Local Context Router

Local Context Router

A multimodal model reads a PDF by extracting its text and rendering every page to an image, then paying for both. On a page that is mostly prose, the image is wasted spend. Run this preflight first and send the model only what each page needs.

When to use

Before reading, summarizing, or extracting from a PDF, scan, or screenshot the user has shared.

Requirements

The localcontextrouter package must be installed (pip install localcontextrouter, macOS). It provides the localctx command used below.

Run

Route the document and read the JSON, rendering any visual pages into a folder:

localctx <path-to-document> --json --vision-dir ./lcr-pages

If the localctx command is not available, run the bundled script with a Python that has localcontextrouter installed (the script imports the same package):

python scripts/preflight.py <path-to-document> --json --vision-dir ./lcr-pages

Use the result

The JSON has tokens_saved and a pages array. Each page carries source, text, text_tokens, image_tokens, and image:

• source: "text": use text directly; do not attach the image.
• source: "ocr": the page was image-only and has been OCR'd on-device; use text.
• source: "vision": the page is a table, chart, or diagram; attach the image at image so the model can read it. The text is a rough fallback only.

Assemble the text and OCR pages in reading order, attach images only for the vision pages, and mention tokens_saved if the user cares about cost.

Notes

Everything runs locally and offline; the document does not leave the machine.