns "{}" rather than "[]". [Read more]( https://github.com/tvcutsem/harmony-reflect/issues/13#issuecomment- |
{
"mcpServers": {
"harmony": {
"command": "npx",
"args": ["-y", "harmony-reflect"]
}
}
}Add to claude_desktop_config.json, then restart Claude Desktop.
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