yaktool-image-mcp

yaktool-image-mcp

Local image tools as an MCP server — compress PNG/JPEG with a visually-guarded smart mode or true lossless mode, optionally converting to WebP/AVIF.

This is the image suite of the yaktool MCP family. It ships the same engine as the browser compressor — same decision pipeline, same documented behaviours, same numbers for the same file. The pure-algorithm validators (GTIN, feeds, e-invoices…) live in the sibling package yaktool-mcp; the packages are split so nobody downloads wasm codecs they don't use.

• Local & private — files are read and written on your machine over stdio; zero network calls
• Deterministic — same input and settings → same result, with a report that shows the work (colours, measured PSNR dB, metadata removed, encoder used)
• Safe by contract — the input file is never modified, an existing output is never overwritten, and if nothing beats the original size no file is written at all (kept-original)
• Honest about lossless — lossless mode keeps pixels byte-identical; smart mode enforces an alpha-weighted PSNR floor and falls back to lossless rather than degrade visibly

Install

Claude Code

claude mcp add yaktool-image -- npx -y yaktool-image-mcp

Claude Desktop — add to claude_desktop_config.json:

{
  "mcpServers": {
    "yaktool-image": { "command": "npx", "args": ["-y", "yaktool-image-mcp"] }
  }
}

Cursor / other MCP clients — any stdio-capable client works with command npx -y yaktool-image-mcp.

Requires Node.js ≥ 20.

Tools

compress_image — compress a local PNG or JPEG file by absolute path.

• mode: smart (default, visually-guarded lossy) or lossless (pixels byte-identical; metadata and encoding only)
• quality: 0–100 (default 60) — sets the PNG PSNR floor and the JPEG/WebP/AVIF encoder quality in smart mode
• format: same (default), webp or avif — both support true lossless
• out: optional absolute output path (default: <name>-compressed.<ext> alongside the input)

Returns { outcome, path, out?, originalBytes, outputBytes?, savedPercent?, report }. Animated PNGs are skipped, never flattened.

convert_image — convert a local PNG/JPEG/WebP/AVIF file between formats, optionally resizing it to a marketplace preset, and recheck the output against that platform's published rules.

• preset: amazon-main, gmc or ebay — sets the target format and size, and the result carries a per-rule verdict list (recheck.verdicts, rule IDs MED-*/IMG-S01) plus recheck.allPass
• target: jpeg | png | webp | avif (defaults to the preset's format, else jpeg)
• width/height + fit (fit never crops, crop centre-crops, pad fills with white); a single dimension scales proportionally
• allowUpscale: default false — when the target is larger than the source the image keeps its size and the report says so (ICV-002), because stretching adds blur, not detail
• out: optional absolute output path (default: <name>-converted.<ext>)

Animated GIFs are refused rather than flattened; JPEG output composites transparency onto white and says so; EXIF/GPS is not carried over and the report states what was dropped. Same resampler (lanczos3) and same rules as the browser converter — the full catalog lives at yaktool.com/mcp.

License

MIT © yaktool.com