SlimSnap connector

Your recent screen captures, as structured data your AI can actually read.

Take a capture in SlimSnap, mark what you mean, then in Claude say "look at my last capture". No pasting, no file paths, no clipboard.

What Claude gets

Not a screenshot. A JSON document: every piece of text on screen with its position and colour, plus the arrows, boxes and callouts you drew, and which element each one points at.

That matters for three reasons.

A screenshot pasted into an agent gets downscaled before the model reads it, and nobody tells you. Anthropic's own docs say to pre-resize and crop your images because resizing "might make text less legible". A tall page loses its text entirely.

Images returned over MCP are worse still. In Claude Code they are passed through as text rather than native image blocks, costing roughly 15-25k tokens against about 1.6k for the same image pasted directly, and the model cannot read them at all (claude-code#31208, closed as not planned). A big enough result blows the per-result token ceiling outright (#9152).

And an oversized screenshot can poison a session permanently. It stays in context, gets re-sent every turn, and there is no way to remove it (#55040).

This connector sidesteps all three by never sending the picture. A typical capture costs a few hundred tokens instead of a few thousand, and the agent gets exact coordinates rather than a guess about which button you meant.

When you genuinely need pixels (visual style, spacing, colour balance) there is a separate tool for that, and the image is already downscaled to a size the model can read.

Related MCP server: Desktop MCP

Install

Claude Code

claude mcp add slimsnap -- npx -y @slimsnap/mcp

Then check it: /mcp should list slimsnap with 4 tools.

Claude Desktop

Download slimsnap.mcpb from Releases and open it. Claude shows an install dialog. The connector then appears under Settings.

As a Claude Code plugin (bundles this connector and the SlimSnap skill together)

/plugin marketplace add bickov/slimsnap-plugin
/plugin install slimsnap@slimsnap

You need SlimSnap 0.5.0 or newer, because that is the version that started keeping recent captures on disk.

Approving the tools

The first time Claude Code uses each tool it asks for permission, and the approval is scoped to the folder you were in. Four tools means four prompts, and they come back in the next project. Nothing is wrong; that is how Claude Code gates MCP tools.

To approve them once, everywhere, add this to ~/.claude/settings.json:

{
  "permissions": {
    "allow": [
      "mcp__slimsnap__get_latest_capture",
      "mcp__slimsnap__list_captures",
      "mcp__slimsnap__get_capture",
      "mcp__slimsnap__get_capture_image"
    ]
  }
}

If the file already exists, merge the allow entries into it rather than replacing it. Restart Claude Code afterwards.

Tools

Four tools on purpose. Tool descriptions are charged against your context window on every turn, so the surface stays small.

Where the data lives

SlimSnap keeps your recent captures in ~/.slimsnap/recent/, newest 20 by default. Each capture is a folder with capture.json, a small meta.json index, and one PNG per frame capped at 1568px on the long edge.

The connector finds that folder by reading ~/.slimsnap/config.json, which SlimSnap rewrites whenever your settings change. Move your save folder and the connector follows, with nothing to reconfigure.

Change how many are kept, or turn the cache off entirely, in SlimSnap under Settings, Export, Recent captures. There is a Clear button in the same place.

Privacy

The server reads files under your home directory and talks to nobody. There is no network code in it. It cannot capture your screen and it cannot ask SlimSnap to capture your screen. It only reads captures you already took and chose to keep.

Nothing is uploaded, there is no account, and no telemetry.

Requirements

SlimSnap 0.5.0 or newer, macOS or Windows.

The Claude Desktop route needs nothing else: Desktop ships its own Node and the .mcpb bundle uses it. The Claude Code route runs node from your PATH, so it needs Node 18 or newer installed. That catches people out on a fresh Windows machine, where Node usually isn't there.

License

MIT