Open-source StreamCut embeds an MCP server: four half-remembered movie quotes in, four trimmed clips out

chulobou · reddit · 2026-10-05

StreamCut, an open-source desktop app (Win/Mac, GPL-3.0) for cutting clips from films without downloading whole files, now embeds an MCP server so an assistant can find and cut clips. A demo message with four half-remembered quotes returned four MP4s.

Implementation:

Hand-written JSON-RPC MCP server on the JDK's built-in HTTP server (no SDK), localhost-only with bearer token, off by default
--mcp-stdio windowless relay mode for stdio-only clients like Claude Desktop
19 tools: title search, line lookup, subtitles, frames, contact sheets, shot-cut detection, clip CRUD

Tool design lessons:

Let the model look: getframes/getcontactsheet return images — the most useful tools since text metadata is often wrong
State trust levels: subtitle timings were off by 2.5 min to 24 min in the demo; findline now re-times against the stream and reports whether timing came from the stream or a file
Long jobs return at once: createclip returns a job id; getclip accepts waitseconds to avoid polling
Warn inside results: liststreams flags files that look like another title
Put cost in descriptions: reads cost proportionally to bitrate, so tool text nudges the model toward smaller files

Limits: direct streams only, clips up to 10 minutes, desktop only, tested on macOS with Claude Code/Desktop. Fork of Nuvio Desktop, free, alpha, ships with no content addons.

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Open-source StreamCut embeds an MCP server: four half-remembered movie quotes in, four trimmed clips out

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