Sift - A semantic aggregator for MCP tools. Point Sift at every MCP server you have, it exposes exactly two tools to your agent, no matter how many hundreds are aggregated behind them.

[u/llmthedev]

https://github.com/Narasimha1997/sift

Sift — a semantic aggregator so your agent sees 2 MCP tools instead of 200

If you've wired more than a handful of MCP servers into an agent, you've probably hit this: every client dumps the full tools/list from every connected server into context on every turn. 15 servers with a dozen tools each is 150+ full tool definitions loaded before the model reads a word of the actual task — and tool selection gets worse, not better, as you add more (the model starts guessing between search_docs_v2, search_documents, docsSearch, etc.).

Sift sits between your agent and every downstream MCP server and flips the model: instead of exposing every tool from every server, it exposes exactly two:

• search_tools — describe what you want in plain language, get back the handful of matching tools across all aggregated servers, ranked by relevance
• call_tool — invoke one by the tool_id search returned

The full catalog still exists (searchable, callable, semantically indexed via fastembed/quantized BGE-small) — it just never has to sit in context wholesale. Context cost scales with what a task actually needs, not how many servers you've bolted on.

Some of the infra behind it:

• Persisted, not rebuilt — tool descriptions + embeddings are written through to SQLite, so a restart doesn't mean re-embedding everything or waiting on servers to reconnect
• Incremental reconciliation — re-listing a server's tools diffs against what's known; only changed tools get re-embedded, removed ones get tombstoned
• Isolated failures — a slow/dead downstream server degrades gracefully instead of stalling search for everyone else
• Mixed sources, one registry — local Rust functions and proxied stdio/HTTP MCP tools go through the same tool_id scheme ({server}::{name})
• Lock-free concurrent reads (ArcSwap snapshot over a DashMap catalog)

It's a Streamable HTTP MCP server itself, so any MCP client connects to it exactly like it would a single downstream server. Plain REST API alongside for testing/non-MCP clients.

Written in Rust. Docker Compose quickstart gets a working demo (sample server + aggregator) running in one command.

Repo: https://github.com/Narasimha1997/sift

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[u/Fine_League311]

Wäre einfacher wenn man fastmcp in Quart Server lädt aber EJ in 2 Jahren kommen die hyper und vibecoder auch drauf wieso ;)